Measurement Guide and Programming Examples

Measurement Guide and Programming Examples
Agilent CSA Spectrum Analyzer
This manual provides documentation for the following instruments:
N1996A-503 (100 kHz to 3 GHz)
N1996A-506 (100 kHz to 6 GHz)
For firmware revision A.02.00 and above
Manufacturing Part Number: N1996-90028
Supersedes N1996-90018
Printed in USA
April 2011
© Copyright 2006 - 2011 Agilent Technologies
2
Notice
The material contained in this document is provided “as is,” and is subject to being changed, without notice, in future editions. Further, to the maximum extent permitted by applicable law, Agilent disclaims all warranties, either express or implied with regard to this manual and any information contained herein, including but not limited to the implied warranties of merchantability and fitness for a particular purpose. Agilent shall not be liable for errors or for incidental or consequential damages in connection with the furnishing, use, or performance of this document or any information contained herein. Should Agilent and the user have a separate written agreement with warranty terms covering the material in this document that conflict with these terms, the warranty terms in the separate agreement will control.”
Technology Licenses
The hardware and/or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license.
Restricted Rights Legend
If software is for use in the performance of a U.S. Government prime contract or subcontract, Software is delivered and licensed as “Commercial computer software” as defined in DFAR 252.227-7014 (June 1995), or as a “commercial item” as defined in FAR 2.101(a) or as “Restricted computer software” as defined in FAR 52.227-19 (June 1987) or any equivalent agency regulation or contract clause. Use, duplication or disclosure of Software is subject to Agilent
Technologies’ standard commercial license terms, and non-DOD Departments and
Agencies of the U.S. Government will receive no greater than Restricted Rights as defined in FAR 52.227-19(c)(1-2) (June 1987). U.S. Government users will receive no greater than Limited Rights as defined in FAR 52.227-14 (June 1987) or
DFAR 252.227-7015 (b)(2) (November 1995), as applicable in any technical data.
Where to Find the Latest Information
Documentation is updated periodically. For the latest information about Agilent
Technologies CSA spectrum analyzers, including firmware upgrades and application information, please visit the following URL: http://www.agilent.com/find/csa
Microsoft
is a U.S. registered trademark of Microsoft Corporation.
3
4
Contents
Making Adjacent Channel Power (ACP (I&M)) Measurements . . . . . . . . . . . . . . . . . . . . 121
5
Contents
8. Demodulating AM/FM Signals (Requires Option N8996A-1FP) . . . . . . . . . . . . . . . . . .145
Demodulating an AM Signal Using the CSA (Requires Option N8996A-1FP) . . . . . . . . .147
Demodulating an FM Signal Using the CSA (Requires Option N8996A-1FP) . . . . . . . . .153
6
Contents
7
Contents
8
1
Installation and Setup
9
Figure 1-1
Installation and Setup
•
•
•
•
•
•
•
•
•
•
This chapter provides the following information that you may need when you first receive your spectrum analyzer:
“Initial Inspection” on page 12
“Safety Information” on page 14
“Power Requirements” on page 27
“Physically Securing Your Analyzer” on page 31
“Turning on the Analyzer for the First Time” on page 32
“Firmware Revision” on page 34
“Printer Setup and Operation” on page 35
“Protecting Against Electrostatic Discharge” on page 36
“Using the Soft Carrying Case” on page 37
CSA 1.0
Figure 1-2 CSA 2.0
10 Chapter 1
Installation and Setup
Introduction
Introduction
The Agilent CSA spectrum analyzer is designed to enable engineers and technicians in a wide variety of industries to make precision RF measurements with speed, ease and confidence. Flexible measurement functionality and high performance are combined with an intuitive user interface to allow faster insight into engineering challenges. Innovative measurement science ensures fast, accurate, and repeatable results. Equipped with USB and LAN connectivity, the
Agilent CSA simplifies common tasks such as remote control, data transfer and firmware update.
Basic test functionality includes:
•
Spectrum Analyzer:
—
Channel Power
•
—
Occupied Bandwidth
Channel Analyzer:
—
Adjacent Channel Power (ACP (I&M))
•
AM/FM Tune & Listen (requires N1996A with Option AFM)
Stimulus/Response Mode (requires N8995A with either Option SR3 or SR6) includes the following measurements:
•
•
•
•
•
•
Two Port Insertion Loss
One Port Insertion Loss
Return Loss
Distance to Fault
Modulation Analyzer Mode (requires N8996A with Option 1FP) includes the following measurements:
Frequency Modulation
Amplitude Modulation
In this chapter, you will learn how to set up the N1996A.
After the Installation and Setup chapter, you will find chapters on each CSA measurement mode with each measurement in that mode, general information on batteries, caring for the CSA, and how to return the instrument for service.
Chapter 1 11
Installation and Setup
Initial Inspection
Initial Inspection
Inspect the shipping container and the cushioning material for signs of stress.
Retain the shipping materials for future use, as you may wish to ship the analyzer to another location or to Agilent Technologies for service. Verify that the contents of the shipping container are complete. The following table lists the items shipped with the analyzer.
Item
Accessories
AC/DC converter
Power Cable (See
Stimulus /Response Calibration kit Option
SRK (pn N1996A-SRK) includes:
Coax Accessories Case
Open/Short
Termination
Standard Documentation Set
Documentation CD-ROM
Description
External power supply 15 VDC 150 W
Connection for AC/DC converter power source.
This item is included ONLY when you have ordered Option SRK.
Coax Accessories Case, plastic and foam
(5000-0912)
Open/Short, 50 ohm, N-type male (85032-60011)
Termination, 50 ohm, N-type male (00909-60009)
Includes electronic (PDF) versions of the documents in the standard set (
CD-ROM” on page 45). In addition, this
Installation and Setup chapter is no the accessible in a standalone electronic (PDF) version and a text file of the complete firmware copyright information. You can view and print the information as needed. See the front of the
CD-ROM for installation information.
12 Chapter 1
Installation and Setup
Initial Inspection
•
•
•
If There Is a Problem
If the shipping materials are damaged or the contents of the container are incomplete:
Contact the nearest Agilent Technologies office to arrange for repair or
replacement (see “Calling Agilent Technologies” on page 229). You will not
need to wait for a claim settlement.
Keep the shipping materials for the carrier’s inspection.
If you must return an analyzer to Agilent Technologies, use the original (or comparable) shipping materials (see
“Returning an Analyzer for Service” on page 231).
Chapter 1 13
WARNING
CAUTION
NOTE
Installation and Setup
Safety Information
Safety Information
General
This product and related documentation must be reviewed for familiarization with safety markings and instructions before operation.
This product has been designed and tested in accordance with IEC 61010-1:2001
Second Edition, and has been supplied in a safe condition. The documentation contains information and warnings that must be followed by the user to ensure safe operation and to maintain the product in a safe condition.
Safety Earth Ground
An uninterruptible safety earth ground must be provided from the main power source to the product input wiring terminals, power cord, or supplied power cord set.
Chassis Ground Terminal
To prevent a potential shock hazard, always connect the rear-panel chassis ground terminal to earth ground when operating this analyzer from a dc power source.
Safety Information
The following safety conventions are used throughout this manual. Familiarize yourself with the symbols and their meaning before operating this instrument.
A Warning denotes a hazard. It calls attention to a procedure which, if not correctly performed or adhered to, could result in injury or loss of life. Do not proceed beyond a warning note until the indicated conditions are fully understood and met.
A Caution denotes a hazard. It calls attention to a procedure that, if not correctly performed or adhered to, could result in damage to or destruction of the instrument. Do not proceed beyond a caution sign until the indicated conditions are fully understood and met.
A Note calls out special information for the user’s attention. It provides operational information or additional instructions of which the user should be aware.
Safety Symbols and Product Markings
The following safety symbols and product markings are located on the analyzer or the external power supply. Familiarize yourself with the symbols and their
14 Chapter 1
Installation and Setup
Safety Information
meaning before operating this analyzer.
!
The instruction documentation symbol. The product is marked with this symbol when it is necessary for the user to refer to the instructions in the documentation.
Indicates hazardous voltages.
Indicates earth (ground) terminal
Indicates chassis ground terminal
ISM 1-A
This symbol is used to mark the on position of the power line switch.
This symbol is used to mark the standby position of the power line switch.
This symbol indicates that the input power required is AC.
The CE mark shows that the product complies with all relevant
European legal Directives (if accompanied by a year, it signifies when the design was proven).
The CSA mark (not to be confused with the Agilent CSA spectrum analyzer) is a registered trademark of the Canadian Standards
Association.
The C-Tick mark is a registered trademark of the Australian
Spectrum Management Agency.
This is a symbol of an Industrial Scientific and Medical Group 1
Class A product (CISPR 11, Clause 4).
This is a marking of an Industrial Scientific and Medical Group 1
Class A product, and to indicate product compliance with the
Canadian Interference-Causing Equipment Standard (ICES-001).
Separate collection symbol.
The Waste Electrical and Electronic Equipment (WEEE) Directive
(2002/96/EC), adopted by EU Commission on 13 Feb. 2003, is introducing producer responsibility on all Electric and Electronic appliances from 13 Aug. 2005. Under EU law, all electric and electronic equipment (EEE) are required to be separated from normal waste for disposal.
Chapter 1 15
WARNING
WARNING
WARNING
WARNING
WARNING
WARNING
WARNING
WARNING
WARNING
Installation and Setup
Safety Information
Safety Considerations For This Analyzer
This is a Safety Class 1 Product (provided with a protective earth ground incorporated in the power cord). The mains plug shall be inserted only in a socket outlet provided with a protected earth contact. Any interruption of the protective conductor inside or outside of the product is likely to make the product dangerous. Intentional interruption is prohibited.
Failure to ground the analyzer properly when using the external power supply can result in personal injury. Before turning on the analyzer, you must connect its protective earth terminals to the protective conductor of the main power cable. Only insert the main power cable plug into a socket outlet that has a protective earth contact. DO NOT defeat the earth-grounding protection by using an extension cable, power cable, or autotransformer without a protective ground conductor.
If this analyzer is to be energized via an autotransformer (for voltage reduction), make sure the common terminal is connected to the earth terminal of the power source.
If this product is not used as specified, the protection provided by the equipment could be impaired. This product must be used only in a normal condition (in which all means for protection are intact).
Whenever it is likely that the protection has been impaired, the analyzer must be made inoperative and be secured against any unintended operation.
To prevent electrical shock, disconnect the Agilent Technologies spectrum analyzer from mains before cleaning. Use a dry cloth or one slightly dampened with water to clean the external case parts. Do not attempt to clean internally.
When operating from an AC power source, always use the three-prong ac power cord supplied with this product. Failure to ensure adequate earth grounding by not using this cord may cause personal injury and/or product damage.
This product is designed for use in Installation Category II and Pollution
Degree 3 per IEC 61010 and IEC 60664 respectively.
The front panel switch is a standby switch only; it is not a LINE switch (power disconnecting device).
Install the product so that the detachable power cord is readily identifiable
16 Chapter 1
WARNING
WARNING
WARNING
WARNING
CAUTION
CAUTION
CAUTION
CAUTION
Installation and Setup
Safety Information and easily reached by the operator. The detachable power cord is the product disconnecting device. It disconnects the mains circuits from the mains supply before other parts of the product. The front panel switch is only a standby switch and is not a LINE switch. Alternatively, an externally installed switch or circuit breaker (which is readily identifiable and is easily reached by the operator) may be used as a disconnecting device.
Danger of explosion if battery is incorrectly replaced. Replace only with the same or equivalent type recommended. Discard used batteries according to manufacturer’s instructions.
This instrument has a recharge circuit. Never install non-rechargeable cells or batteries of a different type.
No operator serviceable parts inside. Refer servicing to qualified personnel.
To prevent electrical shock do not remove covers.
Servicing instructions are for use by qualified personnel only. To avoid electrical shock, do not perform any servicing unless you are qualified to do so.
The opening of covers or removal of parts is likely to expose dangerous voltages. Disconnect the product from all voltage sources while it is being opened.
Adjustments described in the service manual are performed with power supplied to the analyzer while protective covers are removed. Energy available at many points may, if contacted, result in personal injury.
If you are charging the batteries internally—even while the analyzer is powered off—the analyzer may become warm. Take care to provide proper ventilation.
To avoid overheating, always disconnect the analyzer from the external power supply before storing the analyzer in the soft carrying case.
If you prefer to leave the analyzer connected to the external power supply while inside the soft carrying case, you can disconnect the external power supply from its power source to prevent overheating.
The external power supply has autoranging line voltage input. Be sure the supply voltage is within the specified range. (Refer to the specifications guide for your analyzer.)
When operating this product with the external power supply, always use the three-prong power cord supplied with this product. Failure to ensure adequate
Chapter 1 17
CAUTION
Installation and Setup
Safety Information
earth grounding by not using this cord can cause product damage.
VENTILATION REQUIREMENTS: When installing the product in a cabinet, the convection into and out of the product must not be restricted. The ambient temperature (outside the cabinet) must be less than the maximum operating temperature of the product by 4
C for every 100 watts dissipated in the cabinet. If the total power dissipated in the cabinet is greater than 800 watts, then forced convection must be used.
Lifting and Handling
When lifting and handling the Agilent N1996A Spectrum Analyzer use ergonomically correct procedures. If so equipped, lift and carry the analyzer by the bail handle.
18 Chapter 1
Battery Pack Product Safety Data Sheet
Installation and Setup
Safety Information
Product Safety Data Sheet
PRODUCT NAME: Inspired Energy Rechargeable Battery Pack
TRADE NAME: NF2040
CHEMICAL SYSTEM: Lithium Ion
Model: NF2040A22
Volts: 10.8
Approximate Weight: 340 g
SECTION I – MANUFACTURER INFORMATION
Inspired Energy, Inc.
12705 N US Hwy 441
Alachua, FL 32615
SECTION II – HAZARDOUS INGREDIENTS
Telephone: (888) 5-INSPIRE (888-546-7747)
Date Prepared: Jan 13th 2003
Important Note:
The battery should not be opened or burned. Exposure to the ingredients contained within or their combustion products could be harmful
Material Safety Data Sheet Attached:
Review cell manufacturer’s MSDS
SECTION III – OPERATING PARAMETERS
Maximum Charge Voltage:
Minimum Charge Voltage:
Maximum Charge Current:
Maximum Discharge Current:
Recommended Charging Method:
12.6 V
7.5 V
3.0 A
3.0 A
Use an SMBus charger of level 2 or higher to provide a 3.0 A current limited constant voltage of 12.6 V. The charging cycle shall terminate when the average current falls below 150mA.
The information contained within is provided for your information only. This battery is an article pursuant to 29 CFR
1910.1200 and, as such, is not subject to the OSHA Hazard Communication standard requirement for preparation of a material safety data sheet. The information and recommendations set forth herein are made in good faith and are believed to be accurate as of the date of preparation. However, INSPIRED ENERGY, INC. MAKES NO WARRANTY,
EITHER EXPRESSED OR IMPLIED, WITH RESPECT TO THIS INFORMATION AND DISCLAIMS ALL LIABILITY FROM
RELIANCE ON IT.
Chapter 1 19
Installation and Setup
Safety Information
Battery Pack Declaration of Conformity
Declaration of Conformance
PRODUCT: Standard Battery for Inspired Energy
Inspired Energy Part Number: NF2040
SECTION I – MANUFACTURER INFORMATION
Inspired Energy, Inc.
25440 NW 8 th
Place, Newberry FL 32669, USA
Telephone: +1 386 462 3676
Date Prepared: December 21 st
2004
SECTION II – CONFORMANCE INFORMATION
The listed products have been tested in accordance with the UN document
ST/SG/AC.10/11/Rev.3: “Amendments to the Third Revised Edition of the Recommendations
on the Transport of Dangerous Goods, Manual of Tests & Criteria” and found to comply with the stated criteria
Test # Description
T1 Altitude Simulation
T2
T3
Thermal Cycling
Shock
T4 Vibration
T5
T6
Short Circuit
Impact (Cell-Level test)
T7
T8
Overcharge
Forced Discharge (Cell-level test)
Date Tested
June 21, 2004
July 23, 2004
September 30 2004
Test result
Pass
Pass
Pass
October Pass
November 09, 2004
July 2 nd
2003
Pass
Pass
November 15, 2004
July 2 nd
2003
Pass
Pass
Signed:
David W. Hellriegel
Product Test Laboratory manager
The information contained within is provided for your information only. The information and recommendations set forth herein are made in good faith and are believed to be accurate as of the date of preparation. However, INSPIRED ENERGY,
INC. MAKES NO WARRANTY, EITHER EXPRESSED OR IMPLIED, WITH RESPECT TO THIS INFORMATION AND DISCLAIMS ALL
LIABILITY FROM RELIANCE ON IT.
20 Chapter 1
Batteries: Safe Handling and Disposal
Installation and Setup
Safety Information
Chapter 1 21
Installation and Setup
Safety Information
22 Chapter 1
Installation and Setup
Safety Information
Chapter 1 23
Installation and Setup
Safety Information
24 Chapter 1
Installation and Setup
Safety Information
Chapter 1 25
Installation and Setup
Safety Information
26 Chapter 1
WARNING
NOTE
NOTE
NOTE
Table 1-1
Installation and Setup
Power Requirements
Power Requirements
Typically, the only physical installation of your Agilent spectrum analyzer is a connection to a power source.
Before operating or connecting this analyzer to an external power source,
Considerations For This Analyzer” on page 16.
Line voltage does not need to be selected.
This analyzer does not contain customer serviceable fuses.
If your test system requires a common ground, use the grounding lug provided on the back of the instrument.
For detailed analyzer specifications, see the Specifications guide.
In addition to operating the analyzer on AC power using the external AD/DC converter, you can operate it using internal batteries. For information on the installation and use of those batteries, refer to
AC Power Requirements
Description
Voltage
Voltage
Power Consumption, On
Power Consumption, Standby
Specifications
90 to 132 Vrms (47 to 440 Hz)
195 to 250 Vrms (47 to 66 Hz)
< 115 W
< 7 W
AC Power Cord
The analyzer is equipped with a three-wire power cord, in accordance with international safety standards. This cord connects to the external power supply adapter and grounds the external power supply when connected to an appropriate power line outlet. The cord appropriate to the original shipping location is included with the analyzer.
Chapter 1 27
Installation and Setup
Power Requirements
Various AC power cables are available that are unique to specific geographic areas. You can order additional AC power cables for use in different areas.
Power Cords , on page 29 lists the available AC power cables, illustrates the plug
configurations, and identifies the geographic area in which each cable is appropriate.
28 Chapter 1
Table 1-2 AC Power Cords
Installation and Setup
Power Requirements
Chapter 1 29
NOTE
WARNING
Installation and Setup
Power Requirements
Clock Battery Information
The analyzer uses a Poly-carbonmonofluoride Lithium Coin battery to power the analyzer clock. The battery is located on the CPU board.
If the analyzer’s clock does not work, the problem is probably the battery. See
“Returning an Analyzer for Service” on page 231.
Danger of explosion if battery is incorrectly replaced. Replace only with the same or equivalent type recommended. Discard used batteries according to the manufacturer’s instructions.
30 Chapter 1
Installation and Setup
Physically Securing Your Analyzer
Physically Securing Your Analyzer
To prevent unauthorized removal of your analyzer, you can use a Kensington Slim
MicroSaver security cable to attach the analyzer to an immovable object. Your analyzer has a Kensington Security Slot located on the back of the analyzer. The
Kensington Security Slot is identified on the analyzer with this logo: . For more information, visit http://www.microsaver.com.
Basic Instructions for Using the Kensington Slim MicroSaver
Step 1.
Wrap the steel cable around an immovable object.
Step 2.
Insert the lock into the Kensington Security Slot.
Step 3.
Turn the key.
Chapter 1 31
Installation and Setup
Turning on the Analyzer for the First Time
WARNING
NOTE
NOTE
NOTE
Information
Screen
NOTE
CAUTION
Turning on the Analyzer for the First Time
Before operating or connecting this analyzer to an external power source, please read and understand safety information in
page 14 and the safety considerations and all safety warnings in “Safety
Considerations For This Analyzer” on page 16.
o Plug in the power cord. If the analyzer is to be operated on the internal batteries, ensure that both batteries are installed. They are approximately 50% charged when you receive them and will provide full performance if you choose to operate the analyzer without charging them at this time. (View the charge level for each battery on the battery end display.) If the batteries are showing 1 bar or less, recharging is recommended at this time.
For maximum runtime, it is best to have approximately equal charge levels on both batteries. The instrument will shut down if either battery becomes fully discharged during operation.
Do not connect anything else to the analyzer yet.
o Press the power switch (located in the lower left-hand corner of the analyzer’s
front panel) to turn the analyzer on. See “Front Panel Overview” on page 50.
The instrument requires <2 minutes to power-on.
An information screen appears during the initialization process. The information screen contains the analyzer product number and a URL for accessing product
support information on the World Wide Web. See “Where to Find the Latest
It is important for you to Record the firmware revision and serial number, and keep it for reference. If you should ever need to call Agilent Technologies for service or with any questions regarding your analyzer, it will be helpful to have this information readily available. You can also obtain the firmware revision and serial number by pressing
System
,
System Stats
,
Rev Info
. o Allow the spectrum analyzer to warm-up for 30 minutes before making a calibrated measurement. To meet its specifications, the analyzer must meet operating temperature conditions.
Ensure protection of the input mixer by limiting the input level to 50 Vdc, +33 dBm.
o If using non-DHCP LAN, set the IP address of the analyzer to an appropriate number for your network (one that the network recognizes, but that is not yet in
32 Chapter 1
NOTE
NOTE
Installation and Setup
Turning on the Analyzer for the First Time
use):
—
Press
System
,
Controls
,
IP Admin
and note the IP address. This is the IP address that will be used if IP Config is set to Static. To view the IP Address selected by DHCP, press
Mode
.
—
If the current address is not appropriate, press
IP Config
,
Static
,
IP Address
and use the keypad to change it. In addition, you may also need to change the
Net Mask
and
Gateway
settings.
—
Press
Save
.
—
Connect the LAN cable to the LAN connector (not the Timing LAN
connector) located on the rear panel of your analyzer (see “Rear-Panel
—
Cycle the analyzer power. Refer to “Configuring for Network Connectivity” on page 169
It is necessary to cycle the power to the analyzer after plugging in the LAN for the analyzer to recognize the network.
If you are not using a LAN connection, you may want to set the IP Configuration to None to reduce the instrument power-on time.
Why Aren’t All the Personality Options Available?
Many measurement personality options are available for your use and are loaded in the instrument. To make an option available, you must also have a license key entered.
Using an External Reference
If you wish to use an external source as the reference frequency, you must connect an external reference source and set the reference frequency as follows:
1.
Connect an external source to the EXT REF IN connector on the rear panel
(see “Rear-Panel Features” on page 61). The signal level should be greater than
–15 dBm.
2.
Select the frequency of the external reference into the analyzer: a.
b.
c.
d.
Press
System
,
Freq/Time/Ref
Select the up and down arrow navigation keys to highlight the desired reference frequency.
Press
Select
to set the reference source and frequency that you have highlighted.
Press
Cancel
to abort your reference change and retain the previously
selected frequency reference. See “Setting System References” on page
Chapter 1 33
TIP
Installation and Setup
Firmware Revision
Firmware Revision
To view the firmware revision of your analyzer, Press
System
,
System Stats
,
Rev
Info
. If you call Agilent Technologies regarding your analyzer, it is helpful to have this revision and the analyzer serial number available.
You can get automatic electronic notification of new firmware releases and other product updates/information by subscribing to the Agilent Technologies Test &
Measurement E-Mail Notification Service for the Agilent CSA spectrum analyzer at: http://www.agilent.com/find/notifyme
34 Chapter 1
Installation and Setup
Printer Setup and Operation
Printer Setup and Operation
The Agilent CSA spectrum analyzer does not print directly to a printer. You can print a screen image or measurement data by first saving the information to a USB memory device and then use a PC with an attached printer to print the file. You can save a screen image by pressing (Print) (for detail instructions, refer to
“Printing a Screen To a File” on page 165). Also, you can save a screen image or
measurement results by pressing
Save
and Save Now (for detail instructions, refer
to “Saving Data” on page 166).
Chapter 1 35
WARNING
Installation and Setup
Protecting Against Electrostatic Discharge
Protecting Against Electrostatic Discharge
Electrostatic discharge (ESD) can damage or destroy electronic components (the possibility of unseen damage caused by ESD is present whenever components are transported, stored, or used).
•
•
•
Test Equipment and ESD
To help reduce ESD damage that can occur while using test equipment:
Before connecting any coaxial cable to an analyzer connector for the first time each day, momentarily short the center and outer conductors of the cable together.
Personnel should be grounded with a 1 M
resistor-isolated wrist-strap before touching the center pin of any connector and before removing any assembly from the analyzer.
Be sure that all instruments are properly earth-grounded to prevent build-up of static charge.
Do not use these first three techniques above when working on circuitry with a voltage potential greater than 500 volts.
•
•
Perform work on all components or assemblies at a static-safe workstation.
Keep static-generating materials at least one meter away from all components.
•
•
Store or transport components in static-shielding containers.
Always handle printed circuit board assemblies by the edges. This reduces the possibility of ESD damage to components and prevent contamination of exposed plating.
For information on ordering static-safe accessories, see
Additional Information about ESD
For more information about ESD and how to prevent ESD damage, contact the
Electrostatic Discharge Association (http://www.esda.org). The ESD standards developed by this agency are sanctioned by the American National Standards
Institute (ANSI).
36 Chapter 1
Installation and Setup
Using the Soft Carrying Case
Using the Soft Carrying Case
The N1996A soft carrying case is designed to hold the analyzer as well as its cables and accessories.
WARNING
Always disconnect the analyzer from the external power supply before storing the analyzer in the soft carrying case.
Chapter 1 37
Installation and Setup
Using the Soft Carrying Case
38 Chapter 1
2
Options and Accessories
This chapter lists options and accessories available for your analyzer.
39
Options and Accessories
Ordering Options and Accessories
Ordering Options and Accessories
Options and accessories help you configure the analyzer for your specific applications.
Options (see page 41
)
Unless specified otherwise, all options are available when you order a spectrum analyzer; some options are also available as kits that you can order and install after you receive the analyzer. Order kits through your local Agilent Sales and Service
Office.
At the time of analyzer purchase, options can be ordered using your product number and the number of the option you are ordering. For example, if you are ordering Option SRK for an Agilent N1996A, you would order N1996A-SRK.
If you are ordering an option after the purchase of your analyzer, you will need to add a K (for kit) to the product number and then specify which option you are ordering (for example, N1996AK-SRK.)
If you know the option you wish to order, refer to “Options” on page 41 which is in
ascending order by option number and type. Complete option descriptions can be found in the following section, listed in alphabetical order by option name under
“Option Descriptions” on page 43.
For the latest information on Agilent Spectrum Analyzer options and upgrade kits, visit the following URL: http://www.agilent.com/find/sa_upgrades
Accessories (see page 45
)
Order accessories through your local Agilent Sales and Service Office. For information on contacting Agilent Sales and Service, refer to
40 Chapter 2
Options and Accessories
Options
Options
Each option is described below in alpha/numeric order according to option number.
Option Number
0950-5023
0BW
1CM
1CP
271
503
506
ABA
AB2
AFM
BAT
BCG
Name Description
External AC/DC Power Supply External power supply 16 VDC 150 W
Service Documentation
The Service guide describes assembly-level troubleshooting procedures, provides a parts list, and documents post-repair procedures.
Rack Mount Kit
Rack Mount Kit with Handles
Includes rack mount flanges and hardware. Used to rack mount analyzers without front handles (available as P/N N1996-60028).
Includes the parts necessary to rack mount an analyzer with front handles attached (available as P/N N1996-60029). (Includes handles.)
Spectrogram
Provides a display with a history of the spectrum. You can use it to:
•
Locate intermittent signals.
•
Track signal levels over time.
Spectrum Analyzer Frequency Range: 100 kHz to 3 GHz
100 kHz to 3 GHz
1
Spectrum Analyzer Frequency Range: 100 kHz to 6 GHz
Measurement Guide
Measurement Guide,
Simplified Chinese
Localization
AM/FM Tune & Listen
Battery Pack
External Battery Charger
An English language printed copy of the standard Measurement
Guide in addition to the standard documentation on the Manual Set on
CD-ROM shipped with the analyzer. For additional information on the contents of the Documentation CD-ROM, refer to
Provides details on how to measure various signals, and how to use catalogs and files.
In addition, this manual covers unpacking and setting up the analyzer, analyzer features, and how to make a basic measurement. Includes information on options and accessories, and what to do if you have a problem.
A Simplified Chinese language version of the standard Measurement
Guide.
Provides the same information as Option ABA listed above.
Provides the audible detection of AM or FM signals at specific frequency.
Two batteries: 10.8 V 4.56 A-HR LI-ION (pn 1420-0891) (2 batteries are required for the operation of the instrument).
External charger/DC adapter, includes:
External power supply AC/DC adapter
Dual battery charger
Chapter 2 41
Options and Accessories
Options
Option Number Name Description
HTC
N8995A - SR3
N8995A - SR6
N8996A-1FP
0B0
P03
P06
Hard Transit Case
Stimulus/Response
Measurement Suite to 3 GHz
2
Stimulus/Response
Measurement Suite to 6 GHz
3
AM/FM Modulation Analysis
Manual Set on CD-ROM Only
3 GHz Preamplifier
6 GHz Preamplifier
The hard transit case will survive commercial transportation. This rugged case has two wheels and an extendible handle for easy transport. The case can also accommodate two battery packs and ac adapters. To order the option HTC which requires the soft carrying case (option SCC) for filling the space in the hard transit case.
Provides Stimulus/Response measurements:
•
Distance to Fault
•
Two Port Insertion Loss
•
One Port Insertion Loss
•
Return Loss
Provides Stimulus/Response measurements:
•
Distance to Fault
•
Two Port Insertion Loss
•
One Port Insertion Loss
•
Return Loss
Provides AM/FM demodulation measurements:
•
Amplitude Modulation
•
Frequency Modulation
The documentation CD-ROM contains the standard documentation set as well as Adobe Acrobat Reader with Search.
An internal preamplifier assembly. For use with Option 503 only.
Frequency Range: 100 kHz to 3 GHz
An internal preamplifier assembly. For use with Option 506 only.
Frequency Range: 100 kHz to 6 GHz
Provides your analyzer with a 3 year analyzer calibration contract.
R-50C-011-3
R-51B-001-3C
3 Year Inclusive Calibration
Contract
3-Year Warranty Service
Support
A total of 3 years of return-to-Agilent warranty service support. This adds a 2-year service contract to the base analyzer 1-year warranty
SCC
SRK
Soft Carrying Case
Stimulus/Response Calibration
Kit
An ergonomically designed case to hold the analyzer as well as its cables and accessories.
The kit includes:
•
Coax Accessories Case, plastic and foam (5000-0912)
•
Open/Short, 50 ohm, N-type male (85032-60011)
•
Termination, 50 ohm, N-type male (00909-60009)
1. Available only at time of purchase
2. The option replaces N1996A/TG3 + N8995A/1FP in CSA1.0.
3. The option replaces N1996A/TG6 + N8995A/1FP in CSA1.0.
42 Chapter 2
Options and Accessories
Option Descriptions
Option Descriptions
Each option is described below in alphabetical order according to option name.
Name
3 Year Inclusive Calibration
Contract
3-Year Warranty Service
Support
1
100 kHz to 3 GHz Spectrum
Analyzer
100 kHz to 6 GHz Spectrum
Analyzer
Option
Number
Description
Provides your analyzer with a 3 year analyzer calibration contract.
R-50C-011-3
R-51B-001-3C
A total of 3 years of return-to-Agilent warranty service support. This adds a 2-year service contract to the base analyzer 1-year warranty.
Spectrum Analyzer Frequency Range: 100 kHz to 3 GHz
503
Spectrum Analyzer Frequency Range: 100 kHz to 6 GHz
506
AM/FM Modulation Analysis
AM/FM Tune & Listen
Battery Pack
External AC/DC Power Supply
External Battery Charger
Hard Transit Case
Manual Set on CD-ROM Only
Measurement Guide
N8996A-1FP
AFM
BAT
0950-5023
BCG
HTC
0B0
ABA
Provides AM/FM demodulation measurements:
•
Amplitude Modulation
•
Frequency Modulation
Provides the audible detection of AM or FM signals at specific frequency.
Two batteries: 10.8 V 4.56 A-HR LI-ION (pn 1420-0891) (2 batteries are required for the operation of the instrument.)
External power supply 16 VDC 150 W
External charger/DC adapter, includes:
External power supply AC/DC adapter 24 VDC 2.7 A
Dual battery charger
The hard transit case will survive commercial transportation. This rugged case has two wheels and an extendible handle for easy transport. The case can also accommodate two battery packs and AC adapters. To order the option HTC which requires the soft carrying case (option SCC) for filling the space in the hard transit case.
The documentation CD-ROM contains the standard documentation set as well as Adobe Acrobat Reader with Search.
An English language printed copy of the standard Measurement Guide in addition to the standard documentation in the Manual Set on
CD-ROM shipped with the analyzer. For additional information on the
contents of the Documentation CD-ROM, refer to “Manual Set on
Provides details on how to measure various signals, and how to use catalogs and files.
In addition, this manual covers unpacking and setting up the analyzer, analyzer features, and how to make a basic measurement. Includes information on options and accessories, and what to do if you have a problem.
Chapter 2 43
Options and Accessories
Option Descriptions
Name
Option
Number
Description
Measurement Guide,
Simplified Chinese
Localization
Preamplifier, 3 GHz
Preamplifier, 6 GHz
Rack Mount Kit
Rack Mount Kit with Handles
Service Documentation
Soft Carrying Case
Spectrogram
Stimulus/Response Calibration
Kit
Stimulus/Response
Measurement Suite to 3 GHz
2
Stimulus/Response
Measurement Suite to 6 GHz
3
AB2
P03
P06
1CM
1CP
0BW
SCC
271
SRK
N8995A - SR3
N8995A - SR6
A Simplified Chinese language version of the standard Measurement
Guide.
Provides the same information as Option ABA listed above.
An internal preamplifier assembly.
Frequency Range: 100 kHz to 3 GHz
An internal preamplifier assembly.
Frequency Range: 100 kHz to 6 GHz
Includes rack mount flanges and hardware. Used to rack mount analyzers without front handles (available as P/N 5063-9215 and
N1996-60021).
Includes the parts necessary to rack mount an analyzer with front handles attached (available as P/N 5063-9222 and N1996-60021).
(Includes handles.)
The Service guide describes assembly-level troubleshooting procedures, provides a parts list, and documents post-repair procedures.
An ergonomically designed case to hold the analyzer as well as its cables and accessories.
Provides a display with a history of the spectrum. You can use it to:
•
Locate intermittent signals.
•
Track signal levels over time.
The kit includes:
•
Coax Accessories Case, plastic and foam (5000-0912)
•
Open/Short, 50 ohm, N-type male (85032-60011)
•
Termination, 50 ohm, N-type male (00909-60009)
Provides Stimulus/Response measurements:
•
Distance to Fault
•
Two Port Insertion Loss
•
One Port Insertion Loss
•
Return Loss
Provides Stimulus/Response measurements:
•
Distance to Fault
•
Two Port Insertion Loss
•
One Port Insertion Loss
•
Return Loss
1. Available only at time of purchase
2. The option replaces N1996A/TG3 + N8995A/1FP in CSA1.0.
3. The option replaces N1996A/TG6 + N8995A/1FP in CSA1.0.
44 Chapter 2
NOTE
NOTE
Options and Accessories
Accessories
Accessories
A number of accessories are available from Agilent Technologies to help you configure your analyzer for your specific applications. They can be ordered through your local Agilent Sales and Service Office and are listed below.
Manual Set on CD-ROM
•
•
•
•
The documentation CD-ROM contains the standard documentation set in electronic (PDF) format as well as Adobe Acrobat Reader with Search.
The standard documentation set includes:
User’s/Programmer’s Guide: Describes analyzer features in detail, including front-panel key descriptions, basic spectrum analyzer programming information, and SCPI command descriptions.
Measurement Guide: Provides details on how to measure various signals, and how to use catalogs and files. In addition, this manual covers unpacking and setting up the analyzer, analyzer features, and how to make a basic measurement. Includes information on options and accessories, and what to do if you have a problem.
Specifications Guide: Documents specifications, safety, and regulatory information.
Instrument Messages and Functional Tests: Includes instrument messages (and suggestions for troubleshooting them), and manual functional tests.
Refer to the front of the CD-ROM, for installation information.
Service documentation is not included in the standard documentation set. See
“Options” on page 41 for information on ordering.
50 Ohm Load
The Agilent 909 series loads come in several models and options providing a variety of frequency ranges and VSWRs. Also, they are available in either 50 ohm or 75 Ohm. Some examples include the:
909A: DC to 18 GHz
909C: DC to 2 GHz
909D: DC to 26.5 GHz
50 Ohm/75 Ohm Minimum Loss Pad
The Agilent 11852B is a low VSWR minimum loss pad that allows you to make measurements on 75 Ohm devices using an analyzer with a 50 Ohm input. It is effective over a frequency range of dc to 2 GHz.
Chapter 2 45
Options and Accessories
Accessories
75 Ohm Matching Transformer
The Agilent 11694A allows you to make measurements in 75 Ohm systems using an analyzer with a 50 Ohm input. It is effective over a frequency range of 3 to
500 MHz.
AC Probe
The Agilent 85024A high frequency probe performs in-circuit measurements without adversely loading the circuit under test. The probe has an input capacitance of 0.7 pF shunted by 1 M
of resistance and operates over a frequency range of 300 kHz to 3 GHz. High probe sensitivity and low distortion levels allow measurements to be made while taking advantage of the full dynamic range of the spectrum analyzer.
AC Probe (Low Frequency)
The Agilent 41800A low frequency probe has a low input capacitance and a frequency range of 5 Hz to 500 MHz.
Broadband Preamplifiers and Power Amplifiers
•
•
•
•
•
Preamplifiers and power amplifiers can be used with your spectrum analyzer to enhance measurements of very low-level signals.
The Agilent 8447D preamplifier provides a minimum of 25 dB gain from 100 kHz to 1.3 GHz.
The Agilent 87405A preamplifier provides a minimum of 22 dB gain from 10
MHz to 3 GHz. (Power is supplied by the probe power output of the analyzer.)
The Agilent 83006A preamplifier provides a minimum of 26 dB gain from 10
MHz to 26.5 GHz.
The Agilent 85905A CATV 75 ohm preamplifier provides a minimum of 18 dB gain from 45 MHz to 1 GHz. (Power is supplied by the probe power output of the analyzer.)
The 11909A low noise preamplifier provides a minimum of 32 dB gain from 9 kHz to 1 GHz and a typical noise figure of 1.8 dB.
RF and Transient Limiters
The Agilent 11867A and N9355/6 RF Limiters protect the analyzer input circuits from damage due to high power levels. The 11867A operates over a frequency range of dc to 1800 MHz and begins reflecting signal levels over 1 mW up to 10 W average power and 100 watts peak power. The N9355/6 microwave limiter (0.1 to
12.4 GHz, usable to 18 GHz) guards against input signals over 1 milliwatt up to 1 watt average power and 10 watts peak power.
The Agilent 11947A Transient Limiter protects the analyzer input circuits from damage due to signal transients. It specifically is needed for use with a line
46 Chapter 2
Options and Accessories
Accessories
impedance stabilization network (LISN). It operates over a frequency range of 9 kHz to 200 MHz, with 10 dB of insertion loss.
Power Splitters
The Agilent 11667A/B power splitters are two-resister type splitters that provide excellent output SWR, at 50
impedance. The tracking between the two output arms, over a broad frequency range, allows wideband measurements to be made with a minimum of uncertainty.
11667A: DC to 18 GHz
11667B: DC to 26.5 GHz
System II Bottom Feet kit,
•
•
•
System II Feet kit (p/n 5000-0913) is used to make the instrument stackable.
Bottom feet are added to the analyzer. (See Installation Note: 5000-0914). The kit includes:
System II Bottom Feet
Tilt Stand
Key Lock
Static Safe Accessories
9300-1367
9300-0980
Wrist-strap, color black, stainless steel. Four adjustable links and a 7 mm post-type connection.
Wrist-strap cord 1.5 m (5 ft.)
Chapter 2 47
Options and Accessories
Accessories
48 Chapter 2
3
Front and Rear Panel Features
This chapter gives you an overview of the front and rear panels of your analyzer.
For details on analyzer keys and remote programming, refer to the User’s and
Programmer’s Reference. For connector specifications (including input/output levels), see the Specifications guide.
49
Front and Rear Panel Features
Front Panel Overview
Front Panel Overview
•
•
•
This section provides information on the analyzer’s front panel, including:
“Front-Panel Connectors and Keys”
, see below.
“Display Annotations: Spectrum Display” on page 53.
“Display Annotations: Spectrogram (Option 271)” on page 57.
Front-Panel Connectors and Keys
Item
# Name
1
Menu Keys
Description
2
Measurement
Keys
3
Analyzer Setup
Keys
4
Marker Keys
Menu labels identifying the current function of each menu key appear to the left of each key.
Key menus are dependent on the active menu. Also see
Select measurement mode.
Select and set up specific measurements and mode parameters within the current mode.
Set parameters used for making measurements. These settings will affect measurements in all modes.
Enable markers to obtain specific information about the displayed measurement
50 Chapter 3
Front and Rear Panel Features
Front Panel Overview
Item
# Name
5
Utility Keys
Description
6
PROBE PWR
7
Earphone Jack
8
USB Jacks
9
Battery
Indicators
10
RF INPUT 50
Access features used with all analyzer modes and affects the state of the entire spectrum analyzer. See your User’s Guide for more details.
System
functions affect the state of the entire analyzer. Various setup and adjustment routines are accessed with the
System
key.
The
Mode Preset
and
User Preset
keys reset the analyzer to a known state.
The
Save
and
Recall
keys enable you to save and to recall measurement results, traces, states, and screens.
The
key saves the currently displayed screen to a file.
Supplies power for external high frequency probes and accessories.
Jacks for earphone.
Jacks for connecting USB devices. For example, an external memory device.
LEDs indicate the status of batteries 1 and 2.
11
Data Controls
12
Cancel (Esc)
13
Navigation
Keys
14
Return Key
15
Volume Control
Keys/
16
Help Key
17
Window Keys
(Not currently implemented.)
Input for an external signal. Make sure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Change the numeric value of an active function. Entries appear in the active function area of the display. Also see
Pressing this key when operating remotely will put the analyzer in local mode.
Moves cursor between fields on the display.
Increments and decrements active function values.
Exits the current menu and returns to the previous menu.
Enables you to Mute or increase and decrease sound at the internal speaker or the earphones.
Used with AM/FM Tune and Listen, N1996A with Option AFM.
Press the
Help
key to access the embedded help information. Use the menu keys or navigation keys (item 13) to select the desired help topic. Two types of help are available:
1.
Task help that will guide you through making a measurement.
2.
Key function explanations that provide a short description of a key and the associated remote command.
You can exit help by pressing
Cancel (Esc)
.
Next Window
: On displays with multiple windows, changes the highlighted window that is currently active.
Zoom
: Zooms in on the highlighted window.
Multiple Windows
: On displays with multiple windows, switches the view to multiple window.
Chapter 3 51
Front and Rear Panel Features
Front Panel Overview
Item
# Name
18
Power
On/Standby
19
RF OUTPUT
50
Description
Turns the analyzer on. A green light indicates power on. A yellow light indicates standby mode.
NOTE
The front-panel switch is a standby switch, not a LINE switch
(disconnecting device); the analyzer continues to draw power even when the line switch is in standby. Use the detachable power cord to disconnect the analyzer from the mains supply.
NOTE
The internal frequency reference is not powered when in standby mode.
The output for the built-in signal source. This connector is present on all N1996A analyzers, but the output is enabled only on analyzers with either N8995A, N8995A-SR3 or
N8995A-SR6.
52 Chapter 3
Display Annotations: Spectrum Display
For firmware revisions < A.02.00
Front and Rear Panel Features
Front Panel Overview
Item Description
5
6
7
3
4
1
2
Amplitude scale
Reference level
Auto Range On indicator
Active function block
Internal preamp status
Marker
RF attenuation
AMPTD Y Scale, Scale Type
or
AMPTD Y Scale, Scale/Div
AMPTD Y Scale, Ref Level
AMPTD Y Scale, Auto Range
Refer to the description of the activated function.
AMPTD Y Scale
,
Internal Preamp
Marker
AMPTD Y Scale, Elec Atten
Chapter 3 53
Front and Rear Panel Features
Front Panel Overview
11
12
13
21
22
23
24
15
16
17
18
19
20
Item Description
8
9
10
14
25
26
Over Range: Indicates that the attenuation and preamp (if installed) settings are supplying too much power to the detector.
Distortion may result. Set
Auto Range
(On) to clear.
or
<8Smpl/Pt: Indicates that the current instrument settings have reduced the number of samples/display point to fewer than 8. The most accurate averaged amplitude measurement will be made when you have at least 8 samples in each display point.
Ext Gain
AMPTD Y Scale, Elec Atten
AMPTD Y Scale, Internal Preamp
AMPTD Y Scale, Auto Range
Trace/Detector
, More,
Detector
,
Average
Averaging
AMPTD Y Scale, Ext Gain
Trace/Detector, Trace Average
or
Meas Setup
,
Avg Mode, Avg
Number
: The numbers shown indicates current average number and the desired number of averages.
System, Time/Date/Location, Date/Time
Time and date display
Active marker
Trace and detector information
Marker
Trace/Detector
,
Clear Write (W) Trace Average (A) Max Hold (M)
Min Hold (m)
Trace/Detector
,
More, Detector, Peak (P) Sample(S) Negative Peak (p)
Average (A)
Active marker frequency and amplitude
If in zero span, active marker time and amplitude is displayed.
Key menu title
Key menu
Marker
Dependent on menu selection.
Menu key labels
Stop frequency or if in zero span, stop time
FREQ Channel, Stop Freq
Reference frequency source indicator
System, Freq/Time Reference
Battery 1 & 2 status indicator
AC power indicator
System, System Stats, Battery
Control/Sweep, Sweep Time
Indicates that the analyzer is currently powered by the external
AC/DC power converter
Sweep time
Span
Center frequency
Display status line
SPAN X Scale
FREQ Channel, Center Freq
Displays informational and error messages (see “Types of
Spectrum Analyzer Messages” on page 227).
Resolution Bandwidth
Start frequency or if in zero span, 0 sec
BW, Res BW
FREQ Channel, Start Freq
54 Chapter 3
For firmware revision A.02.00 or greater
Front and Rear Panel Features
Front Panel Overview
Item Description
6
7
4
5
1
2
3
Amplitude scale
Reference level
Auto Range On indicator
Active function block
Internal preamp status
Marker
RF attenuation
AMPTD Y Scale, Scale Type
or
AMPTD Y Scale, Scale/Div
AMPTD Y Scale, Ref Level
AMPTD Y Scale, Auto Range
Refer to the description of the activated function.
AMPTD Y Scale
,
Internal Preamp
Marker
AMPTD Y Scale, Elec Atten
Chapter 3 55
Front and Rear Panel Features
Front Panel Overview
11
12
13
21
22
23
24
15
16
17
18
19
20
Item Description
8
9
10
14
25
26
Over Range: Indicates that the attenuation and preamp (if installed) settings are supplying too much power to the detector.
Distortion may result. Set
Auto Range
(On) to clear.
or
<8Smpl/Pt: Indicates that the current instrument settings have reduced the number of samples/display point to fewer than 8. The most accurate averaged amplitude measurement will be made when you have at least 8 samples in each display point.
Ext Gain
Averaging
AMPTD Y Scale, Elec Atten
AMPTD Y Scale, Internal Preamp
AMPTD Y Scale, Auto Range
Trace/Detector
,
More, Detector
,
Average
Time and date display
Active marker
Trace and detector information
AMPTD Y Scale, Ext Gain
Trace/Detector, Trace Average
or
Meas Setup
,
Avg Mode, Avg
Number
: The numbers shown indicates current average number and the desired number of averages.
System, Time/Date/Location, Date/Time
Marker
Trace/Detector
,
Clear Write (W) Trace Average (A) Max Hold (M)
Min Hold (m)
Trace/Detector
,
More, Detector, Peak (P) Sample(S) Negative Peak (p)
Average (A)
Marker
Active marker frequency and amplitude
If in zero span, active marker time and amplitude is displayed.
Key menu title
Key menu
Span
Reference frequency source indicator
Battery 1 & 2 status indicator
AC power indicator
Dependent on menu selection.
Menu key labels
SPAN X Scale
System, Freq/Time Reference
System, System Stats, Battery
Control/Sweep, Sweep Time
Indicates that the analyzer is currently powered by the external
AC/DC power converter
Sweep time
VBW
Center frequency
Display status line
BW, Video BW
FREQ Channel, Center Freq
Displays informational and error messages (see “Types of
Spectrum Analyzer Messages” on page 227).
Resolution Bandwidth
Revision indicator
BW, Res BW
System, System Stats, Show System
56 Chapter 3
Front and Rear Panel Features
Front Panel Overview
Display Annotations: Spectrogram (Option 271)
For firmware revisions < A.02.00
Item Description
4
5
6
1
2
3
Amplitude scale
Reference level
Auto Range On indicator
Active function block
Internal preamp status
RF attenuation
AMPTD Y Scale, Scale Type
or
AMPTD Y Scale, Scale/Div
AMPTD Y Scale, Ref Level
AMPTD Y Scale, Auto Range
Data entry field for the active function.
AMPTD Y Scale
,
Internal Preamp
AMPTD Y Scale, Elec Atten
Chapter 3 57
Front and Rear Panel Features
Front Panel Overview
8
9
10
11
12
13
22
23
24
17
18
19
20
14
15
16
Item Description
7
21
25
Over Range: Indicates that the attenuation and preamp (if installed) settings are supplying too much power to the detector.
Distortion may result. Set
Auto Range
(On) to clear.
or
<8Smpl/Pt: Indicates that the current instrument settings have reduced the number of samples/display point to fewer than 8. The most accurate averaged amplitude measurement will be made when you have at least 8 samples in each display point.
Ext Gain
Color scale legend
Elapsed time clock
AMPTD Y Scale, Elec Atten
AMPTD Y Scale, Internal Preamp
AMPTD Y Scale, Auto Range
Trace/Detector
, More,
Detector
,
Average
AMPTD Y Scale, Ext Gain
Provides a reference for the color scale.
Provides an indicator of the data collection time interval of the displayed spectrogram.
System, Time/Date/Location, Date/Time
Time and date display
Active marker
Trace information
Active marker frequency and amplitude
Key menu title
Key menu
Marker
Trace/Detector
,
Clear Write (W) Trace Average (A) Max Hold (M)
Min Hold (m)
Trace/Detector
,
More, Detector, Peak (P) Sample (S) Negative Peak
(p) Average (A)
Marker
Dependent on menu selection.
Menu key labels
Stop frequency or if in zero span, stop time
FREQ Channel, Stop Freq
Reference frequency source indicator
System, Freq/Time Reference
Battery 1 & 2 status indicator
AC power indicator
Spectrum display
Start frequency or if in zero span, 0 sec
System, System Stats, Battery
AC/DC power converter
Indicates that the analyzer is currently powered by the external
View/Display, Spectrogram
Provides a Spectral display of the spectrum sampled to create the spectrogram.
FREQ Channel, Start Freq
Marker
Display status line
Metrics Panel
Marker
Displays informational and error messages (see “Types of
Spectrum Analyzer Messages” on page 227).
Displays measurement results data metrics.
58 Chapter 3
For firmware revision A.02.00 or greater
Front and Rear Panel Features
Front Panel Overview
Item Description
4
5
6
1
2
3
Amplitude scale
Reference level
Auto Range On indicator
Active function block
Internal preamp status
RF attenuation
AMPTD Y Scale, Scale Type
or
AMPTD Y Scale, Scale/Div
AMPTD Y Scale, Ref Level
AMPTD Y Scale, Auto Range
Data entry field for the active function.
AMPTD Y Scale
,
Internal Preamp
AMPTD Y Scale, Elec Atten
Chapter 3 59
Front and Rear Panel Features
Front Panel Overview
8
9
10
11
12
13
22
23
24
17
18
19
20
14
15
16
Item Description
7
21
25
26
Over Range: Indicates that the attenuation and preamp (if installed) settings are supplying too much power to the detector.
Distortion may result. Set
Auto Range
(On) to clear.
or
<8Smpl/Pt: Indicates that the current instrument settings have reduced the number of samples/display point to fewer than 8. The most accurate averaged amplitude measurement will be made when you have at least 8 samples in each display point.
Ext Gain
Color scale legend
Elapsed time clock
AMPTD Y Scale, Elec Atten
AMPTD Y Scale, Internal Preamp
AMPTD Y Scale, Auto Range
Trace/Detector
,
More, Detector
,
Average
(Log/RMS/V)
AMPTD Y Scale, Ext Gain
Provides a reference for the color scale.
Provides an indicator of the data collection time interval of the displayed spectrogram.
System, Time/Date/Location, Date/Time
Time and date display
Active marker
Trace information
Active marker frequency and amplitude
Key menu title
Key menu
Marker
Display status line
Marker
Trace/Detector
,
Clear Write (W) Average (A) Max Hold (M) Min
Hold (m)
Trace/Detector
,
More, Detector, Peak (P) Sample (S) Negative Peak
(p) Average (A)
Stop frequency or if in zero span, stop time
FREQ Channel, Stop Freq
Reference frequency source indicator
System, Freq/Time Reference
Battery 1 & 2 status indicator
AC power indicator
Spectrum display
Start frequency or if in zero span, 0 sec
System, System Stats, Battery
AC/DC power converter
Indicates that the analyzer is currently powered by the external
View/Display, Spectrogram
Provides a Spectral display of the spectrum sampled to create the spectrogram.
FREQ Channel, Start Freq
Metrics Panel
Revision indicator
Marker
Dependent on menu selection.
Menu key labels
Marker
Displays informational and error messages (see “Types of
Spectrum Analyzer Messages” on page 227).
Displays measurement results data metrics.
System, System Stats, Show System
60 Chapter 3
Rear-Panel Features
Front and Rear Panel Features
Rear-Panel Features
Item
# Name
1
Battery
Compartment
2
DC Power
3
USB, Type A
4
USB, Type B
5
Timing LAN
6
LAN
7
REF OUT
(10 MHz)
8
EXT REF IN
9
EXT TRIGGER
INPUT
10 Reserved for future use.
Description
Location of the two batteries that provide DC power to the analyzer.
The input for the dc power source. Refer to “Power Requirements” on page 27.
Allows connections of external devices such as an external memory device.
Allows connections of external devices such as a PC controller. (not implemented)
A TCP/IP Interface for connecting internal options to external devices. (not implemented)
A TCP/IP Interface.
•
For information on setting the IP address, refer to “Turning on the Analyzer for the First
•
For information on using the analyzer remotely, refer to the User’s/Programmer’s Guide.
An output of the analyzer’s internal 10 MHz frequency reference signal used to lock the frequency reference of the analyzer to other test equipment.
Input for an external frequency reference signal. For additional information on using an external reference, refer to
“Using an External Reference” on page 33.
A TTL input that accepts the positive or negative edge (selectable) of an external voltage input that triggers the analyzer internal sweep source.
Chapter 3 61
Front and Rear Panel Features
Rear-Panel Features
Item
# Name
11
Kensington lock
Slot
12
Mounting tabs
13
Grounding lug
Description
Used in conjunction with Kensington Lock to secures analyzer to work space.
Mounting tabs for mounting the external power supply when analyzer is rack mounted.
Chassis ground connection.
62 Chapter 3
Front and Rear Panel Features
Key Overview
Key Overview
The keys labeled
FREQ Channel
,
System
, and
Marker
are all examples of front-panel keys. The front-panel keys are dark gray, light gray, green, beige, or white in color. Front-panel keys that are white perform an immediate action rather than bringing up a menu. The only green keys are the
Mode Preset
,
User Preset
, and
Help
keys. The Mode Preset and User Preset keys perform an analyzer reset and the Help key accesses the embedded help system. (A summary of all front panel keys and their related menu keys can be found in the User’s Guide for your analyzer). Pressing most of the dark gray, the light gray, or the beige front-panel keys accesses menus of functions that are displayed along the right side of the display. These are called menu keys.
Menu keys list functions other than those accessed directly by the front panel keys.
To activate a menu key function, press the key immediately to the right of the annotation on the screen. The menu keys that are displayed depend on which front-panel key is pressed and which menu level is enabled.
If a menu key function value can be changed, it is called an active function. The function label of the active function is highlighted after that key has been selected.
For example, press
AMPTD Y Scale
. This calls up the menu of related amplitude functions. Note the function labeled
Ref Level
(the default selected key in the
Amplitude menu) is highlighted.
Ref Level
also appears in the active function block (as well as the reference level value), indicating that it is the active amplitude function and can now be changed using any of the data entry controls.
A menu key with On and Off in its label can be used to turn the menu key function on or off. To turn the function on, press the menu key so that On is underlined. To turn the function off, press the menu key so that Off is underlined. In the manual, when On should be underlined, it will be indicated as
Function
(On).
A function with Auto and Man in the label can either be auto-coupled or have its value manually changed. The value of the function can be changed manually using the numeric keypad, knob, or step keys. To auto-couple a function, press the menu key so that Auto is underlined. In the manual, when
Auto
should be underlined, it will be indicated as
Function
(Auto).
In some key menus, one key label will always be highlighted to show which key has been selected. For example, when you press
Marker
, you will access a menu of keys in which some of the keys are grouped together by a yellow highlighted region of the menu. The
Normal
key, which is the
Marker
menu default key, will be highlighted. When you press another key within the yellow region, such as
Delta
, a yellow border around that key becomes visible to show it has been selected.
Chapter 3 63
Front and Rear Panel Features
Key Overview
In other key menus, one key label will always be highlighted to show which key has been selected but the menu is immediately exited when a selection is made.
For example, when you press the
Avg Type
key (on the
Meas Setup
menu), it will bring up its own menu of keys. The
Log-Pwr Avg
key, which is the Avg Type menu default key, will be highlighted. When you press the
Pwr Avg
key, the highlight will move to that key to show it has been selected and the screen will return to the
Meas Setup
menu.
The arrow keys located around the Select key to the left of the analyzer display can be used to navigate within tables or lists, for example the Chan Std table. These keys are used to move between rows. The cursor (inverse video highlight) indicates the active item.
64 Chapter 3
4
Recommended Test Equipment
65
Recommended Test Equipment
Test Equipment for Making Measurements
NOTE
Test Equipment for Making Measurements
Test Equipment
The table below summarizes the test equipment needed to perform all of the measurements shown in this guide. Alternate equipment model numbers are given in case the recommended equipment is not available.
If neither the recommended nor the alternative test equipment are available, substitute equipment that meets or exceeds the critical specifications listed.
To find descriptions of specific analyzer functions, refer to the Agilent
Technologies N1996A Spectrum Analyzer User’s/Programmer’s Reference Guide.
Item Critical Specifications
Adapters
Type-N (m) to BNC (f) (3)
Type N (m) to Type N (m)
Frequency: 10 MHz to 6 GHz
VSWR: 1.08:1
Type N (f) to 3.5 mm (f) (for use with 20 GHz or 26.5 GHz source)
Type N (f) to 2.4 mm (f) (for use with >26.5 GHz source)
Frequency: 10 MHz to 6 GHz
VSWR: 1.08:1
Frequency: 10 MHz to 6 GHz
VSWR:
1.08:1
Cables
BNC, 122-cm (48-in) (3)
Type N (m) to Type N (m),
<=36 inches long
Synthesized Sweeper
(if 8665B, ESG or PSG is not available)
Frequency: 10 MHz to 6 GHz
VSWR: 1.4:1
Cable, BNC (m) to BNC (m),
36 inches long
Signal Source (two are required)
Frequency: 10 MHz nominal
Synthesized Signal Generator
(if 8360-Series sweeper is not used)
Frequency Range: 10 MHz to 6 GHz
Power Level: -10 to +5 dBm
Frequency Range: 10 MHz to 6 GHz
Power Level: -10 to +5 dBm
Recommended
Agilent Model
1250-0780
1250-1472
1250-1745
11903B
10503A
11500B
10503
8665B, E8257D,
E8267D, or
E4438C Opt 506
83620A/B,
83630A/B,
83640A/B,
83650A/B
Alternate
Agilent
Model
66 Chapter 4
5
Spectrum Analyzer
67
Spectrum Analyzer
This Chapter provides information making the following measurements.
“Making a Basic Measurement” on page 69
“Measuring Multiple Signals” on page 75
“Measuring a Low-Level Signal” on page 86
“Making Distortion Measurements” on page 93
“Using the Analyzer as a Fixed Tuned Receiver” on page 101
“Occupied Bandwidth (OBW) Measurement” on page 107
“Making a Basic Occupied BW Measurement” on page 109
“Using the Spectrogram View (Requires Option 271)” on page 111
“Pulse Measurement” on page 115
“Tune and Listen (Requires Option AFM)” on page 117
68 Chapter 5
CAUTION
Spectrum Analyzer
Making a Basic Measurement
Making a Basic Measurement
This section provides information on basic analyzer operation. For more information on making measurements, see the appropriate measurement chapter.
This section is divided into the following sections:
“Presetting the Spectrum Analyzer” on page 71
“Creating a User Preset and Power-Up State” on page 71
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Basic Assumption
The material in this chapter is presented with the assumption that you understand the front and rear panel layout, and display annotations of your analyzer. If you do not, refer to the Measurement Guide
“Front and Rear Panel Features” on page 49.
Entering Data
When setting measurement parameters, there are several ways to enter or modify the value of the active function:
Knob
Arrow Keys
Numeric Keypad
Unit Menu Keys
Enter Key
Increments or decrements the current value.
Increments or decrements the current value.
Enters a specific value. Then press the desired terminator (either a unit menu key, or the
Enter
key).
Terminate a value that requires a unit-of-measurement.
Terminates an entry when either no unit of measure is needed, or you want to use the default unit.
Using Menu Keys
Menu Keys (which appear along the right side of the display) provide access to many analyzer functions. Here are examples of menu key types:
Toggle
Allows you to activate/deactivate states.
Toggles the selection (underlined choice) each time you press the key.
Chapter 5 69
Spectrum Analyzer
Making a Basic Measurement
Example:
Submenu
Displays a new menu of menu keys.
A submenu key allows you to view a new menu of menu keys related to the submenu key category.
Example:
Choice
Allows you to make a selection from a list of values.
A choice key displays the currently selected submenu choice, in this example, dBm. When the choice is made, the submenu automatically returns.
Example:
Adjust
Highlights the menu key and sets the active function.
Press this type of key and enter a value.
The default for menu keys with an automatic (
Auto
) or manual (
Man
) choice is automatic. After pressing the key, the selection changes to manual.
Examples:
70 Chapter 5
NOTE
NOTE
Spectrum Analyzer
Making a Basic Measurement
Presetting the Spectrum Analyzer
Preset provides a known starting point for making measurements. The analyzer has two types of preset:
Mode Preset
User Preset
This type of preset restores the currently selected mode to a known factory-defined state.
Restores the analyzer to a user-defined state. User
Preset uses the factory-defined state until you create a custom user preset file.
For details, see the User’s and Programmer’s Reference manual.
Creating a User Preset and Power-Up State
User Preset recalls the power-up state, applying the defaults you define using the
Save State button. When you save a state to be used as the User Preset power-up state, you must name the state “Powerup”. If you want to use the Agilent-defined defaults at power-up, press
Mode Preset
to restore the Agilent-defined defaults and save that state as a new Powerup state file.
If you constantly use settings which are not the factory defaults, use the following steps to create a user-defined preset:
If “Powerup” state already exists in the catalog list, you can set the state to your preferences and then select “Powerup” in the list. The catalog list can be viewed by selecting
Save
,
Catalog
.
1.
Set analyzer parameters as desired.
2.
Set filename to “Ask”. Press
Save
,
Name
,
Filename
(Ask).
3.
Save to the internal hard drive. Press
Save
,
Location
,
Internal
.
4.
Save Powerup state. Press
Type
,
State
,
Save Now
.
5.
Using the knob or arrow keys, select the letters from the alphabet window to create the word, “Powerup” and press
OK
. The message, “
State was saved successfully: C:Powerup
” is displayed. Press
OK
again to return to the
Save
key menu.
The parameters saved in this “Powerup” state file are now enabled as the user preset option and as the default power-up state.
This process is easier for firmware revision A.02.00 or greater. After configuring the desired parameter settings, press
User Preset
,
Save User Preset
.
Disabling User Preset
To restore the factory defined Power On settings, press
Mode Preset
and follow the steps listed above to save the resulting state as the new “Powerup” state file. This
Chapter 5 71
NOTE
Figure 5-1
Spectrum Analyzer
Making a Basic Measurement
will restore the factory-defined default settings as the power-on settings and as the user preset settings.
For firmware revision A.02.00 or greater, to disable User Preset, the process is easier, press
Mode Preset
, then press
User Preset
,
Save User Preset
.
Viewing a Signal
1.
Select the spectrum analyzer mode. Press
Mode
,
Spectrum Analyzer
.
2.
Preset the analyzer: Press
Mode Preset
.
3.
Connect the analyzer’s rear panel
REF OUT (10 MHz)
to the front-panel input.
Setting Center Frequency, Span, Attenuation, and Reference Level.
1.
Set the center frequency to 30 MHz: Press
FREQ Channel, Center Freq
, 30,
MHz
.
2.
Set the Span to 50 MHz: Press
SPAN X Scale
, 50,
MHz
.
3.
Adjust the attenuation to 20 dB: Press
AMPTD Y Scale
,
Elec Atten
, 20,
dB
.
4.
Adjust the reference level (if the peak of the 10 MHz signal component is not visible): Press
AMPTD Y Scale, Ref Level
, 10, dBm
. For more information on this, refer to
“Changing Reference Level” on page 73 .
The 10 MHz reference signal spectrum appears on the display, as shown in
10 MHz Internal Reference Signal and Associated Spectrum
72 Chapter 5
Spectrum Analyzer
Making a Basic Measurement
Figure 5-2
Reading Frequency & Amplitude
1.
Place a marker (labeled
1
) on the 10 MHz peak, as shown in
Press
Peak Search
. If necessary, use the menu keys to move the marker to the proper peak. In addition, you can go to the Marker menu (press Marker) and use the knob or arrow keys to move the marker.
Note that the frequency and amplitude of the marker appear in the upper-right corner of the screen.
2.
If you have moved the marker, return it to the peak of the 10 MHz signal.
A Marker on the 10 MHz Peak
Changing Reference Level
1.
Press
AMPTD Y Scale
, and note that reference level (
Ref Level
) is now the active function. Press
Marker
Mkr
RL
.
Note that changing the reference level changes the amplitude value of the top graticule line.
shows the relationship between center frequency and reference level. The box represents the analyzer display. Changing the center frequency changes the horizontal placement of the signal on the display. Changing the reference level changes the vertical placement of the signal on the display.
Increasing the span increases the frequency range that appears horizontally across the display.
Chapter 5 73
Figure 5-3
Spectrum Analyzer
Making a Basic Measurement
Relationship Between Frequency and Amplitude
74 Chapter 5
CAUTION
Spectrum Analyzer
Measuring Multiple Signals
Measuring Multiple Signals
This section provides information on measuring multiple signals.
This section is divided into the following sections:
“Comparing Signals on the Same Screen Using Marker Delta” on page 76
“Comparing Signals not on the Same Screen Using Marker Delta” on page 78
“Resolving Signals of Equal Amplitude” on page 80
“Resolving Small Signals Hidden by Large Signals” on page 83
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Basic Assumption
The material in this chapter is presented with the assumption that you understand the front and rear panel layout, and display annotations of your analyzer. If you do not, refer to the Measurement Guide “Front and Rear Panel Features”.
Chapter 5 75
Figure 5-4
Spectrum Analyzer
Measuring Multiple Signals
Comparing Signals on the Same Screen Using Marker Delta
Using the analyzer, you can easily compare frequency and amplitude differences between signals, such as radio or television signal spectra. The analyzer delta marker function lets you compare two signals when both appear on the screen at one time.
In this procedure, harmonics of the 10 MHz reference signal available at the rear of the analyzer are used to measure frequency and amplitude differences between two signals on the same screen. Delta marker is used to demonstrate this comparison.
An Example of Comparing Signals on the Same Screen
Step 1.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer.
Step 2.
Preset the analyzer:
Press
Mode Preset
.
Step 3.
Connect the rear panel REF OUT (
10 MHz)
to the front panel RF input.
Step 4.
Set the analyzer center frequency, span and reference level to view the fundamental and 2nd through fifth harmonics of the 10 MHz reference signal:
Press
FREQ Channel
,
Center Frequency
, 30,
MHz
.
Press
SPAN X Scale
,
Span
, 50,
MHz
.
Press
AMPTD Y Scale
,
Ref Level
, 10,
dBm
Press
AMPTD Y Scale
,
Elec Atten
, 20,
dB
or
Auto Range
(On).
Step 5.
Place a marker at the highest peak on the display (10 MHz):
Press
Peak Search
.
76 Chapter 5
Spectrum Analyzer
Measuring Multiple Signals
The
Next Peak
menu key is available to move the marker from peak to peak. The marker should be on the 3rd harmonic of the 10 MHz reference signal.
Step 6.
Anchor the first marker and activate the Delta marker:
Press
Marker, Delta
.
The label on the second marker reads
1
, indicating that it is the movable marker.
Step 7.
Move the second marker to another signal peak or by using the
Peak Search
key:
Press
Peak Search
,
Next Peak
.
The amplitude and frequency difference between the markers is shown in the upper right corner of the display.
Chapter 5 77
Figure 5-5
Spectrum Analyzer
Measuring Multiple Signals
Comparing Signals not on the Same Screen Using Marker Delta
Measure the frequency and amplitude difference between two signals that do not appear on the screen at one time. (This technique is useful for harmonic distortion tests when narrow span and narrow bandwidth are necessary to measure the low level harmonics.)
In this procedure, frequency and amplitude differences are measured between harmonics of the analyzer’s 10 MHz reference; one harmonic on screen and one harmonic off screen. Delta marker is used to demonstrate this comparison.
Comparing One Signal on Screen with One Signal Off Screen
Step 1.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer.
Step 2.
Preset the analyzer:
Press
Mode Preset
.
Step 3.
Connect the rear panel
REF OUT (10 MHz)
to the front panel RF input.
Step 4.
Set the center frequency, span and reference level to view only the 30 MHz signal:
Press
FREQ Channel
,
Center Freq
, 30,
MHz
.
Press
SPAN X Scale
,
Span
, 5,
MHz
.
Step 5.
Place a marker on the 30 MHz peak:
Press
Peak Search
.
Step 6.
Set the center frequency step size equal to 10 MHz:
Press
FREQ Channel
,
CF Step
(Manual), 10,
MHz
.
Step 7.
Activate the marker delta function:
78 Chapter 5
Spectrum Analyzer
Measuring Multiple Signals
Figure 5-6
Press
Marker, Delta
.
Step 8.
Increase the center frequency by 10 MHz:
Press
FREQ Channel
,
Center Freq
,
,
Peak Search
.
The delta marker (
1) appears on the peak of the 40 MHz harmonic. The delta marker annotation displays the amplitude and frequency difference between the 30 and 40 MHz signal peaks. Refer to
Delta Marker with Reference Signal Off-Screen
Step 9.
Turn the markers off:
Press
Marker, Off
.
Chapter 5 79
Spectrum Analyzer
Measuring Multiple Signals
Figure 5-7
Resolving Signals of Equal Amplitude
In this procedure a decrease in resolution bandwidth is used to resolve two signals of equal amplitude with a frequency separation of 100 kHz. Notice that the final
RBW selection to resolve the signals is the same width as the signal separation.
Step 1.
Connect the output of signal generator #1 to port 2 of the directional coupler and connect the output of signal generator #2 to port 3 (the coupled port) of the
directional coupler as shown in Figure 5-7
.
Setup for Obtaining Two Signals
Step 2.
Set the signal sources as follows:
Set signal generator #1 to 300 MHz at –19 dBm. Set signal generator #2 to
300.1 MHz at –4 dBm (this higher power level overcomes the nominal 16 dB loss through the coupled arm of the directional coupler).
The amplitude of both signals should be approximately
20 dBm at the output of the bridge.
Step 3.
Setup the analyzer to view the signals:
Press
Mode Preset
.
Press
FREQ Channel
,
Center Freq
, 300,
MHz
.
Press
SPAN X Scale
,
Span
, 2,
MHz
.
Press
Meas Setup
,
Avg Mode
,
Exponential
.
Press
Avg Number
, 25,
Enter
.
Press
Trace/Detector
,
Trace Average
.
Press
BW
,
Res BW (Manual)
, 300,
kHz
.
A single signal peak is visible. See Figure 5-8 for an example.
80 Chapter 5
Figure 5-8 Unresolved Signals of Equal Amplitude
Spectrum Analyzer
Measuring Multiple Signals
Figure 5-9
Step 4.
Change the resolution bandwidth (RBW) to 75 kHz so that the RBW setting is less than or equal to the frequency separation of the two signals:
Press
BW,
Res BW (Manual)
, 75,
kHz
.
Notice that the peak of the signal has become flattened indicating that two signals may be present.
Resolving Signals of Equal Amplitude
As the resolution bandwidth is decreased, resolution of the individual signals is improved and the sweep time is increased. For fastest measurement times, use the widest possible resolution bandwidth. Under factory preset conditions, the resolution bandwidth is “coupled” (or linked) to the span.
Since the resolution bandwidth has been changed from the coupled value, a
#
mark appears next to
Res BW
in the lower-left corner of the screen, indicating that the resolution bandwidth is uncoupled. (For more information on resolution
Chapter 5 81
NOTE
Spectrum Analyzer
Measuring Multiple Signals
bandwidth, refer to the
Res BW
description in the Agilent CSA Spectrum
Analyzers User’s and Programmer’s Reference guide.)
To resolve two signals of equal amplitude, the resolution bandwidth must be less than the signal separation. For example, if the signal separation is 200 kHz and the analyzer only has resolution bandwidth settings in a 1-3-10 sequence, a 100 kHz
RBW is the best choice for the 200 kHz signal separation. But some analyzers, such as the Agilent CSA and PSA spectrum analyzers, can select a 180 kHz RBW.
82 Chapter 5
Spectrum Analyzer
Measuring Multiple Signals
Figure 5-10
Resolving Small Signals Hidden by Large Signals
This procedure uses narrow resolution bandwidths to resolve two input signals with a frequency separation of 50 kHz and an amplitude difference of 60 dB.
Step 1.
Connect two sources to the analyzer input as shown in Figure 5-7
. Connect the output of signal generator #1 to port 2 of the directional coupler and connect the output of signal generator #2 to port 3 (the coupled port) of the directional coupler.
Setup for Obtaining Two Signals
Step 2.
Set the signal sources as follows:
Set signal generator #1 to 300 MHz at –9 dBm. Set signal generator #2 to
300.450 MHz at –54 dBm. (These power levels plus the nominal 16 dB loss through the coupled arm and the nominal 1 dB loss through the main arm of the directional coupler results in a signal 60 dB below the first signal).
Step 3.
Set the analyzer as follows:
Press
Mode Preset
.
Press
FREQ Channel
,
Center Freq
, 300,
MHz
.
Press
SPAN X Scale
,
Span
, 5,
MHz
.
Press
BW
,
Res BW
, 100,
kHz
.
Step 4.
Set the 300 MHz signal peak to the reference level:
Press
Peak Search
,
Mkr
,
Mkr
R L
.
Note that the Agilent CSA 100 kHz filter shape factor of 8:1 has a bandwidth of
840 kHz at the 60 dB point. The half-bandwidth (420 kHz) is NOT narrower than the frequency separation of 450 kHz, so the input signals can not be resolved.
Step 5.
Activate averaging to smooth the noise:
Press
Meas Setup
,
Avg Mode
,
Exponential
.
Press
Avg Number
, 25,
Enter
.
Press
Trace/Detector
,
Trace Average
Chapter 5 83
Figure 5-11
Spectrum Analyzer
Measuring Multiple Signals
Signal Resolution with a 100 kHz RBW
Figure 5-12
Step 6.
Reduce the resolution bandwidth filter to view the smaller hidden signal. Place a delta marker on the smaller signal:
Press
BW
, 30,
kHz
.
Press
Peak Search
,
Marker
,
Delta
, 450,
kHz
.
Note that the Agilent CSA 30 kHz filter shape factor of 8.4 has a bandwidth of
252 kHz at the 60 dB point, however noise sidebands will make the 60 dB bandwidth appear wider. The half-bandwidth (including effects of noise sidebands) is narrower than 250 kHz, so the input signals can be resolved.
Signal Resolution with a 30 kHz RBW
NOTE
To determine the resolution capability for intermediate amplitude differences, assume the filter skirts between the 3 dB and 60 dB points are parabolic, like an ideal Gaussian filter. The resolution capability is approximately:
84 Chapter 5
2
12.04 dB
where
f is the separation between the signals.
Spectrum Analyzer
Measuring Multiple Signals
Chapter 5 85
CAUTION
Spectrum Analyzer
Measuring a Low-Level Signal
Measuring a Low-Level Signal
This section provides information on measuring low-level signals and distinguishing them from spectrum noise.
This section is divided into the following sub-sections:
“Reducing Input Attenuation” on page 87
“Decreasing the Resolution Bandwidth” on page 89
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Basic Assumption
The material in this section is presented with the assumption that you understand the front and rear panel layout, and display annotations of your analyzer. If you do not, refer to the Measurement Guide “Front and Rear Panel Features”.
86 Chapter 5
Spectrum Analyzer
Measuring a Low-Level Signal
Reducing Input Attenuation
The ability to measure a low-level signal is limited by internally generated noise in the spectrum analyzer. The measurement setup can be changed in several ways to improve the analyzer sensitivity.
The input attenuator affects the level of a signal passing through the instrument. If a signal is very close to the noise floor, reducing input attenuation can bring the signal out of the noise.
CAUTION
Ensure that the total power of all input signals at the analyzer RF input does not exceed +33 dBm (2 watts).
Figure 5-13
Step 1.
Connect the RF Output of the signal generator to the analyzer RF Input as shown
Setup for Obtaining One Signal
Step 2.
Set the frequency of the signal source to 295 MHz. Set the source amplitude to
80 dBm. Connect the source RF OUTPUT to the analyzer RF INPUT.
Step 3.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer
.
Step 4.
Preset the analyzer:
Press
Mode Preset
.
Step 5.
Set the center frequency, span and reference level:
Press
FREQ Channel
,
Center Freq
, 295,
MHz
.
Press
SPAN X Scale
,
Span
, 1,
MHz
.
Press
AMPTD Y Scale
,
Ref Level
, 40,
dBm
.
Step 6.
Place the marker at the desired peak (in this example, 295 MHz)
Press
Peak Search
.
Step 7.
Activate averaging to smooth the noise:
Chapter 5 87
Spectrum Analyzer
Measuring a Low-Level Signal
Figure 5-14
Press
Meas Setup, Avg Number, 10, Enter
.
Press
Avg Mode, Exponential
.
Press
Trace/Detector, Trace Average
.
Step 8.
To see the signal more clearly, set the attenuation to 0 dB:
Press
AMPTD Y Scale
,
Elect Atten
, 0,
dB
.
shows 0 dB input attenuation.
Measuring a Low-Level Signal Using 0 dB Attenuation
Figure 5-15
Step 9.
Set the attenuation to 20 dB: (as shown in
)
Press
AMPTD Y Scale
,
Elec Atten
, 20, dB
.
Note that increasing the attenuation moves the noise floor closer to the signal level.
Measuring a Low-Level Signal
88 Chapter 5
Spectrum Analyzer
Measuring a Low-Level Signal
Figure 5-16
Decreasing the Resolution Bandwidth
Resolution bandwidth settings affect the level of internal noise without affecting the level of continuous wave (CW) signals. Decreasing the RBW by a decade reduces the noise floor by 10 dB.
Step 1.
Connect the RF Output of the signal generator to the analyzer RF Input as shown
Setup for Obtaining One Signal
Step 2.
Set the frequency of the signal source to 295 MHz. Set the source amplitude to
80 dBm. Connect the source RF OUTPUT to the analyzer RF INPUT.
Step 3.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer
.
Step 4.
Preset the analyzer:
Press
Mode Preset
.
Step 5.
Set the center frequency, span and reference level:
Press
FREQ Channel
,
Center Freq
, 295,
MHz
.
Press
SPAN X Scale
,
Span
, 1,
MHz
.
Press
AMPTD Y Scale
,
Ref Level
, 40,
dBm
.
Step 6.
Decrease the resolution bandwidth:
Press
BW
,
Res BW
(Manual),
The low-level signal appears more clearly because the noise level is reduced (see
Chapter 5 89
Figure 5-17
Spectrum Analyzer
Measuring a Low-Level Signal
Decreasing Resolution Bandwidth
RBW Selections
All Agilent CSA RBWs are digital. Refer to the Agilent Technologies
Specifications Guide to determine the selectivity ratio for the particular RBW of interest. Choosing the next lower RBW for better sensitivity increases the sweep time. Using the knob or keypad, you can select individual RBW from the full range of values. This enables you to make the trade off between sweep time and sensitivity with finer resolution.
90 Chapter 5
Spectrum Analyzer
Measuring a Low-Level Signal
Figure 5-18
Trace Averaging
Averaging is a digital process in which each trace point is averaged with the previous average for the same trace point. Trace averaging can facilitate identifying and characterizing a CW or narrowband signal, such as a carrier or tone in the presence of noise or other broadband signals.
Selecting averaging, when the analyzer is auto coupled, changes the detection mode from peak to average, smoothing the displayed noise level.
Step 1.
Connect the RF Output of the signal generator to the analyzer RF Input as shown
Setup for Obtaining One Signal
Step 2.
Set the frequency of the signal source to 295 MHz. Set the source amplitude to
80 dBm. Connect the source RF OUTPUT to the analyzer RF INPUT.
Step 3.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer
.
Step 4.
Preset the analyzer:
Press
Mode Preset
.
Step 5.
Set the center frequency, span and reference level:
Press
FREQ Channel
,
Center Frequency
, 295,
MHz
.
Press
SPAN X Scale
,
Span
, 5,
MHz
.
Press
AMPTD Y Scale
,
Ref Level
, 40,
dBm
.
Step 6.
Turn trace averaging on:
Press
Meas Setup
,
Avg Number
,
100
,
Enter
.
Press
Trace/Detector
,
Trace Average
.
As the averaging routine smooths the trace, low level signals become more visible.
Avg: Exponential (100/100)
appears above the graticule.
Step 7.
With the average number as the active function, set the number of averages to 25:
Chapter 5 91
NOTE
Spectrum Analyzer
Measuring a Low-Level Signal
Press
Meas Setup
,
Avg Number
, 25,
Enter
.
Annotation above the graticule shows the type of averaging, the number of traces averaged, and the number of averages selected.
Changing most active functions restarts the averaging, as does toggling
Trace Type
back and forth from
Clear Write
to
Trace Average
. Once the set number of sweeps completes, the analyzer continues to provide a running average based on this set number, if the Avg Mode is set to Exponential.
If you want the measurement to stop after the set number of sweeps, use single sweep and the Repeat Average Mode:
Press the front panel key
Meas Setup
, then
Avg Mode
,
Repeat
, and press the front panel key
Control/Sweep
,
Restart
, and then press the front panel key
Single
.
92 Chapter 5
CAUTION
Spectrum Analyzer
Making Distortion Measurements
Making Distortion Measurements
This section provides information on measuring and identifying signal distortion.
This section is divided into the following sections:
“Identifying Distortion Products” on page 94
“Third-Order Intermodulation Distortion” on page 98
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Basic Assumption
The material in this section is presented with the assumption that you understand the front and rear panel layout, and display annotations of your analyzer. If you do not, refer to the Measurement Guide “Front and Rear Panel Features”.
Chapter 5 93
Spectrum Analyzer
Making Distortion Measurements
Identifying Distortion Products
This section provides information on measuring and identifying signal distortion.
This section is divided into the following sections:
“Distortion from the Analyzer” on page 94
“Identifying Analyzer Generated Distortion Example:” on page 94
Distortion from the Analyzer
High level input signals may cause analyzer distortion products that could mask the real distortion measured on the input signal. Using Trace 2 and the RF attenuator, you can determine which signals, if any, are internally generated distortion products.
Identifying Analyzer Generated Distortion Example:
Using a signal from a signal generator, determine whether the harmonic distortion products are generated by the analyzer.
Step 1.
Connect a signal generator to the analyzer INPUT.
Step 2.
Set the signal generator frequency to 200 MHz and the amplitude to 0 dBm.
Step 3.
On the analyzer, perform a mode preset by pressing
Mode Preset
.
Step 4.
Set the center frequency of the analyzer to 400 MHz by pressing
FREQ Channel
,
Center Freq
, 400,
MHz
.
Step 5.
Set the span to 500 MHz by pressing
SPAN X Scale
,
Span
, 500,
MHz
.
Step 6.
Set the attenuation to 10 dB by pressing
AMPTD Y Scale, Elec Atten,
10
dB
.
The signal produces harmonic distortion products in the analyzer input mixer as
.
94 Chapter 5
Figure 5-19 Harmonic Distortion
Spectrum Analyzer
Making Distortion Measurements
Figure 5-20
Step 7.
Change the span to 50 MHz: press
SPAN X Scale
,
Span
, 50,
MHz
.
Step 8.
Ensure that the signal is at the center frequency. If necessary press
Peak Search
,
Marker
,
Mkr
CF
.
Step 9.
Change the attenuation to 0 dB: press
AMPTD Y Scale
,
Elec Atten
, 0, dB
. Your display should be similar to
.
Harmonic Distortion with 0 dB Attenuation
Step 10.
To determine whether the harmonic distortion products are generated by the analyzer, first save the screen data in trace 2 as follows:
Press
Trace/Detector
, Select
Trace (2)
, then
Clear Write
.
Allow the trace to update (two sweeps) and press
Trace/Detector
,
View/Blank
(View)
,
Marker
,
Delta
.
Chapter 5 95
Spectrum Analyzer
Making Distortion Measurements
Figure 5-21
The analyzer display shows the stored data in trace 2 and the measured data in trace 1.
Step 11.
Next, press
Trace/Detector
, Select
Trace (1)
, increase the RF attenuation by 10 dB: press
AMPTD Y Scale
,
Elec Atten
, 10,
dB
. See
.
Notice the
Mkr1
amplitude reading. This is the difference in the distortion product amplitude readings between 0 dB and 10 dB input attenuation settings. If the
Mkr1
amplitude absolute value is approximately
1 dB for an input attenuator change, then distortion is being generated, at least in part, by the analyzer. In this case more input attenuation is necessary.
RF Attenuation of 10 dB
Step 12.
Press
Peak Search
,
Marker
,
Delta
Change the attenuation to 15 dB by pressing
AMPTD Y Scale
,
Elec Atten
, 15, dB
.
If the
Mkr1
amplitude absolute value is approximately
1 dB, then more input attenuation is required; some of the measured distortion is internally generated. If there is no change in the signal level, the distortion is not generated internally. For example, the signal that is causing the distortion, in this case, shown in
, is not high enough in amplitude to cause internal distortion in the analyzer so any distortion that is displayed is present on the input signal.
96 Chapter 5
Figure 5-22 No Harmonic Distortion
Spectrum Analyzer
Making Distortion Measurements
Chapter 5 97
Spectrum Analyzer
Making Distortion Measurements
NOTE
Figure 5-23
Third-Order Intermodulation Distortion
Two-tone, third-order intermodulation distortion is a common test in communication systems. When two signals are present in a non-linear system, they can interact and create third-order intermodulation distortion products that are located close to the original signals. These distortion products are generated by system components such as amplifiers and mixers.
This procedure tests a device for third-order intermodulation using markers. Two sources are used.
Step 1.
Connect two signal generators, two low pass filters, and a directional coupler to the analyzer input as shown in
. Connect the output of signal generator #1 to port 2 of the directional coupler through one of the low pass filters and connect the output of signal generator #2 to port 3 (the coupled port) of the directional coupler through the remaining low pass filter.
This combination of signal generators, low pass filters, and directional coupler
(used as a combiner) results in a two-tone source with very low intermodulation distortion. Although the distortion from this setup may be better than the specified performance of the analyzer, it is useful for determining the TOI performance of the source/analyzer combination. After the performance of the source/analyzer combination has been verified, the device-under-test (DUT) (for example, an amplifier) would be inserted between the directional coupler output and the analyzer input.
The coupler should have a high degree of isolation between the two input ports so the sources do not intermodulate.
Third-Order Intermodulation Equipment Setup
Step 2.
Set the signal sources as follows:
Set signal generator #1 to 295 MHz at –5 dBm. Set signal generator #2 to
98 Chapter 5
Spectrum Analyzer
Making Distortion Measurements
296 MHz at 11 dBm (this higher power level overcomes the nominal 16 dB loss through the coupled arm of the directional coupler). This will result in a frequency separation of 1 MHz.
The amplitude of both signals should be approximately
5 dBm at the output of the bridge.
Step 3.
Set the analyzer center frequency and span:
Press
Mode Preset
.
Press
FREQ Channel
,
Center Freq
, 295.5,
MHz
.
Press
SPAN X Scale
,
Span
, 5,
MHz
.
Press
AMPTD Y Scale
,
Elec Atten
, 10,
dB
.
Step 4.
Reduce the RBW until the distortion products are visible:
Press
BW
,
Res BW
(Manual),
Step 5.
Move the signal to the reference level:
Press
Peak Search
,
Marker
,
Mkr
RL
.
Step 6.
Calculate the attenuator setting required for a –30 dBm mixer level based upon the current reference level setting: Atten = Ref Level – (–30 dBm)
Press
AMPTD Y Scale
,
Elec Atten
, enter the attenuation value for the calculation above and press
dB
.
Step 7.
Reduce the RBW until the distortion products are visible:
Press
BW
,
Res BW
(Manual),
Step 8.
Turn on averaging to increase the visibility of the distortion products:
Press
Avg Mode
,
Exponential
,
Avg Number
, 10,
Enter
.
Step 9.
Activate the second marker and place it on the peak of the distortion product
(beside the test signal) using the
Next Peak
key.
Press
Peak Search
,
Marker
,
Delta
,
Peak Search
,
Next Peak
(active marker should be on the other input signal),
Next Peak
(active marker should be on a distortion product).
Step 10.
Measure the other distortion product:
Press
Next Peak
. (see
)
Chapter 5 99
Figure 5-24
Spectrum Analyzer
Making Distortion Measurements
Measuring the Distortion Product
100 Chapter 5
Spectrum Analyzer
Using the Analyzer as a Fixed Tuned Receiver
CAUTION
Using the Analyzer as a Fixed Tuned Receiver
This section provides information on using the analyzer as an AM receiver to measure modulation parameters.
This section includes the following measurement:
“Measuring the Modulation Rate of an AM Signal” on page 101
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Basic Assumption
The material in this section is presented with the assumption that you understand the front and rear panel layout, and display annotations of your analyzer. If you do not, refer to the Measurement Guide “Front and Rear Panel Features”.
Figure 5-25
Measuring the Modulation Rate of an AM Signal
This section demonstrates how to determine parameters of an AM signal, such as modulation rate and modulation index (depth) by using frequency and time domain
measurements (refer to the concepts chapter in the Measurement Guide “AM and
FM Demodulation Concepts” on page 197 for more information).
To obtain an AM signal, you can either connect a source transmitting an AM signal, or connect an antenna to the analyzer input and tune to a commercial AM broadcast station. For this demonstration an RF source is used to emulate an AM signal.
Step 1.
Connect the RF Output of the signal generator to the analyzer RF Input as shown
Setup for AM Demodulation Measurement
Step 2.
Set the Agilent ESG RF signal source frequency to 300 MHz and the amplitude to
10 dBm. Set the AM depth to 80%, the AM rate to 1 kHz and turn AM on.
Step 3.
Select the spectrum analyzer mode:
Chapter 5 101
Spectrum Analyzer
Using the Analyzer as a Fixed Tuned Receiver
NOTE
Press
Mode
,
Spectrum Analyzer
.
Step 4.
Preset the analyzer.
Press
Mode Preset
.
Step 5.
Set the center frequency, span, RBW and the sweep time.
Press
FREQ Channel
,
Center Freq
, 300,
MHz
.
Press
SPAN X Scale
,
Span
, 500,
kHz
.
Press
BW
,
Res BW
, 30,
kHz
.
Step 6.
Set the y-axis units to volts:
Press
AMPTD Y Scale
,
More
,
Y-Axis Units
,
Volts
.
Step 7.
Position the signal peak near the reference level:
Press
AMPTD Y Scale
,
Ref Level
, (rotate front-panel knob).
Step 8.
Change the y-scale type to linear:
Press
AMPTD Y Scale
,
Scale Type
(Lin).
Step 9.
Set the analyzer in zero span to make time-domain measurements:
Press
SPAN X Scale
,
Zero Span
.
Press
Control/Sweep
,
Sweep Time
, 5,
ms
.
Step 10.
Use the video trigger to stabilize the trace:
Press
Meas Setup
,
Trigger
,
Video
. Adjust the trigger level by using knob for a stable trace.
Since the modulation is a steady tone, you can use video trigger to trigger the analyzer sweep on the waveform and stabilize the trace, much like an oscilloscope.
See
.
If the trigger level is set too high or too low when video trigger mode is activated, the sweep stops. You need to adjust the trigger level up or down with the front-panel knob until the sweep begins again.
Step 11.
Measure the AM rate using delta markers:
Press
Peak Search
,
Marker
,
Delta
,
Peak Search
,
Next Pk
.
Use markers and delta markers to measure the AM rate. Place the marker on a peak and then use a delta marker to measure the time difference between adjacent peaks
(this is the AM rate of the signal)
102 Chapter 5
Spectrum Analyzer
Using the Analyzer as a Fixed Tuned Receiver
NOTE
Figure 5-26
Make sure the delta markers above are placed on adjacent peaks. See Figure 5-26 .
The frequency or the AM rate is 1 divided by the time between adjacent peaks:
AM Rate = 1/1.0 ms = 1 kHz
Measuring Time Parameters
You can also use the marker inverse time readout to calculate AM rate in Hz. Press
Marker
,
More 1 of 2
,
Marker Readout
,
Inverse Time
. Then put the markers properly on adjacent peaks.
Chapter 5 103
Spectrum Analyzer
Channel Power
Channel Power
Figure 5-27
Measuring Signals Using the Channel Power Measurement
You may want to measure the total power of a signal that occupies some bandwidth. The channel power measurement is used to measure the total (channel) power in a selected bandwidth. However, if you are not certain of the characteristics of the signal, or if there are discrete spectral components in the band of interest, you can use the channel power measurement. This example uses the analyzer to measure channel power of standard W-CDMA signal at 1 GHz. The
Agilent ESG is used for generating the W-CDMA signal.
Step 1.
Connect the RF Output of the signal generator to the analyzer RF Input as shown in
.
Setup for Channel Power Measurement
Step 2.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer
.
Step 3.
Preset the analyzer:
Press
Mode Preset
.
Step 4.
Set the center frequency:
Press
FREQ Channel
,
Center Freq
,
1
,
GHz
.
Step 5.
Start the channel power measurement:
Press
Meas
,
Channel Power
.
Step 6.
Set the integration BW:
Press
Meas Setup, Integ BW, 5, MHz
.
Step 7.
Configure the display to show the combined spectrum view with bar graph (span highlighted in blue):
Press
View/Display
,
Bar Graph
(On).
104 Chapter 5
Spectrum Analyzer
Channel Power
Step 8.
To adjust the measurement settings, press
Meas Setup
, then:
1.
Averaging: To set the averaging
On
or
Off
, switch the
Avg Number
key between
On
and
Off
. When averaging is
On
, enter the number of results used in the averaging calculations. The default average setting is
Off
and the default number is 10 when averaging is
On
. If your input signal changes during the average period, wait until the averaging has completed or the next averaging period has started.
2.
Averaging Mode: To change the average mode, press the
Avg Mode
key and select
Exponential
or
Repeat
. The default average mode is
Repeat
.
3.
RRC Filter: Press
More 1 of 2, RRC Filter
to turn the Root Raised Cosine filter
On
or
Off
.
4.
Filter BW: Press
More 1 of 2, Filter BW
to set the Root Raised Cosine filter bandwidth.
5.
Filter Alpha: Press
More 1 of 2, Filter Alpha
to set the alpha value for the Root
Raised Cosine filter.
6.
Meas Preset: Press
More 1 of 2, Meas Preset
to set the default value.
7.
Limits: To set limit settings, press
Limits
:
Press
Upper Limit
to switch the upper limit between
On
and
Off
, the trace points within the Integ BW are checked to see if they are less than Total Pwr
Ref + Upper Limit. If all the points are less than this value, the upper limit test is passed. If any point is greater than the limit, the test is failed.
Press
Lower Limit
to switch the lower limit between
On
and
Off
, the trace points within the Integ BW are checked to see if they are greater than Total Pwr
Ref + Lower Limit. If all the points are greater than this value, the lower limit test is passed. If any point is less than the limit, the test is failed.
Press
Total Pwr Ref
to set the absolute power value for computing the limit.
When set to
Auto
, the total power reference is the measured channel power value. When set to
Man
, the result takes on the last measured value or you can enter the value manually.
Chapter 5 105
Figure 5-28
Spectrum Analyzer
Channel Power
Channel Power measurement
NOTE
When Upper Limit or Lower Limit is set to On, a status bar in the top left corner of the display will show whether the measurement result has passed or failed the limit test.
106 Chapter 5
NOTE
Spectrum Analyzer
Occupied Bandwidth (OBW) Measurement
Occupied Bandwidth (OBW) Measurement
Occupied Bandwidth integrates the power of the displayed spectrum and puts markers at the frequencies between which a selected percentage of the power is contained. The measurement defaults to 99% of the occupied bandwidth power.
The power-bandwidth routine first computes the combined power of all signal responses contained in the trace. For 99% occupied power bandwidth, markers are placed at the frequencies on either side of 99% of the power. This would leave 1% of the power evenly distributed outside the markers. The frequency difference between the two markers is the displayed occupied bandwidth. The difference between the marker frequencies is the 99% power bandwidth and is the value displayed.
The Occupied BW result corresponds to a span between the markers and is a multiple of the span between two points. So, for a 10 MHz span, the OBW will come in multiples of 25 kHz (10 MHz divided by 400 display points). Values will be 25 kHz, 50 kHz, 75 kHz, etc. For narrow signals (TDMA, PDC, etc.) you will need to zoom in on the signal to get a reasonably accurate Occupied BW result.
For a 100 kHz span, the OBW resolution will be 250 Hz (100 kHz divided by 400 display points).
The occupied bandwidth measurement can be made in single or continuous sweep mode. The center frequency and reference level may be set by you.
Zero-span is disabled in OBW measurement.
Chapter 5 107
Spectrum Analyzer
Occupied Bandwidth (OBW) Measurement
108 Chapter 5
Spectrum Analyzer
Occupied Bandwidth (OBW) Measurement
Making a Basic Occupied BW Measurement
NOTE
Figure 5-29
For accurate OBW measurements, it is recommended that you use the sample or average trace detectors. The default detector type is sample. In addition, you should use Exponential Average or Repeat Average with 100 or more averages.
The following example shows how to make an OBW measurement on a GSM signal broadcasting at 950 MHz.
Step 1.
Connect the RF Output of the signal generator to the analyzer RF Input as shown
Setup for OBW Measurement
Step 2.
Set a GSM signal on the signal generator with a frequency of 950 MHz a nd the amplitude set to
10 dBm.
Step 3.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer
.
Step 4.
Preset the analyzer:
Press
Mode Preset
.
Step 5.
Set the center frequency and span:
Press
FREQ Channel
,
Center Frequency
, 950,
MHz
.
Press
SPAN X Scale
,
Span
, 1,
MHz
Step 6.
Select Spectrum Analyzer Occupied BW measurement.
Press
Meas
,
Occupied BW
.
A marker pair will appear on the trace and the occupied bandwidth value and the integrated power in the OBW are displayed in the data window below the trace
Chapter 5 109
Figure 5-30
Spectrum Analyzer
Occupied Bandwidth (OBW) Measurement
OBW Measurement Results
NOTE
NOTE
Step 7.
You can improve the repeatability of the measurements by setting the Average number to 100 or greater:
Press
Meas Setup
,
Avg Number
, 100,
Enter
,
Trace/Detector
,
Trace Average
.
Step 8.
You can change the percentage of power used for calculating the Occupied BW.
The default percentage is 99%.
Press
Meas Setup
,
Power
, 80,
%
.
If you are measuring a narrow signal such as TDMA or PDC, zoom in on the signal for a more accurate OBW results.
Press
SPAN X Scale
,
Span
, enter the frequency using the number keypad, and then press
Hz
,
kHz
,
MHz
, or
GHz
.
For an over the air measurement, connect an antenna and an external filter to the
RF input.
The external filter is necessary to eliminate out-of-band signals that would otherwise reduce the dynamic range of measurements in the band of interest. The effect of the out-of-band signals is to raise the noise floor, possibly hiding some or all of the signal of interest. However, the external filter is optional in this set up:
If you want to limit your search to a specific band of interest, you should use the filter.
If you want to search beyond a specific band, then you can leave the filter off.
110 Chapter 5
Spectrum Analyzer
Using the Spectrogram View (Requires Option 271)
Using the Spectrogram View (Requires Option 271)
This section provides information on making a measurement using the
Spectrogram View.
This section includes the following measurement:
“Spectrogram View Basics” on page 111
“A Spectrogram Measurement Using the OBW Measurement” on page 111
Spectrogram View Basics
The Spectrogram view is available in the Spectrum Analyzer mode only. You can use it with measurements turned off (basic spectrum analyzer) or with the available spectrum analyzer measurements listed in the measurement menu, such as the
Occupied BW measurement.
Troubleshooting a transmitter system is often aided by examining the time evolution of the power distribution.This view provides a history of the spectrum.
You can use it to:
•
•
• locate intermittent signals track signal levels over time.
You may set the following parameters for this view:
Update Interval: Allows you to set the update interval to 1 or more seconds.
Or, you may set it to automatically determine the capture interval that provides the maximum data collection speed.
•
•
A data sample is taken every n th
trace for display on the spectrogram.
Increasing the capture time allows data capturing over a longer period of time in the spectrogram. However, it is a sampling technique that allows intermittent events, which occur between samplings, to be lost. Therefore, if you are searching for intermittent signals, consider using Repeat Max Hold average type in conjunction with increasing the capture time.
Frame Skip: Allows you to set the number of frames you would like to skip when capturing data. You may set this value from skip 0 to 2,147,483,647 frames. Increasing the frame skip value causes the display to redraw the spectrum every n th
trace and a block of lines are shown at once instead of a single line at a time. Higher frame skip values are for use with fast measurements.
Palette: Allows you to set the display to full color or grayscale.
A Spectrogram Measurement Using the OBW Measurement
The following procedure is an example of a Spectrogram measurement using the
Chapter 5 111
Spectrum Analyzer
Using the Spectrogram View (Requires Option 271)
Spectrum Analyzer mode Occupied Bandwidth (OBW) measurement.
Figure 5-31
Performing a Spectrogram Measurement
Step 1.
Connect the RF Output of the signal generator to the analyzer RF Input as shown in
.
Setup for OBW Measurement
Step 2.
Set a GSM signal on the signal generator with a frequency of 950 MHz a nd the amplitude set to
10 dBm.
Step 3.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer
.
Step 4.
Preset the analyzer:
Press
Mode Preset
.
Step 5.
Set the center frequency and span:
Press
FREQ Channel
,
Center Frequency
, 950,
MHz
.
Press
SPAN X Scale
,
Span
, 1,
MHz
Step 6.
Set the number of averages to 25 and turn on averaging.:
Press
Meas Setup
,
Avg Number
, 25,
Enter
.
Press
Trace/Detector
,
Trace Average
Step 7.
Select Spectrum Analyzer Occupied BW measurement.
Press
Meas
,
Occupied BW
.
A marker pair will appear on the trace and the occupied bandwidth value and the integrated power in the OBW are displayed in the data window below the trace graticule. See
112 Chapter 5
Figure 5-32
Spectrum Analyzer
Using the Spectrogram View (Requires Option 271)
OBW Measurement Results – Normal View
Step 8.
To switch to the Spectrogram view:
Press
Spectrogram
,
Spectrogram
(until ON is underlined), 100,
Enter
,
Trace/Detector
,
Trace Average
.
The OBW measurement results display will now be similar to Figure 5-33
Step 9.
If you need to restart the data capture:
Press
Reset Spectrogram
.
Step 10.
If desired set the capture interval:
Press
Update Interval
,
Enter the interval number using the number keypad.
Select
sec
or
Max Speed
.
Max Speed
displays every trace captured.
Step 11.
If you want to set the number of frames to skip:
Press
Frame Skip
Enter the interval number using the number keypad.
Select
frames
.
Step 12.
If you want to set the display color:
Press
Palette
Select
Full Color
or
Grayscale
.
The color/grayscale top and bottom mappings are determined by the Ref Level and
Scale/Div settings. To change the mapping, go to
AMPTD Y Scale
and change
Ref
Level
and
Scale/Div
.
Chapter 5 113
Figure 5-33
Spectrum Analyzer
Using the Spectrogram View (Requires Option 271)
OBW Measurement Results – Spectrogram View
NOTE
In the picture, the elapsed time clock shows the amount of time shown on the graph and stops when the graph is full.
You can also place the markers (the two vertical lines) as shown to see the amplitude change of the specific frequency you care.
114 Chapter 5
Spectrum Analyzer
Pulse Measurement
Figure 5-34
Pulse Measurement
In order to make better measurements of signals whose spectrum varies rapidly with time, such as pulsed signals, For firmware A.02.00 or greater, you can have sweep time control in non-zero spans. This example uses the analyzer to measure the pulsed signal at 100 MHz with period of 20 us and width of 4 us.
Step 1.
Setup the pulsed signal using the signal generator Agilent ESG and connect the RF
Output of the signal generator to the analyzer RF Input as shown in
Setup for Pulse Measurement
NOTE
Step 2.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer
.
Step 3.
Preset the analyzer:
Press
Mode Preset
.
Step 4.
Set the center frequency:
Press
FREQ Channel
,
Center Freq
,
100
,
MHz
.
Step 5.
Set the spectrum analyzer to zero span:
Press
SPAN X Scale
,
Zero Span
.
Step 6.
Set the Resolution BW:
Press
BW
(Manual)
, 5, MHz
.
The larger the Resolution BW, the more power will pass through the Res
BW filter, so the less distortion of the pulse signal there will be. Similarly, more noise will pass through the filter, so the displayed average noise floor will be higher. The setting of Res BW is therefore an important factor in determining your measurement results.
Step 7.
Set the sweep time:
Chapter 5 115
Spectrum Analyzer
Pulse Measurement
NOTE
NOTE
Figure 5-35
Press
Control/Sweep, Sweep Time, 50, us
.
Step 8.
Set the vertical scale:
Press
AMPTD Y Scale
,
Autoscale
.
You can set Ref Level, Scale/Div to adjust the AMPTD Y Scale display. For more information on this front panel key, please see the User’s and Programmer’s
Reference Manual.
Step 9.
To adjust the trigger settings, press
Meas Setup
,
Trigger
and select the trigger mode
Free Run
,
Video
(unfiltered),
External
and
RF Burst
.
The primary difference between the trigger mode Video and RF Burst is trigger bandwidth. The RF Burst trigger has a bandwidth that is >50 MHz, while the
Video has <5 MHz. For measuring pulses using Video Trigger, you may also have to enable Auto Trigger (press
Trigger
,
More 1 of 2
,
Auto Trig
) with a time greater than the pulse period.
Pulse Measurement
NOTE
For more information of each soft key under Meas Setup menu, you can refer to spectrum analyzer section of User’s and Programmer’s Reference manual.
116 Chapter 5
Spectrum Analyzer
Tune and Listen (Requires Option AFM)
NOTE
Tune and Listen (Requires Option AFM)
AM/FM Tune and Listen demodulates at the frequency of interest to permit audible detection of AM or FM modulated signals. This example uses the analyzer to listen to a FM radio signal at 97.4 MHz.
Step 1.
Select the spectrum analyzer mode:
Press
Mode
,
Spectrum Analyzer
.
Step 2.
Set the center frequency:
Press
FREQ Channel
,
Center Freq
,
97.4
,
MHz
.
Step 3.
Set the span:
Press
SPAN X Scale
,
10
,
MHz
Step 4.
Set the demodulation type at marker place:
Press
Demod
,
Demod at Marker Type
,
FM
.
Step 5.
Set the demodulation at marker:
Press
Demod
,
Demod at Marker, On
.
Step 6.
Set the demodulation time:
Press
Demod
,
Demod Time
,
50
,
s
.
Set the demodulation time longer to listen to continuous voice material such as from a broadcast station. Set the demodulation time shorter (less than 5 seconds) to listen to two-way radio transmissions.
You can use the three keys below the screen in the front panel to mute, decrease the volume or increase the volume.
Chapter 5 117
Spectrum Analyzer
Tune and Listen (Requires Option AFM)
118 Chapter 5
6
Channel Analyzer Measurements
119
CAUTION
Channel Analyzer Measurements
This chapter provides information on measuring signal power.
This chapter includes the following measurement:
“Making Adjacent Channel Power (ACP (I&M)) Measurements” on page 121
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Basic Assumption
The material in this chapter is presented with the assumption that you understand the front and rear panel layout, and display annotations of your analyzer. If you do not, refer to the Measurement Guide “Front and Rear Panel Features”.
120 Chapter 6
Channel Analyzer Measurements
Making Adjacent Channel Power (ACP (I&M)) Measurements
CAUTION
CAUTION
NOTE
Making Adjacent Channel Power (ACP (I&M))
Measurements
Adjacent Channel Power (ACP (I&M)) is a measure of the power that leaks into adjacent transmit channels. The ACP measurements, as currently implemented, are suitable for quick checks in installation and maintenance (I&M) applications. They are not necessarily suitable for ACP measurements in manufacturing or R & D applications.
The adjacent channel power (ACP (I&M)) measurement is also referred to as the adjacent channel power ratio (ACPR) and adjacent channel leakage ratio (ACLR).
We use the term ACP to refer to this measurement.
ACP measures the total power (rms voltage) in the specified channel and up to three pairs of offset frequencies. The measurement result reports the ratios of the offset powers to the main channel power.
The measurement results can help you determine whether the power is set correctly and whether the transmitter filter is working properly. Once you have set the limits, you can easily see whether a test falls within those limits using the mask feature and the color-coded metrics. You can measure the adjacent channel power on one to three adjacent channels on each side of your center channel in the
CDMA, TDMA, UMTS (W-CDMA), GSM EDGE and GPRS, AMPS, NMT-450,
Tetra, and iDEN channel bands.
When measuring multiple adjacent channels, the combined channel power must not exceed +33 dBm at the RF Input.
The maximum power for the RF Input 50
is 33 dBm (2 W). When directly coupled to a transmitter, the analyzer can be damaged by excessive power applied to any of these ports.
To prevent damage in most situations when you directly couple the analyzer to a transmitter, connect a high power attenuator between the analyzer RF Input 50
and the transmitter.
For complex modulation such as CDMA, W-CDMA, GSM, the frequency error measurement is not accurate.
The following example shows how to make an ACP measurement on a simulated
W-CDMA base station signal broadcasting at 1.955 GHz.
Step 1.
Connect the RF Output of the signal generator to the analyzer RF Input 50
as shown in
Chapter 6 121
Figure 6-1
Channel Analyzer Measurements
Making Adjacent Channel Power (ACP (I&M)) Measurements
Setup for ACP Measurement
Figure 6-2
Step 2.
Using the signal generator to setup a W-CDMA signal transmitting at 1.955 GHz and
10 dBm.
Step 3.
Select the channel analyzer mode and the adjacent channel power measurement:
Press
Mode
,
Channel Analyzer
.
Step 4.
Preset the analyzer.
Press
Mode Preset
.
Step 5.
Set the center frequency to 1.955 GHz:
Press
FREQ Channel
,
Center Freq
, 1.955,
GHz
.
Step 6.
Set the analyzer radio mode to W-CDMA as a base station device:
Press
Meas Setup
,
Format/BW
,
Format Type
(List),
Format List
, select W-CDMA sing the up and down arrow buttons, press Select
.
ACP Measurement Results
122 Chapter 6
Channel Analyzer Measurements
Making Adjacent Channel Power (ACP (I&M)) Measurements
Figure 6-3
The frequency offsets, channel integration bandwidths, and span settings can all be modified when you select
Meas Setup
,
Format Type
(Cust).
Step 7.
Turn the limit test on:
Press
Meas Setup
,
Limits
,
Power Limits
,
Power Limits
(On).
ACP Results with Offset Limits
Step 8.
You may set different pass/fail limits for each offset:
Press
Meas Setup
,
Limits
,
Power Limits
,
Center Chan High Limit
,
10,
dBm
,
Center
Chan Low Limit
,
30,
dBm
,
Adj Chan 1 High Limit
,
45,
dB
, and
Adj Chan 2 High Limit
,
60,
dB
.
notice that ACP 2 Low and ACP 2 High have both failed, however all other channels have passed.
Chapter 6 123
Figure 6-4
Channel Analyzer Measurements
Making Adjacent Channel Power (ACP (I&M)) Measurements
Setting Offset Limits
124 Chapter 6
7
Stimulus Response Measurements
(Requires N8995A)
125
CAUTION
Stimulus Response Measurements (Requires N8995A)
This chapter provides information on measuring signal loss in cables and devices and making cable fault measurements.
This chapter is divided into the following sections:
“Two Port Insertion Loss” on page 127
“One Port Insertion Loss” on page 130
“Distance to Fault” on page 138
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Basic Assumption
The material in this chapter is presented with the assumption that you understand the front and rear panel layout, and display annotations of your analyzer. If you do not, refer to the Measurement Guide “Front and Rear Panel Features”.
126 Chapter 7
Stimulus Response Measurements (Requires N8995A)
Two Port Insertion Loss
NOTE
Two Port Insertion Loss
This procedure measures the loss or gain of a filter, amplifier, cable, or other devices over a specified frequency range.
Insertion loss measurements are important in accurately quantifying the amount of loss or gain a signal will incur as it passes through a device. In S-parameter terms, insertion loss is referred to as an S
21
measurement. “S” stands for scattering.
Before you perform a two port insertion loss measurement, you must first normalize the measured values for insertion loss by compensating for the loss associated with the devices (adapters, cables) that connect the analyzer to the device or assembly being tested. Otherwise, your measurement will be inaccurate.
CAUTION
Note that in step 6 on page 127
, excessive signal input may damage the DUT. Do not exceed the maximum power that the device under test can tolerate.
NOTE
CAUTION
DO NOT make the connection at this time. You will be directed when to make the connections later in the procedure.
Step 1.
To measure the rejection of a low pass filter, connect the RF Output of the analyzer to the RF Input.
This example uses a 50 MHz low pass filter as the DUT.
Step 2.
Set the analyzer to the Two Port Insertion Loss measurement:
Press
Mode
,
Stimulus/Response
,
Meas
,
Two Port Insertion Loss
Step 3.
Preset the analyzer:
Press
Mode Preset
.
Step 4.
Set the start and stop frequencies:
Press
FREQ Channel
,
Start Freq
, 10,
MHz
.
Press
FREQ Channel
,
Stop Freq
, 250,
MHz
.
Step 5.
Turn averaging off:
Press
Meas Setup
,
Avg Mode, Off
.
Step 6.
Set the signal source output power of analyzer to –15 dBm:
Press
Source
,
Source Level
(Manual), –15,
dBm
.
Excessive signal input may damage the DUT. Do not exceed the maximum power that the device under test can tolerate.
Chapter 7 127
Stimulus Response Measurements (Requires N8995A)
Two Port Insertion Loss
NOTE
In this step, the Source Level is set to Manual. In Manual mode, the output level can be set to any value between –15 dBm and –30 dBm and the output level will vary typically <+/-1 dB from the value selected. If Source Level is set to Auto, the output power level will be set to the maximum available at any given frequency.
The output power may vary from 0 dBm to –15 dBm when set to Auto. The user cannot control the nominal output power when Source Level is set to Auto.
Figure 7-1
Step 7.
Connect the cable (but not the DUT) from the analyzer RF Output to the RF Input as shown in
.
Two Port Insertion Loss Normalization Test Setup
NOTE
Step 8.
Normalize the frequency response:
Press
FREQ Channel
,
Normalize
and follow the instructions on the Normalize
Wizard.
After normalization, the word “UnNormalized” on the top left of the screen will turn to “Normalized”.
The normalization is needed each time you change the frequency setting.
Step 9.
To measure the rejection of a low pass filter:
Connect the DUT between the RF Input and RF Output of the analyzer as shown in
.
Note that the units of the reference level are dB, indicating that this is a relative measurement.
128 Chapter 7
Figure 7-2
Stimulus Response Measurements (Requires N8995A)
Two Port Insertion Loss
Two Port Insertion Loss Measurement Test Setup
Step 10.
Place the reference marker at the specified cutoff frequency:
Press
Marker
,
Normal
, 50,
MHz
.
Step 11.
Place the second marker at 100 MHz:
Figure 7-3
Press
Delta
, 50,
MHz
.
In this example, the attenuation over this frequency range is 66.9 dB/octave (one octave above the cutoff frequency).
Step 12.
Use the front-panel knob to place the marker at the highest peak in the stop band to determine the minimum stop band attenuation. In this example, the peak occurs at
102.589 MHz. The attenuation is 63.2 dB.
Minimum Stop Band Attenuation
Chapter 7 129
NOTE
Stimulus Response Measurements (Requires N8995A)
One Port Insertion Loss
One Port Insertion Loss
The one port insertion loss measurement allows you to quantify signal loss in a cable or other device without connecting both ends of the cable or device to the analyzer. This measurement can be especially useful in measuring the loss of a feedline connected to the antenna on a tower. This method of measuring insertion loss is accurate for results up to 10 dB.
This measurement is less accurate than Two Port Insertion Loss. When it is practical to connect both ends of a device to the analyzer or for insertion loss measurements greater than 10 dB — for example when measuring a 40 dB attenuator — it is better to use Two Port Insertion Loss.
Test signals can cause interference. When testing cables attached to antennas, test signals are radiated. Verify that the signal used for the test cannot cause interference to another antenna.
Calibration - Minimizing your Workload
The One-Port Insertion Loss calibration is the same calibration as performed for the Return Loss and Distance to Fault (when it is performed with Frequency
Range set to manual) measurements. If you have already calibrated for any of these three measurements, the calibration will apply to the other two measurements and “Calibrated”, together with the frequency range over which the calibration was performed, will be displayed on top left of the screen, indicating the user calibration data is used.
If you have not previously performed a calibration, the word “Factory Calibration” appears at the top left of the measurement screen, indicating the factory calibration data is used.
It is important that you keep the calibration frequency range as close as possible to the actual sweep frequencies you intend using for the measurement or measurements. Calibrating over a large frequency range (for example, 1 GHz) when you only intend measuring over a much smaller range (a few MHz, for example) will induce inaccuracies in your results. Furthermore, even if the measurement frequency range is a subset of the calibration frequency range, the calibration data can be disregarded if the calibration frequency step (calibration frequency range / 255) is greater than the factory calibration frequency step (2.926
MHz). In such cases, the factory calibration data will be used.
If you plan to perform a combination of One-Port Insertion Loss measurement,
Return Loss measurement, and Distance to Fault measurements using a frequency range that you will set manually, you can perform one calibration for all three measurements as long as you calibrate over a frequency range that incorporates all three of your measurements, your cables do not change, and the calibration frequency step is not greater than that of the factory calibration. For this reason, if you are doing Distance to Fault measurements (using a frequency range that you
130 Chapter 7
NOTE
Stimulus Response Measurements (Requires N8995A)
One Port Insertion Loss
have set manually) as well as any type of Insertion Loss measurement, Agilent recommends that you select your cable type before performing calibrations. Press
Mode
,
Stimulus/Response
,
Meas
,
Distance to Fault
,
Meas Setup
,
Cable Type
to set the cable type.
The calibration remains valid until you do any one of the following:
•
•
•
•
•
•
•
• set the Distance to Fault frequency range to Auto. Note that the calibration will become valid again as soon as you switch from Auto back to Manual
Frequency Range power off the analyzer change the start frequency to a new value that lies below the start frequency of your previous calibration change the stop frequency to a new value that lies above the stop frequency of your previous calibration change the start or stop frequency when the calibration frequency step is greater than the factory calibration frequency step change any of the cables that you used for the calibration change any of the (optional) attenuators that might have been used for the calibration change the type of cable specified under the
Cable Type
menu key
Performing a One Port Insertion Loss Measurement
DO NOT make the connection at this time. You will be directed when to make the connections later in the procedure.
Step 1.
Connect the calibrating devices to the analyzer RF Output when prompted in the procedure, as shown in
Figure 7-4 , or as shown in the calibration wizard.
To calibrate your spectrum analyzer, you will need the following calibration kit:
•
•
Open/Short connector.
Calibrated 50 ohm Load connector.
This example uses a 10 feet cable as the DUT.
Chapter 7 131
Figure 7-4
Stimulus Response Measurements (Requires N8995A)
One Port Insertion Loss
One Port Insertion Loss Measurement
Step 2.
Set the analyzer to the One Port Insertion Loss measurement:
Press
Mode
,
Stimulus/Response
,
Meas
,
One Port Insertion Loss
Step 3.
Preset the analyzer:
Press
Mode Preset
,
Meas
,
One Port Insertion Loss
.
Step 4.
Set the start and stop frequencies:
Press
FREQ Channel
,
Start Freq
, 100,
MHz
.
Press
FREQ Channel
,
Stop Freq
, 500,
MHz
.
Step 5.
Turn averaging off:
Press
Meas Setup
,
Avg Mode
,
Off
.
Step 6.
Calibrate the measurement:
Press
FREQ Channel
,
Calibrate
and follow the instructions on the Calibration
Wizard. The analyzer will calibrate over the desired frequency range.
Step 7.
Connect the DUT to the analyzer, as described in step 1 . Note that the units of the
reference level are dB, indicating that this is relative measurement.
Step 8.
Change the amplitude scale to 1 dB per division:
Press
AMPTD Y Scale
,
Scale/Div
, 1,
dB
.
Step 9.
Place a marker on the results at the frequency of interest. In this example, the marker is placed at 299.216 MHz. As you can see the loss is 0.8 dB.
132 Chapter 7
Figure 7-5
Stimulus Response Measurements (Requires N8995A)
One Port Insertion Loss
One Port Insertion Loss Measurement Results, Normalized.
Chapter 7 133
NOTE
Stimulus Response Measurements (Requires N8995A)
Return Loss
Return Loss
Return loss is a measure of reflection characteristics. One way you can use the return loss measurement is to detect problems in an antenna feedline system or the antenna itself. A portion of the incident power will be reflected back to the source from each transmission line fault as well as the antenna. The ratio of the reflected voltages to the incident voltage is called the reflection coefficient. The reflection coefficient is a complex number, meaning it has both magnitude and phase information. In S-parameter terms, Return Loss is referred to as an S
11 measurement.
Test signals can cause interference. When testing cables attached to antennas, test signals are radiated. Verify that the signal used for the test cannot cause interference to another antenna.
Calibration - Minimizing your Workload
The Return Loss calibration is the same calibration as performed for the Distance
to Fault and One-Port Insertion Loss (when it is performed with Frequency Range set to manual) measurements. If you have already calibrated for any of these three measurements, the calibration will apply to the other two measurements and
“Calibrated”, together with the frequency range over which the calibration was performed, will be displayed on top left of the screen, indicating the user calibration data is used.
If you have not previously performed a calibration, the word “Factory Calibration” appears at the top left of the measurement screen, indicating the factory calibration data is used.
It is important that you keep the calibration frequency range as close as possible to the actual sweep frequencies you intend using for the measurement or measurements. Calibrating over a large frequency range (for example, 1 GHz) when you only intend measuring over a much smaller range (a few MHz, for example) will induce inaccuracies into your results. Furthermore, even if the measurement frequency range is a subset of the calibration frequency range, the calibration data can be disregarded if the calibration frequency step (calibration frequency range / 255) is greater than the factory calibration frequency step (2.926
MHz). In such cases, the factory calibration data will be used.
If you plan to perform a combination of One-Port Insertion Loss measurement,
Return Loss measurement, and Distance to Fault measurements using a frequency range that you will set manually, you can perform one calibration for all three measurements as long as you calibrate over a frequency range that incorporates all three of your measurements, your cables do not change, and the calibration frequency step is not greater than that of the factory calibration. For this reason, if you are doing Distance to Fault measurements (using a frequency range that you have set manually) as well as any type of Insertion Loss measurement, Agilent recommends that you select your cable type before performing calibrations. Press
134 Chapter 7
Stimulus Response Measurements (Requires N8995A)
Return Loss
Mode
,
Stimulus/Response
,
Meas
,
Distance to Fault
,
Meas Setup
,
Cable Type
to set the cable type.
The calibration remains valid until you do any one of the following:
•
•
•
•
•
•
•
• set the Distance to Fault frequency range to Auto. Note that the calibration will become valid again as soon as you switch from Auto back to Manual
Frequency Range power off the analyzer change the start frequency to a new value that lies below the start frequency of your previous calibration change the stop frequency to a new value that lies above the stop frequency of your previous calibration change the start or stop frequency when the calibration frequency step is greater than the factory calibration frequency step change any of the cables that you used for the calibration change any of the (optional) attenuators that might have been used for the calibration change the type of cable specified under the
Cable Type
menu key
Performing a Return Loss Measurement
Step 1.
Set the analyzer to the Stimulus/ Response Mode and the Return Loss measurement:
Press
Mode
,
Stimulus/Response, Meas, Return Loss
Step 2.
Preset the analyzer:
Press
Mode Preset, Meas, Return Loss
.
Step 3.
Set the start and stop frequencies:
This example uses a 50 MHz low pass filter as the DUT.
Press
FREQ Channel
,
Start Freq
, 10,
MHz
.
Press
FREQ Channel
,
Stop Freq
, 250,
MHz
.
Step 4.
Turn averaging off:
Press
Meas Setup
,
Avg Mode
,
Off
.
Step 5.
Calibrate the measurement:
Press
FREQ Channel
,
Calibrate
and follow the instructions on the Calibration
Wizard. The analyzer will calibrate over the desired frequency range.
To calibrate your spectrum analyzer, you will need the following calibration kit:
Chapter 7 135
Stimulus Response Measurements (Requires N8995A)
Return Loss
Figure 7-6
•
Open/short connector.
•
Calibrated 50 ohm Load connector.
Step 6.
Connect the test cable (if used) and calibration devices to the analyzer RF Output, as shown in
, or in the calibration wizard. (If the DUT is a two-port device, be sure to terminate the unused port in the characteristic impedance of the device.)
This example uses a 50 MHz low pass filter as the DUT.
Note that the units of the reference level are dB, indicating that this is a relative measurement.
Return Loss Measurement
Step 7.
Change the reference level.
Press
AMPTD Y Scale
,
Ref Level
, -5,
dB
.
Step 8.
Use the markers to measure the return loss and SWR at any point.
Press
Marker
,
Normal
. Use the knob to place the marker at a frequency of interest.
136 Chapter 7
Figure 7-7
Stimulus Response Measurements (Requires N8995A)
Return Loss
Return Loss Measurement Results, Calibrated.
Chapter 7 137
Stimulus Response Measurements (Requires N8995A)
Distance to Fault
Distance to Fault
A signal is transmitted from the RF Output connector of the analyzer to the cable-under-test. The signals reflected from faults in the cable are received by the analyzer.
In performing this measurement, the analyzer uses frequency domain reflectometry. The changing interference of the transmitted and reflected signals contains information about the distance to one or more faults. This information can be used to find the physical distance to the faults. The distance displayed on the analyzer is the physical distance to the probable faults, corrected for the cable loss and velocity factor of the cable.
Measured Distance - the Effects of Frequency and Points
It is not always obvious how frequency range affects measured distance and resolution, and it often appears to be counter-intuitive. If you are new to making
Distance to Fault measurements, this section will help clarify what is happening.
In the following equations
•
The Speed of Light (‘c’) is a constant value of 3 x 10
8
meters per second.
•
Your test cable’s transmission speed (relative to light) is V
Rel
The
Measured Distance
(in meters) of the DTF (Distance to Fault) measurement is determined by the following equation:
Measured Distance (in meters)
=
1
---
4
Number of Points
Frequency Span c
V
Rel
•
•
You can see from this equation that:
To
increase
the measured distance:
— you can
increase
the
number of points
, or
— you can
reduce
the
frequency span
.
To
reduce
the measured distance:
— you can
reduce
the
number of points
, or
— you can
increase
the
frequency span
.
138 Chapter 7
NOTE
NOTE
Stimulus Response Measurements (Requires N8995A)
Distance to Fault
Resolution - the Effects of Frequency and Points
It is not always obvious how frequency range affects measured distance and resolution, and it often appears to be counter-intuitive. If you are new to making
Distance to Fault measurements, this section will help clarify what is happening.
Resolution Distance
(in meters) of the DTF (Distance to Fault) measurement, that is, the shortest distance between two faults that can still be resolved by the analyzer, is determined by the following equation: lution Distance (in meters)
=
Measured Distance (in mete
----------------------------------------------------------------------------
1
2
Number of Points
Please be careful how you interpret this equation. Note that to increase the
resolution, you need to reduce the Resolution Distance; to reduce the resolution, you need to increase the Resolution Distance.
You can see from this equation that:
•
•
To
increase
the resolution, that is, to reduce the Resolution Distance:
— you can
increase
the
number of points
, or
— you can
reduce
the
measured distance
.
To
reduce
the resolution, that is, to increase the Resolution Distance:
— you can
reduce
the
number of points
, or
— you can
increase
the measured distance.
Although you can set your number of points to 256, 512, or 1024, you will only ever be able to save 256 data points when you save trace data. This is because only
256 points are ever used to display the trace, regardless of how many points you have used to actually make the measurement. You will not, however, be losing any resolution, or reducing the quality of your data. The results will still reflect the true number of data points that you specified.
Automatic and Manual Distance to Fault Measurements
•
The analyzer provides two ways of measuring distance to fault:
Automatic Frequency Range. You select the measurement distance and the analyzer automatically selects the
Start Frequency
and the
Stop Frequency
. The measurement distance is set using the
Start Distance
and the
Stop Distance
menu keys on the
Freq/Dist/Calibrate
menu. In this mode, the displayed and measured distances are the same. There are always 256 measurement points across the distance you set, so adjusting the distance settings allows you to
Chapter 7 139
NOTE
Stimulus Response Measurements (Requires N8995A)
Distance to Fault
• display the maximum resolution for the portion of the cable you are testing.
The disadvantage is that the start and stop frequencies are automatically set and may limit the analyzer's ability to sweep through filters or lightning protectors.
This mode is best used for checking a cable that has no frequency limiting devices.
Example 1:
If you set
Start Distance
to 0 m (0 ft) and the
Stop Distance
to 60 m
(197 ft), and you specify 256 Data Points (
Meas Setup
,
FFT Size
,
256
), the instrument automatically selects a
Start Freq
of 10 MHz and a
Stop Freq
of
220.88 MHz.
Example 2:
If you again set
Start Distance
to 0 m (0 ft) and the
Stop Distance
to
60 m (197 ft), but this time you specify 1024 Data Points (
Meas Setup
,
FFT
Size
,
1024
) to give you greater resolution, the instrument automatically selects a
Start Freq
of 10 MHz and a
Stop Freq
of 853.52 MHz.
Manual Frequency Range. When set to
Manual
, you must specify the
Start
Frequency
and the
Stop Frequency
, and the measured distance is computed from these frequencies. Generally, the typical start and stop frequencies you use will result in a measured distance that will be larger than the distance over which you want to look for faults.
The
Measured Distance
and the
Displayed Distance
can be different. The distance over which the instrument has made its measurements, and which has been derived from the frequencies you specified, is called the
Measured Distance
.
This is displayed at the top right corner of the measurement screen.
The
Displayed Distance
refers to that part of the entire
Measured Distance
that you choose to display on your measurement screen. You set the
Displayed
Distance
manually by pressing the
Start Distance
and the
Stop Distance
menu keys on the
Freq/Dist/Calibrate
menu.
To help isolate faults over the length of interest, you can set a displayed distance less than the measured distance. The displayed distance is set using the
Start Distance
and the
Stop Distance
menu keys on the
Freq/Dist/Calibrate
menu.
Keep in mind that there are 256, 512, or 1024 measurement points across the measured distance. The exact number of measurement points is set using the
FFT Size
key on the
Meas Setup
menu. Therefore, the measurement points across the chosen displayed distance will be a ratio of displayed distance to measured distance times the number of points you have specified. The higher the number of data points, the greater the measurement resolution.
In most cases, the default resolution using 256 data points will be adequate to locate the faults, but if more resolution is needed you can increase the span between the start and stop frequencies (which will decrease the measured distance) or use the other approach, automatic frequency range. If the measurement distance is not long enough for the cable you are testing, reduce the span between the start and stop frequencies (which will increase the measurement distance) or use automatic frequency range.
140 Chapter 7
NOTE
Stimulus Response Measurements (Requires N8995A)
Distance to Fault
When testing cables attached to antennas, test signals are radiated from the test antenna Verify that the signal used for the test, and therefore being radiated from the test antenna, cannot interfere with other radiated signals from other antennas.
Calibration - Minimizing your Workload
The Distance to Fault calibration is the same calibration as performed for the
Return Loss and One-Port Insertion Loss (when it is performed with Frequency
Range set to manual) measurements. If you have already calibrated for any of these three measurements, the calibration will apply to the other two measurements and “Calibrated”, together with the frequency range over which the calibration was performed, will be displayed on top left of the screen, indicating the user calibration data is used.
If you have not previously performed a calibration, the word “Factory Calibration” appears at the top left of the measurement screen, indicating the factory calibration data is used.
It is important that you keep the calibration frequency range as close as possible to the actual sweep frequencies you intend using for the measurement or measurements. Calibrating over a large frequency range (for example, 1 GHz) when you only intend measuring over a much smaller range (a few MHz, for example) will induce inaccuracies into your results. Furthermore, even if the measurement frequency range is a subset of the calibration frequency range, the calibration data can be disregarded if the calibration frequency step (calibration frequency range / 255) is greater than the factory calibration frequency step (2.926
MHz). In such cases, the factory calibration data will be used.
If you plan to perform a combination of One-Port Insertion Loss measurement,
Return Loss measurement, and Distance to Fault measurements using a frequency range that you will set manually, you can perform one calibration for all three measurements as long as you calibrate over a frequency range that incorporates all three of your measurements, your cables do not change, and the calibration frequency step is not greater than that of the factory calibration. For this reason, if you are doing Distance to Fault measurements (using a frequency range that you have set manually) as well as any type of Insertion Loss measurement, Agilent recommends that you select your cable type before performing calibrations. Press
Mode
,
Stimulus/Response
,
Meas
,
Distance To Fault
,
Meas Setup
,
Cable Type
to set the cable type.
The calibration remains valid until you do any one of the following:
•
•
• set the Distance to Fault frequency range to Auto. Note that the calibration will become valid again as soon as you switch from Auto back to Manual
Frequency Range power off the analyzer change the start frequency to a new value that lies below the start frequency of your previous calibration
Chapter 7 141
NOTE
Stimulus Response Measurements (Requires N8995A)
Distance to Fault
•
•
•
•
• change the stop frequency to a new value that lies above the stop frequency of your previous calibration change the start or stop frequency when the calibration frequency step is greater than the factory calibration frequency step change any of the cables that you used for the calibration change any of the (optional) attenuators that might have been used for the calibration change the type of cable specified under the
Cable Type
menu key
The distance to fault calibration for the auto frequency range is unique, however. It is not applicable to return loss or one port insertion loss, or even to the manual frequency range method for distance to fault.
For distance to fault measurements, separate calibrations need to be performed for each frequency range mode.
Performing a Distance to Fault Measurement
Step 1.
Set the analyzer to the Stimulus/Response mode.
Press
Mode
,
Stimulus/Response
.
Step 2.
Preset the analyzer and select the Distance to Fault measurement.
Press
Mode Preset
.
Press
Meas
,
Distance to Fault
.
Step 3.
Select the cable type:
Press
Meas Setup
,
Cable Type
.
If the cable being measured has an “RG” designation, such as RG-214, select:
Cable Type (RG)
. or select:
Cable Type (BTS)
. Press,
Select Cable
. You will then be given a list of cable types to select. Use the knob or the up/down arrow navigation keys to highlight the correct cable type and press
Select
. If the type of cable you are measuring is not listed, you need to select
Cust
(Custom Cable) as the cable type then setup
Cable Atten
(the attenuation per unit distance of the cable) and
Vel Factor
(the relative propagation velocity of the cable).
Step 4.
Set the frequency range to auto.
Press
FREQ Channel
,
Freq Range
(Auto).
The start and stop frequencies are then automatically set by the start and stop distances.
Step 5.
Set the distance units:
Press
FREQ Channel
,
Units
(Feet).
142 Chapter 7
Stimulus Response Measurements (Requires N8995A)
Distance to Fault
Figure 7-8
Each time you press this menu key, the selected option (Feet or Meters) changes.
The unit you choose here will be used as the unit of the start and stop distances.
Step 6.
Set the start and stop distances for the cable you are measuring. In this example, the cable is approximately 23 feet.
Press
FREQ Channel
,
Start Distance
, 0,
ft
[feet],
Stop Distance
, 30,
ft
[feet].
You can also use meters as the unit in this step, the number you enter will be calculated to feet and shown.
Step 7.
Calibrate the measurement:
Press
FREQ Channel
,
Calibrate
and follow the instructions on the Calibration
Wizard. The analyzer will calibrate over the desired frequency range.
To calibrate your spectrum analyzer, you will need the following calibration kit:
•
•
Open/short connector.
Calibrated 50 ohm Load connector.
Distant to Fault Measurement
Step 8.
Connect the calibration devices and test cable to the analyzer RF Output, as shown
in Figure 7-8 , or in the calibration wizard.
Chapter 7 143
Figure 7-9
Stimulus Response Measurements (Requires N8995A)
Distance to Fault
Distance to Fault Measurement, Calibrated
Step 9.
Connect the DUT to the analyzer RF Output, as shown in
Figure 7-10
This example uses an RG8A type cable as the DUT.
Step 10.
The triangles (up to 4) will indicate the worst faults. Below the graticule, the
Return Loss, Distance, and VSWR of each fault is indicated. (This cable has a fault indicated at 23 feet.)
Distance to Fault Measurement Results.
144 Chapter 7
8
Demodulating AM/FM Signals
(Requires Option N8996A-1FP)
145
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
This Chapter provides information making the following measurements.
“Demodulating an AM Signal Using the CSA (Requires Option
“Demodulating an FM Signal Using the CSA (Requires Option N8996A-1FP)” on page 153
.
146 Chapter 8
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an AM Signal Using the CSA (Requires Option N8996A-1FP)
Demodulating an AM Signal Using the CSA (Requires
Option N8996A-1FP)
This section demonstrates how to demodulate an AM signal using the CSA built-in
AM demodulator with Option N8996A-1FP.
Using the CSA built in AM demodulator you can tune to an AM signal and view the results displayed in the time domain or the frequency domain (refer to the concepts chapter in the Measurement Guide
,
“Modulation Distortion Measurement Concepts” on page 204 and
SINAD Measurement Concepts” on page 205
for more information).
CAUTION
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Figure 8-1
Step 1.
Connect an Agilent ESG RF signal source to the analyzer RF INPUT as shown in
Figure 8-1 . Set the ESG frequency to 300 MHz and the amplitude to -10 dBm. Set
the AM depth to 80%, the AM rate to 1 kHz and turn AM on.
Setup for AM Demodulation Measurement
Step 2.
Select the Modulation Analyzer mode and mode preset:
Press
Mode
,
Modulation Analyzer
, then press
Mode Preset
.
Step 3.
Select AM measurement:
Press
Meas
,
AM
.
Step 4.
Select the demodulation waveform view:
Press
View/Display
,
Demod Waveform
.
Demod Waveform is the default setting of View/Display.
Step 5.
Set the center frequency to the center of the AM signal (in this case 300 MHz):
Press
FREQ Channel
,
Center Freq
,
300
,
MHz
.
Chapter 8 147
NOTE
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an AM Signal Using the CSA (Requires Option N8996A-1FP)
There is a function called Global CF in
Mode
,
Mode Setup
,
Use Global CF
(On or
Off). If you turn this On, the CF (center frequency) will use the same center frequency value as other modes which also have the Global CF switched On. This means when you want to switch between different modes, you can keep the same
CF.
For example, if you set
Use Global CF
to On in Modulation Analyzer mode, and also set
Use Global CF
to On in Spectrum Analyzer mode, all measurements made in either mode will use the same center frequency. Any change you make to center frequency in one measurement or mode will be applied across all measurements in either mode.
Step 6.
Set the IF bandwidth to Auto.
Press
Meas Setup
,
IFBW
(Auto).
For most measurements, you can use the Auto setting of IF bandwidth. If the AM depth is lower than 2%, you need to set the IF bandwidth manually. You should first calculate the minimum required bandwidth
IFBW
=
2 x Modulation Rate
Your IFBW must be greater than this minimum value. Use the IFBW menu key to select a suitable IFBW.
NOTE
The IFBW can be set to the following values: 5 MHz, 3 MHz, 1.25 MHz, 1 MHz,
500 kHz, 300 kHz, 250 kHz, 100 kHz, 50 kHz, 30 kHz, 10 kHz, 5 kHz, 3 kHz.
Step 7.
Set the horizontal scaling:
Press
SPAN X Scale
,
Scale/Div
, 500,
s
.
Step 8.
Set the vertical scaling:
Press
AMPTD Y Scale
,
Scale/Div
, 40,
%
.
Step 9.
Set your view to show the results in the best way for you. Press
View/Display
, and then select
Demod Waveform
,
Demod Spectrum
, or
Numerical Results
. Examples of these three views are shown below.
The Demod Waveform View of the measurement results is shown in Figure 8-2
.
148 Chapter 8
Figure 8-2
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an AM Signal Using the CSA (Requires Option N8996A-1FP)
AM Demod Waveform (ESG AM Signal with 80% Modulation Index)
Figure 8-3
The Demod Spectrum View of the measurement results is shown in Figure 8-3 .
AM Demod Spectrum (ESG AM Signal with 80% Modulation Index)
The numeric results shown in the Demod Waveform view or the Demod Spectrum view are the current or the average measurement results in the Numerical Results view.
The Numerical Results view shown in
Figure 8-4 gives the detailed measurement
results for AM index, Carrier Power, Modulation Rate, Distortion and SINAD including the minimum value for AM Index and maximum value for all five parameters.
Chapter 8 149
Figure 8-4
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an AM Signal Using the CSA (Requires Option N8996A-1FP)
AM Numerical Results (ESG AM Signal with 80% Modulation Index)
Step 10.
To adjust the measurement settings, press
Meas Setup
, then:
1.
Avg Number: To set the averaging
On
or
Off
, switch the
Avg Number
key between
On
and
Off
. When averaging is
On
, enter the number of results used in the averaging calculations. The default average setting is
Off
and the default number is 10 when averaging is
On
. If your input signal changes during the average period, wait until the averaging has completed or the next averaging period has started.
When the Avg Number is On, the column title “Current” in Numerical Results view will change to “Avg”.
2.
Avg Mode: To change the average mode, press the
Avg Mode
key and select
Exponential
or
Repeat
. The default average mode is
Repeat
.
3.
Demod: To change the demodulation settings, press the
Demod
menu key, then:
To change detector, press
AM Detector
to select a detector
Peak+
,
Peak-
,
Peak+-/2
, or
RMS
.
Peak+ is typically used when analyzing stationary signals like CW or sinusoids, but is not good for displaying noise, since it will not show the true randomness of the noise.
Peak+-/2 is the average of Peak+ and Peak-.
RMS is best for measuring the power of signals.
To change the length of time over which your measurement is performed, press
Meas Time
and use the numeric keypad to enter the measurement time.
150 Chapter 8
NOTE
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an AM Signal Using the CSA (Requires Option N8996A-1FP)
If a pulsed signal is being measured, the Meas Time should be set less than or equal to the Search Length.
When the AM Detector is Peak+ or Peak-, you can access
Peak Hold
to switch between
On
and
Off
. If Peak Hold is On, the measurement result of the AM
Index is the maximum (when AM Detector is Peak+) or minimum (when AM
Detector is Peak-) value of these peaks over the whole measurement time. If peak hold is Off, the measurement result of the AM Index (Peak+ or Peak- mode) is the average of these peaks over the whole measurement time.
Toggle the
Meas Filter
key to switch measurement filter between
On
and
Off
. If
IFBW is greatly larger than the AM rate, a lot of noise will contaminate the normal signal. In order to decrease the interference of noise, you can select the
Meas Filter to filter out the noise and improve the accuracy of measurement.
4.
Burst Search: To change the settings of the burst search, press
Burst Search
, then:
Press
Sync
to select
None
or
RF Amptd
. If RF Amptd is chosen, a burst search begins.
Press
Burst Search Threshold
to enter the burst searching power threshold. The unit is dB because this threshold is defined as the logarithmic ratio of the power of idle data portion to the power of data portion.
Press
Search Length
to enter the searching time for the pulsed signal. The setting of search length should be:
Search Length
2 x length of idle data portion + length of data portion
5.
Trigger: To change the settings of trigger, press
Trigger
, then:
To select the trigger type, press
Free Run
,
External
or
RF Burst
.
If External is chosen, the Trigger Slope and Trigger Delay are available. If RF
Burst is chosen, the Trigger Level and Trigger Delay are available.
To set the trigger level, press
Trigger Level,
then enter the numeric data to set the absolute trigger level for the RF burst envelope.
Press
Trigger Slope
to control the trigger polarity.
Press
Trigger Delay
to set the wait time of the analyzer before the analyzer starts a sweep.
6.
Limits: To change the limit settings, press
More 1 of 2
, then press
Limits
:
Toggle
Limits
between
On
and
Off
to activate or deactivate the limits display.
When the setting is On, the green word “PASS” or the red word “FAIL” at the
Chapter 8 151
Figure 8-5
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an AM Signal Using the CSA (Requires Option N8996A-1FP)
top left of the display indicates whether the measurement results have passed or failed the limits test. The mark “(P)” or “(F)” beside the measurement result means this value is passed or failed.
Press
Carrier Power Upper
to enter the maximum RF carrier power, the measured maximum value will be changed from green to red when it exceeds the limit set here.
Press
AM Index Upper
to enter the maximum AM index to warn you if the measured maximum value exceeds the limit specified here.
Press
AM Index Lower
to change the minimum AM index limit.
The measurement results are failed in the Figure 8-5 with the maximum AM
Index exceeds the limit.
AM Numerical Results with Limits On
152 Chapter 8
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an FM Signal Using the CSA (Requires Option N8996A-1FP)
Demodulating an FM Signal Using the CSA (Requires
Option N8996A-1FP)
This section demonstrates how to demodulate an FM signal using the CSA built-in
FM demodulator with Option N8996A-1FP.
Using the CSA built in FM demodulator you can tune to an FM signal and view the results displayed in the time domain or the frequency domain (refer to the concepts chapter in the Measurement Guide
,
“Modulation Distortion Measurement Concepts” on page 204 and
SINAD Measurement Concepts” on page 205
for more information).
CAUTION
Ensure that the total power of all signals at the analyzer input does not exceed +33 dBm (2 watts).
Figure 8-6
Step 1.
Use an Agilent ESG RF signal generator or an antenna to get an FM signal to analyze. In this example an ESG is used transmitting at 300 MHz with FM deviation of 10 kHz and FM rate of 1 kHz.
Step 2.
Connect the RF OUTPUT of the Agilent ESG RF signal generator to the analyzer
RF INPUT as shown in Figure 8-6
.
Setup for FM Demodulation Measurement
Step 3.
Select the Modulation Analyzer mode and mode preset:
Press
Mode
,
Modulation Analyzer
, then press
Mode Preset
.
Step 4.
Select FM measurement:
Press
Meas
,
FM
.
Step 5.
Select the demodulation waveform view:
Press
View/Display
,
Demod Waveform
.
Step 6.
Set the center frequency to the center of the FM signal (in this case 300 MHz):
Press
FREQ Channel
,
Center Freq
, 300,
MHz
.
Chapter 8 153
NOTE
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an FM Signal Using the CSA (Requires Option N8996A-1FP)
There is a function called Global CF in
Mode
,
Mode Setup
,
Use Global CF
(On or
Off). If you turn this On, the CF (center frequency) will use the same center frequency value as other modes which also have the Global CF switched On. This means when you want to switch between different modes, you can keep the same
CF.
For example, if you set
Use Global CF
to On in Modulation Analyzer mode, and also set
Use Global CF
to On in Spectrum Analyzer mode, all measurements made in either mode will use the same center frequency. Any change you make to center frequency in one measurement or mode will be applied across all measurements in either mode.
Step 7.
Set the IF bandwidth to Auto.
Press
Meas Setup
,
IFBW
(Auto).
For measurements with
>1(is the ratio of frequency deviation to modulation rate), you can use the automatic setting of IF Bandwidth. For measurements with
<1, you need to set IF bandwidth manually, you should first calculate the minimum required bandwidth, Then with CSA IFBW selections, choose a suitable
IFBW
=
2 x Frequency Deviation
+
2 x Modulation Rate
IFBW:
NOTE
The IFBW can be set as the following values: 5 MHz, 3 MHz, 1.25 MHz, 1 MHz,
500 kHz, 300 kHz, 250 kHz, 100 kHz, 50 kHz, 30 kHz, 10 kHz, 5 kHz, 3 kHz.
Step 8.
Set the horizontal scaling:
Press
SPAN X Scale
,
Scale/Div
, 500,
s
.
Step 9.
Set the vertical scaling:
Press
AMPTD Y Scale
,
Scale/Div
, 5,
kHz
.
Step 10.
Set your view to show the results in the best way for you. Press
View/Display
, and then select
Demod Waveform
,
Demod Spectrum
, or
Numerical Results
. Examples of these three views are shown below.
The Demod Waveform View of the measurement results is shown in Figure 8-7
.
154 Chapter 8
Figure 8-7
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an FM Signal Using the CSA (Requires Option N8996A-1FP)
FM Demod Waveform (ESG FM Signal with 10 kHz Deviation)
Figure 8-8
The Demod Spectrum View of the measurement results is shown in Figure 8-8 .
FM Demod Spectrum (ESG FM Signal with 10 kHz Deviation)
The numeric results shown in the Demod Waveform view or the Demod Spectrum view are the current or the average measurement results in the Numerical Results view.
The Numerical Results view shown in
Figure 8-9 gives the detailed measurement
results for Carrier Frequency Offset, Frequency Deviation, Carrier Power,
Modulation Rate, Distortion and SINAD including the minimum value for
Frequency Deviation and maximum value for all the six parameters.
Chapter 8 155
Figure 8-9
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an FM Signal Using the CSA (Requires Option N8996A-1FP)
FM Numerical Results (ESG FM Signal with 10 kHz Deviation)
Step 11.
To adjust the measurement settings, press
Meas Setup
, then:
1.
Averaging: To set the averaging
On
or
Off
, switch the
Avg Number
key between
On
and
Off
. When averaging is
On
, enter the number of results used in the averaging calculations. The default average setting is
Off
and the default number is 10 when averaging is
On
. If your input signal changes during the average period, wait until the averaging has completed or the next averaging period has started.
When the Avg Number is On, the column title “Current” in numerical results view will change to “Avg”.
2.
Averaging Mode: To change the average mode, press the
Avg Mode
key and select
Exponential
or
Repeat
. The default average mode is
Repeat
.
3.
Demod Settings: To change the demodulation settings, press the
Demod
menu key, then:
To change the detector, press
FM Detector
to select a detector
Peak+
,
Peak-
,
Peak+-/2
, or
RMS
.
Peak+ is typically used when analyzing stationary signals like CW or sinusoids, but is not good for displaying noise, since it will not show the true randomness of the noise.
Peak+-/2 is the average of Peak+ and Peak-.
RMS is best for measuring the power of signals.
To change the length of time over which your measurement is performed, press
Meas Time
and use the numeric keypad to enter the measurement time.
156 Chapter 8
NOTE
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an FM Signal Using the CSA (Requires Option N8996A-1FP)
If a pulsed signal is being measured, the Meas Time should be less than or equal to the Search Length.
When the FM Detector is Peak+ or Peak-, you can access
Peak Hold
to switch between
On
and
Off
. If Peak Hold is On, the measurement result of the frequency deviation is the maximum (when FM Detector is Peak+) or minimum (when FM Detector is Peak-) value of these peaks over the whole measurement time. If peak hold is Off, the measurement result of the frequency deviation (Peak+ or Peak- mode) is the average of these peaks over the whole measurement time.
Press
AutoCarrFreq
to switch between
On
and
Off
. When the setting is On, the analyzer will calculate the carrier frequency offset between the signal source and signal analyzer then correct this offset for the demodulated baseband signal. The frequency deviation can be measured more accurate using the setting On.
Press
Meas Filter
to switch between
On
and
Off
. Measurement Filter here is used to filter the FM demodulated signal. If IFBW is greatly larger than the modulation rate, a lot of noise will contaminate the normal signal. In order to decrease the interference of noise, you can select the Meas Filter On to filter out noise and improve the accuracy of measurement.
4.
Burst Search: To change the settings of the burst search, press
Burst Search
, then:
Press
Sync
to select
None
or
RF Amptd
. If RF Amptd is chosen, the burst searching begin.
Press
Burst Search Threshold
to enter the burst searching power threshold. The unit is dB because this threshold is defined as the logarithmic ratio of the power of idle data portion to the power of data portion.
Press
Search Length
to enter the searching time for the pulsed signal, the setting of search length should be:
Search Length
2 x length of idle data portion + length of data portion
5.
Trigger: To change the settings of trigger, press
Trigger
, then:
To select the trigger type, press
Free Run
,
External
or
RF Burst
.
If External is chosen, the Trigger Slope and Trigger Delay are available. If RF
Burst is chosen, the Trigger Level and Trigger Delay are available.
To set the trigger level, press
Trigger Level,
then enter the numeric data to set the absolute trigger level for the RF burst envelope.
Press
Trigger Slope
to control the trigger polarity.
Chapter 8 157
Demodulating AM/FM Signals (Requires Option N8996A-1FP)
Demodulating an FM Signal Using the CSA (Requires Option N8996A-1FP)
Figure 8-10
Press
Trigger Delay
to set the wait time of the analyzer before the analyzer starts a sweep.
6.
Limits: To change limit settings, press
More 1 of 2
, then press
Limits
:
Press
Limits
key between
On
and
Off
to activate or deactivate the limits display.
Press
Carrier Power Upper
to enter the maximum RF carrier power. The color of the measured maximum value will be changed from green to red when the value exceeds the limit set here.
Press
Freq Deviation Upper
to enter the maximum frequency deviation to warn you when the measured maximum value exceeds the limit specified here.
Press
Freq Deviation Lower
to change the minimum frequency deviation limit.
Press
Carrier Freq Offset Upper
to set the maximum carrier frequency offset limit.
The Figure 8-10 show the failure result with the maximum carrier power
exceeds the limit.
FM Numerical Results with Limits On
NOTE
When Limits is set to On, the word “PASS” or “FAIL” in the left top corner of the display indicates the measurement results is passed or failed. The mark “(P)” or
“(F)” beside the measurement result means this value has passed or failed the limit test.
158 Chapter 8
9
Basic System Operations
159
Basic System Operations
This chapter contains information on the following Basic System Operations:
“System Reference Introduction” on page 162
“Setting System References” on page 163
“Selecting a Frequency/Timing Reference” on page 163
“Setting System Time/Date” on page 164
“Setting Real Time Clock” on page 164
“Printing a Screen To a File” on page 165
“Printing Screens” on page 165
“File Naming Options” on page 167
“Setting Up Automatic File Naming” on page 167
“Setting Up User File Naming” on page 167
“Setting Up Asking For Filename” on page 168
“Configuring for Network Connectivity” on page 169
“IP Administration Using DHCP” on page 169
“IP Administration Without DHCP (Static IP Address)” on page 169
“Setting the Display” on page 171
“Setting the Screen Saver” on page 171
“Setting the Brightness” on page 171
“Saving, Recalling, and Deleting Instrument States” on page 172
“Saving the State” on page 172
“Saving the Power-Up State” on page 172
“Recalling the State” on page 172
“Returning the Power-Up State to Factory Defaults” on page 173
“Viewing System Statistics” on page 175
“Viewing System Release Versions” on page 175
“Viewing System Memory” on page 175
“Viewing Battery Statistics” on page 175
“Using the Option Manager” on page 176
160 Chapter 9
“Viewing Installed Options” on page 176
“Viewing Installed Options” on page 176
“Installing an Option” on page 176
“Viewing Installation Information” on page 177
“Testing System Functions” on page 178
“Testing Your Display” on page 178
“Testing Your Keyboard” on page 178
Basic System Operations
Chapter 9 161
Basic System Operations
System Reference Introduction
System Reference Introduction
•
•
•
•
The N1996A Agilent CSA spectrum analyzers provide a system utility that allows you to perform non-measurement activities and to configure the analyzer for:
General operations
System status updates
Data manipulation
Basic system functions testing
162 Chapter 9
NOTE
Basic System Operations
Setting System References
Setting System References
The Agilent CSA provides a utility to preconfigure the global settings for your analyzer.
Selecting a Frequency/Timing Reference
Perform this procedure to select a common frequency or timing reference to be used for all measurement tools (when applicable).
1.
Press
System
,
Freq/Time Reference
2.
Using the knob or the up/down arrow navigation keys to highlight the frequency/timing reference you want.
3.
Press
Select
.
A frequency/time reference indicator in the lower-right of the screen shows both the selected reference and its status.
Reference indicators include: Int Ref, Even Sec, Ext 1.0 MHz, Ext 2.048 MHz,
Ext 4.95 MHz, Ext 10 MHz, Ext 13 MHz, Ext 15 MHz, or Ext 19.66 MHz.
•
•
•
Status indicators include:
Green dot to indicate that the reference is locked
Yellow triangle to indicate that the reference is acquiring lock
Red X to indicate that the reference is not locked
Chapter 9 163
Basic System Operations
Setting System Time/Date
Setting System Time/Date
The Agilent CSA provide a utility to preconfigure the Time/Date settings for your analyzer.
Setting Real Time Clock
Perform this procedure to set the system time and date.
1.
Press
System
,
Time/Date/Location
,
Time/Date
.
2.
Press
Set Time
, using the numeric keys or the up/down arrow navigation keys to enter the time as format hh:mm:ss.
3.
Press
Set Date
, using the numeric keys or the up/down arrow navigation keys to enter the date as format mm/dd/yyyy.
4.
Press
Data Format
to choose the data display is
MDY
(month-day-year) or
DMY
(day-month-year).
5.
Press
Time/Date
between
On
and
Off
, when the setting is
On
, the real-time clock is shown on the right top of the display.
164 Chapter 9
Basic System Operations
Printing a Screen To a File
Printing a Screen To a File
The N1996A lets you save screen images to PNG files. You can save the image files to a USB mass storage device.
Printing Screens
1.
Display data on a measurement screen.
2.
Connect a USB mass storage device.
3.
Select how you want to name the data file you’re saving (see
This step must only be performed prior to the first time you save a file, or if you want to change the method you use.
4.
Press ), there will be a status massage “Screen Image capture in progress” and “*” gives the progress of the saving process at the bottom of the display.
5.
Enter a name for the file (or it is done automatically, depending on the file naming method you selected) and press OK.
6.
When the screen capture is complete, press
Ok
.
Chapter 9 165
Basic System Operations
Saving Data
Saving Data
Saving Data
You may save and manage data on an external storage device or the internal analyzer drive. You can save the current screen image, the current analyzer state, current trace data, and measurement results. To save data:
1.
Display data on a measurement screen.
2.
Press
Save
,
Type
and select the type of data you want to save.
3.
If you have selected a data type of Trace, press
Source
, and select the trace for the data you want to save. Your choices are: Trace 1, Trace 2, Trace 3, Trace 4, or All.
4.
Select how you want to name the data file you are saving (see “File Naming
This step must only be performed prior to the first time you save a file, or if you want to change the method you use.
5.
If you have previously saved a file of the same type or name, select how the new data will be saved. New data can be saved by action: overwriting an existing file, appending the new data to the existing file, prompting you to determine how each save will be handled, automatically increment the file name number, or timestamping the file to chronologically differentiate between files. (see
“File Naming Options” on page 167).
This step must only be performed prior to the first time you save a file, or if you want to change the method you use.
6.
Enter a name for the file (or it is done automatically, depending on the file naming method you selected).
7.
If you have set data type as State or Trace, select the location where you want to store the file by pressing
Save
,
Location
and press
Internal
or
USB
. For
Screen or Measurement type of data, the choice of location can only be USB.
This step must only be performed prior to the first time you save a file, or if you want to change the file storage location.
8.
If you have selected USB as the storage location: a.
Connect a USB mass storage device.
9.
Press
Save Now
.
10.
When the data save is complete, press
Ok
.
166 Chapter 9
Basic System Operations
File Naming Options
File Naming Options
•
•
•
You have three options for naming image files. You can:
Name each file automatically using this format:
For a screen image, the format is Screen_YYYYMMDD_HHMMSS.png. For measurement results, “Screen” is replaced by “Data”. For State, “Screen” is replaced by “State”. For Trace, “Screen” is replaced by “Trace”. In this example, the “.png” extension is only for Data Type set to Screen. Other Data
Type have other extensions.
Name each file individually, and enter the name you want. This is called User file naming.
Have the analyzer ask you how you want to name each file for each file you save.
Setting Up Automatic File Naming
You can choose to have the analyzer automatically assign a file name that includes the file type and a three-digit number that the analyzer chooses to be the lowest number in the current sequence that does not conflict with an existing file name.
The format of the file name will be DataType_YYYYMMDD_HHMMSS.xxx. the extension is different for different type of data.
1.
Press
Save, Name
.
2.
On
Filename
select Auto.
Each time you press this softkey, the selected option changes.
Setting Up User File Naming
You can choose to have the analyzer use the file name you assign.
1.
Press
Save
,
Name
.
2.
On
Filename
select User.
Each time you press this softkey, the selected option changes.
3.
Setup file naming.
a.
Press
User Filename
b.
If the filename does not exist, spell out the name using the knob or up and down arrow buttons to select a letter and the buttons on the left to change cursor position.
c.
For each character entered, press
Enter
or
Select
. d.
Press
Ok
.
Chapter 9 167
Basic System Operations
File Naming Options
4.
If you have previously saved a file of the same type or name, press
If File Exists
.
5.
Press action:
Overwrite
,
Append
,
Prompt
,
Auto Incr
, or
Timestamp
•
•
•
•
•
Overwrite—overwrites existing file data with new file data.
Append—appends the new data to the end of the existing file data. (Type =
Measurement Results only)
Prompt—prompts you to input a new file name.
Auto Incr—automatically adds the numeric characters to the filename or increments the existing numeric character to the next higher number.
Timestamp—attaches a timestamp to the filename to distinguish it from the existing file.
Setting Up Asking For Filename
You can choose to have the analyzer ask you to name the file you wish to save or print. For every file you save, you enter the filename you want.
1.
Press
Save
,
Name
.
2.
On
Filename
select Ask.
Each time you press this softkey, the selected option changes.
168 Chapter 9
Basic System Operations
Configuring for Network Connectivity
Configuring for Network Connectivity
The N1996A can operate as a device on any compatible network. Therefore, in order to be accessible on the network, certain information must be entered so the analyzer can communicate with other devices. Configuring the analyzer for network activity is performed by using the IP administrator located in the system utilities.
IP Administration Using DHCP
Perform this procedure to allow your analyzer to be integrated into an existing network that uses DHCP to dynamically assign IP addresses. This procedure requires that you have the Host Name (available from your network administrator).
1.
Press
System
,
Controls
,
IP Admin
,
Host Name
.
2.
Enter the name of the analyzer. This is assigned by the network administrator.
3.
Press
Ok
4.
Press
IP Config
,
DHCP
. An IP address and other network information will automatically be assigned if the Host Name is recognized by the network.
5.
Press
Save
,
Yes
. Saves the current configuration. DHCP will dynamically assign an IP address.
6.
Cycle the power of the analyzer to access the network and have valid network information assigned.
IP Administration Without DHCP (Static IP Address)
•
•
•
•
Perform this procedure to allow your analyzer to be integrated into an existing network that uses a technique other than DHCP as its IP address assignments. This procedure requires the following specific data from the network administrator:
Host name
IP address
Net mask
Gateway
1.
Press
System
,
Controls
,
IP Admin
,
Host Name
.
2.
Enter the name of the analyzer. This is assigned by the network administrator.
3.
Press
Ok
4.
Press
IP Config
,
Static
. Now you must specify relevant network information for the analyzer to be recognized. Contact your network administrator if you do not have this information.
5.
Press
IP Address
.
Chapter 9 169
NOTE
Basic System Operations
Configuring for Network Connectivity
6.
Enter the IP address using the knob or the up and down arrows, and menu keys on the left.
7.
Press
Ok
8.
Press
Net Mask
9.
Enter the Net Mask using the knob or the up and down arrows, and menu keys on the left.
10.
Press
Ok
11.
Press
Gateway
12.
Enter the Gateway using the knob or the up and down arrows, and menu keys on the left.
13.
Press
Save
,
Yes
. Saves the current configuration.
14.
Cycle the power of the analyzer to access the network and have valid network information assigned.
If you are not using a LAN connection, you may want to set the IP Configuration to None to reduce the instrument power-on time.
170 Chapter 9
Basic System Operations
Setting the Display
Setting the Display
You can activate the screen save function and the time delay before the screen saver activates. Also you can set the brightness of the screen.
Setting the Screen Saver
Active the screen saver function to save the power, you can set the time delay to different values before the screen saver activates depending on the power source, battery or external DC power supply.
1.
Press
System
,
Controls
,
Display Settings
.
2.
If the power source is battery, press
Screen Save (Battery)
, using the up/down arrow navigation keys or the knob to highlight the delay time before the screen saver activates, press
Select
.
3.
If the power source is eternal DC power supply, press
Screen Save (Ext DC)
, using the up/down arrow navigation keys or the knob to highlight the delay time before the screen saver activates, press
Select
.
The screen will turn to black after the time delay you set. Also a status massage at the bottom of the display “Back light turning off in 4 seconds...” will be shown when the residual time is 4 seconds. and after the screen saver activates, you can press any front panel key to turn on the back light.
Setting the Brightness
There are six brightness level to choose. 6 is the brightest level.
1.
Press
System
,
Controls
,
Adjust Brightness
.
2.
Select the desired brightness level.
Chapter 9 171
NOTE
Basic System Operations
Saving, Recalling, and Deleting Instrument States
Saving, Recalling, and Deleting Instrument States
You can save the current configuration and settings for recall at a later time. You can also save a customized power-up state, which the analyzer will use each subsequent time it is powered on. This enables you to configure common usage and power-on states to make measurements quickly.
Saving the State
1.
Configure all measurement settings you want to save. Make sure you are viewing the screen you want to recall later.
2.
Press
Save
,
Name
,
Filename
(Ask).
3.
Press
Return
(the front panel key located below the screen window),
Location
,
Internal
or
USB
.
4.
Press
Save
,
Type
,
State
,
Save Now
5.
Enter your preferred state name, for example, “Remote base station”.
6.
Press
OK.
The message, “
State was saved successfully:
C:<filename>
” is displayed. Press
OK
again to return to the
Save
key menu.
Saving the Power-Up State
1.
Configure all measurement settings you want to save. Make sure you are viewing the screen you want to recall later.
2.
Press
Save
,
Name
,
Filename
(Ask).
3.
Press
Return
(the front panel key located below the screen window),
Location
,
Internal
or
USB
.
4.
Press
Save
,
Type
,
State
,
Save Now
5.
Enter “Powerup” as the state name (the analyzer is case-sensitive, so be sure to capitalize the “P”). This is the name the analyzer uses to identify the power-up state. It is also the state loaded by User Preset.
6.
Press
Ok
This process is easier for firmware revision A.02.00 or greater. After configuring the measurement settings, press
User Preset
,
Save User Preset
.
Recalling the State
1.
Press
Recall
,
Type
,
State
2.
Select the location from which you want to recall the file by pressing
Location
and press
Internal
or
USB
.
172 Chapter 9
Basic System Operations
Saving, Recalling, and Deleting Instrument States
This step must only be performed prior to the first time you recall a file, or if you want to change the file recall location.
3.
If you have selected USB as the recall location, connect the USB mass storage device.
4.
If necessary, select how you want the state files sorted by pressing
Sort
and then press
By Date
,
By Name
,
By Extension
,
By Size
, or
Order
.
5.
Press
Recall Now
.
6.
Select from the file list the state file you want to recall using the knob or up and down arrow buttons.
All states, in addition to two supplied in the analyzer (listed below), are displayed:
•
•
Powerup - The default power-up state shipped with the analyzer, or the power-up state last saved with the analyzer.
Factory Defaults - The default power-up state shipped with the analyzer.
You can always revert to it by selecting it in this procedure.
7.
Press
Select
Returning the Power-Up State to Factory Defaults
1.
Press
Recall
,
Type
,
State
2.
Select the location from which you want to recall the file by pressing
Location
and press
Internal
.
This step must only be performed prior to the first time you recall a file, or if you want to change the file recall location.
3.
If necessary, select how you want the state files sorted by pressing
Sort
and then press
By Date
,
By Name
,
By Extension
,
By Size
, or
Order
.
4.
Press
Recall Now
. (Note that
Save
,
Name
,
Filename
(Auto) (User) (Ask) must be set to
Ask
.)
5.
Select from the file list the “Factory Defaults” state file using the knob or up and down arrow buttons.
6.
Press
Select
.
7.
When the recall is complete, press
Save
,
Type
,
State
,
Save Now
. (Note that
Save
,
Name
,
Filename
(Auto) (User) (Ask) must be set to
Ask
.)
8.
Enter as the state name, “Powerup” (the analyzer is case-sensitive, so be sure to capitalize the “P”). This is the name the analyzer uses to identify the power-up state.
9.
Press
OK
, and then
OK
again to get back to the
Save
Menu.
Chapter 9 173
NOTE
Basic System Operations
Saving, Recalling, and Deleting Instrument States
Deleting States
If you have saved a state you will no longer use, you can delete it.
1.
Press
Recall
,
Type
,
State
,
Location
(Internal),
Catalog
.
2.
Select from the file list the state file you want to delete using the knob or up and down arrow buttons or
All
to delete all saved states.
3.
Press
Delete
. You will then be asked, “
Are you sure you wish to delete the <filename> state?
” Press
Yes
.
Selecting
All
does not delete the Powerup or Factory Defaults states.
174 Chapter 9
Basic System Operations
Viewing System Statistics
Viewing System Statistics
Viewing System Release Versions
Perform this procedure to view the current version of software and firmware for enabled features.
1.
Press
System
,
System Stats
,
Rev Info
, and view version information for system firmware.
2.
Press
Page Up
or
Page Down
to scroll to next screen.
3.
Press
Return
to go back to the System Stats key menu.
Viewing System Memory
Perform this procedure to view current allocation and usage statistics of the memory available.
1.
Press
System
,
System Stats
,
Memory
, and view status of total, used, and available memory.
2.
Press
Return
to go back to the System Stats key menu.
Viewing Battery Statistics
Perform this procedure to view current status and battery usage.
1.
Press
System
,
System Stats
,
Battery
, and view the status of battery conditions.
For details, see “System Statistics—Battery Screen” on page 182.
2.
Press
Return
to go back to the System Stats key menu.
Viewing System Copyrights
Perform this procedure to view current copyrights statistics.
1.
Press
System
,
System Stats
,
Copyrights
, and view copyrights of Agilent
Technologies, Inc. and the copyrights for software components from other manufactures used in the analyzer.
2.
Press
Return
to the System Stats key menu.
Viewing System Identification
Perform this procedure to view current system identification.
1.
Press
System
,
System Stats
,
Show System
, and view a list of instrument identification information.
2.
Press
Return
to go back to the System Stats key menu.
Chapter 9 175
Basic System Operations
Using the Option Manager
Using the Option Manager
Viewing Installed Options
1.
Press
System
,
Option Manager
,
Installed Options
. This provides a list of all installed options as well as their associated license keys.
2.
Press
Page Up
or
Page Down
as necessary to scroll to next screen.
Viewing Installed Options
Perform this procedure to view a list of all options that you can install for the analyzer. Two lists are displayed: options you can install yourself and options that must be installed by Agilent.
1.
Press
System
,
Option Manager
,
Installable Options
. This provides a list of options that can be installed.
2.
Press
Page Up
or
Page Down
as necessary to scroll to next screen.
3.
Press
Return
to go back to the Option Manager key menu.
Installing an Option
1.
Press
System
,
Option Manager
,
Install an Option
.
2.
If available, press
From List
. This key will not be available if all options have already been licensed.
3.
Highlight the option to be installed from the list using knob or the up/down arrow navigation keys then press
Select
.
4.
If you already have the license key for the option selected, press
Install Option
and follow the on-screen instructions. Otherwise, you need to order a license key for this option upgrade by contacting your Agilent sales representative.
5.
If the option to be installed is not listed, there are two possible reasons:
•
The option to be installed requires a newer firmware revision than the revision that is currently installed. For example, Option AFM, AM/FM
Tune and Listen, requires firmware revision A.02.00 or later. You have two alternatives in such a case. Either upgrade the firmware to the firmware necessary to support the option and then license the option, or use the
Type
Option
feature (press
Cancel
,
Type Option
) to license the option now and upgrade the firmware later. Either way, the new option will be available when it is licensed and the minimum firmware revision is installed.
•
The option to be installed is no longer offered for sale with the current firmware revision. For example, N1996A Option TG3 and N1996A Option
TG6 have been replaced by N8995A Option SR3 and N8995A Option SR6, respectively, beginning with firmware revision A.02.00 or later. You can
176 Chapter 9
Basic System Operations
Using the Option Manager
still install the TG3 or TG6 option using the
Type Option
feature (press
Cancel
,
Type Option
) to license the option.
6.
If you want to cancel the installation process, press
Return
to go back to the
Option Manager key menu.
Viewing Installation Information
Perform this procedure to view current manufacturing information about your analyzer that must be provided to Agilent to install a user-installable option.
1.
Press
System
,
Option Manager
,
Install Info
.
2.
When you call your Agilent sales representative to order an option, you will need to provide the information you see on this screen:
•
•
•
Model number
Serial number
Host ID
3.
Press
Return
to go back to the Option Manager key menu.
Chapter 9 177
Basic System Operations
Testing System Functions
Testing System Functions
The N1996A provides two simple tests you can perform to test the basic system functionality: a display test and a keyboard test.
Testing Your Display
Perform this procedure to verify the correct operation of your display.
1.
Press
System
,
Service
,
Verification
,
Display Test
.
2.
Follow the on-screen instructions.
Testing Your Keyboard
Perform this procedure to verify the correct operation of your keyboard device.
1.
Press
System
,
Service
,
Verification
,
Keyboard Test
.
2.
Press the available buttons and view the results on the screen.
178 Chapter 9
10
Working with Batteries
179
Working with Batteries
This chapter contains the following topics on your Agilent CSA batteries:
“Installing Batteries” on page 181
“Viewing Battery Status” on page 182
“Charging Batteries” on page 184
“Recalibrating Batteries” on page 186
“Battery Specifications” on page 190
180 Chapter 10
Installing Batteries
Working with Batteries
Installing Batteries
WARNING
NOTE
1.
Open the battery door by turning the latch counterclockwise several times until loose. Then pull the battery door open.
2.
Insert two batteries. Both batteries must be installed for the instrument to operate properly.
3.
Close the battery door and turn the latch clockwise until tight to secure the battery door.
This instrument has a recharge circuit. Never install non-rechargeable cells or batteries of a different type.
When operating the analyzer on battery power, batteries of different capacities will share current in proportion to individual battery capacity. Therefore, when purchasing and installing batteries, ensure that both batteries have equivalent capacities. Even batteries that appear physically identical, can have different capacities. It is recommended that batteries be purchased and installed in pairs.
Chapter 10 181
NOTE
Working with Batteries
Viewing Battery Status
Viewing Battery Status
•
•
•
•
You can view information about battery status in four ways:
Two battery LEDs on the analyzer front panel (below the USB connectors, refer to
“Front-Panel Connectors and Keys” on page 50)
Icons in the lower right of the front panel screen
System Statistics—Battery screen, available from the System menu
LCD gauge built into each battery
Battery LEDs
LED
Green
Blinking green
Charging Status
When battery charging
Battery charging completes
The battery status LEDs will function only when the analyzer is in standby mode and connected to external power.
Front Panel Icons
Icon Status
Plug icon
2 solid batteries
1 solid battery
% displayed beneath battery
Connected to external power through AC adapter converter
2 batteries installed
1 battery installed
Amount of charge capacity remaining for battery
System Statistics—Battery Screen
To view the battery status, press
System
,
System Stats
,
Battery
. The Battery screen displays several kinds of information:
•
•
Temperature—the internal temperature of each battery as measured by a sensor embedded in each battery
Voltage—for each battery cell stack as measured by each battery’s sensor
182 Chapter 10
Working with Batteries
Viewing Battery Status
•
•
•
•
Run Time to Empty—while using external power, External DC Power is displayed; while using battery power, the predicted remaining battery run time is displayed in minutes at the present rate of discharge. The instrument mode you select affects the discharge rate, which determines the run time to empty.
Stimulus/Response uses the most power. The remaining modes use the least power.
Fuel Gauge Error—the present accuracy of each battery’s fuel gauge or remaining charge capacity. If the error exceeds 10%, you should recalibrate the battery using the optional stand alone battery charger.
Percent Charged—the predicted charge capacity of each battery in percent.
Battery Status—For Battery 1 and Battery 2, Present or Missing tells you whether a battery is installed.
Built-In Battery Gauge
Each Lithium Ion battery has a five-segment LCD gauge that displays its charge status. Each segment represents 20% of the charge capacity. The gauge is active unless the battery is in shutdown mode. You can view the gauge with the door open.
Chapter 10 183
CAUTION
NOTE
NOTE
NOTE
Working with Batteries
Charging Batteries
Charging Batteries
You can charge batteries internally or using the external battery charger (Option
BCG). The external charger provides much faster charging time.
Charge batteries internally or with the appropriate charger, an SMBus charger of level II or higher.
Never use a non-SMBus charger because the battery issues commands over the
SMBus to the charger to control the charge rate and voltage.
Never use a modified or damaged charger.
To ensure proper instrument function when operating the analyzer on battery power, both of the batteries must have equal charge levels.
For maximum runtime, it is best to have approximately equal charge levels on both batteries. The instrument will shut down if either battery becomes fully discharged during operation.
Internal Charging
You can use the N1996A to recharge the batteries while the analyzer is operating or shut down. For a fully depleted battery, charging time is approximately 4 hours if the analyzer is in standby, 8 hours if the analyzer is operating.
If two batteries are installed, the analyzer charges both batteries simultaneously.
To charge a battery internally, simply attach the external power supply and turn on external power.
Additional spurious responses may appear when operating the analyzer while charging a battery. These spurious responses are most noticeable when the battery is nearly depleted.
External Charging
The external battery charger (available as part of Option BCG) lets you charge two batteries simultaneously. If the batteries are fully depleted, it takes up to 4 hours to recharge them.
You have the option of charging batteries before they become fully depleted.
Doing this does not shorten battery life. But repeatedly charging a battery before it’s fully discharged will impair the accuracy of its internal charge-remaining indicator.
184 Chapter 10
Working with Batteries
Charging Batteries
External Battery Charger LED Charging Status
Green on
Green flashing
Blue flashing
Blue
Red flashing
Red on
Charging complete
Charging
Calibrating—the accuracy of the battery’s internal LCD charge gauge is being renewed. Refer to
“Recalibrating Batteries” on page 186.
Calibration is complete
Battery fuel gauge recalibration recommended
Error
Chapter 10 185
NOTE
Working with Batteries
Recalibrating Batteries
Recalibrating Batteries
Each battery contains a microchip that monitors battery usage and tracks how much capacity is available. This function can become less accurate because of temperature fluctuations, aging, self-discharge, repeated partial charging, and other factors. This inaccuracy is displayed on the System Statistics—Battery screen as
Fuel Gauge Error.
To ensure the accuracy of the battery’s internal capacity tracking system, occasionally you need to recalibrate the battery. Recalibrating is done by fully charging the battery, fully discharging it, recharging it again, and then verifying that the error has been corrected.
You can recalibrate a battery with the optional external charger. The charger makes the process simpler.
Determining if a Battery Needs Recalibration
To view the battery status, press
System
,
System Stats
,
Battery
.
After recalibrating, if the battery is not fully charged or still shows more than a
10% Fuel Gauge Error reading, repeat the recalibrating procedure. If the second recalibrating does not restore a full charge and an error reading of 10% or less, the battery needs replacement. This error will affect all of the displayed battery charge indicators.
Recalibrating with the External Battery Charger
1.
Insert a battery into the external battery charger. Only one of the two battery bays is capable of recalibrating the battery.
2.
If fuel gauge recalibration is recommended by the charger (LED flashing red), press the button on the front of the external battery charger to initiate a recalibration cycle.
The charger will charge the battery fully, discharge it completely, then recharge it fully again. The entire process can take up to 10 hours.
3.
Install the battery into the analyzer.
4.
On the System Statistics—Battery screen, verify that the battery is fully charged and recalibrated.
186 Chapter 10
WARNING
Working with Batteries
Battery Care
Battery Care
•
•
•
•
•
•
•
•
•
•
Lithium Ion and lithium polymer cells and battery packs may get hot, explode, or ignite and cause serious injury if exposed to abuse conditions. Be sure to follow these safety warnings:
Do not install the battery backward, so the polarity is reversed.
Do not connect the positive terminal and negative terminal of the battery to each other with any metal object (such as wire).
Do not carry or store the battery with necklaces, hairpins, or other metal objects.
Do not pierce the battery with nails, strike the battery with a hammer, step on the battery, or otherwise subject it to strong impacts or shocks.
Do not solder directly onto the battery.
Do not expose the battery to water or salt water, or allow the battery to get wet.
Do not disassemble or modify the battery. The battery contains safety and protection devices, which, if damaged, may cause the battery to generate heat, explode, or ignite.
Do not place the battery in or near fire, on stoves, or in other high temperature locations. Do not place the battery in direct sunlight, or use or store the battery inside cars in hot weather. Doing so may cause the battery to generate heat, explode, or ignite. Using the battery in this manner may also result in a loss of performance and a shortened life expectancy.
Danger of explosion if battery is incorrectly replaced. Replace only with the same or equivalent type recommended. Discard used batteries according to manufacturer’s instructions.
Do not throw batteries away but collect as small chemical waste
Chapter 10 187
WARNING
Working with Batteries
Battery Care
Do not discharge the battery using any device except the specified device.
When the battery is used in devices other than the specified device, it may damage the battery or reduce its life expectancy. If the device causes an abnormal current to flow, it may cause the battery to become hot, explode, or ignite and cause serious injury.
•
•
•
•
•
•
•
•
•
Maximizing Battery Life
The Lithium Ion battery used in the N1996A has a life span of approximately 300 charge cycles at room temperature, with normal charge and discharge rates. You can maximize the number of charge cycles with reasonable battery care:
Clean the battery contacts occasionally, using a pencil eraser or alcohol and a cotton swab. Make sure no residue from the eraser or cotton swab is left on the contact points.
Cycle each battery through a full charge and full discharge on a regular basis, preferably monthly. Even if you use external power most of the time, you will lengthen battery life by occasionally cycling through a full discharge/recharge cycle.
Do not leave a battery unused and fully charged for an extended period.
Batteries that sit idle eventually lose their ability to hold a charge.
Store batteries in a cool, dry location, away from metal objects and corrosive gases. To extend battery life during long-term battery storage, store the batteries with a 50% charge level. Storage limits are –20 °C to 60 °C 80% RH.
Extended exposure to high humidity or temperatures above 45 degrees Celsius
(113 degrees Fahrenheit) can impair battery performance and shorten battery life.
Allow a battery to warm to room temperature before charging it. Temperature shock can damage the battery chemistry and in some cases cause a short circuit.
Always charge batteries at temperatures between 0 and 45 degrees Celsius (32 to 113 degrees Fahrenheit).
Operate the analyzer on battery power between the temperatures of 0 and 50 degrees Celsius (32 to 122 degrees Fahrenheit). Using the batteries at lower or higher temperatures can damage the batteries and reduce operating life. Cold temperatures affect battery chemistry, reducing charge capacity, especially below 0 degrees Celsius (32 degrees Fahrenheit).
Batteries are shipped with a minimum of 20% charge capacity to provide at least a 6-month shelf life at room temperature, before the battery electronics go into shutdown mode. When a battery has discharged down to 7.1 volts, it goes into shutdown mode. When this occurs, the battery electronics self-disconnect, removing their electronic load from the cells. This provides approximately 1 year of room temperature storage before the cells self-discharge to the point beyond which they should not be recharged. Once a battery has reached shutdown mode the battery will undergo a self-test immediately upon being put
188 Chapter 10
NOTE
Working with Batteries
Battery Care
into charge. The charger will then attempt to pre-charge the battery at a very low initial charge rate. If the voltage does not recover, the battery pack has been allowed to discharge beyond the point of safe recovery. The charge cycle will be terminated, and the battery pack needs to be replaced.
If the battery does recover from a shutdown mode, the fuel gauge accuracy will be reduced. Complete a battery recalibration as soon as possible to calibrate the fuel gauge.
Initial Charge Cycle
New batteries must be rapid-charged (typically to 80%), then trickle-charged
(slowly charged to 100%) for 24 hours, before their first use and for the first two or three uses.
Because the batteries you receive for use with the N1996A are new, they have a minimal charge when you receive them. All batteries require a “break-in” period, so do not be alarmed if a battery doesn't hold a full charge right away. A new battery commonly will show a false full charge (voltage) as indicated on the analyzer or charger, and may not power up the analyzer upon first use. Before using a new battery, leave it charging for 24 hours.
Batteries are not standard on the N1996A, but they can be ordered with a new analyzer or later as an upgrade kit.
Lithium Ion Battery Disposal
When you notice a large decrease in charge capacity after proper recharging, it is probably time to replace the battery.
Li-Ion batteries need to be disposed of properly. Contact your local waste management facility for information regarding environmentally sound collection, recycling, and disposal of the batteries. Regulations vary for different countries.
Dispose of in accordance with local regulations.
Chapter 10 189
Working with Batteries
Battery Specifications
Battery Specifications
•
•
The N1996A Agilent CSA Series Spectrum Analyzer uses the Inspired Energy
NF2040HD24 Smart Battery, which produces 10.8 volts DC at approximately 6 A.
The NF2040HD24 is a Lithium Ion battery pack, which uses the System
Management Bus (SMBus) interface to communicate with the analyzer and charger. To charge the batteries, use only the Agilent approved SMBus charger of
Level II or higher or the N1996A.
The battery is designed for approximately 300 full charge/discharge cycles at room temperature and under normal rates of discharge.
The NF2040HD24 uses electronically programmable read-only memory
(EPROM) to store key data regarding the battery cells and charge capacity.
Protection Electronics
The NF2040HD24 SMBus battery uses several protection devices to prevent damage to the battery and analyzer. The battery is internally protected against excessive current draws and reduced loads (shorts), excessive voltage and temperatures.
During charging and discharging, the battery will monitor and report its voltage, current, and temperature. If any of these monitored conditions exceeded their safety limits, the battery will terminate any further charge or discharge until the error condition is corrected.
Analyzer Operation: Battery Current Drain in the Off Mode
When the analyzer is operating from battery power, it continues to draw current in the off mode. When in off mode, the analyzer draws <10 mA per hour, or approximately 38 days to discharge. Agilent recommends that if the analyzer is not going to be used for an extended period of time, remove the batteries from your analyzer. This will ensure you have sufficient battery capacity if you intend to operate the analyzer from battery power.
Battery and Charger Part Numbers
Option BAT
Description
NF2040HD24 Battery (quantity 2)
Part Number
1420-0891
Option BCG
Description
Dual Battery Charger
Part Number
0950-4776
190 Chapter 10
NOTE
NOTE
Working with Batteries
Battery Specifications
Replace only with NF2040HD24 or equivalent, Agilent-approved battery.
Additional batteries are also available directly from Inspired Energy, Inc. To purchase additional or replacement batteries, visit www.inspired-energy.com, or call toll free USA 1-888-5-INSPIRE (546-7747).
When operating the analyzer on battery power, batteries of different capacities will share current in proportion to individual battery capacity. Therefore, when purchasing and installing batteries, ensure that both batteries have equivalent capacities. Even batteries that appear physically identical, can have different capacities. It is recommended that batteries be purchased and installed in pairs.
Chapter 10 191
Working with Batteries
Battery Specifications
192 Chapter 10
11
Concepts
193
Concepts
Resolving Closely Spaced Signals
Resolving Closely Spaced Signals
Resolving Signals of Equal Amplitude
Two equal-amplitude input signals that are close in frequency can appear as a single signal trace on the analyzer display. Responding to a single-frequency signal, a swept-tuned analyzer traces out the shape of the selected internal IF
(intermediate frequency) filter (typically referred to as the resolution bandwidth or
RBW filter). As you change the filter bandwidth, you change the width of the displayed response. If a wide filter is used and two equal-amplitude input signals are close enough in frequency, then the two signals will appear as one signal. If a narrow enough filter is used, the two input signals can be discriminated and appear as separate peaks. Thus, signal resolution is determined by the IF filters inside the analyzer.
The bandwidth of the IF filter tells us how close together equal amplitude signals can be and still be distinguished from each other. The resolution bandwidth function selects an IF filter setting for a measurement. Typically, resolution bandwidth is defined as the 3 dB bandwidth of the filter. However, resolution bandwidth may also be defined as the 6 dB or impulse bandwidth of the filter.
Generally, to resolve two signals of equal amplitude, the resolution bandwidth must be less than or equal to the frequency separation of the two signals. If the bandwidth is equal to the separation and the video bandwidth is less than the resolution bandwidth, a dip of approximately 3 dB is seen between the peaks of the two equal signals, and it is clear that more than one signal is present.
When the Agilent CSA spectrum analyzer span is > 0 Hz, the sweep time is set automatically to keep the analyzer measurement calibrated. When the resolution bandwidth is < 1 kHz, there will be large increases in the sweep time as you decrease the RBW in a 1, 3, 10 sequence. Fortunately, the Agilent CSA allows you to also set the RBW to discrete values, thereby allowing you greater flexibility in trading off sweep time and resolution.
For the shortest measurement times, use the widest resolution bandwidth that still permits discrimination of all desired signals.
For example, in a 10 MHz span, the sweep time with a 300 Hz RBW is 1.23 s, and the sweep time with a 100 Hz RBW is 9.01 s. If the 300 Hz RBW does not provide sufficient resolution, and the sweep time with a 100 Hz RBW is too long, you could try the 200 Hz RBW. The sweep time with a 200 Hz RBW is 2.52 s, over 3 times faster than the sweep time with a 100 Hz RBW.
Resolving Small Signals Hidden by Large Signals
When dealing with the resolution of signals that are close together and not equal in amplitude, you must consider the shape of the IF filter of the analyzer, as well as its 3 dB bandwidth. (See
“Resolving Signals of Equal Amplitude” on page 194 for
more information.) The shape of a filter is defined by the selectivity, which is the
194 Chapter 11
Figure 11-1
Concepts
Resolving Closely Spaced Signals
ratio of the 60 dB bandwidth to the 3 dB bandwidth. If a small signal is too close to a larger signal, the smaller signal can be hidden by the skirt of the larger signal.
To view the smaller signal, select a resolution bandwidth such that k is less than a
). The separation between the two signals (a) must be greater than half the filter width of the larger signal (k), measured at the amplitude level of the smaller signal.
The digital filters in the Agilent CSA have filter widths about one-half to one-third as wide as typical analog RBW filters. This enables you to resolve close signals with a wider RBW (for a faster sweep time).
RBW Requirements for Resolving Small Signals
Chapter 11 195
Concepts
Trigger Concepts
Trigger Concepts
With firmware versions prior to A.02.00, the trigger functions are only available when the Agilent CSA is in zero span. With firmware version A.02.00 and later, the trigger functions are available in both zero span and non-zero span.
Selecting a Trigger
1. Video Triggering
Video triggering controls the sweep time based on the detected envelope signal to steady the signal on the display. Video triggering triggers the measurement at the point at which the rising signal crosses the trigger level horizontal green line on the display:
Press
Meas Setup
,
Trigger
,
Video
,
30
,
dBm
.
2. External Triggering
In the event that you have an external trigger available that can be used to synchronize with the signal of interest, connect the trigger signal to the rear of the Agilent CSA using the EXT TRIGGER IN connector. You can change the slope of the external trigger signal on which you want the analyzer to trigger using the Trigger Slope feature.
Press
Meas Setup
,
Trigger, External
.
3. RF Burst Triggering
RF burst triggering occurs in the IF circuitry chain, as opposed to after the video detection circuitry with video triggering. In the event video triggering is used, the detection filters are limited to the maximum width of the resolution bandwidth filters. The RF burst signal level can be set using the Trigger Level feature.
Press
Meas Setup
,
Trigger
,
RF Burst
.
Trigger Delay
Trigger delay can be used to move the sweep trigger point arbitrarily to allow closer examination of waveform patterns (Press
Trigger
,
Trigger Delay
, and enter a delay time).
196 Chapter 11
Concepts
AM and FM Demodulation Concepts
Figure 11-2
AM and FM Demodulation Concepts
Demodulating an AM Signal Using the Analyzer as a Fixed Tuned
Receiver (Time-Domain)
The zero span mode can be used to recover amplitude modulation on a carrier signal.
The following functions establish a clear display of the waveform:
• Triggering stabilizes the waveform trace by triggering on the modulation envelope. If the modulation of the signal is stable, video trigger synchronizes the sweep with the demodulated waveform.
• Linear display mode should be used in amplitude modulation (AM) measurements to avoid distortion caused by the logarithmic amplifier when demodulating signals.
• Sweep time to view the rate of the AM signal.
• RBW is selected according to the signal bandwidth.
Demodulating an FM Signal Using the Analyzer as a Fixed Tuned
Receiver (Time-Domain)
To recover the frequency modulated signal, a spectrum analyzer can be used as a manually tuned receiver (zero span). However, in contrast to AM, the signal is not
tuned into the passband center, but to one slope of the filter curve as Figure 11-2
.
Determining FM Parameters using FM to AM Conversion
Here the frequency variations of the FM signal are converted into amplitude variations (FM to AM conversion). The reason we want to measure the AM component is that the envelope detector responds only to AM variations. There are no changes in amplitude if the frequency changes of the FM signal are limited to the flat part of the RBW (IF filter). The resultant AM signal is then detected with the envelope detector and displayed in the time domain.
Chapter 11 197
NOTE
Concepts
Stimulus Response Measurement Concepts
Stimulus Response Measurement Concepts
Stimulus response measurements require the N8995A Stimulus Response
Measurement Suite and either option SR3 or SR6.
Stimulus Response Overview
Stimulus response measurements require a source to stimulate a device under test
(DUT), a receiver to analyze the frequency response characteristics of the DUT, and, for return loss measurements, a directional coupler or bridge. The Agilent
CSA signal source options include a built-in RF bridge. Characterization of a DUT can be made in terms of its transmission or reflection parameters. Examples of transmission measurements include flatness and rejection. Return loss is an example of a reflection measurement.
A spectrum analyzer combined with a signal source forms a stimulus response measurement system. With the signal source as the swept source and the analyzer as the receiver, operation is the same as a single channel scalar network analyzer.
The signal source output frequency must be made to precisely track the analyzer input frequency for good narrow band operation. A narrow band system has a wide dynamic measurement range. This wide dynamic range will be illustrated in the following example.
There are three basic steps in performing a stimulus response measurement, whether it is a transmission or a reflection measurement. The first step is to set up the analyzer, the second is to normalize, and the last step is to perform the measurement.
Normalization Concepts
To make a transmission measurement accurately, the frequency response of the test system must be known. Normalization is used to eliminate this error from the measurement. To measure the frequency response of the test system, connect the cable (but not the DUT) from the signal source output to the analyzer input.
Press
Mode, Stimulus/Response
,
Two Port Insertion Loss
. Set the desired start and stop frequencies. Press
Normalize
,
Continue
.
The frequency response of the test system is automatically stored and a normalization is performed. This means that the active displayed trace is now the ratio of the input data to the data stored in memory.
When normalization is on, trace math is performed on the active trace, with the result placed into the selected trace.
Reconnect the DUT to the analyzer. Note that the units of the reference level are dB, indicating that this is a relative measurement.
To make a reflection measurement accurately, it is necessary to perform an
198 Chapter 11
Concepts
Stimulus Response Measurement Concepts
open/short/load calibration. An open, short, and load are included in the Stimulus
Response Calibration Kit, Option SRK.
Press
Mode, Stimulus/Response, Return Loss.
Set the desired start and stop frequencies. Press
Calibrate
and follow the instructions.
After the calibration is complete, connect the DUT to the RF OUTPUT connector to make your return loss measurement. The marker readout returns the amplitude values in both return loss and VSWR.
Chapter 11 199
Concepts
AM Concepts
Figure 11-3
AM Concepts
AM waveform
Figure 11-4
In AM (Amplitude Modulation), the instantaneous amplitude of the modulated carrier signal changed in proportion to the instantaneous amplitude of the information signal.
Calculation AM index in time and frequency domain
Equation 11-1
The modulation index m represents the amount of the modulation or the degree to which the information signal modulates the carrier signal.The index for an AM signal can be calculated from the amplitudes of the carrier and either of the sidebands by the equation: m =
E max c
–
E c
--------------------- =
E
E max
E min
-------------------------- =
E max
–
+
E min
E
USB
+ c
E
LSB
-------------------------- =
E
2E
SB
----------
E c
For 100% modulation, the modulation index is 1.0, and the amplitude of each sideband will be one-half of the carrier amplitude expressed in voltage. On a decibel power scale, each sideband will thus be 6 dB less than the carrier, or one-fourth the power of the carrier. Since the carrier power does not change with amplitude modulation, the total power in the 100% modulated wave is 50% higher
200 Chapter 11
Equation 11-2
Concepts
AM Concepts
than in the unmodulated carrier. The relationship between m and the logarithmic display can be expressed as:
E
SB
E c
dB + 6dB = 20 log m
Chapter 11 201
Concepts
FM Concepts
Figure 11-5
FM Concepts
FM waveform
Equation 11-3
FM (Frequency Modulation) and PM (Phase modulation) belong to angle modulation. In FM, the instantaneous frequency deviation of the modulated carrier signal changed in proportion to the instantaneous amplitude of the modulating signal. And in PM, the instantaneous phase deviation of the modulated carrier with respect to the phase of the unmodulated carrier is directly proportional to the instantaneous amplitude of the modulating signal.
The modulation index for angle modulation,
, is expressed by this equation:
= f p m p
Where
fp is the peak frequency deviation, fm is the frequency of the modulating signal, and
p is the peak phase deviation.
This expression tells us that the angle modulation index is really a function of phase deviation, even in the FM case. Also, note that the definitions for frequency and phase modulation do not include the modulating frequency. In each case, the modulated property of the carrier, frequency or phase, deviates in proportion to the instantaneous amplitude of the modulating signal, regardless of the rate at which the amplitude changes. However, the frequency of the modulating signal is important in FM and is included in the expression for the modulating index because it is the ratio of peak frequency deviation to modulation frequency that equates to peak phase.
Unlike the modulation index for AM, there is no specific limit to the value of
, since there is no theoretical limit to the phase deviation; thus there is no equivalent of 100% AM. However, in real world systems there are practical limits.
202 Chapter 11
Figure 11-6
Concepts
FM Concepts
Unlike AM, which is a linear process, angle modulation is nonlinear. This means that a single sine wave modulating signal, instead of producing only two sidebands, yields an infinite number of sidebands spaced by the modulating frequency.
The Bessel function graph shows the amplitudes of the carrier and the sidebands as a function of modulation index,
. The spectral components, including the carrier, change their amplitudes as the modulation index varies.
Carrier and sideband amplitude for angle-modulated signals
In theory, for distortion-free detection of the modulating signal, all the sidebands must be transmitted. However, in practice, the sideband amplitudes become negligibly small beyond a certain frequency offset from the carrier, so the spectrum of a real-world FM signal is not infinite.
Chapter 11 203
Concepts
Modulation Distortion Measurement Concepts
Equation 11-4
Modulation Distortion Measurement Concepts
Purpose
This measurement is used to measure the amount of modulation distortion contained in the Modulated signal by determining the ratio of harmonic and noise power to fundamental power. This measurement verifies the modulation quality of the signal from the UUT.
Measurement Technique
Modulation Distortion is defined as:
%
ModulationDistortion
=
P
P
–
P total
100% where: P total
= the power of the total signal,
P signal
= the power of the wanted modulating signal, and
P total
- P signal
= total unwanted signal which includes harmonic distortion and noise.
First, the received signal is demodulated and filtered to remove DC. Then the filtered signal is transformed by an FFT into frequency domain. Next, total power in the total filter band is measured as P total
, the peak power of the modulated signal is computed as P signal
, the square root of the ratio of P total
- P signal
to P total
is calculated. The result is signal’s modulation distortion. It can be expressed as dB or %.
204 Chapter 11
Concepts
Modulation SINAD Measurement Concepts
Equation 11-5
Modulation SINAD Measurement Concepts
Purpose
Modulation SINAD (SIgnal to Noise And Distortion) measures the amount of
Modulation SINAD contained in the modulated signal by determining the ratio of fundamental power to harmonic and noise power. Modulation SINAD is reciprocal of modulation distortion provided by Modulation Distortion measurement. This is another way to quantify the quality of the modulation process
Measurement Technique
Modulation SINAD is defined as: dB
ModulationSINAD
=
20
log
P
P total total
–
P signal where: P total
= the power of the total signal,
P signal
= the power of the wanted modulating signal, and
P total
- P signal
= the total unwanted signals which include harmonic distortion and noise.
First, the received signal is demodulated and filtered to remove DC, then the filtered signal is transformed by an FFT into frequency domain. Next, total power in the total filter band is measured as P total
, the peak power of the modulated signal is computed as P signal
, the square root of the ratio of P total
to P total
- P signal
is calculated. The result is signal’s Modulation SINAD. It can be expressed as dB or
%.
Chapter 11 205
Concepts
Modulation SINAD Measurement Concepts
206 Chapter 11
12
Programming Examples
207
Programming Examples
Finding Examples and More Information
Finding Examples and More Information
The latest version of programming examples are available from the following
URL:
http://www.agilent.com/find/saprogramming
Interchangeable Virtual Instruments COM (IVI-COM) drivers
: Develop system automation software easily and quickly. IVI-COM drivers take full advantage of application development environments such as Visual Studio using Visual Basic, C# or Visual C++ as well as Agilent's Test and
Measurement Toolkit. You can now develop application programs that are portable across computer platforms and I/O interfaces. With IVI-COM drivers you do not need to have in depth test instrument knowledge to develop sophisticated measurement software. IVI-COM drivers provide a compatible interface to all. COM environments. The IVI-COM software drivers can be found at the URL
http://www.agilent.com/find/ivi-com
208 Chapter 12
Programming Examples
Programming Examples Information and Requirements
Programming Examples Information and Requirements
• The programming examples were written for use on an IBM compatible PC.
• The programming examples use C, Visual Basic and VEE programming languages.
• The programming examples use the LAN interface.
• Most of the examples are written in C using the Agilent VISA library.
The VISA transition library must be installed. The Agilent I/O libraries contain the latest VISA library and is available at:
www.agilent.com/find/iolib
Chapter 12 209
Programming Examples
Programming in C Using the VISA
Programming in C Using the VISA
The C programming examples that are provided are written using the C programming language and the Agilent (VISA library). This section includes some basic information about programming in the C language. Note that some of this information may not be relevant to your particular application. (For example, if you are not using VXI instruments, the VXI references will not be relevant).
Refer to your C programming language documentation for more details. The following topics are included:
“Typical Example Program Contents” on page 211
“Linking to VISA Libraries” on page 212
“Compiling and Linking a VISA Program” on page 212
“Including the VISA Declarations File” on page 214
“Opening a Session” on page 215
“Addressing a Session” on page 216
“Closing a Session” on page 218
210 Chapter 12
Programming Examples
Programming in C Using the VISA
Typical Example Program Contents
The following is a summary of the VISA function calls used in the example programs.
visa.h
This file is included at the beginning of the file to provide the function prototypes and constants defined by VISA.
ViSession
The
ViSession
is a VISA data type. Each object that will establish a communication channel must be defined as
ViSession
.
viOpenDefaultRM
You must first open a session with the default resource manager with the viOpenDefaultRM
function. This function will initialize the default resource manager and return a pointer to that resource manager session.
viOpen
This function establishes a communication channel with the device specified. A session identifier that can be used with other
VISA functions is returned. This call must be made for each device you will be using.
viPrintf viScanf viClose
These are the VISA formatted I/O functions that are patterned after those used in the C programming language. For example, the viPrintf
call sends the IEEE 488.2
*RST
command to the instrument to put it in a known state. The viPrintf
call is used again to query for the device identification (
*IDN?
). The viScanf
call is then used to read the results.
This function must be used to close each session. When you close a device session, all data structures that had been allocated for the session will be de-allocated. When you close the default manager session, all sessions opened using the default manager session will be closed.
Chapter 12 211
Programming Examples
Programming in C Using the VISA
Linking to VISA Libraries
Your application must link to one of the VISA import libraries:
32-bit Version:
C:\VXIPNP\WIN95\LIB\MSC\VISA32.LIB
for Microsoft compilers
C:\VXIPNP\WIN95\LIB\BC\VISA32.LIB
for Borland compilers
16-bit Version:
C:\VXIPNP\WIN\LIB\MSC\VISA.LIB
for Microsoft compilers
C:\VXIPNP\WIN\LIB\BC\VISA.LIB
for Borland compilers
See the following section, “Compiling and Linking a VISA Program” for
information on how to use the VISA run-time libraries.
Compiling and Linking a VISA Program
32-bit Applications
The following is a summary of important compiler-specific considerations for several C/C++ compiler products when developing WIN32 applications.
For Microsoft Visual C++ version 2.0 compilers:
• Select
Project | Update All Dependencies
from the menu.
• Select
Project | Settings
from the menu. Click on the
C/C++
button.
Select
Code Generation
from the
Use Run-Time Libraries
list box. VISA requires these definitions for WIN32. Click on
OK
to close the dialog boxes.
• Select
Project | Settings
from the menu. Click on the
Link
button and add visa32.lib
to the
Object / Library Modules
list box.
Optionally, you may add the library directly to your project file. Click on
OK
to close the dialog boxes.
• You may wish to add the include file and library file search paths. They are set by doing the following:
1. Select
Tools | Options
from the menu.
2. Click on the
Directories
button to set the include file path.
3. Select
Include Files
from the
Show Directories For
list box.
4. Click on the
Add
button and type in the following:
C:\VXIPNP\WIN95\INCLUDE
5. Select
Library Files
from the
Show Directories For
list box.
6. Click on the
Add
button and type in the following:
C:\VXIPNP\WIN95\LIB\MSC
For Borland C++ version 4.0 compilers:
212 Chapter 12
Programming Examples
Programming in C Using the VISA
• You may wish to add the include file and library file search paths. They are set under the
Options | Project
menu selection. Double click on
Directories
from the
Topics
list box and add the following:
C:\VXIPNP\WIN95\INCLUDE
C:\VXIPNP\WIN95\LIB\BC
16-bit Applications
The following is a summary of important compiler-specific considerations for the
Windows compiler.
For Microsoft Visual C++ version 1.5:
• To set the memory model, do the following:
1. Select
Options | Project
.
2. Click on the
Compiler
button, then select
Memory Model
from the
Category
list.
3. Click on the
Model
list arrow to display the model options, and select
Large
.
4. Click on
OK
to close the
Compiler
dialog box.
• You may wish to add the include file and library file search paths. They are set under the
Options | Directories
menu selection:
C:\VXIPNP\WIN\INCLUDE
C:\VXIPNP\WIN\LIB\MSC
Otherwise, the library and include files should be explicitly specified in the project file.
Chapter 12 213
Programming Examples
Programming in C Using the VISA
Example Program
This example program queries a LAN device for an identification string and prints the results. Note that you must change the address.
/*idn.c - program filename */
#include "visa.h"
#include <stdio.h>
void main ()
{
/*Open session to LAN device at IP address 192.168.0.2
*/
ViOpenDefaultRM (&defaultRM);
ViOpen (defaultRM, "TCPIP0::192.168.0.2::inst0::INSTR",
VI_NULL,
VI_NULL, &vi);
/*Initialize device */
viPrintf (vi, "*RST\n");
/*Send an *IDN? string to the device */
printf (vi, "*IDN?\n");
/*Read results */
viScanf (vi, "%t", &buf);
/*Print results */
printf ("Instrument identification string: %s\n", buf);
/* Close sessions */
viClose (vi); viClose (defaultRM);
}
Including the VISA Declarations File
For C and C++ programs, you must include the visa.h
header file at the beginning of every file that contains VISA function calls:
#include “visa.h”
This header file contains the VISA function prototypes and the definitions for all
VISA constants and error codes. The visa.h
header file includes the visatype.h
header file.
The visatype.h
header file defines most of the VISA types. The VISA types are used throughout VISA to specify data types used in the functions. For example, the viOpenDefaultRM
function requires a pointer to a parameter of type
ViSession
. If you find
ViSession
in the visatype.h
header file, you will find that
ViSession
is eventually typed as an unsigned long.
214 Chapter 12
NOTE
Programming Examples
Programming in C Using the VISA
Opening a Session
A session is a channel of communication. Sessions must first be opened on the default resource manager, and then for each device you will be using. The following is a summary of sessions that can be opened:
• A resource manager session is used to initialize the VISA system. It is a parent session that knows about all the opened sessions. A resource manager session must be opened before any other session can be opened.
• A device session is used to communicate with a device on an interface. A device session must be opened for each device you will be using. When you use a device session you can communicate without worrying about the type of interface to which it is connected. This insulation makes applications more robust and portable across interfaces. Typically a device is an instrument, but could be a computer, a plotter, or a printer.
All devices that you will be using need to be connected and in working condition prior to the first VISA function call ( viOpenDefaultRM
). The system is configured only on the first viOpenDefaultRM
per process. Therefore, if viOpenDefaultRM
is called without devices connected and then called again when devices are connected, the devices will not be recognized. You must close
ALL resource manager sessions and re-open with all devices connected and in working condition.
Device Sessions
There are two parts to opening a communications session with a specific device.
First you must open a session to the default resource manager with the viOpenDefaultRM
function. The first call to this function initializes the default resource manager and returns a session to that resource manager session. You only need to open the default manager session once. However, subsequent calls to viOpenDefaultRM
returns a session to a unique session to the same default resource manager resource.
Next, you open a session with a specific device with the viOpen
function. This function uses the session returned from viOpenDefaultRM
and returns its own session to identify the device session. The following shows the function syntax: viOpenDefaultRM (sesn); viOpen (sesn, rsrcName, accessMode, timeout, vi);
Chapter 12 215
Programming Examples
Programming in C Using the VISA
The session returned from viOpenDefaultRM
must be used in the sesn parameter of the viOpen
function. The viOpen
function then uses that session and the device address specified in the rsrcName parameter to open a device session. The
vi parameter in viOpen
returns a session identifier that can be used with other
VISA functions.
Your program may have several sessions open at the same time by creating multiple session identifiers by calling the viOpen
function multiple times.
The following summarizes the parameters in the previous function calls:
sesn This is a session returned from the viOpenDefaultRM function that identifies the resource manager session.
rsrcName
accessMode
This is a unique symbolic name of the device (device address).
This parameter is not used for VISA. Use VI_NULL.
timeout
vi
This parameter is not used for VISA. Use VI_NULL.
This is a pointer to the session identifier for this particular device session. This pointer will be used to identify this device session when using other VISA functions.
The following is an example of opening sessions with a GPIB multimeter and a spectrum analyzer on LAN:
ViSession defaultRM, dmm, sa;
.
.
viOpenDefaultRM(&defaultRM); viOpen (defaultRM, "GPIB0::22::INSTR", VI_NULL,
VI_NULL, &dmm); viOpen (defaultRM, "TCPIP0::192.168.0.2::inst0::INSTR",
VI_NULL,
VI_NULL, &sa);
.
.
viClose (sa); viClose (dmm); viClose(defaultRM);
The above function first opens a session with the default resource manager. The session returned from the resource manager and a device address is then used to open a session with the GPIB device at address 22. That session will now be identified as dmm when using other VISA functions. The session returned from the resource manager is then used to open a session with the LAN device at IP
Address 192.168.0.2. That session will now be identified as sa when using other
VISA functions. See the following section for information on addressing particular devices.
Addressing a Session
As seen in the previous section, the rsrcName parameter in the viOpen
function is
216 Chapter 12
NOTE
Programming Examples
Programming in C Using the VISA
used to identify a specific device. This parameter is made up of the VISA interface name and the device address. The interface name is determined when you run the
VISA Configuration Utility. This name is usually the interface type followed by a number. The following table illustrates the format of the rsrcName for the different interface types:
Interface
VXI
GPIB-VXI
GPIB
TCPIP
Syntax
VXI [board]::VXI logical address[::INSTR]
GPIB-VXI [board]::VXI logical address[::INSTR]
GPIB [board]::primary address[::secondary address][::INSTR]
TCPIP [board]::host address[::LAN device name]::INSTR
The following describes the parameters used above:
board This optional parameter is used if you have more than one interface of the same type. The default value for board is 0.
VSI logical
address
primary
address
secondary
address
This is the logical address of the VXI instrument.
This is the primary address of the GPIB device.
This optional parameter is the secondary address of the GPIB device. If no secondary address is specified, none is assumed.
host
address The IP address (in dotted decimal notation) or the name of the host computer/gateway.
LAN device
name
INSTR
The assigned name for a LAN device. The default is inst().
This is an optional parameter that indicates that you are communicating with a resource that is of type INSTR, meaning instrument.
If you want to be compatible with future releases of VISA and VISA, you must include the INSTR parameter in the syntax.
The following are examples of valid symbolic names:
XI0::24::INSTR Device at VXI logical address 24 that is of VISA type INSTR.
VXI2::128 Device at VXI logical address 128, in the third VXI system
(VXI2).
GPIB-VXI0::24 A VXI device at logical address 24. This VXI device is connected via a GPIB-VXI command module.
Chapter 12 217
Programming Examples
Programming in C Using the VISA
GPIB0::7::0 A GPIB device at primary address 7 and secondary address 0 on the GPIB interface.
TCPIP::[email protected]::INSTR
A TCPIP device using VXI-11 located at the specified address.
This uses the default LAN Device Name of inst0.
The following is an example of opening a device session with the GPIB device at primary address23.
ViSession defaultRM, vi;
.
.
viOpenDefaultRM (&defaultRM); viOpen (defaultRM, "GPIB0::23::INSTR", VI_NULL,VI_NULL,&vi);
.
.
viClose(vi); viClose (defaultRM);
Closing a Session
The viClose
function must be used to close each session. You can close the specific device session, which will free all data structures that had been allocated for the session. If you close the default resource manager session, all sessions opened using that resource manager will be closed.
Since system resources are also used when searching for resources ( viFindRsrc
) or waiting for events ( viWaitOnEvent
), the viClose
function needs to be called to free up find lists and event contexts.
218 Chapter 12
13
Connector Care
219
Connector Care
This chapter contains the following topics on care of your Agilent CSA connectors:
“Using, Inspecting, and Cleaning RF Connectors” on page 221
“RF Cable and Connector Care” on page 221
“Proper Connector Torque” on page 222
“Connector Wear and Damage” on page 222
“Cleaning Procedure” on page 222
220 Chapter 13
CAUTION
Connector Care
Using, Inspecting, and Cleaning RF Connectors
Using, Inspecting, and Cleaning RF Connectors
Taking proper care of cables and connectors will protect the ability of your analyzer to make accurate measurements. Inaccurate measurements often result from improperly made connections or dirty or damaged connectors. Worn, out-of-tolerance, or dirty connectors degrade the accuracy and repeatability of measurements.
Repeatability
•
•
If you make two identical measurements with your analyzer, the differences should be so small that they do not affect the value of the measurement. Repeatability (the amount of similarity from one measurement to another of the same type) can be affected by:
Dirty or damaged connectors
Connections that have been made without using proper torque techniques (this applies primarily when connectors in the analyzer have been disconnected, then reconnected)
This analyzer contains devices that are static-sensitive. Always take proper electrostatic precautions before touching the center conductor of any connector, or the center conductor of any cable that is connected to the analyzer.
RF Cable and Connector Care
Connectors are the most critical link in a precision measurement. These devices are manufactured to extremely precise tolerances and must be used and maintained with care to protect the measurement accuracy and repeatability of your analyzer.
•
•
•
•
•
•
•
•
To Extend the Life of Your Cables or Connectors:
Avoid repeated bending of cables—a single sharp bend can ruin a cable instantly.
Avoid repeated connection and disconnection of cable connectors.
Inspect the connectors before connection; look for dirt, nicks, and other signs of damage or wear. A bad connector can ruin the good connector instantly.
Clean dirty connectors. Dirt and foreign matter can cause poor electrical connections and may damage the connector.
Minimize the number of times you bend cables.
Never bend a cable at a sharp angle.
Do not bend cables near the connectors.
If any of the cables will be flexed repeatedly, buy a back-up cable. This will
Chapter 13 221
CAUTION
Table 13-1
WARNING
Connector Care
Using, Inspecting, and Cleaning RF Connectors
allow immediate replacement and will minimize your analyzer’s down time.
•
•
Before Connecting the Cables to Any Device:
Check all connectors for wear or dirt.
When making the connection, torque the connector to the proper value.
Proper Connector Torque
•
•
Provides more accurate measurements
Keeps moisture out the connectors
•
Eliminates radio frequency interference (RFI) from affecting your measurements
The torque required depends on the type of connector. Refer to
. Do not overtighten the connector.
Never exceed the recommended torque when attaching cables.
Proper Connector Torque
Connector
Type-N
3.5 mm
SMA
Torque cm-kg
52
9.2
5.7
Torque
N-cm
508
90
56
Torque in-lbs
45
8
5
Wrench part number
8710-1935
8710-1765
8710-1582
Connector Wear and Damage
Look for metal particles from the connector threads and other signs of wear (such as discoloration or roughness). Visible wear can affect measurement accuracy and repeatability. Discard or repair any device with a damaged connector. A bad connector can ruin a good connector on the first mating. A magnifying glass or jeweler’s loupe is useful during inspection.
Cleaning Procedure
1.
Blow particulate matter from connectors using an environmentally-safe aerosol such as Ultrajet. This product is recommended by the United States
Environmental Protection Agency and contains chlorodifluoromethane.
2.
Use an alcohol wipe to wipe connector surfaces. Wet a small swab with alcohol
(from the alcohol wipe) and clean the connector with the swab.
Use alcohol in a well ventilated area and allow adequate time for fumes to
222 Chapter 13
CAUTION
Connector Care
Using, Inspecting, and Cleaning RF Connectors disperse and moist alcohol to evaporate.
3.
Allow the alcohol to evaporate off the connector before making connections
Do not allow excessive alcohol to run into the connector. Excessive alcohol entering the connector collects in pockets in the connector’s internal parts. The liquid will cause random changes in the connector’s electrical performance. If excessive alcohol gets into a connector, lay it aside to allow the alcohol to evaporate. This may take up to three days. If you attach that connector to another device it can take much longer for trapped alcohol to evaporate.
Chapter 13 223
Connector Care
Using, Inspecting, and Cleaning RF Connectors
224 Chapter 13
14
In Case of Difficulty
This chapter includes information on how to check for a problem with your
Agilent Technologies spectrum analyzer, and how to return it for service.
If you experience a problem or would like additional information about your
225
WARNING
NOTE
In Case of Difficulty
•
• analyzer, Agilent Technologies’ worldwide organization is ready to provide the support you need. Before calling Agilent Technologies, however (or returning an analyzer for service), perform the quick checks listed in
“Check the Basics” on page 228. This check may eliminate the problem.
If a problem persists, you may choose to:
Repair the analyzer yourself. See
“Service Options” on page 229.
Return the analyzer to Agilent Technologies for repair. See “Returning an
Analyzer for Service” on page 231, for more information.
No operator serviceable parts inside. Refer servicing to qualified personnel.
To prevent electrical shock, do not remove covers.
If the analyzer is still under warranty or is covered by a maintenance contract, it will be repaired under the terms of the warranty or plan (the warranty is located in the Specifications Guide).
If the analyzer is no longer under warranty or is not covered by an Agilent
Technologies maintenance plan, Agilent Technologies will notify you of the cost of the repair after examining the analyzer.
226 Chapter 14
Table 14-1
In Case of Difficulty
Types of Spectrum Analyzer Messages
Types of Spectrum Analyzer Messages
The analyzer can generate various messages that appear on the display during operation.
For a complete list of spectrum analyzer messages, see the Instrument Messages and Functional Tests manual. The following table describes the three types of spectrum analyzer messages.
Types of Messages
Type of Message Location Notes
Informational messages typically provide verification that an action has occurred. In general, no user intervention is required.
Status messages indicate a condition that may result in erroneous data being displayed.
Multiple status messages may be displayed at the same time.
User Error messages appear when an attempt has been made to set a parameter incorrectly or an operation has failed (such as saving a file).
Bottom of the display in the status line.
Bottom of the display in the status line and/or in the SCPI Status
Register system.
Bottom of the display in the status line and in the SCPI Error
Queue.
Messages will remain until the message is cleared by pressing
Esc
or it is overwritten by another message.
Messages in the display status line will remain until the message is cleared by pressing
Esc
or it is overwritten by another message.
Messages in the display status line will remain until you clear the error or another message is displayed in the status line.
Pressing the
Esc
key will clear error messages from the display, but the messages will remain in the error queue.
Chapter 14 227
NOTE
TIP
In Case of Difficulty
Before Calling Agilent Technologies
Before Calling Agilent Technologies
Check the Basics
o Is there power at the receptacle? o Is the analyzer turned on? Check to see if the green LED above the power switch is on. Also, listen for internal fan noise to determine if the analyzer cooling fan is running. o If other equipment, cables, and connectors are being used with your spectrum analyzer, make sure they are connected properly and operating correctly. o Review the measurement procedures being performed when the problem first appeared. Are all of the settings correct? o If the analyzer is not functioning as expected, return the analyzer to a known state by pressing
Mode Preset
.
o Is the measurement being performed, and the results that are expected, within the specifications and capabilities of the analyzer? Refer to the Specifications guide for your analyzer.
The analyzer must be powered on with the LAN already connected in order to recognize the LAN port.
o Is the analyzer displaying an error message? If so, refer to the Instrument
Messages and Functional Tests guide.
o If the necessary equipment is available, perform the functional tests in the
Instrument Messages and Functional Tests guide for your analyzer.
You can get automatic electronic notification of new firmware releases and other product updates/information by subscribing to the Agilent Technologies Test &
Measurement E-Mail Notification Service for the Agilent CSA Series analyzers at: http://www.agilent.com/find/emailupdates
228 Chapter 14
In Case of Difficulty
Before Calling Agilent Technologies
Read the Warranty
The warranty for your analyzer is in the front of your Specifications Guide. Please read it and become familiar with its terms.
If your analyzer is covered by a separate maintenance agreement, please be familiar with its terms.
Service Options
Agilent Technologies offers several optional maintenance plans to service your analyzer after the warranty has expired. Call your Agilent Technologies office for full details.
If you want to service the analyzer yourself after the warranty expires, you can purchase the service documentation that provides all necessary test and maintenance information.
You can order the service documentation, Option 0BW (assembly level troubleshooting) through your Agilent Technologies office.
You can order calibration software N7813A. This provides performance verification and calibration software. In addition, you will need to purchase a license for each Agilent CSA with which you will use the software.
Calling Agilent Technologies
Agilent Technologies has offices around the world to provide you with complete support for your analyzer.
For help with product selection and configuration, technical and application assistance, consulting and integration services, rental and leasing options, refurbished equipment, product purchases, education and training, and obtaining servicing information (including order replacement parts repair, or calibration), contact the nearest Agilent Technologies office by going to http://www.agilent.com/find/assist
or refer to the numbers listed in Table 14-2 on page 230.
In any correspondence or telephone conversations, refer to your analyzer by its product number, full serial number, and firmware revision. To obtain the serial number, firmware revision, Host identification information, and IP address press
Mode
and view the information displayed on the screen. (A serial number label is also attached to the rear panel of the analyzer.)
Chapter 14 229
In Case of Difficulty
Before Calling Agilent Technologies
Table 14-2 Contacting Agilent Technologies
Online assistance: http://www.agilent.com/find/assist
Americas
(tel) 1 800 829 4444
(fax) 1 800 829 4433
Canada
(tel) 1 877 894 4414
(fax) 1 800 746 4866
Japan
(tel) 0120 421 345
(fax) 0120 421 678
New Zealand
(tel) 64 4 939 0636
(fax) 64 4 972 5364
Europe
(tel) 31 (0) 20 547 2111
(fax) 31 (0) 20 547 2190
Australia
(tel) 1 800 629 485
(fax) 1 800 142 134
Africa, Middle East
(tel) 32 (0) 2 404 9340
(fax) 32 (0) 2 404 9395
230 Chapter 14
NOTE
NOTE
In Case of Difficulty
Returning an Analyzer for Service
Returning an Analyzer for Service
Please notify Agilent Technologies before returning your system for service. Any special arrangements for the system can be discussed at this time. This will help
Agilent Technologies repair and return your system as quickly as possible.
For specific analyzer packing instructions, refer to “Preparing the Analyzer for
Adjustment, Maintenance, or Repair of the Analyzer
Any adjustment, maintenance, or repair of the N1996A Series Analyzer must be performed by qualified personnel. Contact your customer engineer through your local Agilent Technologies Service Center. You may contact Agilent through the
Internet or by telephone. For contact information refer to “Calling Agilent
Service Tag
•
•
•
When you are returning an analyzer to Agilent Technologies for service, fill out and attach one of the blue service tags provided at the end of this chapter. Please be as specific as possible about the nature of the problem. If you have recorded any error messages that appeared on the display, have completed a functional test, or have any other specific data on the performance of your analyzer, please include a copy of this information.
Write a complete description of the failure and attach it to the system. Include any specific performance details related to the problem. The following information should be returned with the system:
Type of service required
Date system was returned for repair
Description of the problem:
•
•
•
•
•
—
—
—
—
—
—
Whether problem is constant or intermittent
Whether system is temperature-sensitive
Whether system is vibration sensitive
System settings required to reproduce the problem
Error Code
Performance data
Company Name and return address
Name and phone number of technical contact person
Model number of returned system
Full serial number of returned system
List of any accessories returned with the system
Chapter 14 231
CAUTION
In Case of Difficulty
Returning an Analyzer for Service
Packaging
Cover electrical connectors to protect sensitive components from electrostatic damage.
Spectrum analyzer damage can result from using packaging materials other than the original materials.
Never use styrene pellets in any shape as packaging materials. They do not adequately cushion the equipment or prevent it from shifting in the carton. They cause equipment damage by generating static electricity and by lodging in the analyzer louvers, blocking airflow.
Original Packaging
When an analyzer is returned to Agilent Technologies for servicing, it must be
adequately packaged (see “Preparing the Analyzer for Shipping” on page 232) and
have a complete description of the failure symptoms attached.
Before shipping, pack the unit in the original factory packaging materials if they
are available. If the original materials were not retained, see “Other Packaging”
(below).
•
•
Other Packaging
You can repackage the analyzer with commercially available materials. If using alternative packing material, observe the following material requirements and
follow the shipping procedure given in “Preparing the Analyzer for Shipping” on page 232.
Use a strong shipping container. The carton must be both large enough and strong enough to accommodate the analyzer. A double-walled, corrugated cardboard carton with 159 kg (350 lb) bursting strength is adequate. Allow at least 3 to 4 inches on all sides of the analyzer for packing material.
Surround the equipment with three to four inches of packing material and prevent the equipment from moving in the carton. If packing foam is not available, the best alternative is S.D.-240 Air Cap™ from Sealed Air
Corporation (Hayward, California, 94545). Air Cap looks like a plastic sheet filled with 1-1/4 inch air bubbles. Use the pink-colored Air Cap to reduce static electricity. Wrapping the equipment several times in this material should both protect the equipment and prevent it from moving in the carton.
Preparing the Analyzer for Shipping
1.
Attach a completed service tag to the analyzer. Refer to
2.
Pack the system in the original shipping containers. Original materials are available through Agilent Technologies office.
232 Chapter 14
In Case of Difficulty
Returning an Analyzer for Service
3.
Wrap the system in anti-static plastic to reduce the possibility of damage caused by electrostatic discharge.
4.
Seal the carton with strong nylon adhesive tape.
5.
Mark the shipping container “FRAGILE, HANDLE WITH CARE” to ensure careful handling
6.
Retain copies of all shipping papers.
Chapter 14 233
In Case of Difficulty
Returning an Analyzer for Service
234 Chapter 14
15
Copyright Information
235
Copyright Information
Where to Find Additional Copyright Information
Additional Copyright information is available on the Documentation CD-ROM and in the front matter of this manual.
Copyright 1999 The Apache Software Foundation. All rights reserved.
The Apache Software License, Version 1.1
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
1.
Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3.
The end-user documentation included with the redistribution, if any, must include the following acknowledgment: “This product includes software developed by the Apache Software Foundation ( http://www.apache.org
).”
Alternately, this acknowledgment may appear in the software itself, if and wherever such third-party acknowledgments normally appear.
4.
The names “Xerces” and “Apache Software Foundation” must not be used to endorse or promote products derived from this software without prior written permission. For written permission, please contact [email protected]
.
5.
Products derived from this software may not be called “Apache”, nor may
“Apache” appear in their name, without prior written permission of the
Apache Software Foundation.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
DAMAGE.
=====================================================
This software consists of voluntary contributions made by many individuals on behalf of the Apache Software Foundation and was originally based on software copyright
1999, International Business Machines, Inc., http://www.ibm.com
.
For more information on the Apache Software Foundation, please see
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.
Copyright 1994-2004 Sun Microsystems, Inc. All Rights Reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
•
•
Redistribution of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistribution in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
Neither the name of Sun Microsystems, Inc. or the names of contributors may be used to endorse or promote products derived from this software without specific prior written permission.
This software is provided “AS IS,” without a warranty of any kind. ALL
EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
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You acknowledge that this software is not designed, licensed or intended for use in the design, construction, operation or maintenance of any nuclear facility.
Copyright 1989, 1991 Free Software Foundation, Inc.
GNU General Public License Version 2, June 1991.
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Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
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1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this License and to the absence of any warranty; and give any other recipients of the Program a copy of this License along with the Program.
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These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the
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Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.
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238 Chapter 15
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However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it.
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NO WARRANTY
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS
NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING
THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE
PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER
EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
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NECESSARY SERVICING, REPAIR OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR
AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY
OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE
PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY
TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES
SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE
PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF
SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
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Copyright 1991, 1999 Free Software Foundation, Inc.
GNU Lesser General Public License Version 2.1, February 1999.
Free Software Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA
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Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. [This is the first released version of the
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Copyright 1998-2004, CEE-J, Skelmir, LLC. All rights reserved.
248 Chapter 15
Index
Numerics
10 MHz REF OUTPUT
,
50 ohm load
,
50 ohm/75 ohm minimum loss pad
,
75 ohm matching transformer
A
AC probe
accessories
50 ohm load
50 ohm/75 ohm minimum loss pad
,
75 ohm matching transformer
,
AC probe
,
broadband preamplifiers
power splitters
,
RF limiters
transient limiters
active function address, IP
,
,
adjacent channel power
,
adjacent channel power measurement
,
adjustment, maintenance, or repair of test set
Agilent Technologies calling
,
sales offices
,
AM demodulation time-domain demodulation, manually calculating
AM signal demodulation
amplifiers
analyzer distortion products
,
annotations, display
arrow keys, using
,
attenuation input, reducing
,
setting manually
averaging description
,
types
B
batteries built-in battery gauge
caring for
,
charger part numbers
charging
,
disposal
front panel icons
,
installing
LEDs
maximizing battery life
,
part numbers
,
precautions
reconditioning/recalibrating
specifications
,
statistics
,
status
system statistics - battery screen
working with
,
battery clock
,
memory
bench top conversion kit
,
broadband preamplifiers
C
C language addressing sessions
,
closing sessions
compiling and linking
,
creating
,
example
opening session
sessions
,
using VISA library
,
using VISA transition library
,
cable and connector care
,
carrying case using
,
channel analyzer measurements
channel power measurement noise-like signals
charging batteries
,
cleaning supplies, connector
clock setting
clock, battery
comparing signals two signals
,
two signals not on the same screen
,
concepts
AM demodulation
,
FM demodulation
IF filter, defined
,
modulation distortion measurement
,
modulation SINAD measurement
,
resolving signals of equal amplitude
,
resolving small signals hidden by large signals
,
stimulus response
,
configuring for network connectivity
,
connectors
10 MHz ref output
care
,
cleaning
,
cleaning RF
,
front panel
,
inspecting for wear
inspecting RF
ordering cleaning supplies
reference input
RF OUT 50 ohm
,
torque specifications
,
USB type A
,
USB type B
copyrights
D
data entering from front panel
,
saving
DC probes use of
,
delta marker
demodulating
AM
,
AM overview
AM signal
FM
FM overview
DHCP
,
display testing
,
display annotations
,
display, information screen
,
distance to fault measurement
,
distortion measurements identifying TOI distortion
,
distortion products
documentation additional set
CD-ROM
,
CD-ROM only
localized manuals
,
service
standard set
E
electrostatic discharge (ESD) protecting against
Enter key, using
,
equipment
functional tests
ESD safety accessories
,
examples
ACP
AM demodulation
CSA
,
manual demodulation averaging, trace
,
distortion
249
Index
TOI
FM demodulation
ESA built-in FM demodulation
,
input attenuation, reducing
noise channel power, using
power measurements
OBW
resolution bandwidth, reducing
,
signals low-level, overview
,
off-screen, comparing
,
on-screen, comparing
,
resolving, equal amplitude
resolving, small signals hidden by large signals
signals, viewing
trace averaging
EXTERNAL REF INPUT
external reference
,
F
factory preset, description
feet system II feet kit
file naming asking for
,
automatic
,
options
user
,
finding hidden signals
,
FM demodulation time-domain demodulation, manually calculating
,
FM signal demodulation
,
frequency/timing reference
front panel connectors and keys
,
display annotations
,
entering data
functional tests equipment list
See also individual functional tests
functionality in the test set
H
harmonic distortion measuring low-level signals
,
I
identifying distortion products
,
information screen
input attenuation, reducing
,
insertion loss measurement one port
two port
installation information
installing a battery
,
instrument preset
,
intermodulation distortion, third order
,
introduction to the test set
IP address
,
IP administration using DHCP
,
IP administration without DHCP
K
key overview
keyboard testing
,
keypad, using
keys
knob, using
L
LAN, setting IP address
licenses
lifting and handling the test set
limiters
RF and transient
load, 50 ohm
low-level signals harmonics, measuring
input attenuation, reducing
,
resolution bandwidth, reducing
trace averaging
,
M
manuals ordering
,
standard set
marker frequency and amplitude, reading
moving to peak
,
to reference level
with knob or arrow key
marker annotation location
markers delta
measurement technique modulation distortion measurement concepts
,
modulation SINAD measurement concepts
,
measurements
ACP or adjacent channel power
distortion
TOI
noise channel power
,
TV fast time-domain sweeps
measuring distance to fault
,
measuring insertion loss one port
two port
,
measuring return loss
memory battery
,
menu keys
menu keys, auto and man mode
,
menu keys, basic types
missing options
modulation distortion measurement concepts
,
measurement technique
purpose
modulation SINAD measurement concepts
,
measurement technique
purpose
N
navigating tables
,
network configuring
connectivity
network connectivity
noise measurements channel power, using
,
normalization reference position
Normalize On Off key
numeric keypad, using
O
OBW measurement
,
occupied bandwidth measurement
,
occupied BW measurement
option manager
options
,
installing
,
option name listing
,
option number listing
,
ordering
viewing installable
,
viewing installed
,
options not in instrument memory
,
ordering options
,
overview, keys and key menus
,
overviews low-level signal
resolving signals
,
250
Index
P
packaging
,
personality options not in instrument
,
power amplifiers
power measurements
OBW
occupied bandwidth
,
power splitters
power suite channel power
,
preamplifiers
preset factory
types
user, creating
Print key
,
printer setup
printing screens
probes
AC and DC
,
product markings
programming example using C language
,
using C language
,
pulse measurement
purpose modulation distortion measurement concepts
,
modulation SINAD measurement concepts
,
R
RBW selections
,
real time clock setting
,
rear panel features
reconditioning/recalibrating batteries
,
reference level, setting release versions
,
resolution bandwidth adjusting
resolving signals
resolving signals small signals hidden by large signals
,
resolving two signals equal amplitude
,
resolving, equal amplitude
,
return loss measurement
returning the test set for service
,
,
RF cable and connector care
,
RF connectors
,
RF limiters
,
RF OUT 50 ohm
RPG, using
,
S
safety considerations
safety symbols saving data
saving displayed screen
saving screens
screen printing
screen annotation
,
screen, information
,
screens saving
,
service returning the test set
shipping the test set
service options
setting real time clock
,
shipping packaging
,
packaging original
packaging other
shipping the test set
,
signals low-level, overview
off-screen, comparing
on-screen, comparing
resolving, overview
,
separating, overview
,
signals, viewing
,
spectrogram measurement
,
spectrum analyzer occupied BW measurement
spectrogram measurement
spectrogram view
,
uses
,
splitters
,
state deleting
,
power-up
,
recalling
,
returning power-up to factory defaults
,
saving
,
static safety accessories
statistics system
,
viewing
,
stimulus response, concepts
sweep time and sensitivity trade off
system memory
release versions
statistics
,
system II feet
System key
system operations configuring for network connectivity
IP administration using DHCP
IP administration without DHCP
,
printing screens
,
saving data
saving screens
selecting a timing reference
setting real time clock
setting system references using the option manager
,
,
viewing battery statistics
viewing system memory
,
viewing system release versions
viewing system statistics
T
tab key
,
table navigation
,
test equipment
,
test set functionality
,
third order intermodulation distortion example
,
timing/frequency reference
,
torque
,
tracking generator normalization
,
stimulus response
transient limiter
tune and listen
turning on the analyzer for the first time
,
33
U
unit menu keys, using
,
URL, sales and service
,
USB type A interface connector
,
USB type B interface connector user preset creating
,
description
,
disabling
using connectors
using the occupied BW measurement
,
V
viewing battery statistics
VISA library
,
251
Index
VTL, compiling and linking C language
W
warm-up time
,
warranty
,
working with batteries
252
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