Agilent 83482A Optical/ Electrical Plug-In Module User’s Guide

Agilent 83482A Optical/ Electrical Plug-In Module User’s Guide
Agilent 83482A Optical/
Electrical Plug-In Module
User’s Guide
© Copyright
Agilent Technologies 2000
All Rights Reserved. Reproduction, adaptation, or translation without prior written
permission is prohibited,
except as allowed under copyright laws.
Agilent Part No. 83482-90005
Printed in USA
April 2000
Agilent Technologies
Lightwave Division
1400 Fountaingrove Parkway
Santa Rosa, CA 95403-1799,
USA
(707) 577-1400
Notice.
The information contained in
this document is subject to
change without notice. Companies, names, and data used
in examples herein are fictitious unless otherwise noted.
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regard to this material, including but not limited to, the
implied warranties of merchantability and fitness for a
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Technologies shall not be liable for errors contained herein
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performance, or use of this
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Data and Computer Software
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for DOD agencies, and subparagraphs (c) (1) and (c) (2)
of the Commercial Computer
Software Restricted Rights
clause at FAR 52.227-19 for
other agencies.
Warranty.
This Agilent Technologies
instrument product is warranted against defects in
material and workmanship for
a period of one year from date
of shipment. During the warranty period, Agilent Technologies will, at its option, either
repair or replace products
which prove to be defective.
For warranty service or repair,
this product must be returned
to a service facility designated by Agilent Technologies. Buyer shall prepay
shipping charges to Agilent
Technologies and Agilent
Technologies shall pay shipping charges to return the
product to Buyer. However,
Buyer shall pay all shipping
charges, duties, and taxes for
products returned to Agilent
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Agilent Technologies warrants that its software and
firmware designated by Agilent Technologies for use with
an instrument will execute its
programming instructions
when properly installed on
that instrument. Agilent Technologies does not warrant that
the operation of the instrument, or software, or firmware
will be uninterrupted or errorfree.
Limitation of Warranty.
The foregoing warranty shall
not apply to defects resulting
from improper or inadequate
maintenance by Buyer, Buyersupplied software or interfacing, unauthorized modification or misuse, operation
outside of the environmental
specifications for the product,
or improper site preparation
or maintenance.
No other warranty is
expressed or implied. Agilent
Technologies specifically disclaims the implied warranties
of merchantability and fitness
for a particular purpose.
Exclusive Remedies.
The remedies provided herein
are buyer's sole and exclusive
remedies. Agilent Technolo-
ii
❍ The OFF symbols
are used to mark the
positions of the instrument power line
switch.
gies shall not be liable for any
direct, indirect, special, incidental, or consequential damages, whether based on
contract, tort, or any other
legal theory.
The CE mark is a registered trademark of
the European Community.
Safety Symbols.
CAUTION
The caution sign denotes a
hazard. It calls attention to a
procedure which, if not correctly performed or adhered
to, could result in damage to
or destruction of the product.
Do not proceed beyond a caution sign until the indicated
conditions are fully understood and met.
The CSA mark is a registered trademark of
the Canadian Standards Association.
The C-Tick mark is a
registered trademark
of the Australian Spectrum Management
Agency.
WARNING
The warning sign 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 sign until
the indicated conditions are
fully understood and met.
The instruction manual symbol. The product is marked with this
warning symbol when
it is necessary for the
user to refer to the
instructions in the
manual.
The laser radiation
symbol. This warning
symbol is marked on
products which have a
laser output.
The AC symbol is used
to indicate the
required nature of the
line module input
power.
| The ON symbols are
used to mark the positions of the instrument
power line switch.
ISM1-A
This text denotes the
instrument is an
Industrial Scientific
and Medical Group 1
Class A product.
Typographical Conventions.
The following conventions are
used in this book:
Key type for keys or text
located on the keyboard or
instrument.
Softkey type for key names that
are displayed on the instrument’s screen.
Display type for words or
characters displayed on the
computer’s screen or instrument’s display.
User type for words or charac-
ters that you type or enter.
Emphasis type for words or
characters that emphasize
some point or that are used as
place holders for text that you
type.
General Safety Considerations
General Safety Considerations
This product has been designed and tested in accordance with IEC Publication 61010-1, Safety Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use, and has been supplied in a safe condition. The
instruction 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.
WARNING
If this instrument is not used as specified, the protection provided by
the equipment could be impaired. This instrument must be used in a
normal condition (in which all means for protection are intact) only.
WARNING
To prevent electrical shock, disconnect the Agilent 83482A 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.
WARNING
This is a Safety Class 1 product (provided with a protective earthing
ground incorporated in the power cord). The mains plug shall only be
inserted in a socket outlet provided with a protective 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.
WARNING
For continued protection against fire hazard, replace line fuse only
with same type and ratings, (type T 0.315A/250V for 100/120V
operation and 0.16A/250V for 220/240V operation). The use of other
fuses or materials is prohibited. Verify that the value of the linevoltage fuse is correct.
• For 100/120V operation, use an IEC 127 5×20 mm, 0.315 A, 250 V, Agilent
part number 2110-0449.
• For 220/240V operation, use an IEC 127 5×20 mm, 0.16 A, 250 V, Agilent
Technologies part number 2110-0448.
WARNING
No operator serviceable parts inside. Refer servicing to qualified
personnel. To prevent electrical shock, do not remove covers.
iii
General Safety Considerations
CAUTION
Before switching on this instrument, make sure that the line voltage selector
switch is set to the line voltage of the power supply and the correct fuse is
installed. Assure the supply voltage is in the specified range.
CAUTION
This product is designed for use in Installation Category II and Pollution
Degree 2 per IEC 1010 and 664 respectively.
CAUTION
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.
CAUTION
Always use the three-prong ac power cord supplied with this instrument.
Failure to ensure adequate earth grounding by not using this cord may cause
instrument damage.
CAUTION
Do not connect ac power until you have verified the line voltage is correct.
Damage to the equipment could result.
CAUTION
This instrument has autoranging line voltage input. Be sure the supply voltage
is within the specified range.
CAUTION
Electrostatic discharge (ESD) on or near input connectors can damage circuits
inside the instrument. Repair of damage due to misuse is not covered under
warranty. Before connecting any cable to the electrical input, momentarily
short the center and outer conductors of the cable together. Personnel should
be properly grounded, and should touch the frame of the instrument before
touching any connector.
iv
Measurement Accuracy
Measurement Accuracy
CAUTION
The Agilent 83482A’s input circuitry can be damaged when the total input
power levels exceed +18 dBm on the optical channel or 10 dBm on the
electrical channel. To prevent input damage, this specified level must not be
exceeded.
Measurement accuracy—it’s up to you!
Fiber-optic connectors are easily damaged when connected to dirty or damaged cables
and accessories. The Agilent 83482A’s front-panel INPUT connector is no exception.
When you use improper cleaning and handling techniques, you risk expensive instrument repairs, damaged cables, and compromised measurements.
Before you connect any fiber-optic cable to the Agilent 83482A, “Cleaning Connections
for Accurate Measurements” on page 5-7.
v
Contents
1 Getting Started
Step 1. Inspect the Shipment 1-3
Step 2. Install the Plug-in Module 1-4
Returning the Instrument for Service 1-5
2 Channel Setup Menu
The Agilent 83482A Optical/Electrical Plug-In Module 2-2
Options and Accessories 2-3
The Agilent 83482A Optical/Electrical Plug-In Module 2-4
Menu and Key Conventions 2-9
Channel Setup Menu 2-10
Displaying the Channel Setup Menus 2-13
3 Calibration Overview
Factory Calibrations 3-4
User Calibrations—Optical and Electrical 3-7
Complete Calibration Summary 3-19
4 Specifications and Regulatory Information
Specifications 4-3
Characteristics 4-7
Declaration of Conformity 4-9
5 Reference
In Case of Difficulty 5-2
Error Messages 5-5
Cleaning Connections for Accurate Measurements 5-7
Agilent Technologies Service Offices 5-17
Contents-1
1
Step 1. Inspect the Shipment 1-3
Step 2. Install the Plug-in Module 1-4
Returning the Instrument for Service 1-5
Getting Started
Getting Started
Getting Started
Getting Started
The instructions in this chapter show you how to install your Agilent 83482A
optical/electrical plug-in module.
Refer to Chapter 2, “Channel Setup Menu” for information on operating the
plug-in module.
Refer to Chapter 3, “Calibration Overview” for calibration information.
Refer to Chapter 4, “Specifications and Regulatory Information” for information on operating conditions such as temperature.
For GPIB programming information, refer to the Agilent 83480A, 54750A
Programmer’s Guide supplied with the mainframe. For service information,
refer to the optional Agilent 83482A Service Guide.
CAUTION
This product is designed for use in INSTALLATION CATEGORY II and
POLLUTION DEGREE 2, per IEC 1010 and 664 respectively.
CAUTION
The input circuits can be damaged by electrostatic discharge (ESD).
Therefore, avoid applying static discharges to the front-panel input connectors.
Before connecting any coaxial cable to the connectors, momentarily short the
center and outer conductors of the cable together. Avoid touching the frontpanel input connectors without first touching the frame of the instrument. Be
sure that the instrument is properly earth-grounded to prevent buildup of
static charge.
1-2
Getting Started
Step 1. Inspect the Shipment
Step 1. Inspect the Shipment
1 Verify that all system components ordered have arrived by comparing the
shipping forms to the original purchase order. Inspect all shipping containers.
The shipment includes:
• Agilent 83482A optical/electrical plug-in module with the ordered options and adapters.
• APC 3.5 (f-f) adapter, Agilent part number 1250-1749.
• APC 2.4 (f-f) adapter, Agilent 11900B
• SMA 50Ω termination, Agilent part number 1810-0118, 1 each
• 2.4 mm connector shipping cap, Agilent part number 54124-24101, 1 each
If your shipment is damaged or incomplete, save the packing materials and
notify both the shipping carrier and the nearest Agilent Technologies
Service office. Agilent Technologies will arrange for repair or replacement of
damaged or incomplete shipments without waiting for a settlement from the
transportation company. Notify the Agilent Technologies customer engineer
of any problems.
2 Make sure that the serial number and options listed on the instrument’s rearpanel label match the serial number and options listed on the shipping
document. The following figure is an example of the rear-panel serial number
label:
1-3
Getting Started
Step 2. Install the Plug-in Module
Step 2. Install the Plug-in Module
You do not need to turn off the mainframe to install or remove the plug-in
modules.
If you wish to use the Agilent 83482A optical/electrical plug-in module in an
Agilent 54750A digitizing oscilloscope, a firmware upgrade must first be
installed. Order the Agilent 83480K communications firmware kit and follow
the installation instructions.
The plug-in module can be installed in slots 1 and 2 or 3 and 4 on the
Agilent 83480A, 54750A mainframe. The plug-in module will not function if it
is installed in slots 2 and 3.
To make sure the analyzer meets all of the published specifications, there
must be a good ground connection from the plug-in module to the mainframe.
The RF connectors on the rear of the plug-in module are spring loaded, so finger-tighten the knurled screw on the front panel of the plug-in module to
make sure the plug-in is securely seated in the mainframe.
CAUTION
Do not use extender cables to operate the plug-in module outside of the
mainframe. The plug-in module using extender cables can be damaged by
improper grounding when using extender cables.
Note
The Agilent 83482A optical/electrical plug-in module requires firmware revision 5.0 or
higher.
1-4
Getting Started
Returning the Instrument for Service
Returning the Instrument for Service
The instructions in this section show you how to properly return the instrument for repair or calibration. Always call the Agilent Technologies Instrument
Support Center first to initiate service before returning your instrument to a
service office. This ensures that the repair (or calibration) can be properly
tracked and that your instrument will be returned to you as quickly as possible. Call this number regardless of where you are located. Refer to “Agilent
Technologies Service Offices” on page 5-17 for a list of service offices.
Agilent Technologies Instrument Support Center. . . . . . . . . . . (800) 403-0801
If the instrument is still under warranty or is covered by an Agilent Technologies maintenance contract, it will be repaired under the terms of the warranty
or contract (the warranty is at the front of this manual). If the instrument 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 unit.
When an instrument is returned to a Agilent Technologies service office for
servicing, it must be adequately packaged and have a complete description of
the failure symptoms attached. When describing the failure, please be as specific as possible about the nature of the problem. Include copies of additional
failure information (such as the instrument failure settings, data related to
instrument failure, and error messages) along with the instrument being
returned.
Preparing the instrument for shipping
1 Write a complete description of the failure and attach it to the instrument.
Include any specific performance details related to the problem. The following
1-5
Getting Started
Returning the Instrument for Service
information should be returned with the instrument.
• Type of service required.
• Date instrument was returned for repair.
• Description of the problem:
• Whether problem is constant or intermittent.
• Whether instrument is temperature-sensitive.
• Whether instrument is vibration-sensitive.
• Instrument settings required to reproduce the problem.
• Performance data.
• Company name and return address.
• Name and phone number of technical contact person.
• Model number of returned instrument.
• Full serial number of returned instrument.
• List of any accessories returned with instrument.
2 Cover all front or rear-panel connectors that were originally covered when you
first received the instrument.
CAUTION
Cover electrical connectors to protect sensitive components from electrostatic
damage. Cover optical connectors to protect them from damage due to physical
contact or dust.
CAUTION
Instrument damage can result from using packaging materials other than the
original materials. Never use styrene pellets as packaging material. They do not
adequately cushion the instrument or prevent it from shifting in the carton.
They may also cause instrument damage by generating static electricity.
3 Pack the instrument in the original shipping containers. Original materials are
available through any Agilent Technologies office. Or, use the following
guidelines:
• Wrap the instrument in antistatic plastic to reduce the possibility of damage
caused by electrostatic discharge.
• For instruments weighing less than 54 kg (120 lb), use a double-walled, corrugated cardboard carton of 159 kg (350 lb) test strength.
• The carton must be large enough to allow approximately 7 cm (3 inches) on
all sides of the instrument for packing material, and strong enough to accommodate the weight of the instrument.
• Surround the equipment with approximately 7 cm (3 inches) of packing material, to protect the instrument and prevent it from moving in the carton. If
packing foam is not available, the best alternative is S.D-240 Air Cap™ from
1-6
Getting Started
Returning the Instrument for Service
Sealed Air Corporation (Commerce, California 90001). Air Cap looks like a
plastic sheet filled with air bubbles. Use the pink (antistatic) Air Cap™ to
reduce static electricity. Wrapping the instrument several times in this material will protect the instrument and prevent it from moving in the carton.
4 Seal the carton with strong nylon adhesive tape.
5 Mark the carton “FRAGILE, HANDLE WITH CARE”.
6 Retain copies of all shipping papers.
1-7
2
The Agilent 83482A Optical/Electrical Plug-In Module
Options and Accessories 2-3
Front panel of the plug-in module 2-5
Menu and Key Conventions 2-9
Channel Setup Menu 2-10
Displaying the Channel Setup Menus 2-13
Channel Setup Menu
2-2
Channel Setup Menu
The Agilent 83482A Optical/Electrical Plug-In Module
The Agilent 83482A Optical/Electrical Plug-In
Module
The Agilent 83482A optical/electrical plug-in module incorporates a 30 GHz
optical measurement channel and a 40 GHz electrical channel. The electrical
channel also has a reduced-bandwidth setting of 18 GHz for improved noise
performance.
The integrated optical channel reduces mismatch loss variation by eliminating
signal distorting cables and connectors associated with the use of external
receivers in order to accurately characterize optical waveforms. The optical
channel is calibrated at 1310 nm and 1550 nm to provide both accurate display
of the received optical waveform in optical power units and measurement of
the signal’s average power. In addition, the User Cal feature provides for consistent accuracy at any wavelength between 1000 nm and 1600 nm using a
source and power meter.
The optical channel frequency response is designed to minimize distortion of
the displayed optical pulse. To achieve this performance the Agilent 83482A
does not include any provision for switching a SONET/SDH filter into the
channel. For applications requiring a switched SONET/SDH filter, an
Agilent 83485A or 83485B plug-in module should be used.
The electrical measurement channel may be used to perform measurements
on tributary electrical signals, to evaluate receiver performance in transceiver
testing, for measurements with Agilent Technologies’ wide range of external
optical receivers, or for general purpose measurements.
The Agilent 83482A optical/electrical plug-in module provides:
• 30 GHz optical channel
• 18 GHz and 40 GHz electrical channel
• Trigger channel input to the mainframe
2-2
Channel Setup Menu
Options and Accessories
Options and Accessories
Agilent 83482A
options
Option 001 Latest operating system firmware for the Agilent 83480A
mainframe
Option 002 Latest operating system firmware for the Agilent 54750A
mainframe
Option UK6 Calibration certificate with data
Optical connector Option 011 Diamond HMS-10
interface options Option 012 FC/PC
Option 013 DIN 47256
Option 014 ST
Option 015 Biconic
Option 017 SC
Optional
accessories
Agilent 54006A 6 GHz divider probe
Agilent 54008A 22 ns delay line
Agilent 54118A 500 MHz to 18 GHz trigger
Agilent 10086A ECL terminator
Connection
devices
Agilent 81000AI Diamond HMS-10 connector interface
Agilent 81000FI FC/PC/SPC/APC connector interface
Agilent 81000KI SC connector interface
Agilent 81000SI DIN 47256/4108.6 connector interface
Agilent 81000VI ST connector interface
Agilent 81000WI Biconic
Agilent 11900B 2.4 (f-f) adapter
Agilent 11901B SMA 3.5/2.4 (f-f) adapter
SMA (f-f) adapter, Agilent part number 1250-1158
APC 3.5 (f-f) adapter, Agilent part number 1250-1749
2-3
Channel Setup Menu
The Agilent 83482A Optical/Electrical Plug-In Module
The Agilent 83482A Optical/Electrical Plug-In
Module
The Agilent 83482A optical/electrical plug-in modules is one of several plug-in
modules available for the Agilent 83480A, 54750A mainframes. The main features of the Agilent 83482A are:
•
•
•
•
•
•
•
•
Integrated, calibrated optical channel.
Electrical measurement channel.
2.5 GHz trigger channel.
30 GHz optical channel bandwidth and user selectable 18 or 40 GHz electrical
channel bandwidth.
2.4 mm (m) connectors on the electrical measurement channel and 3.5 mm
(m) on the trigger channel.
One probe power connector.
One auxiliary power connector.
Optical channel has an Agilent Technologies universal adapter for 9/125 µm
single-mode fiber input.
NOTE
If you wish to use the Agilent 83482A optical plug-in module in an Agilent 54750A digitizing oscilloscope, a firmware upgrade must first be installed. Order the Agilent 83480K
communications firmware kit and follow the installation instructions.
The purpose of the plug-in module is to provide measurement channels,
including sampling, for the mainframe. The plug-in module scales the input
signal, sets the bandwidth of the system, and allows the offset to be adjusted
so the signal can be viewed. The output of the plug-in module is an analog signal that is applied to the ADCs on the acquisition boards inside the mainframe.
The plug-in module also provides a trigger signal input to the time base/trigger
board inside the mainframe.
2-4
Channel Setup Menu
The Agilent 83482A Optical/Electrical Plug-In Module
Front panel of the plug-in module
The plug-in module takes up two of the four mainframe slots. The optical
channel provides calibrated measurement of optical waveforms in power
units. Bandwidths are selectable on both channels to optimize sensitivity and
bandwidth.
The front panel of the plug-in module has two channel inputs and an external
trigger input. The front panel also has a Probe Power connector for
Agilent 54700-series probes, an Aux Power connector for general purpose use,
and a key for each channel that displays the softkey menu. The softkey menu
allows you to access the channel setup features of the plug-in module.
The front-power Probe Power connector allows automatic channel scaling and
probe calibration with Agilent 54700 series probes. The front-panel Aux Power
connector provides only power to Agilent 54700 series probes for use as a trigger input. Probe calibration and scaling are not required for a trigger input.
frn tp n l
Front panel of the plug-in module.
2-5
Channel Setup Menu
The Agilent 83482A Optical/Electrical Plug-In Module
Getting the best performance
To ensure you obtain the specified accuracy, you must perform a plug-in module vertical calibration. The calibration must also be performed when you
move a plug-in module from one slot to another, or from one mainframe to
another. Refer to Chapter 3, “Calibration Overview” for information on performing a plug-in module vertical calibration.
Installing the plug-in module
You do not need to turn off the mainframe to install or remove the plug-in
modules. Refer to “Step 2. Install the Plug-in Module” on page 1-4 for information on installing the plug-in module.
NOTE
If you wish to use the Agilent 83482A optical plug-in module in an Agilent 54750A digitizing oscilloscope, a firmware upgrade must first be installed. Order the Agilent 83480K
communications firmware kit and follow the installation instructions.
CAUTION
Do not use extender cables to operate the plug-in module outside of the
mainframe. The plug-in module using extender cables can be damaged by
improper grounding when using extender cables.
2-6
Channel Setup Menu
The Agilent 83482A Optical/Electrical Plug-In Module
Trigger
The external trigger level range for this plug-in module is ±1 V. The trigger
source selection follows the slots the plug-in module is installed in. For example, if the plug-in module is installed in slots 1 and 2, then the trigger source is
listed as trigger 2. If it is installed in slots 3 and 4, then the trigger source is
listed as trigger 4.
CAUTION
The maximum safe input voltage is ±2 V + peak ac (+16 dBm).
CAUTION
The input circuits can be damaged by electrostatic discharge (ESD).
Therefore, avoid applying static discharges to the front-panel input connectors.
Before connecting any coaxial cable to the connectors, momentarily short the
center and outer conductors of the cable together. Avoid touching the frontpanel input connectors without first touching the frame of the instrument. Be
sure that the instrument is properly earth-grounded to prevent buildup of
static charge.
2-7
Channel Setup Menu
Measurement Accuracy
Measurement Accuracy
CAUTION
The Agilent 83482A optical/electrical plug-in module’s input circuitry can be
damaged when the total input power levels exceed +18 dBm on the optical
channel or 10 dBm on the electrical channel. To prevent input damage, this
specified level must not be exceeded.
Measurement accuracy—it’s up to you!
Fiber-optic connectors are easily damaged when connected to dirty or damaged cables
and accessories. The Agilent 83482A optical/electrical plug-in module’s front-panel
INPUT connector is no exception. When you use improper cleaning and handling techniques, you risk expensive instrument repairs, damaged cables, and compromised measurements.
Before you connect any fiber-optic cable to the Agilent 83482A optical/electrical plug-in
module, “Cleaning Connections for Accurate Measurements” on page 5-7.
2-8
Channel Setup Menu
Menu and Key Conventions
Menu and Key Conventions
The keys labeled Trigger, Disk, and Run are all examples of front-panel keys.
Pressing some front-panel keys accesses menus of functions that are displayed along the right side of the display screen. These menus are called softkey menus.
Softkey menus list functions other than those accessed directly by the frontpanel keys. To activate a function on the softkey menu, press the unlabeled
key immediately next to the annotation on the screen. The unlabeled keys
next to the annotation on the display are called softkeys.
Additional functions are listed in blue type above and below some of the frontpanel keys. These functions are called shifted functions. To activate a shifted
function, press the blue front-panel Shift key and the front-panel key next to
the desired function.
Throughout this manual front-panel keys are indicated by a box around the
key label, for example, Timebase. Softkeys are indicated by shading on the key
label, for example, Mask Align. The softkeys displayed depend on the frontpanel key pressed and which menu is selected. Shifted functions are indicated
by the front-panel Shift key followed by the shaded shifted function, for example the Local function (above the Stop/Single front-panel key) will be shown as
Shift, Local.
A softkey with On and Off in its label can be used to turn the softkey’s function
on or off. To turn the function on, press the softkey so On is highlighted. To
turn the function off, press the softkey so Off is highlighted. An On or Off softkey function will be indicated throughout this manual as:Test On.
A softkey such as Sweep Triggered Freerun offers you a choice of functions. In this
case you could choose Triggered by pressing the softkey until Triggered is
highlighted, or choose Freerun by pressing the softkey until Freerun is highlighted. A choices softkey will be indicated throughout this manual as:Sweep
Triggered Freerun Triggered.
When some softkeys, such as Calibrate probe, are pressed the first time, a measurement will be made and the result will be provided. Some softkeys, such as
Offset require the entry of a numeric value. To enter or change the value, use
the general purpose knob located below the front-panel Measure section.
2-9
Channel Setup Menu
Channel Setup Menu
Channel Setup Menu
This chapter describes the Channel Setup menu. A key tree and description of
the available functions is included.
CAUTION
The input circuits can be damaged by electrostatic discharge (ESD).
Therefore, avoid applying static discharges to the front-panel input connectors.
Before connecting any coaxial cable to the connectors, momentarily short the
center and outer conductors of the cable together. Avoid touching the frontpanel input connectors without first touching the frame of the instrument. Be
sure that the instrument is properly earth-grounded to prevent buildup of
static charge.
At the top of the plug-in module are the Channel keys. These keys give you
access to the Channel Setup menu for each input. The Channel Setup menu is
displayed on the right side of the screen when the Channel key is pressed.
There are several types of softkeys available. A description of the different
softkeys and their functions is provided in the Agilent 83480A, 54750A
User’s Quick Start Guide supplied with the mainframe.
NOTE
The plug-in module has both an electrical channel and an optical channel. Although
many of the softkeys are similar, some differences exist. The examples in this book use
the optical channel and note when the user would see differences if using the electrical
channel.
2-10
Channel Setup Menu
Channel Setup Menu
Figure 2-1. Optical Channel Setup menu.
2-11
Channel Setup Menu
Channel Setup Menu
Figure 2-2. Electrical Channel Setup menu.
2-12
Channel Setup Menu
Displaying the Channel Setup Menus
Displaying the Channel Setup Menus
To display the optical Channel Setup menu, press the optical Channel key
located above the optical input connector.
To display the electrical Channel Setup menu, press the electrical Channel key
located above the electrical input connector.
Display
The Display function turns the channel display off and on. When the channel
display is on, a waveform is displayed for that channel, unless the offset is
adjusted so the waveform is clipped off of the display.
The channel number, vertical scaling, and offset are displayed at the bottom
left of the waveform area. They remain on the display until the channel is
turned off, or an automatic measurement is performed. The automatic measurement results share the same area of the display as the channel setups.
When the channel display is off, the waveform display for that channel is
turned off, pulse parameter measurements are stopped and acquisition on
that channel is stopped, unless it is needed as an operand for waveform math
functions.
Even though the channel display is off, you can still use the plug-in as a trigger
source or as a function source in the Math menu. However, the analyzer will
not trigger unless one or more of the other channel displays are turned on, or
unless a math function is using one of the channels.
Key Path
Channel, Display
2-13
Channel Setup Menu
Scale
Scale
The Scale softkey controls the vertical scaling of the waveform. If the fine
mode is off, then the knob and arrow keys change the vertical scaling in a
1-2-5 sequence. When fine mode is on, the knob and arrow keys change the
vertical scaling in 1 mV increments. You can also use the keypad to enter values in 1 mV increments, independent of the fine mode selection.
The units the scale is displayed in depend on the unit of measure selected
with the Units softkey. The choices for units are volts or watts. (Amperes, or
unknown are available on electrical channels only.)
Key Path
Channel, Scale
Offset
The Offset softkey moves the waveform vertically. It is similar to the position
control on analog oscilloscopes. The advantage of digital offset is that it is calibrated. The offset voltage for electrical channels is the voltage at the center of
the graticule area, and the range of offset is ±12 times the full resolution channel scale. For optical channels, the offset wattage is the wattage two graticule
divisions above the bottom of the screen. This is set because, unlike voltage
displays, "negative" power levels do not exist but the zero power level can be
viewed clearly when the offset is set to zero watts. You can use the knob,
arrow keys, or keypad to change the offset setting. The fine mode also works
with offset.
When an Agilent 54700-series active probe is used with the plug-in module
and is connected to the probe power connector adjacent to the channel input,
the offset control adjusts the external scale factor and offset of the hybrid
inside the active probe. A probe connected to the auxiliary power connector
adjacent to the trigger input will function, but the channel scale factor will not
be adjusted automatically.
The optical channel displays the value in watts and the electrical channel displays the value in volts.
Key Path
Channel, Offset
2-14
Channel Setup Menu
Bandwidth/Wavelength....
Bandwidth/Wavelength....
You can use the Bandwidth/Wavelength.... softkey to change the bandwidth and
wavelength settings.
Bandwidth
This function is available on the electrical channel only.
You can use the Bandwidth function to select either the 18 GHz or 40 GHz
bandwidth.
Key Path
Channel, Bandwidth/Wavelength...., Bandwidth
Filter
The Filter function turns the filter on and off.
Key Path
Channel, Bandwidth/Wavelength...., Filter On Off
Wavelength
This function is only available on the optical channel.
The Wavelength function selects the desired wavelength for calibrated measurements. Factory calibrated wavelengths are 1310 nm and 1550 nm. A usercalibrated wavelength is also available and can be calibrated in the range from
1000 nm to 1600 nm. Refer to Chapter 3, “Calibration Overview” for additional
information on performing a calibration.
Key Path
Channel, Bandwidth/Wavelength...., Wavelength
Channel autoscale
The Channel Autoscale function provides a convenient and fast method for
determining the standard vertical scale setting with the highest resolution that
will not clip the waveform. Timebase and trigger settings are not affected.
This function is useful in manufacturing environments where the timebase
and trigger settings remain constant and only the vertical scale needs to be
adjusted for signal level variations in multiple DUTs.
Key Path
Channel, Channel autoscale
2-15
Channel Setup Menu
External scale....
External scale....
The External Scale function allows you to setup the analyzer to use external
optical-to-electrical converters or attenuators. Scaling is automatically
adjusted to account for the external device.
Key Path
Channel, External scale....
Atten units
The Atten Units function lets you select how you want the probe attenuation
factor represented. The choices are either decibel or ratio. The formula for
calculating decibels is:
Vout
Pout
20 log ------------ or10 log -----------Vin
Pin
Attenuation
The Attenuation function lets you select an attenuation that matches the
device connected to the analyzer. When the attenuation is set correctly, the
analyzer maintains the current scale factors if possible. All marker values and
voltage or wattage measurements will reflect the actual signal at the input to
the external device.
The attenuation range is from 0.0001:1 to 1,000,000:1. When you connect a
compatible active probe to the probe power connector, adjacent to the channel input, the instrument automatically sets the attenuation. For all other
devices, set the probe attenuation with the knob, arrow keys, or keypad.
Note
Refer to Chapter 3, “Calibration Overview” for information on calibrating to the tip of the
probe.
Key Path
Channel, External scale...., Attenuation
2-16
Channel Setup Menu
External scale....
Units
The Units function lets you select the unit of measure appended to the channel scale, offset, trigger level, and vertical measurement values. For the optical
channel these units are Volts or Watts. For the electrical channel the units are
Volts, Amperes, Watts, or unknown. Use Volt for voltage probes, Ampere for
current probes, Watt for optical-to-electrical (O/E) converters, and unknown
when there is no unit of measure or when the unit of measure is not one of the
available choices.
Key Path
Channel, External scale...., Units
Ext gain and Ext offset When you select Ampere, Watt, or unknown on an electrical channel or Volt on
an optical channel, two additional functions become available: External Gain
and External Offset. These two additional functions allow you to compensate
for the actual characteristics of the probe rather than its ideal characteristics.
For example, you might have an amplified lightwave converter with ideal characteristics of 300 V/W with 0 V offset. But, its actual characteristics are 324 V/
W with 1 mV of output offset. Therefore, set the External Gain to 324 V/W and
the External Offset to 1 mV.
Key Path
Channel, External scale...., Units Volt Ext gain or Ext Offset
Channel, External scale...., Units Watt Ext gain or Ext Offset
Channel, External scale...., Units Unknown Ext gain or Ext Offset
2-17
Channel Setup Menu
Calibrate
Calibrate
The calibrate menu allows you to null out any skew between probes or cables,
remove the effects of offsets in the internal O/E converter, recalibrate the
responsivity of the O/E converter, and check the present calibration status of
the analyzer.
Key Path
Channel, Calibrate
Skew
The Skew function changes the horizontal position of a waveform on the display. The Skew function has a range of ≈ +100 µs. You can use skew to compensate for differences in cable or probe lengths. It also allows you to place
the triggered edge at the center of the display when you are using a power
splitter connected between the channel and trigger inputs. Another use for
skew is when you are comparing two waveforms that have a timing difference
between them. If you are more interested in comparing the shapes of two
waveforms rather than the actual timing difference between them, you can
use Skew to overlay one waveform on top of the other waveform.
To skew two channels
Turn both channels on and overlay the signals vertically.
Expand the time base so the rising edges are at about a 45 degree angle.
Adjust the skew on one of the channels so that the rising edges overlap at the 50 percent points.
Key Path
Channel, Calibrate, Skew
2-18
Channel Setup Menu
Calibrate
Cal status
The Cal Status function displays a screen similar to Figure 2-3.
Key Path
Channel, Calibrate, Cal Status
Figure 2-3. A typical Cal Status display.
Current Date
This is the current date and time. You can compare this to the last plug-in
module calibration time. That way you will know how long it has been since
the last plug-in module calibration was performed.
Current Frame
∆Temp
This is the temperature change on the inside of the instrument since the last
mainframe calibration was performed. A positive number indicates how many
degrees warmer the mainframe is currently as compared to the temperature
of the mainframe at the last mainframe calibration.
Channel 1
Calibration
Status
The instrument displays Calibrated or Uncalibrated, depending on
whether the last plug-in module calibration is still valid. A calibration can be
invalidated if:
• The mainframe has cycled power.
• The plug-in has been repaired, reprogrammed, or removed from the
mainframe.
• The instrument’s operating temperature has changed and remains more than
5°C from the temperature at which the Plug-in calibration was performed.
Uncalibrated indicates the plug-in module vertical calibration is invalid.
2-19
Channel Setup Menu
Calibrate
Plug-in
The Plug-in function lists the model number, serial number, date, time, and
temperature delta. The temperature ∆ is the temperature change from the
temperature of the mainframe when the last calibration was performed. If this
temperature ∆ is greater than ±5°C since the last mainframe calibration, then
you must perform a plug-in module calibration to achieve the specified dc
accuracy.
Offset zero
The Offset Zero function performs a quick offset calibration on the optical
channel. Since the primary source of calibration error on the optical channel is
offset drift, this function is useful between the plug-in module vertical calibrations if the plug-in module has not been removed or reinstalled and the operating temperature has not changed more than ±5°C. In order to ensure that
instrument specifications are met, perform the plug-in vertical calibration.
Performing an Offset Zero calibration is much faster than performing a complete vertical calibration.
Key Path
Channel, Calibrate, Offset zero
O/E cal
The plug-in module is provided with factory optical calibrations at 1310 nm
and 1550 nm. The O/E Calibration function allows you to calibrate the instrument for use at one additional user-defined wavelength between 1000 nm and
1600 nm. This calibration does not affect the factory calibrations.
Calibrate probe
Connect a voltage probe to the plug-in and then press, Calibrate probe
The analyzer calibrates to the tip of the probe by setting the probe attenuation
to the actual attenuation ratio of the probe. The analyzer also automatically
compensates for any offset the probe may introduce. The CAL signal is internally routed to the probe tip for Agilent Technologies probes.
Key Path
Channel, Calibrate, Calibrate probe
2-20
3
Factory Calibrations 3-4
User Calibrations—Optical and Electrical
Complete Calibration Summary 3-19
Calibration Overview
3-7
Calibration Overview
Calibration Overview
Calibration Overview
This chapter describes the calibration of the mainframe and the plug-in modules. It is intended to give you, or the calibration laboratory personnel, an
understanding of the various calibration procedures available, and how they
were intended to be used. There is a description of the calibration menu
included in the manuals provided with the plug-in modules and probes.
Proper calibration is critical to measurement accuracy and repeatability. The
Agilent 54750A/83480A and their associated modules and accessories require
that both factory and user calibrations be implemented at the recommended
intervals in order to perform measurements at their published specifications.
This chapter is divided into three sections. The first section describes factory
calibrations. A factory calibration consists of verifying instrument performance to all specifications. If an instrument fails to meet specifications,
adjustment or repair may be necessary. For most users, this will mean shipping the instrument back to an authorized service center. Some users may
purchase the required instrumentation and perform the factory timebase calibrations themselves using the optional Agilent 83480A, 54750A Service
Guide.
The second part of the chapter addresses calibrations that are routinely performed by the end user. Subsections in each of the two main sections discuss
the individual calibrations. In addition, there are summary tables at the end of
each of these sections summarizing the main areas addressed. The third part
of the chapter consists of a complete calibration summary table. Both factory
and user calibrations must be performed regularly in order to ensure proper
measurement accuracy and repeatability.
3-2
Calibration Overview
Calibration Overview
CAUTION
The input circuits can be damaged by electrostatic discharge (ESD). Avoid
applying static discharges to the front-panel input connectors. Before
connecting a coaxial cable to the connectors, momentarily short the center and
outer connectors of the cable together. Avoid touching the front panel input
connectors without first touching the frame of the instrument. Be sure that the
instrument is properly earth-grounded to prevent buildup of static charge. It is
strongly recommended that an antistatic mat and wristband be used when
connecting to electrical channel inputs.
Calibration
interval
Agilent Technologies recommends that the factory calibration be performed
on a periodic basis. Agilent Technologies designs instruments to meet specifications over the recommended calibration interval provided that the instrument is operated within the specified operating environment. To maintain
specifications, periodic recalibrations are necessary. We recommend that the
plug-in module be calibrated at an Agilent Technologies service facility every
12 months. Users are encouraged to adjust the calibration cycle based on their
particular operating environment or measurement accuracy needs.
Required warm-up The instrument requires a 1 hour warm-up period before any of the calibratime
tions mentioned in this chapter are performed. It is not enough for the instrument to be in the standby setting. It must be turned on and running for the
entire hour.
Remote operation Remote programming commands for calibrations are included in the
Agilent 83480A/Agilent 54750A Programming’s Guide. Performing calibrations remotely is slightly different than the operation of front-panel calibrations.
3-3
Calibration Overview
Factory Calibrations
Factory Calibrations
The following calibrations are performed at the factory:
Mainframe Calibration
O/E Factory Wavelength Calibration
Table 3-1. Factory Calibration Summary
Measurements
Affected
Recommended
Interval
Accuracy and
continuity of the
timescale
Channels affected:
optical & electrical. All
time base
measurements such as
rise time, fall time, eye
width, and jitter.
The photodetector
responsivity
Channels affected:
optical. Amplitude
accuracy of all optical
channel
measurements. Optical
power meter accuracy.
Annually at Agilent
service center or if
operating temp has
changed and remains
5°C or more from
calibration
temperature. See
service manual.
Annual factory recalibration of standard
wavelengths.
Calibration
What is calibrated
Mainframe
Calibration
O/E Factory
Wavelength
Calibration
Softkey Path
Utility
Calibrate
Calibrate frame
Not user accessible.a
a. Refer to “O/E User-Wavelength Calibration” on page 3-9.
Mainframe Calibration
Mainframe calibration affects both optical and electrical measurements. Mainframe calibration improves timebase accuracy. All timebase measurements
such as rise time, fall time, eye width, jitter, and so forth are affected by the
timebase accuracy.
The calibration factors are stored in the nonvolatile RAM of the instrument.
There is a switch on the back panel of the instrument that allows the mainframe calibration to be protected or unprotected. Next to the switch there is a
3-4
Calibration Overview
Factory Calibrations
drawing that shows each switch’s function and protected position. Refer to the
optional Agilent 83480A, 54750A Service Guide for more details about the
mainframe calibration, and the position of the rear-panel memory protect
switches.
CAUTION
To prevent access to the mainframe calibration switch, place a sticker over the
access hole to this switch.
CAUTION
Do not attempt a Mainframe calibration without consulting the
Agilent 83480A, 54750A Service Guide.
A mainframe calibration should be performed on a periodic basis, annually, or
when the ambient operating temperature has changed by and remains 5°C different than the operating temperature at which the last mainframe calibration
was performed. To see how much the operating temperature has changed
since the last mainframe calibration and the date of the last mainframe calibration, check the Calibration status by pressing the following key sequence:
Utility, Calibrate, and then Cal status on.
The temperature change is displayed at the top of the display as shown in the
following figure.
Figure 3-1. Current Frame ∆Temp condition
3-5
Calibration Overview
Factory Calibrations
If the Current Frame ∆Temp listing is greater than ±5°C, then the mainframe should either be calibrated at the current operating temperature or be
placed in an ambient air temperature that is within 5°C of the temperature of
the current calibration.
O/E Factory Wavelength Calibration
Optical/electrical (O/E) factory wavelength calibration, compensates for the
photodetector responsivity. The accuracy of all optical channel measurements
is dependent on proper O/E calibration. O/E calibrations should be performed
annually. Most customers return their optical plug-ins to an authorized Agilent
Technologies service center for this calibration at the same time they are having their mainframes re-calibrated.
The Agilent 83480-series optical modules have one or two standard wavelengths (850 nm or 1310/1550 nm). The O/E Calibration function allows you to
calibrate the instrument for use at one additional user-defined wavelength.
This calibration does not affect the factory calibrations. See the following section on User Calibrations for additional information on this procedure.
3-6
Calibration Overview
User Calibrations—Optical and Electrical
User Calibrations—Optical and Electrical
The following calibrations can be performed by the user:
O/E User Wavelength Calibration
Plug-in Module Vertical Calibration
Offset Zero Calibration
Dark Calibration
Probe Calibration
Channel Skew
External Scale
Electrical channels have calibration procedures for:
• adjusting timebase skew, for matching propagation delay between channels,
probes, cables, and so forth
• using external probes
Optical channels have calibration procedures for:
• adjusting timebase skew
• monitoring and adjusting internal offsets
• performing a user-defined O/E responsivity adjustment
CAUTION
The input circuits can be damaged by electrostatic discharge (ESD). Avoid
applying static discharges to the front panel input connectors. Before
connecting a coaxial cable to the connectors, momentarily short the center and
outer connectors of the cable together. Avoid touching the front panel input
connectors without first touching the frame of the instrument. Be sure the
instrument is properly earth-grounded to prevent buildup of static charge. An
antistatic mat and wristband are strongly recommended, particularly when
working with TDR modules.
3-7
Calibration Overview
User Calibrations—Optical and Electrical
Table 3-2. Optical and Electrical Channel User Calibration Summary
Calibration
What is calibrated
O/E User Wavelength
Calibration
The photodetector
responsivity
Plug-in Vertical
Calibration
Vertical offset and
vertical scale accuracy
for both electrical and
optical channels.
Offset Zero
Calibration
Vertical offset is
calibrated for the
optical channel only.
This calibration
doesn’t include vertical
scale accuracy.
Dark Calibration
Dark calibration
measures the channel
offset signal without
any light present and
this value is used in
the extinction ratio
algorithm.
3-8
Measurements
Affected
Recommended
Interval
Key Path
Channels affected:
optical. All optical
channel
measurements at user
wavelengths.
Channels affected:
optical & electrical.
Any optical or
electrical vertical
measurements such as
Vp to p, eye height,
extinction ratio, and
the optical power
meter
Channels affected:
optical. Any optical
vertical measurements
including: Vp to p, eye
height, and extinction
ratio.
Annual re-calibration
of user defined nonfactory wavelengths
Optical Channel Setup
Calibrate
O/E Cal
Perform after any
power cycle or once
every 10 hours during
continuous use or if
operating temperature
changes by more than
2°C.
Utility
Calibrate
Calibrate Plug-in
Perform a plug-in
vertical calibration in
order to meet
published
specifications.
Because the offset
zero calibration
performs only the
offset portion of the
plug-in vertical
calibration, it should
only be used before
fast non-critical
measurements.
Before extinction ratio
measurements if the
vertical scale or offset
has changed since the
last dark calibration or
after a plug-in vertical
calibration is
performed.
Optical Channel Setup
Calibrate
Offset 0
Channels affected:
optical & electrical.
Extinction ratio.
Shift, Meas eye
Extinction ratio
Dark Cal
Calibration Overview
User Calibrations—Optical and Electrical
Table 3-3. Miscellaneous User Calibration Summary
Calibration
What is calibrated
Probe calibration
Probe Attenuation
Channel Skew
Calibrates out the
small differences in
delay between
channels. Useful for
looking at timing
differences between
channels
Compensates for gain
or loss associated with
external devices
(calibrates vertical
scale to external
device
External Scale
Measurements
Affected
Recommended
Interval
Channels affected:
electrical. Any
electrical
measurement taken
with the probe
Channels affected:
optical & electrical.
Multiple channel
measurements.
Whenever a probe is
connected
Electrical Channel Setup
Calibrate
Calibrate probe
Before multiple
channel
measurements when
measuring timing
differences between
channels.
Channel Setup
Calibrate
Skew
Whenever using
external devices
(component or
transducer)
Channel Setup
External Scale
Channels affected:
optical & electrical.
Any measurement
taken through an
external device
(component or
transducer
Key Path
O/E User-Wavelength Calibration
This optional optical/electrical (O/E) calibration is for optical measurements
only. It compensates for the photodetector’s responsivity. The vertical accuracy of all optical channel user wavelength measurements is dependent on
proper O/E user wavelength calibration. O/E user-wavelength calibrations
should be performed annually or whenever a new wavelength is being measured. To perform a O/E user-wavelength calibration, a CW optical source with
a known optical output power level is required. Refer to the specifications for
the plug-in module for the acceptable power level ranges.
3-9
Calibration Overview
User Calibrations—Optical and Electrical
NOTE
The optical channel calibration accuracy is heavily dependent on the accuracy to which
you know the optical source power. For best results, measure the optical source power
with an optical power meter such as the Agilent 8153A and use precision optical connectors. In addition, proper connector cleaning procedures are essential to obtaining an
accurate calibration.
To perform an O/E user-wavelength calibration
1 Press the plug-in module’s front-panel optical channel SETUP key.
2 Press Calibrate, and then O/E cal.
3 Input the correct wavelength, and follow the instructions on the screen.
Figure 3-2. Plug-in calibration menu
To use an O/E user-wavelength calibration
1 Press the plug-in module’s front-panel optical channel SETUP key.
2 Press Bandwidth/wavelength and then wavelength.
3 Press Usr wavelength and then Enter.
3-10
Calibration Overview
User Calibrations—Optical and Electrical
Plug-in Module Vertical Calibration
The plug-in module vertical calibration is for both optical and electrical measurements. It allows the instrument to establish the calibration factors for a
specific plug-in when the plug-in is installed in the mainframe. The plug-in calibration factors are valid only for the specific mainframe slot in which it was
calibrated. The plug-in vertical calibration establishes vertical accuracy.
A plug-in vertical calibration should be done if:
• The mainframe has cycled power.
• The plug-in has been repaired, reprogrammed, or removed from the
mainframe.
• The instrument’s operating temperature has changed and remains more than
5°C from the temperature at which the Plug-in calibration was performed.
To obtain the best measurement results, it is recommended that a user vertical calibration be performed after every 10 hours of continuous use or if the
temperature has changed by greater than 2°C from the previous vertical calibration.
To view the temperature change
This procedure displays the temperature change that the instrument has
undergone since the last Plug-in Vertical Calibration.
1 Press the front-panel channel SETUP key.
2 Press Calibrate and then Cal status on.
The current plug-in ∆Temp value is listed for each installed module.
To perform a plug-in module vertical calibration
1 Remove any front-panel connections from electrical channels.
2 Cover the optical inputs for the optical channels.
3 Press Utility, Calibrate...., and then Calibrate plug-in.....
4 Select the plug-in module to be calibrated, press 1 and 2 or 3 and 4.
5 Press Start cal to start the calibration.
6 Follow the on-screen instructions.
3-11
Calibration Overview
User Calibrations—Optical and Electrical
No additional equipment is required to perform a plug-in vertical calibration.
Reference signals are both generated and routed internally, for the optical and
electrical channels. If you are prompted to connect the calibrator output to
the electrical channel during an optical vertical calibration, then the factory O/
E calibration has been lost. The module must then be returned to Agilent
Technologies for calibration.
Offset Zero Calibration
The offset zero calibration performs a quick offset calibration on the optical
channel for optical measurements. Since the primary source of calibration
error on the optical channel is offset drift, this function is useful between the
plug-in module vertical calibrations if the plug-in module has not been
removed or reinstalled and the operating temperature has not changed more
than ±5°C. In order to ensure that instrument specifications are met, perform
the plug-in vertical calibration.
Performing an offset zero calibration is much faster than performing a complete vertical calibration. For critical measurements where offset measurement uncertainty is important to consider, perform an offset zero calibration
between module vertical calibrations. Perform an offset zero calibration if the
vertical scale or offset changes.
To initiate an offset calibration
1 Disconnect all inputs from the module being calibrated.
2 Cover all optical inputs.
3 Press the plug-in module’s front-panel optical channel SETUP key.
4 Press Calibrate and then Offset zero.
3-12
Calibration Overview
User Calibrations—Optical and Electrical
Figure 3-3. Offset Zero Calibration
Dark Calibration
The dark calibration is for optical measurements, or electrical measurements
if an external O/E is being used. This calibration measures the optical channel
offset signal when there isn’t any light present and then uses this information
in performing extinction ratio measurements. Dark calibrations should be
done for the following conditions:
•
•
•
•
•
Before any critical extinction ratio measurements are made
After a plug-in vertical calibration
If a module has been removed
If the mainframe power has been cycled
If extinction ratio measurements are being made after the vertical scale or the
offset has changed.
If the line power has been cycled, the dark calibration invokes either the offset
zero calibration or plug-in vertical calibration as needed. This increases the
time required for the dark calibration to complete. The Dark cal softkey is
located within the Extinction ratio menu.
3-13
Calibration Overview
User Calibrations—Optical and Electrical
To initiate a dark calibration
1 Press the Display key. Press the Color grade softkey, and set its setting to on.
Color grade must be enabled to perform an extinction ratio measurement and
a dark calibration. In addition, the dark level (amplitude when there is no signal
present) must be on the screen to perform a dark calibration.
2 Press the blue shift key, and then the Meas eye softkey which is located beneath
the display.
3 Press Extinction ratio... and then Dark cal.
Disconnect all inputs from the module, including the trigger signal, and block
any ambient light to the photodetector with a connector plug. Follow the
instructions on the screen.
Figure 3-4. Dark calibration menu
3-14
Calibration Overview
User Calibrations—Optical and Electrical
Channel Skew Calibration
This calibration affects both optical and electrical measurements. The skew
calibration changes the horizontal position of a waveform on the display. The
skew calibration has a range of approximately 100 µs. You can use skew to
compensate for the differences in cable or probe lengths. It also allows you to
place the trigger edge at the center of the display when you are using a power
splitter connected between the channel and trigger inputs. Another use for
skew is when you are comparing two waveforms that have a timing difference.
If you are interested in comparing the shapes of two waveforms rather than
the actual timing difference, you can use skew to overlay one waveform on top
of the other waveform.
To skew two channels
1 Turn both channels on and overlay the signals vertically.
2 Expand the time base so that the rising edges are at about a 45° angle.
3 Press the plug-in module’s front-panel channel SETUP key.
4 Press Calibrate and then Skew.
5 Adjust the skew on one of the channels so that the rising edges overlap at the
50% points.
Probe Calibration
Probe calibration applies to electrical measurements only. For active probes
such as the Agilent 54701A, which the instrument can identify through the
probe power connector, the instrument automatically adjusts the channel vertical scale factors to the probe’s nominal attenuation, even if a probe calibration is not performed.
For passive probes or non-identified probes, the instrument adjusts the vertical scale factors only if a probe calibration is performed. Probe calibration
allows the instrument to establish the gain and offset of specific probes that
are connected to a channel of the instrument, and then apply those factors to
the calibration of that channel.
The analyzer calibrates to the tip of the probe by setting the probe attenuation
to the actual attenuation ratio of the probe. The CAL signal is internally routed
to the probe tip for Agilent Technologies active probes.
3-15
Calibration Overview
User Calibrations—Optical and Electrical
The mainframe’s CAL signal is a voltage source, therefore you can let the
instrument compensate for the actual characteristics of your probe by letting
the instrument calibrate to the tip of the probe. The instrument automatically
calibrates to the tip of the probe, sets the probe attenuation, and compensates
for any probe offset.
If you do not perform a probe calibration but want to use a passive probe,
enter the attenuation factor using the following steps:
1 Press the plug-in module’s front-panel channel SETUP key.
2 Press External scale and then Attenuation.
You can use the probe calibration to calibrate any network, including probes or
cable assemblies. The instrument calibrates the voltage at the tip of the probe
or the cable input.
To calibrate an Agilent Technologies identifiable probe
1 Press the plug-in module’s front-panel-channel SETUP key.
2 Press Calibrate and then Calibrate Probe.
To calibrate a non-identifiable probe
1 Connect the voltage probe to the plug-in.
2 Attach the probe tip to the CAL hook that is located near the floppy disk drive.
3 Press the plug-in module’s front-panel channel SETUP key.
4 Press Calibrate and then Calibrate probe.
If the probe being calibrated has an attenuation factor that allows the instrument to adjust the gain (in hardware) to produce even steps in the vertical
scale factors, the instrument will do so. Typically, probes have standard attenuation factors such as divide by 10, divide by 20, or divide by 100.
3-16
Calibration Overview
User Calibrations—Optical and Electrical
Figure 3-5. Electrical Channel Calibrate Menu
To calibrate other devices
The information in this section applies to both optical and electrical measurements. Since the mainframe’s CAL signal is a voltage source, it cannot be used
to calibrate to the probe tip when the units are set to Ampere, Watt, or
Unknown. Instead, set the external gain and external offset to compensate for
the actual characteristics of the probe or device. If you do not know the actual
characteristics, you can refer to the typical specifications that came with the
probe or device.
1 Press the plug-in module’s front-panel channel SETUP key.
2 Press External scale.
3 Press Atten units Ratio, Attenuation 1:1, and then Units Ampere (Volt, Watt, or
Unknown).
4 Press Ext gain, and enter the actual gain characteristics of the probe or device.
5 Press Ext offset, and enter the offset introduced by the probe or device.
3-17
Calibration Overview
User Calibrations—Optical and Electrical
External Scale
Both optical and electrical channels have an External scale setting which
allows the user to enter in an offset value to compensate for gains or losses not
associated with the device under test. This feature is useful for adjusting out
the effects of devices such as test fixtures and attenuators so that the reading
on the display gives the measurement value associated with only the actual
device under test.
To adjust the external scale
1 Press the plug-in module’s front-panel channel SETUP key.
2 Press External scale, and set the Atten units to "decibel".
3 Press Attenuation, and enter the appropriate values.
Figure 3-6. External Scale Menu
3-18
Calibration Overview
Complete Calibration Summary
Complete Calibration Summary
Table 3-4. Complete Calibration Summary (1 of 2)
Measurements
Affected
Recommended
Interval
Accuracy and
continuity of the
timescale
Channels affected:
optical & electrical. All
time base
measurements such
as rise time, fall time,
eye width, and jitter.
O/E Factory
Wavelength
Calibration
The photodetector
responsivity
O/E User Wavelength
Calibration
The photodetector
responsivity
Plug-in Vertical
Calibration
Vertical offset and
vertical scale accuracy
for both electrical and
optical channels.
Channels affected:
optical. Amplitude
accuracy of all optical
channel
measurements.
Optical power meter
accuracy.
Channels affected:
optical. All optical
channel
measurements at user
wavelengths.
Channels affected:
optical & electrical.
Any optical or
electrical vertical
measurements such
as Vp to p, eye height,
extinction ratio, and
the optical power
meter
Annually at Agilent
service center or if
operating temp has
changed and remains
5°C or more from
calibration
temperature. See
service manual.
Annual factory recalibration of standard
wavelengths.
Calibration
What is calibrated
Mainframe Calibration
Key Path
Utility
Calibrate
Calibrate frame
Not user accessible.a
Annual re-calibration
of user defined nonfactory wavelengths
Optical Channel Setup
Calibrate
O/E Cal
Perform after any
power cycle or once
every 10 hours during
continuous use or if
operating temperature
changes by more than
2°C.
Utility
Calibrate
Calibrate Plug-in
3-19
Calibration Overview
Complete Calibration Summary
Table 3-4. Complete Calibration Summary (2 of 2)
Measurements
Affected
Recommended
Interval
Vertical offset is
calibrated for the
optical channel only.
This calibration
doesn’t include
vertical scale
accuracy.
Channels affected:
optical. Any optical
vertical measurements
including: Vp to p, eye
height, and extinction
ratio.
Dark Calibration
Dark calibration
measures the channel
offset signal without
any light present and
this value is used in
the extinction ratio
algorithm.
Channels affected:
optical & electrical.
Extinction ratio.
Probe calibration
Probe Attenuation
Channel Skew
Calibrates out the
small differences in
delay between
channels. Useful for
looking at timing
differences between
channels
Compensates for gain
or loss associated
with external devices
(calibrates vertical
scale to external
device
Channels affected:
electrical. Any
electrical
measurement taken
with the probe
Channels affected:
optical & electrical.
Multiple channel
measurements.
Perform a plug-in
vertical calibration in
order to meet
published
specifications.
Because the offset
zero calibration
performs only the
offset portion of the
plug-in vertical
calibration, it should
only be used before
fast non-critical
measurements.
Before extinction ratio
measurements if the
vertical scale or offset
has changed since the
last dark calibration or
after a plug-in vertical
calibration is
performed.
Whenever a probe is
connected
Calibration
What is calibrated
Offset Zero Calibration
External Scale
Channels affected:
optical & electrical.
Any measurement
taken through an
external device
(component or
transducer)
a. Refer to “O/E User-Wavelength Calibration” on page 3-9.
3-20
Key Path
Optical Channel Setup
Calibrate
Offset 0
Shift, Meas eye
Extinction ratio
Dark Cal
Electrical Channel
Setup
Calibrate
Calibrate probe
Before multiple
channel
measurements when
measuring timing
differences between
channels.
Channel Setup
Calibrate
Skew
Whenever using
external devices
(component or
transducer)
Channel Setup
External Scale
4
Specifications 4-3
Characteristics 4-7
Declaration of Conformity
4-9
Specifications and Regulatory
Information
Specifications and Regulatory Information
Specifications and Regulatory Information
Specifications and Regulatory Information
This chapter lists specifications and characteristics of the Agilent 83482A
optical/electrical plug-in module. Specifications apply over the temperature
range +15°C to +35°C (unless otherwise noted) after the instrument’s temperature has been stabilized after 60 minutes of continuous operation.
Refer to the Agilent 54701A Active Probe Service Guide for complete probe
specifications.
Specifications
Specifications described warranted performance.
Characteristics
Characteristics provide useful, nonwarranted, information about the functions and performance of the instrument. Characteristics are printed in
italics.
Calibration cycle
Agilent Technologies designs instruments to meet specifications over the recommended calibration interval provided that the instrument is operated
within the specified operating environment. To maintain specifications, periodic recalibrations are necessary. We recommend that the plug-in module be
calibrated at an Agilent Technologies service facility every 24 months. Users
are encouraged to adjust the calibration cycle based on their particular operating environment or measurement accuracy needs.
4-2
Specifications and Regulatory Information
Specifications
Specifications
Table 4-1. Agilent 83482A Electrical Channel Vertical Specifications
Bandwidth (–3 dB)
dc to 40 GHz, or dc to 18 GHz, user selectable
dc Accuracy—single voltage marker a
18 GHz
±0.4% of full scale
±2 mV ±1.5% (reading – channel offset)
± (2%/°C) (∆Tcal b) (reading)
40 GHz
±0.4% of full scale
±2 mV ±3% (reading – channel offset)
± (2%/°C) (∆Tcal b) (reading)
dc Difference—two marker accuracy
on same channel a
12.4 GHz
±0.8% of full scale
±1.5% of delta marker reading
± (2%/°C) (∆Tcal b) (reading) – 0.4%/hr (∆Timecal c) (reading)
20 GHz
±0.8% of full scale
±3% of delta marker reading
± (2%/°C) (∆Tcal b) (reading) – 0.4%/hr (∆Timecal c) (reading)
Transition Time (10% to 90%,
calculated from T=0.35/bandwidth)
18 GHz
≤19.5 ps
40 GHz
≤.9 ps
Maximum RMS Noise
18 GHz
≤0.5 mV (0.25 mV typical)
40 GHz
1.0 mV (0.5 mV typical)
4-3
Specifications and Regulatory Information
Specifications
Table 4-1. Agilent 83482A Electrical Channel Vertical Specifications (Continued)
Scale Factor (full scale is eight
divisions)
Minimum
1 mV/div
Maximum
100 mV/div
±500 mV
dc Offset Range
Inputs:
Dynamic Range
±400 mV relative to channel offset
Maximum Safe Input Voltage
16 dBm peak ac ±2V dc
Nominal Impedance
50 Ω
Reflections
≤5% for 20 ps rise time
Connector
2.4mm (m)
a. It is recommended that a user vertical calibration be performed after every 10 hours of continuous use or if the temperature has changed
by greater than 2°C from the previous vertical calibration.
b. Where ∆Tcal represents the temperature change in Celsius from the last user vertical calibration. Note that the temperature term goes to
zero upon execution of a vertical calibration.
c. Where ∆Timecal represents the time since the last user vertical calibration. The uncertainty due to time typically stabilizes after 24 hours.
This term goes to zero upon execution of a vertical calibration.
Table 4-2. Agilent 83482A Optical Channel Vertical Specifications
Bandwidth (–3 dB)
dc to 30 GHz
dc Accuracy a
(Optical Channel referenced to
average power meter)
±50 µW ±4% of (reading - channel offset)
± (2%/°C) (∆Tcal b) (reading)
dc Difference a
(two marker accuracy, same channel,
referenced to average power monitor)
±4% of delta reading
± (2%/°C) (∆Tcal b) (reading)
Transition Time (10% to 90%)
<13 ps
Maximum RMS Noise
<30 µW (<15 µW typical)
Scale Factor (full scale is eight divisions)
20 µW/div
Minimum
4-4
Specifications and Regulatory Information
Specifications
Table 4-2. Agilent 83482A Optical Channel Vertical Specifications (Continued)
Maximum
500 µW/div
dc Offset Range
+1 mW to –3 mW, referenced to two divisions
above bottom of screen
Connector Type
9/125 µm single mode, user selectable connector
. Input Return Loss
30 dB (HMS-10 connector)
Calibrated Wavelength
1310 nm and 1550 nm
Average Power Monitor
Specified Operating Range
–27 dBm to +3 dBm (2 µW to 2 mW)
Factory Calibrated Accuracy (20°C to 30°C)
±5% of reading ±100 nW ±connector uncertainty
User Calibrated Accuracy (>5°C temp
change)
±2% of reading ±100 nW ±power-meter uncertainty
Maximum Specified Input Power
2 mW
Maximum Safe Input
10 mW peak
Wavelength Range
1000 to 1600 nm
a. It is recommended that a user vertical calibration be performed after every 10 hours of continuous use or if the temperature has changed
by greater than 2°C from the previous vertical calibration.
b. Where ∆Tcal represents the temperature change in Celsius from the last user vertical calibration. Note that the temperature term goes to
zero upon execution of a vertical calibration.
Table 4-3. Electrical and Optical Channels
Temperature
Operating
Non-operating
Humidity
Operating
Non-operating
15°C to +35°C
–40°C to +70°C
up to 90% relative humidity (non-condensing) at ≤35°C
up to 95% relative humidity (non-condensing) at ≤65°C
4-5
Specifications and Regulatory Information
Specifications
Table 4-4. Power Requirements
Supplied by mainframe.
Table 4-5. Weight
Net
Shipping
4-6
approximately 1.2 kg (2.6 lb.)
approximately 2.1 kg (4.6 lb.)
Specifications and Regulatory Information
Characteristics
Characteristics
The following characteristics are typical for the Agilent 83482A optical/electrical plug-in module. Refer to the Agilent 54701A Active Probe Service Guide
for complete probe characteristics.
Table 4-6. Trigger Input Characteristics for Electrical and Optical Channels
Nominal Impedance
50 Ω
Input Connector
3.5 mm (m)
Trigger Level Range
±1 V
Maximum Safe Input Voltage
±2 Vdc + ac peak (+16 dBm)
Percent Reflection
≤10% for 100 ps rise time
Refer to the Agilent 83480A, 54750A User’s Guide for trigger specifications.
4-7
Specifications and Regulatory Information
Characteristics
Impulse response
The following figures show the characteristic impulse response of the
Agilent 83482A optical/electrical plug-in module.
The impulse response of the Agilent 83482A optical/electrical plug-in module displayed at 200 ps/division.
The impulse response of the Agilent 83482A optical/electrical plug-in module displayed at 20 ps/division.
4-8
Specifications and Regulatory Information
Declaration of Conformity
Declaration of Conformity
4-9
5
In Case of Difficulty 5-2
Error Messages 5-5
Cleaning Connections for Accurate Measurements
Agilent Technologies Service Offices 5-17
Reference
5-7
Reference
In Case of Difficulty
In Case of Difficulty
This section provides a list of suggestions for you to follow if the plug-in module fails to operate. A list of messages that may be display is also included. For
complete service information, refer to the optional Agilent 83482A Optical/
Electrical Plug-In Module Service Guide.
Review the procedure being performed when the problem occurred. Before
calling Agilent Technologies or returning the unit for service, a few minutes
spent performing some simple checks may save waiting for your instrument to
be repaired
If the mainframe does not operate
Make the following checks:
❒ Is the line fuse good?
❒ Does the line socket have power?
❒ Is the unit plugged in to the proper ac power source?
❒ Is the mainframe turned on?
❒ Is the rear-panel line switch set to on?
❒ Will the mainframe power up without the plug-in module installed?
If the mainframe still does not power up, refer to the optional
Agilent 83480A, 54750A Service Guide or return the mainframe to a qualified service department.
5-2
Reference
In Case of Difficulty
If the plug-in does not operate
1 Make the following checks:
• Is the plug-in module firmly seated in the mainframe slot?
• Are the knurled screws at the bottom of the plug-in module finger-tight?
• Is a trigger signal connected to a trigger input?
• If other equipment, cables, and connectors are being used with the plug-in
module are they connected properly and operating correctly?
• Review the procedure for the test being performed when the problem appeared. Are all the settings correct? Can the problem be reproduced?
• Are the connectors clean? See “Cleaning Connections for Accurate Measurements” on page 5-7 for more information about cleaning the connectors.
2 Perform the following procedures:
• Make sure the instrument is ready to acquire data by pressing Run.
• Find any signals on the channel inputs by pressing Autoscale.
• See if any signals are present at the channel inputs by pressing Trigger, Sweep,
freerun.
After viewing the signal, press triggered.
• Make sure Channel Display is on by pressing Channel, Display on off, on.
• Make sure the channel offset is adjusted so the waveform is not clipped off
the display.
• If you are using the plug-in module only as a trigger source, make sure at
least one other channel is turned on. If all of the channels are turned off, the
mainframe will not trigger.
• Make sure the mainframe identifies the plug-in module by pressing Utility,
then System config....
The calibration status of the plug-in modules is listed near the bottom of the
display, in the box labeled “Plug-ins”. If the model number of the plugin module is listed next to the appropriate slot number, then the mainframe
has identified the plug-in.
If “~known” is displayed instead of the model number of the plug-in
module, remove and reinsert the plug-in module in the same slot. If
5-3
Reference
In Case of Difficulty
“~known” is still displayed, then the memory contents of the plug-in
module are corrupt. Refer to the optional Agilent 83482A Optical/
Electrical Plug-In Module Service Guide or contact a qualified service
department.
If all of the above steps check out okay, and the plug-in module still does not
operate properly, then the problem is beyond the scope of this book. Refer to
the optional Agilent 83482A Optical/Electrical Plug-in Module Service
Guide or return the plug-in module to a qualified service department.
5-4
Reference
Error Messages
Error Messages
The following error messages are for the plug-in module. Typically, the error
messages indicate there is a problem with either the plug-in or the mainframe.
This section explains what the messages mean and offers a few suggestions
that might help resolve the error condition. If the suggestions do not eliminate
the error message, then additional troubleshooting is required that is beyond
the scope of this book. Refer to the optional Agilent 83482A Optical/Electrical Plug-In Module Service Guide and Agilent 83480A, 54750A Service
Guide for additional troubleshooting information.
Additional error messages are listed in the Agilent 83480A, 54750A User’s
Guide for the mainframe.
Memory error occurred in plug-in_:Try reinstalling plug-in
The mainframe could not correctly read the contents of the memory in the
plug-in.
1 Remove and reinstall the plug-in module. Each time a plug-in is installed, the
mainframe re-reads the memory in the plug-in module.
2 Verify the plug-in module is firmly seated in the mainframe slot.
3 Verify the knurled screws at the bottom of the plug-in module are finger-tight.
4 Install the plug-in in a different slot in the mainframe.
Busy timeout occurred with plug-in_:Try reinstalling plug-in
The mainframe is having trouble communicating with the plug-in module.
Make sure there is a good connection between the mainframe and the plug-in
module.
1 Remove and reinstall the plug-in module.
2 Verify the plug-in module is firmly seated in the mainframe slot.
3 Verify the knurled screws at the bottom of the plug-in module are finger-tight.
4 Install the plug-in in a different slot in the mainframe.
Communications failure exists at slot_:Service is required
5-5
Reference
Error Messages
An illegal hardware state is detected at the mainframe-to-plug-in module
interface of the specified slot.
If the slot is empty, there is a mainframe hardware problem. Refer to the
Agilent 83480A, 54750A Service Guide.
If a plug-in is installed in the slot, there is a plug-in module hardware problem.
Refer to the optional Agilent 83482A Optical/Electrical Plug-In Module
Service Guide.
ID error occured in plug-in_:Service is required
The information read from the memory of the plug-in module does not match
the hardware in the plug-in module. This can be caused by a communication
problem between the mainframe and the plug-in module. Make sure there is a
good connection between the mainframe and the plug-in.
1 Remove and re-install the plug-in module.
2 Verify the plug-in module is firmly seated in the mainframe slot.
3 Verify the knurled screws at the bottom of the plug-in module are finger tight.
4 The standard Agilent 54750A mainframe does not accept the Agilent 83482A
optical/electrical plug-in module. To use the module, a firmware upgrade must
first be installed. Order the Agilent 83480K communications firmware kit and
install according to the instructions.
5 The Agilent 83480A, 54750A mainframes do not accept plug-in modules
designed for use with the Agilent 54710A, 54720A.
Cal not possible
The power is too low to perform a user O/E calibration.
5-6
Reference
Cleaning Connections for Accurate Measurements
Cleaning Connections for Accurate
Measurements
Today, advances in measurement capabilities make connectors and connection techniques more important than ever. Damage to the connectors on calibration and verification devices, test ports, cables, and other devices can
degrade measurement accuracy and damage instruments. Replacing a damaged connector can cost thousands of dollars, not to mention lost time! This
expense can be avoided by observing the simple precautions presented in this
book. This book also contains a brief list of tips for caring for electrical connectors.
Choosing the Right Connector
A critical but often overlooked factor in making a good lightwave measurement is the selection of the fiber-optic connector. The differences in connector types are mainly in the mechanical assembly that holds the ferrule in
position against another identical ferrule. Connectors also vary in the polish,
curve, and concentricity of the core within the cladding. Mating one style of
cable to another requires an adapter. Agilent Technologies offers adapters for
most instruments to allow testing with many different cables. Figure 5-1 on
page 5-8 shows the basic components of a typical connectors.
The system tolerance for reflection and insertion loss must be known when
selecting a connector from the wide variety of currently available connectors.
Some items to consider when selecting a connector are:
• How much insertion loss can be allowed?
• Will the connector need to make multiple connections? Some connectors are
better than others, and some are very poor for making repeated connections.
• What is the reflection tolerance? Can the system take reflection degradation?
• Is an instrument-grade connector with a precision core alignment required?
• Is repeatability tolerance for reflection and loss important? Do your specifica-
5-7
Reference
Cleaning Connections for Accurate Measurements
tions take repeatability uncertainty into account?
• Will a connector degrade the return loss too much, or will a fusion splice be required? For example, many DFB lasers cannot operate with reflections from
connectors. Often as much as 90 dB isolation is needed.
Figure 5-1. Basic components of a connector.
Over the last few years, the FC/PC style connector has emerged as the most
popular connector for fiber-optic applications. While not the highest performing connector, it represents a good compromise between performance, reliability, and cost. If properly maintained and cleaned, this connector can
withstand many repeated connections.
However, many instrument specifications require tighter tolerances than most
connectors, including the FC/PC style, can deliver. These instruments cannot
tolerate connectors with the large non-concentricities of the fiber common
with ceramic style ferrules. When tighter alignment is required, Agilent
Technologies instruments typically use a connector such as the Diamond
HMS-10, which has concentric tolerances within a few tenths of a micron. Agilent Technologies then uses a special universal adapter, which allows other
cable types to mate with this precision connector. See Figure 5-2.
5-8
Reference
Cleaning Connections for Accurate Measurements
Figure 5-2. Universal adapters to Diamond HMS-10.
The HMS-10 encases the fiber within a soft nickel silver (Cu/Ni/Zn) center
which is surrounded by a tough tungsten carbide casing, as shown in
Figure 5-3.
Figure 5-3. Cross-section of the Diamond HMS-10 connector.
The nickel silver allows an active centering process that permits the glass fiber
to be moved to the desired position. This process first stakes the soft nickel
silver to fix the fiber in a near-center location, then uses a post-active staking
to shift the fiber into the desired position within 0.2 µm. This process, plus the
keyed axis, allows very precise core-to-core alignments. This connector is
found on most Agilent Technologies lightwave instruments.
5-9
Reference
Cleaning Connections for Accurate Measurements
The soft core, while allowing precise centering, is also the chief liability of the
connector. The soft material is easily damaged. Care must be taken to minimize excessive scratching and wear. While minor wear is not a problem if the
glass face is not affected, scratches or grit can cause the glass fiber to move
out of alignment. Also, if unkeyed connectors are used, the nickel silver can be
pushed onto the glass surface. Scratches, fiber movement, or glass contamination will cause loss of signal and increased reflections, resulting in poor return
loss.
Inspecting Connectors
Because fiber-optic connectors are susceptible to damage that is not immediately obvious to the naked eye, poor measurements result without the user
being aware. Microscopic examination and return loss measurements are the
best way to ensure good measurements. Good cleaning practices can help
ensure that optimum connector performance is maintained. With glass-toglass interfaces, any degradation of a ferrule or the end of the fiber, any stray
particles, or finger oil can have a significant effect on connector performance.
Where many repeat connections are required, use of a connector saver or
patch cable is recommended.
Figure 5-4 shows the end of a clean fiber-optic cable. The dark circle in the
center of the micrograph is the fiber’s 125 µm core and cladding which carries
the light. The surrounding area is the soft nickel-silver ferrule. Figure 5-5
shows a dirty fiber end from neglect or perhaps improper cleaning. Material is
smeared and ground into the end of the fiber causing light scattering and poor
reflection. Not only is the precision polish lost, but this action can grind off the
glass face and destroy the connector.
Figure 5-6 shows physical damage to the glass fiber end caused by either
repeated connections made without removing loose particles or using
improper cleaning tools. When severe, the damage of one connector end can
be transferred to another good connector endface that comes in contact with
the damaged one. Periodic checks of fiber ends, and replacing connecting
cables after many connections is a wise practice.
The cure for these problems is disciplined connector care as described in the
following list and in “Cleaning Connectors” on page 5-14.
5-10
Reference
Cleaning Connections for Accurate Measurements
Use the following guidelines to achieve the best possible performance when
making measurements on a fiber-optic system:
• Never use metal or sharp objects to clean a connector and never scrape the
connector.
• Avoid matching gel and oils.
Figure 5-4. Clean, problem-free fiber end and ferrule.
Figure 5-5. Dirty fiber end and ferrule from poor cleaning.
5-11
Reference
Cleaning Connections for Accurate Measurements
Figure 5-6. Damage from improper cleaning.
While these often work well on first insertion, they are great dirt magnets. The
oil or gel grabs and holds grit that is then ground into the end of the fiber.
Also, some early gels were designed for use with the FC, non-contacting connectors, using small glass spheres. When used with contacting connectors,
these glass balls can scratch and pit the fiber. If an index matching gel or oil
must be used, apply it to a freshly cleaned connector, make the measurement,
and then immediately clean it off. Never use a gel for longer-term connections
and never use it to improve a damaged connector. The gel can mask the extent
of damage and continued use of a damaged fiber can transfer damage to the
instrument.
• When inserting a fiber-optic cable into a connector, gently insert it in as
straight a line as possible. Tipping and inserting at an angle can scrape material
off the inside of the connector or even break the inside sleeve of connectors
made with ceramic material.
• When inserting a fiber-optic connector into a connector, make sure that the fiber end does not touch the outside of the mating connector or adapter.
• Avoid over tightening connections.
Unlike common electrical connections, tighter is not better. The purpose of
the connector is to bring two fiber ends together. Once they touch, tightening
only causes a greater force to be applied to the delicate fibers. With connectors that have a convex fiber end, the end can be pushed off-axis resulting in
misalignment and excessive return loss. Many measurements are actually
improved by backing off the connector pressure. Also, if a piece of grit does
happen to get by the cleaning procedure, the tighter connection is more likely
to damage the glass. Tighten the connectors just until the two fibers touch.
5-12
Reference
Cleaning Connections for Accurate Measurements
• Keep connectors covered when not in use.
• Use fusion splices on the more permanent critical nodes. Choose the best connector possible. Replace connecting cables regularly. Frequently measure the
return loss of the connector to check for degradation, and clean every connector, every time.
All connectors should be treated like the high-quality lens of a good camera.
The weak link in instrument and system reliability is often the inappropriate
use and care of the connector. Because current connectors are so easy to use,
there tends to be reduced vigilance in connector care and cleaning. It takes
only one missed cleaning for a piece of grit to permanently damage the glass
and ruin the connector.
Measuring insertion loss and return loss
Consistent measurements with your lightwave equipment are a good indication that you have good connections. Since return loss and insertion loss are
key factors in determining optical connector performance they can be used to
determine connector degradation. A smooth, polished fiber end should produce a good return-loss measurement. The quality of the polish establishes
the difference between the “PC” (physical contact) and the “Super PC” connectors. Most connectors today are physical contact which make glass-to-glass
connections, therefore it is critical that the area around the glass core be clean
and free of scratches. Although the major area of a connector, excluding the
glass, may show scratches and wear, if the glass has maintained its polished
smoothness, the connector can still provide a good low level return loss connection.
If you test your cables and accessories for insertion loss and return loss upon
receipt, and retain the measured data for comparison, you will be able to tell in
the future if any degradation has occurred. Typical values are less than 0.5 dB
of loss, and sometimes as little as 0.1 dB of loss with high performance connectors. Return loss is a measure of reflection: the less reflection the better
(the larger the return loss, the smaller the reflection). The best physically
contacting connectors have return losses better than 50 dB, although 30 to
40 dB is more common.
5-13
Reference
Cleaning Connections for Accurate Measurements
Visual inspection of fiber ends
Visual inspection of fiber ends can be helpful. Contamination or imperfections
on the cable end face can be detected as well as cracks or chips in the fiber
itself. Use a microscope (100X to 200X magnification) to inspect the entire
end face for contamination, raised metal, or dents in the metal as well as any
other imperfections. Inspect the fiber for cracks and chips. Visible imperfections not touching the fiber core may not affect performance (unless the
imperfections keep the fibers from contacting).
WARNING
Always remove both ends of fiber-optic cables from any instrument,
system, or device before visually inspecting the fiber ends. Disable all
optical sources before disconnecting fiber-optic cables. Failure to do
so may result in permanent injury to your eyes.
Cleaning Connectors
The procedures in this section provide the proper steps for cleaning fiberoptic cables and Agilent Technologies universal adapters. The initial cleaning,
using the alcohol as a solvent, gently removes any grit and oil. If a caked-on
layer of material is still present, (this can happen if the beryllium-copper sides
of the ferrule retainer get scraped and deposited on the end of the fiber during
insertion of the cable), a second cleaning should be performed. It is not
uncommon for a cable or connector to require more than one cleaning.
CAUTION
Agilent Technologies strongly recommends that index matching compounds
not be applied to their instruments and accessories. Some compounds, such as
gels, may be difficult to remove and can contain damaging particulates. If you
think the use of such compounds is necessary, refer to the compound
manufacturer for information on application and cleaning procedures.
Table 5-1. Cleaning Accessories
Item
Agilent Part Number
Any commercially available denatured alcohol
—
Cotton swabs
8520-0023
Small foam swabs
9300-1223
Compressed dust remover (non-residue)
8500-5262
5-14
Reference
Cleaning Connections for Accurate Measurements
Table 5-2. Dust Caps Provided with Lightwave Instruments
Item
Agilent Part Number
Laser shutter cap
08145-64521
FC/PC dust cap
08154-44102
Biconic dust cap
08154-44105
DIN dust cap
5040-9364
HMS10/dust cap
5040-9361
ST dust cap
5040-9366
To clean a non-lensed connector
CAUTION
Do not use any type of foam swab to clean optical fiber ends. Foam swabs can
leave filmy deposits on fiber ends that can degrade performance.
1 Apply pure isopropyl alcohol to a clean lint-free cotton swab or lens paper.
Cotton swabs can be used as long as no cotton fibers remain on the fiber end
after cleaning.
2 Clean the ferrules and other parts of the connector while avoiding the end of
the fiber.
3 Apply isopropyl alcohol to a new clean lint-free cotton swab or lens paper.
4 Clean the fiber end with the swab or lens paper.
Do not scrub during this initial cleaning because grit can be caught in the
swab and become a gouging element.
5 Immediately dry the fiber end with a clean, dry, lint-free cotton swab or lens
paper.
6 Blow across the connector end face from a distance of 6 to 8 inches using
filtered, dry, compressed air. Aim the compressed air at a shallow angle to the
fiber end face.
Nitrogen gas or compressed dust remover can also be used.
5-15
Reference
Cleaning Connections for Accurate Measurements
CAUTION
Do not shake, tip, or invert compressed air canisters, because this releases
particles in the can into the air. Refer to instructions provided on the
compressed air canister.
7 As soon as the connector is dry, connect or cover it for later use.
If the performance, after the initial cleaning, seems poor try cleaning the connector again. Often a second cleaning will restore proper performance. The
second cleaning should be more arduous with a scrubbing action.
To clean an adapter
The fiber-optic input and output connectors on many Agilent Technologies
instruments employ a universal adapter such as those shown in the following
picture. These adapters allow you to connect the instrument to different types
of fiber-optic cables.
Figure 5-7. Universal adapters.
1 Apply isopropyl alcohol to a clean foam swab.
Cotton swabs can be used as long as no cotton fibers remain after cleaning. The
foam swabs listed in this section’s introduction are small enough to fit into
adapters.
Although foam swabs can leave filmy deposits, these deposits are very thin, and
the risk of other contamination buildup on the inside of adapters greatly outweighs the risk of contamination by foam swabs.
2 Clean the adapter with the foam swab.
3 Dry the inside of the adapter with a clean, dry, foam swab.
4 Blow through the adapter using filtered, dry, compressed air.
Nitrogen gas or compressed dust remover can also be used. Do not shake, tip,
or invert compressed air canisters, because this releases particles in the can
into the air. Refer to instructions provided on the compressed air canister.
5-16
Reference
Agilent Technologies Service Offices
Agilent Technologies Service Offices
Before returning an instrument for service, call the Agilent Technologies
Instrument Support Center at (800) 403-0801, visit the Test and Measurement
Web Sites by Country page at http://www.tm.agilent.com/tmo/country/English/
index.html, or call one of the numbers listed below.
Agilent Technologies Service Numbers
Austria
01/25125-7171
Belgium
32-2-778.37.71
Brazil
(11) 7297-8600
China
86 10 6261 3819
Denmark
45 99 12 88
Finland
358-10-855-2360
France
01.69.82.66.66
Germany
0180/524-6330
India
080-34 35788
Italy
+39 02 9212 2701
Ireland
01 615 8222
Japan
(81)-426-56-7832
Korea
82/2-3770-0419
Mexico
(5) 258-4826
Netherlands
020-547 6463
Norway
22 73 57 59
Russia
+7-095-797-3930
Spain
(34/91) 631 1213
Sweden
08-5064 8700
Switzerland
(01) 735 7200
United Kingdom
01 344 366666
United States and Canada
(800) 403-0801
5-17
Index
Bandwidth key, 2-15
Bandwidth/Wavelength... softkey, 2-15
Bessel-Thomson filter, 2-15
display, 2-13
input, 2-5
scale, 2-17
setup, 1-2, 2-10
Channel 1 Calibration Status message, 2-19
Channel autoscale softkey, 2-15
Channel key, 1-2, 2-10
classification
product, iii
cleaning
adapters, 5-16
cabinet, iii
fiber-optic connections, 5-7, 5-15
non-lensed connectors, 5-15
compressed dust remover, 5-14
connector
care, 5-7
cotton swabs, 5-14
Current Date message, 2-19
Current Frame Delta Temp, 2-19
C
D
A
accuracy performance, 2-6
active probe, 2-14
Agilent 11900B adapter, 1-3
Agilent offices, 5-17
APC 2.4 (f-f) adapter, 1-3
APC 3.5 (f-f) adapter, 1-3
Atten units softkey, 2-16
attenuation
range, 2-16
Attenuation softkey, 2-16
attenuator scaling, 2-16
automatic measurement, 2-13
auxiliary power connector, 2-5
B
cabinet, cleaning, iii
Cal status softkey, 2-19
Calibrate probe softkey, 2-20
Calibrate softkey, 2-18
calibration
external scale, 3-14
factory, 3-4
mainframe, 3-4
O/E, 2-20, 3-6
O/E converters, 3-14
O/E user wavelength, 3-9
offset zero, 2-20, 3-12
overview, 3-1
plug-in module vertical calibration, 3-11
probe, 3-15
probes, 3-14
skew, 3-14
user, 3-7
validity, 2-19
vertical, 2-6
voltage probe, 3-15
care
of cabinet, iii
care of fiber optics, v, 2-8
channel
damaged shipment, 1-3
decibel calculation, 2-16
declaration of conformity, 4-7
digital offset, 2-14
Display softkey, 2-13
dust caps, 5-15
E
Ext gain softkey, 2-17
Ext offset softkey, 2-17
extender cables, 1-4
external scale calibration, 3-14
External scale... softkey, 2-16
external trigger
input, 2-5
level, 2-7
F
factory calibration, 3-4
fiber optics
care of, v, 2-8
cleaning connections, 5-7
connectors, covering, 1-6
Index-1
Index
foam swabs, 5-14
front panel overview, 2-5
fuse, 1-4
values, iii
H
horizontal waveform, 2-18
I
IEC Publication 61010-1, iii
input
connector, 5-7
INPUT connector, v, 2-8
inspecting
instrument, 1-3
installing the plug-in module, 2-6
instrument
returning for service, 1-5
P
packaging for shipment, 1-6
plug-in message, 2-20
plug-in module
features, 2-4
front panel, 2-5
installation, 2-6
purpose, 2-4
serial number, 1-3
plug-in module vertical calibration, 3-11
power
maximum input, v, 2-8
power level, 2-14
probe
attenuation, 2-16, 2-20
attenuation factor, 2-16
characteristics, 2-17
power, 2-14
power connector, 2-5
probe calibration, 3-14, 3-15
pulse parameter measurements, 2-13
K
key conventions, 2-9
R
M
regulatory information, 4-2
returning for service, 1-5
RF connectors, 2-6
mainframe calibration, 3-4
mainframe troubleshooting, 5-2
marker value, 2-16
math function, 2-13
maximum power input, v, 2-8
menu overview, 2-9
O
O/E cal softkey, 2-20
O/E calibration, 3-6
O/E converter calibration, 3-14
O/E user wavelength calibration, 3-9
offset, 2-13, 2-14, 2-17, 2-20
Offset softkey, 2-14
offset zero calibration, 3-12
Offset zero softkey, 2-20
optical
channel, 2-15
optical-to-electrical converter scaling, 2-16
Index-2
S
safety, iii
information, 1-2, 1-4
laser classification, iii
sales and service offices, 5-17
Scale softkey, 2-14
serial number, 1-3
service, 1-5
returning for, 1-5
sales and service offices, 5-17
shifted function keys, 2-9
shipping
procedure, 1-5
skew calibration, 3-14
Skew softkey, 2-18
SMA 50W termination, 1-3
softkey
menu, 2-5
overview, 2-9
Index
SONET/SDH filter, 2-15
specifications, 4-2
swabs, 5-14
T
temperature change, 2-20
trigger
external, 2-7
level, 2-17
source, 2-13
troubleshooting, 5-2
U
Units softkey, 2-14, 2-17
user calibrations, 3-7
V
vertical
calibration, 2-6
measurement, 2-17
scale, 2-13, 2-14, 2-15
waveform, 2-14
voltage
measurement, 2-16
probe, 2-20
voltage probe calibration, 3-15
W
wattage measurement, 2-16
waveform
display, 2-13
horizontal, 2-18
Wavelength key, 2-15
wavelength settings, 2-15
Index-3
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