HP 8530A automated measurements User Manual

HP 8530A Automated Measurements

This document introduces you to HP 8530A automated measurements.

Automated operation consists of two major categories:

Remote Programming

This is an introduction to controlling the receiver with a computer.

High Speed Operation

(Fast CW mode) This section explains how to acquire data at up to 5,000 points per second using the 100,000 point data buffer. This material is written for programmers, and contains programming examples.

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Contents

Remote Programming

What is Remote Programming?

What this Section Explains

Transferable Data

Available Data Transfer Formats

High Speed Automated Operation (Fast CW and Fast IF Switching)

CW Configuration

Multiple Frequency/Switch Control Configuration

What is Fast CW Mode?

Description of Fast CW Modes

Which Parameter is Measured in Fast CW Mode?

How to Transfer Fast CW Data

Facts about Overall Measurement Speed

Switch Speed

Frequency Switching Speed

Receiver Raw Data Acquisition Speed

Data Transfer Speed

Is Data Acquisition Synchronous with Data Transfer?

Transfer Speed Reduction Caused by Computer or HP-IB Extenders

Limitations

How Averaging Works with the Fast CW Buffer

Frequency Relationship Between RF and LO Source

Timing Considerations

Changing Minimum Re-Trigger Time

Standard Fast CW Mode

Fast Data Collection Mode

Autoranged Data Collection Mode

Fast IF Multiplexing

Using Fast IF Multiplexing Mode

Operating Notes and Driver Circuitry Requirements

HP BASIC Fast CW Programming Examples

HP BASIC Fast IF Multiplexing Mode Programming Example

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Remote Programming

What is Remote Programming?

"Remote programming" describes computer-controlled receiver operation. The receiver can be ordered to make measurements, change settings, send data to the computer, or accept data from the computer. Data that can be sent back and forth includes measurement data, calibration coefficient sets, and so on. You can remotely use all front panel features, and more.

Remote programming is often called "HP-IB operation" or "HP-IB programming."

Commands should be given in the same order as the equivalent front panel keystrokes.

What this Section Explains

This section briefly describes the main features of remote programming. "HP-IB

Programming" in the HP 8530A Operating and Programming Manual explains remote programming in detail. The HP 8530A Keyword Dictionary lists all programming

(HP-IB) codes, and explains each command in detail.

Transferable Data

After making a measurement, you can send raw, corrected, or formatted measurement data to the computer. These arrays represent different stages of data processing, illustrated Figure 1. There are two entirely different, parallel, data processing paths. One path is for Channel 1 and one is for Channel 2. Each channel has raw, corrected, and formatted data arrays. In fact, you can modify the data using the computer, and send it back into the array. The receiver will process the modified data through all following stages.

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Figure 1. Data Processing Stages in the Receiver

The following data arrays can be read by an external computer:

Raw Data

Table 1. Data Types

This data array contains the ratioed and averaged measurement data results. (Note: In Fast CW mode, raw data is the only available format.) To transfer the data from this array to the computer, use the HP-IB command

OUTPRAW n , where n is the desired parameter (1, 2, 3 or 4). The

INPURAW n command sends data from the computer into the desired raw array. The raw array data is in real,imaginary pairs. Refer to the HP 8530A the Keyword

Dictionary for syntax and other information on this command, and the commands mentioned below.

Corrected

Data

Formatted

Data

Calibration

Coefficients

Delay Table

Memory

Data

In addition to ratioing and averaging, corrected data has been through time domain and calibration processing. Remember that these features must be

ON to affect the data. To transfer data from this array to the computer, use the HP-IB command

OUTPDATA n , where n is the desired parameter (1 to 4).

The

INPUDATA n command sends data from the computer into the desired corrected data array. The corrected data array is in real,imaginary pairs.

This data is scalar (magnitude-only) and reflects display format, scaling, and trace math processing. To transfer data from this array to the computer, use the HP-IB command

OUTPFORM n , where n is the desired parameter (1 to 4).

The

INPUFORM n command sends data from the computer into the desired corrected data array. Formatted data is a simple integer that represents the data units shown on the display.

These are the error correction coefficients created during calibration (also called a "Cal Set"). The error coefficient arrays can be read from, or sent to a computer, just like the arrays described above. Refer to the descriptions for the

OUTPCALC

and

INPUCALC commands in the

HP 8530A the

Keyword Dictionary .

Each parameter has its own special array called a "delay table." The table can be retrieved by external computer, modified, then returned to the receiver. The receiver will process the modified data as if it were actual measured data. The table contains real/imaginary data pairs in the internal

Form 1 compressed format. A typical use is to modify frequency domain data to synthesize a special window shape for use in time domain RCS measurements. Refer to the descriptions for the

OUTPDELA

and

INPUDELA commands in the

HP 8530A the Keyword Dictionary.

Valid data can be read from this array if data has been stored to memory .

Refer to the descriptions for the

OUTPMEMO

command in the

HP 8530A the

Keyword Dictionary . (There is no command to send data directly into a memory from the computer. However, you can send data to the raw or corrected array, then save it to memory using

DATI

)

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Available Data Transfer Formats

In remote programming you can choose among four binary data formats, or one ASCII data format. The formats are listed below:

Form 1

Table 2. Available Data Transfer Formats

This is the native internal data format of the receiver. Each point of data contains a header byte, followed by three, 16-bit words. Form 1 offers very fast transfer speeds, and Form 1 data can be converted to floating point data in the computer.

If you use Fast CW mode, the only data format available is Form 1. In fast CW mode, Form 1 does not have the header information.

Form 2

Form 3

Form 4

Form 5

32-bit IEEE 728 format. This format is not commonly used.

This is the recommended format for use with HP 9000 Series 200/300 workstations. It consists of a header, a two-byte number indicating how many bytes follow, then the real and imaginary data pairs for each stimulus point. Form

3 follows the 64-bit IEEE 728 standard format.

This format is ASCII.

This is the recommended format for use with IBM PCs and compatibles. This is a

32-bit DOS-compatible floating point format.

Refer to the Keyword Dictionary under “Form1,” “Form2,” “Form3,” “Form4,” or

“Form5” for more detailed information.

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High Speed Automated Operation

Fast CW mode is a feature that optimizes HP 8530A data acquisition speed. There are two major system configurations that use Fast CW modes:

Single Frequency Configuration

Multiple Frequency Configuration

These configurations are described on the following pages.

Note about Markers

If you are making computer-controlled measurements using "normal" sweep modes

(Frequency List, Single Point, Ramp, Step, Single Angle, or Swept Angle); measurement speed will increase with markers turned OFF. Markers will not slow down Fast CW measurements.

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Single Frequency Configuration

This configuration uses the HP 8530A, RF and LO sources, and a controlling computer.

Only CW measurements are possible.

Stage Description

1 The computer selects the frequency of measurement, RF power, and other measurement settings.

2 Open-collector TTL measurement triggers are asserted on the

HP 8530A EVENT TRIGGER input. A measurement is taken for each negative-going TTL trigger. This data is stored in the

HP 8530A 100,000 point FIFO buffer. The HP 8530A can acquire data at speeds between 1650 and 5000 points per second, depending on the selected fast CW mode

, and whether data is being transfered at the same time. More is expained on this issue later. Data acquisition occurs independently of data transfer . There are situations where

you can have very fast data acquisition, but a slow data transfer rate could be slowing the overall speed of the

system. More on this topic is explained later.

3 The computer executes a command such as the HP BASIC

TRANSFER command. This reads one data point out of the buffer. Again, situations can occur where the speed of transfer can be slower than the actual data acquisition.

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Multiple Frequency/Switching Configuration

9

3

4

5

Stage

1

2

Description

The computer sets source power levels, and other settings to the RF/LO sources, and microwave receiver.

The computer downloads a frequency list and switch channel list to the HP 85330A run time controller.

The computer places the HP 85330 into run-time mode.

The HP 85330A sets the first switch position.

The HP 85330A increments the frequency of the RF and LO sources using high speed TTL lines. (Does not occur on the very first measurement)

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6

7

8

Refer to Figure 6-2 in the HP 85330A Manual.

If using HP 85330A TTL trigger mode

(RUNt:EVENt:TRIGger TTL):

The HP 85330A waits for a TTL trigger on its EVENT

TRIGGER input.

If using HP 85330A IMMEDIATE trigger mode

(RUNt:EVENt:TRIGger IMM

No input on the HP 85330A EVENT TRIGGER line is required.

Data is acquired immediately (refer to step 7).

Using Time Delays:

A time delay can be set for switch settling time using the

HP 85330A command RUN:SWIT:DEL.

If you need a time delay before any data aquisition, use the

HP 8530A FASPARMTIME command.

At this time the HP 85330A sends a trigger to the HP 8530A

EVENT TRIGGER input. The data is acquired and stored in the

HP 8530A 100,000 point FIFO buffer. The HP 8530A can acquire data at speeds between 1650 and 5000 points per second, depending on the selected fast CW mode

, and whether data is being transfered at the same time. More is expained on this issue later. Data acquisition occurs independently of data transfer . There are situations where

you can have very fast data acquisition, but a slow data transfer rate could be slowing the overall speed of the

system. More on this topic is explained later.

The computer executes a command such as the HP BASIC

TRANSFER command. This reads one data point out of the buffer. Again, situations can occur where the speed of transfer can be slower than the actual data acquisition.

What is Fast CW Mode?

The HP 8530A provides two primary methods allowing extremely fast antenna,

RCS, or CW frequency measurements:

Fast CW mode (there are four types of Fast CW mode to choose from.

An optional fast pulse mode is available in HP 8530A H02

Fast CW modes are explained in this section. Fast Pulse is described in the HP 8530A

H02 manual.

There are actually four standard "Fast CW" modes:

Standard Fast CW

Fast Data Collection

Autoranged Data Collection (most commonly used)

Fast IF Multiplexing

Fast CW modes are only available when you are controlling the receiver with a computer.

These modes buffers measurement data in a 100,000 point (First-In First-Out) data buffer.

Each of these modes is explained below.

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Description of the Fast CW Modes

All the Fast CW modes can be externally triggered, using the (TTL) EVENT TRIGGER input - or over HP-IB.

Standard Fast

CW

Table 3. Description of Fast CW Modes

Measures at rates of up to 5,000 data points per second. This speed is not sustainable continuously. The reason: at this speed, data is not being

transferred out of the instrument. Once the 100,000 point FIFO buffer is full the data must be transferred out. Fast CW can sustain a continuous transfer speed of 3,333 points per second.

Burst data acquisition speed: 5,000 points per second

Sustained data acquisition speed: 3,333 points per second

Handshaking: NO

The allowable point-to-point amplitude variation of the measured signal is

+12 dB. If you have point-to-point variations greater than +12 dB, use the

Autoranged Data Collection feature, described below.

Fast Data

Collection

This mode is similar to the Fast CW mode, but has one more feature: It pulls the rear panel STOP SWEEP and RECEIVER READY lines LOW during data acquisition. These lines go HIGH when the receiver is ready to take more data. Trigger pulses are ignored when STOP SWEEP is

LOW. This "handshake" allows external hardware to coordinate measurements.

Burst data acquisition speed: 4,000 points per second

Sustained data acquisition speed: 3,333 points per second

Handshaking: STOP SWEEP and RECEIVER READY

Adjacent Point to Point Power Variation: +12 dB

This mode is recommended when measuring signals that make sudden changes in amplitude, with an upper limit of +12 dB between two

adjacent measurement data points. (A typical application for this mode is when a multiplexer is used to switch between antennas.)

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Autoranged

Data

Collection

Fast IF

Multiplexing

Mode

Use this mode if signal levels vary by more than +12 dB between

adjacent points. This mode allows you to accurately measure signals across the full dynamic range of the receiver. This is the mode used when in TURBO MODE in the ORBIT/FR 959 software, and all near-field measurement software produced by Nearfield Systems Inc.

Burst data acquisition speed: 2,500 points per second

Sustained data acquisition speed: 2,500 points per second

Handshaking: STOP SWEEP and RECEIVER READY

Adjacent Point to Point Power Variation: Full dynamic range of reciever

This mode is recommended when measuring signals that make sudden changes in amplitude between adjacent measurement points. The signal can change any amount, up to the maximum dynamic range of the receiver. (A typical application for this mode is when an external PIN multiplexer is used to switch between antennas. Or when measuring multiple inputs from a co-polarized and cross-polarized antenna.)

This mode switches between up to four measurement ratios internally to the receiver. This can eliminate the need for pin switches (and the required VXI controller) in systems measuring up to three test signals .

Burst data acquisition speed: 4,000 points per second

Sustained data acquisition speed: 3,333 points per second

Handshaking: STOP SWEEP and RECEIVER READY

The ratios available are: b1/a1, b2/a1, b1/a2, b2/a2. Up to four ratios can be measured in a predetermined automated sequence.

You can choose to trigger once for all ratios, or require a trigger for each ratio measured.

Fast Pulse

Mode

(Optional)

This mode only exists in the pulse compatible HP 8530A H02. Turbo mode systems also require an H02 or H03 version of the HP 85330A.

This mode allows pulsed measurements at rates that are faster than non-turbo measurements.

Burst data acquisition speed: 1,650 points per second

Sustained data acquisition speed: 1,650 points per second

Handshaking: STOP SWEEP and RECEIVER READY

This mode is discussed in detail in the HP 85330A H02 manual.

Special Note on Averaging

To make averaging work in wideband mode, you have to set the multiple source offset value to 20.000017 MHz instead of 20 MHz. This setting will work for normal bandwidth measurements as well.

Perform the following steps:

Press:

[SYSTEM] {MORE} {EDIT MULT. SRC.}

{RECEIVER} {OFFSET FREQUENCY} 20.000017 [MHz]

{MULT. SRC. ON / SAVE}

Averaging only functions in ratioed measurements, not when viewing individual service channels.

To use high speed operation you must have a basic understanding of instrument HP-IB programming.

Which Parameter is Measured in Fast CW Mode?

If you have HP 8530A firmware revision 1.40 or above, you can measure 1 to 4 different input ratios in Fast CW Mode.

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How to Transfer Fast CW Data

There are two ways to transfer data when using Fast CW mode:

Burst

Transfer

Table 4. Data Transfer Methods

You can fill the buffer, partially or completely, then transfer it using the HP

BASIC

ENTER command. The receiver can measure up to 5,000 points per second while the buffer is being filled. Data can then be transferred out of the receiver at an

HP-IB rate of approximately 5,000 points per second. This mode usually does not save time because you have to stop making measurements while the buffer’s contents are transferred. This mode can save time if:

·

The scan you are making has fewer than 100,000 data points, AND

·

There is a dead time during which you’re positioner must move before more measurements are taken. Data is transferred out at around 5,000 points per second in all modes.

Example 1. Assume you took 10 seconds of data in the FASC mode

(5,000 points per second), it would take at least 10 seconds to transfer the data.

Example 2. Assume you used FASAD (most commonly used mode) and took data for 30 seconds (2,500 points per second). You could have the data transferred out in about 15 seconds).

If using another programming language, simply wait until the measurement is finished, then transfer the data. For example, at the end of the positioner’s sweep, or at the end of a near field scan line.

Continuous

Transfer

You can transfer data to your computer continuously using the HP BASIC

TRANSFER

command. Using this method, data can be taken for as long as desired with out ever filling up the data buffer.

If using a another programming language, use the appropriate command to transfer after each data point is measured.

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Facts about Overall Measurement Speed

When determining the speed of a system, people often look at the raw performance of the microwave receiver, and stop there. It is important to know that the raw measuring speed of the receiver is not the only factor involved! Other factors include:

The speed of any switches in the system.

The frequency switching speed. Note that sources take longer to cross band switching boundaries. Also, HP 8360 series sources execute a "learn sweep" on the first sweep (or after any source frequency settings are changed). This first sweep takes much longer than subsequent sweeps.

Computer, HP-IB extenders, or HP-IB cards. For example, HP-IB extenders set to slow mode anywhere in the system can slow measurement speeds.

Measurement Software can affect measurement speed as well. This is usually out of the control of Hewlett-Packard.

You can see that there are other important considerations when estimating the speed at which a system can make measurements.

Switch Speed

PIN switches are solid-state, and switch so fast that they have little impact on measurement speed. You should also calculate any delays needed by your device under test.

If you are using third party software to control the system, it will usually have a switch delay command. If you are writing your own code, you would use the HP 85330A’s

RUNTime:SWITch:DELay command. This is described in the HP 85330A manual. For

Fast CW modes, 2 us delay is recommended.

For example, Line 1090 in Programming Example 1 uses two microseconds as the switch delay:

1090 OUTPUT @HP 85330;"RUNT:SWIT:DEL 2;"

Mechanical switches require between 15 to 50 ms to switch. Find out the switching speed of the switch you are using, and set switch delay as explained above.

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Frequency Switching Speed

The first sweep using HP 8360 sources is slower than usual: In step or list mode, the first sweep through the frequency list is much slower than subsequent sweeps. During the first sweep, the source is in learn mode, where it stores a lookup table of pretune settings.

The learn sweep is repeated if any frequency settings are changed.

Recommendation: If developing your own software, run through the frequency list once before initiating measurements

Source settling time affects phase and amplitude accuracy: Sources require a certain amount of settling time. Sources have frequency bands, and it takes longer when a bandcrossing is encountered.

When the Frequency Change is:

CW manual mode, Inside a band

All modes, at a bandcrossing

Step or List mode, in band

The Change Takes this Long:

15ms + 5ms / GHz approximately

50 ms

5 ms +5ms / GHz

The exact magnitude and phase accuracy after this minimum settling time is not specified or documented.

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Receiver Raw Data Acquisition Speed

The data acquisition speed of the HP 8530A microwave receiver is of significance in the overall measurement speed of the system. However, this is not the only consideration when determining the overall measurement speed of your system. Do not assume your

system will perform at these raw data acquisition speeds.

Burst transfer: only stores data in the HP 8530A 100,000 FIFO buffer. This speed is only possible when data is not being transferred to the computer.

Continuous transfer: is the maximum data acquisition speed when data is being transferred to the computer concurrently with data acquisition.

Fast CW mode Speeds

Mode

Fast CW

Fast Data Acquisition

Burst Transfer Data

Acquisition Speed

0.2 ms/data point

5,000 points/second

0.25 ms/data point

4,000 points/second

Autoranging Fast Data Acquisition

0.4 ms/data point

2,500 points/second

Fast Multiplexing Mode

Fast Pulse Mode (optional)

0.25 ms/data point

4,000 points/second

0.6 ms/data point

1,666 points/second

Continuous Transfer

Data Acquisition Speed

0.3 ms/data point

3,333 points/second

0.3 ms/data point

3,333 points/second

0.4 ms/data point

2,500 points/second

0.3 ms/data point

3,333 points/second

0.6 ms/data point

1,666 points/second

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Data Transfer Speed

As mentioned before, data acquisition speed is only one factor in overall measurement speed. Another important factor is the actual transfer speed of the data to the computer controller. The following can affect transfer speed:

HP-IB Extenders

Computer Speed

HP-IB Card Speed

Speed decreases :

1. As range Length increases.

2. If more than two extenders are in the same chain.

3. If extenders on the main HP-IB bus are set to slow mode.

Much more detail is provided on the following pages.

A slow computer, or one that is multi-tasking with other processes, could slow transfer speed.

Potentially, an old HP-IB card could affect transfer speed.

Is Data Acquisition Synchronous with Data Transfer?

This depends on the software in use. HP examples assume that the HP equipment is being triggered by a hardware pulse (from a positioner system for example). In this case the data acquisition process is asynchronous with data transfer. If you are writing your own software, be sure that you do not let the 100,000 point buffer overflow. This could happen if acquisition speed is greater than transfer speed.

Third party software often keeps track of the entire measurement process, and usually triggers the HP hardware over HP-IB. This makes the two processes synchronous.

Measurement Software

Third party measurement software can also have a significant affect on measurement speed. Discuss measurement speed with the software supplier.

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Speed Reductions Due to Computer Controller or HP-IB Extenders

The computer controller or HP-IB bus can limit data transfer speed.

Computer-Caused Speed Reductions

The computer’s data transfer rate may be slower than the receiver. If you plan to use continuous transfer, do some tests to see if your computer slows down the transfer process. (If fewer than 3,333 points/second are transferred, your computer or the HP-IB bus is the limiting factor.)

HP-IB Extender-Caused Speed Reductions

HP-IB extenders can slow down measurements significantly in Fast CW modes. You will see speed reduction in the following situations:

HP-IB Speed Degrades If:

There are more than two extenders on a single chain.

Recommedations

Use separate chains of 2 each. This applies to all extender types, Fiber Optical or Coax.

If HP-IB extenders are set to SLOW mode.

Many users know that HP-IB extenders must be in slow mode if they are placed on the HP 8510/30

Local bus. In fast CW modes, sources are not

on the local bus - they are on the main HP-IB

bus. The slow mode restriction does not apply in this case! Use the extenders in FAST mode

unless extenders are >250 meters apart. (This limitation does not apply to fiber optical extenders.)

Use optical extenders if range length is greater

than 250 meters.

Always Use Slow Mode when Using HP-IB Extenders are on the HP 8530

Local Bus

In manual measurement configurations, sources are controlled over the 8530 Local Bus.

If you put HP-IB extenders on the local bus, they must be set to SLOW mode. This will not affect manual measurement performance.

How Bus Extenders Slow Down Measurements

When you connect a slow HP-IB device to the bus all activity on the bus slows to match the speed of the slowest device. SLOW mode drastically cuts the speed of the entire

HP-IB bus. This slows the data transfer from the HP 8530A to the computer. This in turn slows down the overall measurement speed of the system.

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HP-IB Extender Performance

Limitations

Fast CW operation allows you to measure data at very fast rates. The following measurement limitations apply when measuring 5,000 points per second:

If you have firmware revisions below 1.40, only one parameter in the receiver may be measured (the active parameter). For multiple parameters, an external PIN multiplexer must be used, or you must upgrade the firmware. Firmware upgrades are easy to arrange, simply contact your local HP representative.

Only raw data is available (raw data includes averaging) in Form 1 data format.

To take advantage of 5,000 points/second, data must be stored in the 100,000 point buffer.

The allowable point-to-point magnitude variation is +12 dB, otherwise you must use Autoranged Data Collection mode (2,500 points/second). Autoranged Data

Collection is often needed if you externally multiplex between different antennas or antenna outputs. This is due to the sudden amplitude changes that often occur in such systems.

How Averaging Works with the Buffer

Averaging occurs before data is stored in the buffer. Only the final, averaged, values are stored. Therefore, using averaging does not increase the amount of data stored in the buffer, nor does it increase required transfer time.

Example: Assume you are measuring a +90 degree angle scan with an increment angle of

0.5 degrees (a total of 361 angles measured). Averaging is set to 16.

Because averaging is set to 16, the receiver must measure each angle 16 times. This means 5,776 individual measurements must be made (16 x 361). However, the data buffer does not store each averaging measurement, it only stores the final averaged value for

each angle. Therefore, only 361 buffer points are used in the measurement.

In buffer mode, 5,776 points of measured data require 1.16 seconds to take. This data is averaged, and the 361 resultant data points are stored in the buffer. It will take 0.08

seconds to transfer 361 data points (remember, this time estimate can be affected by the speed of your computer).

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Frequency Relationship between RF and LO Source

If you are writing your own software, be sure LO frequency is always 20 MHz above

the RF frequency. If LO frequency is below the RF, the phase of your measurements will be reversed from normal. For example, lengthening electrical length will cause a clockwise phase rotation.

Timing Considerations

If you are using External triggering, a trigger pulse at least 1 us wide must be sent to the rear panel EVENT TRIGGER input.

The pulse width must be 1us to 100 us. A 1us pulse is recommended.

The receiver triggers on the falling edge of the trigger pulse. The trigger pulse should be a negative pulse that is normally high. Refer to the “Negative Trigger Pulse” figure below.

If a positive pulse is used the receiver will not trigger until the falling edge of the trigger is detected. This will cause a delay in the trigger as shown in the “Positive Trigger Pulse” figure below:

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When the STOP SWEEP is low in the FASD, FASAD and FASMD modes the signal level being measured must remain at a constant level after the trigger is sent to the receiver. The FASC mode requires the signal level remain constant for 200 us after the trigger is received.

If averaging is turned ON the measurement time will be increased by 200 us for each average. For example, in FASD mode with eight averages, the total measurement time will be 1600 us. The STOP SWEEP will remain low for the entire measurement time.

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Changing Minimum Re-Trigger Time

To change the default re-trigger time for Fast CW modes FASD, FASMD, and FASAD, send the HP-IB command FASPARMTIMEn, where n is the desired time interval (in microseconds) before STOP SWEEP goes HIGH. The minimum time allowed in this command is 200 us, maximum time is 1360 us.

25

Standard Fast CW Mode

HP-IB Command: FASC

Standard Fast CW will measure data at rates up to 5,000 points per second. The amplitude variation between any two adjacent measured points must be within +12 dB.

Refer to the figure below. When the trigger is received, the receiver waits 70 us, which is equal to the IF delay of the receiver, and then latches (measures) the data. The receiver is ready to take another data point after 200 us. There is no handshaking performed on the

STOP SWEEP or RECEIVER READY outputs. Any trigger received before the HP

8530A is ready will be ignored.

The HP-IB Command

FASTPARMTIME

can be used to delay the data acquisition longer than 200 us.

Timing

Standard Fast CW Mode (FASC)

EVENT

TRIGGER

1us to 100us

>200us

70us

Ready for Trigger

Data Latched fasc.vsd

26

Fast Data Collection Mode

HP-IB Command: FASD

Note: All references to STOP SWEEP in this section also apply to the RECEIVER

READY line, which could be used instead.

Handshaking

This mode is similar to the Fast CW mode, but has one more feature: It pulls the STOP

SWEEP line (rear panel BNC) LOW during data acquisition. (The figure only shows

STOP SWEEP). These lines go HIGH when the receiver is ready to take more data. Any trigger pulses received when STOP SWEEP is LOW causes a "TRIGGER TOO FAST" error message. This "handshake" allows external hardware to coordinate measurements.

The STOP SWEEP handshake allows external multiplexers to switch measurement inputs. Do not pull the STOP SWEEP "LOW" during the measurement.

Timing

The figure (see next page) shows the timing relationships in this mode. STOP SWEEP starts HIGH, indicating that the receiver is reading to measure data. When the trigger arrives, STOP SWEEP goes LOW.

The receiver latches (measures) the data 60 us before the STOP SWEEP goes high. After

200 us STOP SWEEP goes HIGH, indicating the receiver is ready to measure another data point. The STOP SWEEP delay may be changed by using the

FASPARMTIME command.

The HP-IB Command

FASTPARMTIME

can be used to delay the data acquisition longer than 250 us.

27

Note: The timing values in the following example are typical and do not represent specifications.

Fast Data Collection Mode (FASD)

No Averaging

EVENT

TRIGGER

1us to 100us

STOP SWEEP or

RECEIVER READY

Ready for

Trigger

250us

When STOP SWEEP or RECEIVER READY are HIGH, the receiver is READY to take data

When STOP SWEEP or RECEIVER READY are LOW, the receiver

IGNORES trigger pulses, and gives TRIGGER TOO FAST error.

The 250us minimum wait time can be set to a longer duration using FASTPARMTIME command.

With Averaging

EVENT

TRIGGER

1us to 100us

STOP SWEEP or

RECEIVER READY

250us

250us

600us

(4 averages)

First data point (250us)

Averaging setup overhead (250us)

200us x (# averages -1)

Total time with 4 averages: 1,100us

Ready for

Trigger fasd.vsd

28

Autoranged Data Collection Mode

HP-IB Command: FASAD

Use this mode if signal levels vary by more than +12 dB between two immediately

adjacent data points. Wide swings in amplitude often occur when measuring signals from an external multiplexer or pin switches. This mode allows you to measure adjacent data points with huge amplitude differences, up to the full dynamic range of the receiver.

This is the mode used when in TURBO MODE in the ORBIT/FR 959 software, and all near-field measurement software produced by Nearfield Systems Inc.

Note: All references to STOP SWEEP in this section also apply to the RECEIVER

READY line, which could be used instead.

Similarities Compared to FASD mode

This mode is similar to the FASD mode:

It pulls the STOP SWEEP line (rear panel BNC) LOW during data acquisition.

STOP SWEEP goes HIGH when the receiver is ready to take more data.

Any trigger pulses received when STOP SWEEP is LOW causes a "TRIGGER

TOO FAST" error message. This "handshake" allows external hardware to coordinate measurements. The STOP SWEEP handshake allows external multiplexers to switch measurement inputs. Do not pull the STOP SWEEP "LOW" during the measurement.

The figure (next page) shows the timing relationships in this mode. STOP SWEEP starts

HIGH, indicating the receiver is ready to measure data. When the trigger arrives, STOP

SWEEP goes LOW.

Timing

The receiver latches (measures) the data 60 us before the STOP SWEEP goes HIGH.

After 400us STOP SWEEP goes HIGH, indicating the receiver is ready to measure another data point. The STOP SWEEP delay may be changed by using the

FASPARMTIME

command. If the signal levels vary more than +12 dB reducing the

FASPARMTIME

time to less than 400 us is possible, but will reduce the measurement accuracy.

29

Note: The timing values in the following example are typical and do not represent specifications.

Autoranged Data Collection Mode (FASAD)

No Averaging

EVENT

TRIGGER

1us to 100us

STOP SWEEP or

RECEIVER READY

400us

Ready for

Trigger

When STOP SWEEP or RECEIVER READY are HIGH, the receiver is READY to take data

When STOP SWEEP or RECEIVER READY are LOW, the receiver

IGNORES trigger pulses, and gives TRIGGER TOO FAST error.

The 400us minimum wait time can be set to a longer duration using FASTPARMTIME command.

With Averaging

EVENT

TRIGGER

1us to 100us

STOP SWEEP or

RECEIVER READY

400us 250us

600us

(4 averages)

First data point (400us)

Averaging setup overhead (250us)

200us x (# averages -1)

Total time with 4 averages: 1,250us

Ready for

Trigger fasad.vsd

30

Fast IF Multiplexing

HP-IB Command: FASMD

Fast IF multiplexing mode can measure up to four different input ratios at each stimulus point. Signal switching is performed inside the receiver. This mode is similar to the fully autoranged Fast CW mode (FASAD), but:

Fast IF Multiplexing is faster, measuring up to 4,000 points per second.

Fast IF Multiplexing adds the capability of IF multiplexing. This can eliminate the need for external PIN switches, and the VXI controller that drive them.

This mode is also useful in millimeter wave systems, where good external PIN switches are difficult to obtain. Fast IF multiplexing switches the signals at IF frequencies, rather than at millimeter frequencies.

Trigger Requirements

Use a negative trigger pulse that is normally high. A trigger signal that is normally low will prevent further triggering. If you are driving EVENT TRIGGER with your custom circuitry, make sure it uses open-collector TTL. Using other types of circuitry can cause strange problems. A pulse generator with burst output mode works well with Fast IF

Multiplexing, or other fast CW modes. The trigger must be 1us to 100us wide.

Note: All references to STOP SWEEP in this section also apply to the RECEIVER

READY line, which could be used instead.

Timing

The figure below shows the timing relationships in this mode. STOP SWEEP starts

HIGH, indicating the receiver is ready to measure data. When the trigger arrives, STOP

SWEEP goes LOW.

After 250 us the receiver latches (measures) the data. After 400 us STOP SWEEP goes

HIGH, indicating the receiver is ready to measure another data point. The STOP SWEEP delay may be changed by using the FASPARMTIME command. If the signal levels vary more than +12 dB reducing the FASPARMTIME time to less than 250 us will reduce the measurement accuracy.

Note that in mode 2, 4, 8, 10, 12, and 14 the STOP SWEEP or RECEIVER READY will go high for 100ns between each parameter. Ignore this high and do not send a trigger during this time. Do not pull STOP SWEEP low while in the FASMD mode.

31

Note: The timing values in the following examples are typical and do not represent specifications.

Timing Diagram for Fast Mux Modes 1, 3, 5, 7, 9, 11, 13

(A trigger is required for each ratio measured)

No Averaging

EVENT TRIGGER

1us to

100us

STOP SWEEPor

RECEIVER READY

first ratio second ratio

Mode

11,13 only

250us 250us

Approx.= # ratios x 250us

Mode

13 only

With Averaging (only one ratio shown)

The following example applies to all modes

EVENT

TRIGGER

1us to 100us

STOP SWEEP or

RECEIVER READY

250us 250us

600us

(4 averages)

First data point (250us)

Averaging setup overhead (250us)

200us x (# averages -1)

Total time with 4 averages: 1,100us per ratio

Total time w/averaging approx. = (time for one ratio) x (# of ratios) fastmux1.vsd

32

Timing Diagram for Fast Mux Modes 2, 4, 6, 8, 10, 12, 14

(One trigger measures all ratios)

No Averaging

EVENT TRIGGER

STOP SWEEPor

RECEIVER READY

1us to

100us first ratio

250us second ratio

Mode

12,14 only

250us

250us

# ratios x 250us

Mode

14 only

250us fastmux2.vsd

33

Using Fast IF Multiplexing Mode

When using this mode the first step is to set up the receiver to make a measurement. Set up the instrument as follows:

Step 1. Enter Manual Settings

[key] denotes an instrument key

{softkey} denotes an instrument softkey

[PARAM 1]

{TRIGGER INTERNAL}

{SINGLE POINT}

{CENTER FREQUENCY} nn [x1]

{xx GAIN:AUTO}

{AVERAGING} nn [x1]

Where nn is the desired value.

The receiver should be properly making a measurement before continuing.

Step 2. Issue the Fast IF Multiplexing Command over HP-IB

The next step is to select the type of Fast IF Multiplexing measurement you want to make. The HP-IB command is

FASMUXMODE

n. The number n selects a specific configuration of the Fast Multiplexing measurement, described in the table below. The different configuration numbers select:

The number of ratioed measurements that will be made (two, three, or four).

The specific ratios (b1/a1, b2/a1, and so on).

The number of triggers required to complete the measurement (a single trigger measures all ratios, or one trigger is required for each ratio).

34

10

12

14

4

8

13

2

3

7

9

5

6

11

0

1

FASMUXMODEn n=

Table 4. Fast Multiplexing Mode Select Numbers

Parameters Measured Trigger Pulses Required

No Multiplexing b1/a1, b2/a1

Not Applicable

One trigger is required to measure each ratio.

b1/a2, b2/a2 b1/a1, b1/a2 b2/a1, b2/a2 b1/a1, b2/a2 b1/a2, b2/a1 b1/a1, b2/a1, a2/a1 b1/a1, b2/a1, b1/a2, b2/a2 b1/a1, b2/a1 b1/a2, b2/a2 b1/a1, b2/a2 b1/a2, b2/a1 b1/a1, b2/a1, a2/a1 b1/a1, b2/a1, b1/a2, b2/a2

One trigger measures all ratios.

Two triggers are required to measure all of the ratios. The first trigger measures the first two parameters. The second trigger measures the next two parameters.

Note: The ratios are measured in the order shown in the table. Data points in the Fast CW buffer are stored in the same order as the data was measured. Remember, the buffer is the

First In First Out (FIFO) type.

Step 3. Set Extra Measurement Delay if Necessary

Use the

FASPARMTIME

command if necessary. Refer to the keyword dictionary for details.

Step 4. Initiate Actual Measurements

Now, activate the Fast IF Multiplexing mode by sending the

FASMD

command.

Example:

FASMUXMODE 10;FASMD

A complete programming example for Fast IF Multiplexing mode is shown at the end this document.

35

Operating Notes and Driver Circuitry Requirements

You should be aware of the following:

Required Circuitry

Data Form

Trigger Polarity

Minimum Time Delay

Ready Status

Table 4. Operating Notes

Make sure you drive the Event Trigger input with open-collector

TTL circuitry. Other types of driver circuitry (for example, dual-differential) will cause bizarre timing problems.

When you are using FASMD mode, FORM1 data transfers do not have the normal "#A bytea byteb" header. Refer to "FORM1" in the

HP 8530A Keyword Dictionary .

Use a negative trigger pulse that is normally high. A positive trigger that is normally low will block further triggers. The trigger pulse must be at least 1 us and no greater than 100 us wide.

A specific amount of time must elapse between trigger signals.

The required time delay between trigger pulses must be >(# of parameters) multiplied by

FASPARMTIME

(250us by default). For example, in

FASMUXMODE10

the time between trigger pulses must be greater than: 2 x 250 us = 500 us.

Monitor the STOP SWEEP or RECEIVER READY the same way as when in the FASAD mode. Do not send trigger signals when

STOP SWEEP or is low.

36

To Turn Fast IF Multiplexing Mode OFF

To turn off the fast IF multiplexing mode, issue these commands:

ABORT7

CLEAR7

SING

(or any other sweep mode command)

Instead of placing the receiver in a single sweep mode (

SING

), you could place it in any other sweep mode, or simply recall an instrument state.

How Long Does the FASMUXMODE Selection Stay Valid?

Once you select one of the

FASMUXMODE

codes, that selection stays valid, even if you take the receiver out of fast IF multiplexing mode. If you later turn fast IF multiplexing

ON again, the previous

FASMUXMODE

code will still be in effect. The only exceptions to this are when:

You perform a User or Factory Preset.

AC Power is turned OFF.

37

HP BASIC Fast CW Programming

The following programming examples show how to use a computer to make Fast CW measurements. There are two HP-IB commands used to read measurement data:

ENTER

Reads the entire buffer.

TRANSFER Performs continuous transfer, reading one data point at a time.

The examples use an HP Series 300 computer, running HP BASIC revision 5.0 or greater, or HP BASIC running on a PC. If you are using a different computer or operating system, then use these programming examples as a guide for your programming.

Each example is set up to run as an independent program. The programs are self-documenting. Each line’s function is explained in the BASIC comment field.

Fast CW measurements output the measurement data in FORM 1. Both examples convert the output data from FORM 1 to FORM 3 in the computer. The SUB Build_table creates the exponents used in the conversion.

38

Fast CW Using the ENTER Command

This example uses the

ENTER

command to read the data from the receiver into the computer. The

ENTER

command reads the entire contents of the buffer. Use this command after all the measurement data has been taken. Be sure that the receiver’s data buffer does not fill up.

10 ALLOCATE REAL Exp_tbl(0:255)

20 GOSUB Build_table

30 !

40 ! USING FAST DATA WITH AUTO-RANGING AND ENTER STATEMENTS. THIS

50 ! WILL READ ALL THE DATA FROM THE RECEIVER AND THEN CONVERT

60 ! THE DATA TO REAL AND IMAGINARY PAIRS.

70 !

80 Points=181 ! NUMBER OF DATA POINTS TO BE

TAKEN.

90 ALLOCATE INTEGER Data_f1(1:Points,0:2) ! DATA FROM RECEIVER IN FORMAT

FORM1.

100 ALLOCATE Data_f3(1:Points,1:2) ! DATA FROM RECEIVER IN FORMAT

FORM3 (REAL

110 ! AND IMAGINARY PAIRS).

120 !

130 ASSIGN @Rec TO 716 ! ASSIGN RECEIVER HPIB.

140 !

150 !

160 Set_up: ! SET UP RECEIVER FOR FAST DATA.

170 !

180 OUTPUT @Rec;"SINP;" ! SET RECEIVER TO SINGLE POINT.

190 !

200 ! OUTPUT @REC; commands to set FREQUENCY, AVERAGES, PARAMETER, etc.

210 !

220 OUTPUT @Rec;"FASAD;" ! SET THE RECEIVER TO FAST DATA w/

AUTO-RANGE,

230 ! OR "FASD;" OR "FASC;".

240 !

250 REPEAT ! WAIT UNTIL THE RECEIVER IS READY TO

260 WAIT .001 ! TO TAKE DATA.

270 UNTIL BIT(SPOLL(@Rec),2) !

280 TRIGGER @Rec ! ISSUE HPIB TRIGGER TO BEGIN FAST DATA MODE.

290 !

300 ASSIGN @Rec;FORMAT OFF ! ASSIGN COMPUTER HPIB FOR FORM1 DATA.

310 !

320 !

330 Trigger_monitor: ! MONITOR THE RECEIVER UNTIL READY FOR

TRIGGER.

340 !

350 ! monitor receiver STOP SWEEP

360 ! IF "FASAD;" OR "FASD;", THEN MONITOR THE

RECEIVER’S

370 ! STOP SWEEP. WHEN STOP SWEEP IS HIGH, THEN

OK TO

380 ! ISSUE EXTERNAL TRIGGERS. CONTINUE TO

MONITOR STOP

390 ! SWEEP BEFORE EACH TRIGGER IS ISSUED FOR

HIGHEST

400 ! DATA TAKING SPEED.

410 !

420 ! IF "FASC;", THEN MONITOR IS NOT NEEDED.

INSTEAD

430 ! WAIT 1 SECOND UNTIL EXTERNAL TRIGGERS ARE

ISSUED.

440 !

450 ! issue EXTERNAL TRIGGERS

460 !

470 !

480 Read_data: !

490 !

39

500 ENTER @Rec;Data_f1(*) ! READ ALL THE DATA FROM RECEIVER.

510 !

520 ASSIGN @Rec;FORMAT ON ! ASSIGN COMPUTER HPIB FOR ASCII DATA.

530 OUTPUT @Rec;"SINP;" ! TURN FAST DATA OFF.

540 !

550 !

560 Convert_data: ! CONVERTS DATA FROM FORM 1 TO FORM 3.

570 FOR N=1 TO Points

580 Exp=Exp_tbl(BINAND(Data_f1(N,2),255))

590 Data_f3(N,1)=Data_f1(N,1)*Exp ! REAL DATA

600 Data_f3(N,2)=Data_f1(N,0)*Exp ! IMAGINARY DATA

610 NEXT N

620 !

630 !

640 Print_data: ! PRINT MEASURED DATA. THIS IS NOT REQUIRED.

650 !

660 FOR N=1 TO Points

670 PRINT Data_f3(N,1),Data_f3(N,2)

680 NEXT N

690 !

700 !

710 STOP

720 !

730 !

740 Build_table: ! BUILDS TABLE FOR FORM 1 TO

FORM 3

750 ! CONVERSION.

760 !

770 Exp_tbl(0)=2^(-15)

780 FOR N=0 TO 126

790 Exp_tbl(N+1)=Exp_tbl(N)+Exp_tbl(N)

800 NEXT N

810 Exp_tbl(128)=2^(-143)

820 FOR N=128 TO 254

830 Exp_tbl(N+1)=Exp_tbl(N)+Exp_tbl(N)

840 NEXT N

850 RETURN

860 !

870 END

40

Fast CW Using the TRANSFER Command

This example uses the

TRANSFER

command to read the data from the receiver. This performs continuous transfer of data.

TRANSFER

can read the data as soon as it is available at the receiver. Use this method when there will be more data points measured than the receiver’s data buffer can store.

The

TRANSFER

command can also allow other HP BASIC tasks to be performed when data is not being transferred.

10 ALLOCATE REAL Exp_tbl(0:255)

20 GOSUB Build_table

30 !

40 ! USING AUTORANGED FAST CW AND TRANSFER STATEMENTS. THIS

50 ! WILL READ THE DATA FROM THE RECEIVER AND THEN CONVERT

60 ! THE DATA TO REAL AND IMAGINARY PAIRS AFTER EACH POINT

70 ! IS READ FROM THE RECEIVER.

80 !

90 Points=18000 ! NUMBER OF DATA POINTS TO BE TAKEN.

100 INTEGER Data_f1(1:18000,0:2) BUFFER ! DATA FROM RECEIVER IN FORMAT FORM1.

110 ALLOCATE Data_f3(1:Points,1:2) ! DATA FROM RECEIVER IN FORMAT FORM3 (REAL

120 ! AND IMAGINARY PAIRS).

130 !

140 ASSIGN @Rec TO 716 ! ASSIGN RECEIVER HPIB.

150 ASSIGN @Buffer TO BUFFER Data_f1(*) ! ASSIGN INPUT BUFFER.

160 !

170 !

180 Set_up: ! SET UP THE RECEIVER FOR FAST DATA.

190 !

200 OUTPUT @Rec;"SINP;" ! SET THE RECEIVER TO SINGLE POINT.

210 !

220 ! OUTPUT @Rec commands to set FREQUENCY, AVERAGES, PARAMETER, etc.

230 !

240 OUTPUT @Rec;"FASAD;" ! SET THE RECEIVER TO AUTORANGED FAST CW,

250 ! "FASD;" OR "FASC;" CAN BE USED.

260 !

270 REPEAT ! WAIT UNTIL THE RECEIVER IS READY TO

280 WAIT .001 ! TO TAKE DATA.

290 UNTIL BIT(SPOLL(@Rec),2) !

300 TRIGGER @Rec ! ISSUE HPIB TRIGGER TO BEGIN FAST DATA MODE.

310 !

320 !

330 Transfer_data: ! TRANSFER DATA FROM RECEIVER

340 !

350 TRANSFER @Rec TO @Buffer;RECORDS Points,EOR (COUNT 6)

360 !

370 N=1 ! N IS THE CURRENT POINT.

380 !

390 !

400 Tigger_monitor: ! MONITOR THE RECEIVER WHEN READY FOR TRIGGERS.

410 !

420 ! monitor receiver STOP SWEEP

430 ! IF "FASAD;" OR "FASD;", THEN MONITOR RECEIVER’S

440 ! STOP SWEEP. WHEN STOP SWEEP IS HIGH, THEN OK TO

450 ! ISSUE EXTERNAL TRIGGERS. CONTINUE TO MONITOR

460 ! STOP SWEEP BEFORE EACH TRIGGER IS ISSUED FOR

470 ! HIGHEST DATA TAKING SPEED.

480 !

490 ! IF "FASC;", THEN MONITOR IS NOT NEEDED. INSTEAD

500 ! WAIT 1 SECOND UNTIL ISSUE EXTERNAL TRIGGERS.

510 !

520 ! issue EXTERNAL TRIGGERS

530 !

540 REPEAT

550 !

41

560 ! do something here if you wish

570 !

580 STATUS @Buffer,4;R4 ! READ NUMBER OF BYTES IN BUFFER.

590 IF R4>=6*N THEN GOSUB Convert_data ! IF A NEW POINT EXISTS IN BUFFER THEN

600 ! CONVERT DATA TO FORM 3.

610 !

620 UNTIL N>Points

630 !

640 CONTROL @Buffer,8;0 ! TERMINATE TRANSFER.

650 OUTPUT @Rec;"SINP;" ! TURN FAST DATA OFF.

660 !

670 !

680 Print_data: ! PRINT MEASURED DATA. THIS IS NOT REQUIRED.

690 !

700 FOR N=1 TO Points

710 PRINT N,Data_f3(N,1),Data_f3(N,2)

720 NEXT N

730 !

740 !

750 STOP

760 !

770 !

780 Convert_data: ! CONVERTS FROM FORM 1 TO FORM 3.

790 !

800 Exp=Exp_tbl(BINAND(Data_f1(N,2),255))

810 Data_f3(N,1)=Data_f1(N,1)*Exp ! REAL DATA

820 Data_f3(N,2)=Data_f1(N,0)*Exp ! IMAGINARY DATA

830 N=N+1

840 RETURN

850 !

860 !

870 Build_table: ! BUILDS TABLE FOR FORM 1 TO FORM 3 CONVERSION.

880 !

890 Exp_tbl(0)=2^(-15)

900 FOR N=0 TO 126

910 Exp_tbl(N+1)=Exp_tbl(N)+Exp_tbl(N)

920 NEXT N

930 Exp_tbl(128)=2^(-143)

940 FOR N=128 TO 254

950 Exp_tbl(N+1)=Exp_tbl(N)+Exp_tbl(N)

960 NEXT N

970 RETURN

980 !

990 END

42

HP BASIC Fast IF Multiplexing Mode Programming Example

The following programming examples show how to use a computer to make a Fast IF multiplexing measurement.

1 CALL Fast_mux

2 END

10 SUB Fast_mux

20 Fast_mux: ! This is a stand alone sub-program which demonstrates

30 ! 8530 fast mux operation

40 !

50 INTEGER Data_buffer(1:30000) BUFFER

60 INTEGER Setup

70 REAL Set_pointer,Param_pt,Data_pt,Reps,I,Old_pointer

80 REAL Log_mag(1:2),Phase(1:2)

90 REAL Exp_tbl(0:255),Exp,Data_16bit(0:800,0:1)

100 DIM Display$[80],Report$[200]

110 COMPLEX Data_set(1:2)

120 ASSIGN @A8530_data TO 716;FORMAT OFF

130 ASSIGN @A8530_control TO 716;FORMAT ON

140 Setup=0

150 Dwell_time=250 !FAST PARAMETER PER POINT MEASUREMENT TIME IN MICROSECONDS (NO AVERAGING)

160 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

170 ! DISPLAY INITIALIZATION AND INSTRUCTIONS

180 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

190 PRINTER IS CRT

200 DEG

210 GRAPHICS OFF

220 PRINT USING "@"

230 PRINT "This example demonstrates the FAST IF MULTIPLEXING feature of "

240 PRINT "the HP 8530A. It requires firmware rev 1.2 or higher. An external"

250 PRINT "trigger source should be connected to the 8530A Event Trigger input"

260 PRINT "on the rear panel. The STOP SWEEP input should be disconnected for"

270 PRINT "this test. During the test, the 8530A will be in MUX MODE 2 in which"

280 PRINT "both b1/a1 and b2/a1 measurements are taken upon the receipt of each"

290 PRINT "event trigger. The trigger should be a negative going TTL pulse with"

300 PRINT "a pulse width between 1uS and 100uS. For this example, the minimum "

310 PRINT "period between two triggers is 500 us (ASSUMES NO AVERAGING)."

320 DISP " PREPARE SYSTEM FOR TEST AS DESCRIBED AND CONTINUE (OR EXIT)"

330 FOR N=0 TO 4

340 ON KEY N LABEL "CONTINUE" GOTO Setup

350 ON KEY N+5 LABEL " EXIT " GOTO No_go

360 NEXT N

370 LOOP

380 END LOOP

390 Setup: !

400 DISP "SETTING UP 8530 FOR MEASURMENT"

410 FOR N=0 TO 9

420 OFF KEY N

430 NEXT N

440 GOSUB Setup_fastmux ! INITIALIZATION ROUTINE PUTS 8530A INTO FAST MUX MODE 2

450 No_go:IF Setup=0 THEN

460 PRINT USING "@"

470 DISP ""

480 OUTPUT @A8530_control;"RECA8"

490 LOCAL @A8530_control

500 SUBEXIT

510 END IF

520 GOSUB Build_table ! CREATES ARRAY EXP_TBL(*) USED TO CONVERT COMPRESSED DATA

530 ! TO BASIC REAL VALUES

540 Take_data: !

550 WAIT 1

560 Reps=0

570 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

580 ! DATA DISPLAY

590 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

600 PRINT TABXY(1,13)

610 PRINT " _______________________________________________________________________"

620 PRINT "| b1/a1 || b2/a1 | MEASUREMENT COUNT |"

630 PRINT "| || | |"

640 PRINT "| MAGNITUDE PHASE || MAGNITUDE PHASE | |"

650 PRINT "| (dB) | (DEG) || (dB) | (DEG) | |"

660 PRINT "| | || | | |"

670 PRINT "| | || | | |"

680 PRINT "| | || | | |"

43

690 PRINT "|___________|___________||___________|___________|______________________|"

700 DISP "TRIGGER MEASUREMENTS, PRESS SOFTKEY LABELED ’EXIT’ WHEN FINISHED"

710 !

720 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

730 ! CONTINUOUS TRANSFER DATA LOOP. USING TRANSFER ALLOWS FOR RAPID INPUT OF DATA

740 ! FROM THE 8530A. DATA IS DISPLAYED DURING COMPUTERS "SPARE TIME"

750 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

760 LOOP

770 ASSIGN @Buffer TO BUFFER Data_buffer(*) ! INITIALIZE TRANSFER BUFFER

780 Old_pointer=0

790 Set_pointer=1

800 !

810 !! TRANSFER STATEMENT: EACH MEASUREMENT IS TRANSFERED IN THREE INTEGERS, OR 6 BYTES

820 !! SO COUNT 6 ALLOWS TRACKING OF THE BUFFER AS IT COLLECTS DATA FROM THE INSTRUMENT.

830 TRANSFER @A8530_data TO @Buffer;RECORDS 10000,EOR (COUNT 6)

840 FOR N=0 TO 10

850 ON KEY N LABEL " EXIT ",15 GOTO Finished

860 NEXT N

870 LOOP

880 STATUS @Buffer,4;Data_pt

890 !! SINCE WE ARE MAKING TWO MEASUREMENTS AT A TIME, THE DISPLAY IS ONLY UPDATED WHEN

900 !! THE DATA POINTER IS POINTING TO THE END OF A NEW PAIR OF MEASUREMENTS. THIS

910 !! TECHNIQUE SKIPS A LOT OF DATA DURING FAST MEASUREMENTS, BUT ALLOWS THE DISPLAY

920 !! TO KEEP UP WITH THE DATA FLOW.

930 IF Data_pt MOD 12=0 THEN

940 IF Data_pt>Old_pointer THEN

950 Old_pointer=Data_pt

960 !!

970 !!! THE FOLLOWING LOOP CONVERTS TWO MEASUREMENTS FROM THE 8530 COMPRESSED FORMAT

980 !!! TO BASIC COMPLEX VALUES. IT THEN CALCULATES THE MAGNITUDE AND PHASE OF EACH

990 !!! MEASUREMENT AND UPDATES THE DISPLAY

1000 !!

1010 FOR Param_pt=1 TO 2

1020 Data_pt=Old_pointer-6*(2-Param_pt)

1030 Exp=Exp_tbl(BINAND(Data_buffer(Data_pt/2),255))

1040

Data_set(Param_pt)=CMPLX(Data_buffer(Data_pt/2-1)*Exp,Data_buffer(Data_pt/2-2)*Exp)

1050 Log_mag(Param_pt)=20*LGT(ABS(Data_set(Param_pt)))

1060 Phase(Param_pt)=ARG(Data_set(Param_pt))

1070 OUTPUT Display$ USING

"""|"",2(2X,S3D.2D,2X,""|""),#";Log_mag(Param_pt),Phase(Param_pt)

1080 PRINT TABXY(1+25*(Param_pt-1),20),Display$

1090 NEXT Param_pt

1100 Data_pt=Old_pointer

1110 !!

1120 !! NOW PRINT THE CURRENT MEASUREMENT COUNT

1130 !!

1140 PRINT TABXY(5+25*(Param_pt-1),20);Data_pt/12+5000*Reps

1150 END IF

1160 END IF

1170 EXIT IF Data_pt/12=5000 ! THE BUFFER IS RE-INITIALIZED TO PREVENT OVERFLOW

1180 END LOOP

1190 Reps=Reps+1

1200 ASSIGN @Buffer TO *

1210 END LOOP

1220 Finished: !

1230 DISP "CLEARING I/O CHANNEL AND RE-SETTING 8530A"

1240 ABORTIO @A8530_data ! TURN OFF THE TRANSFER

1250 ASSIGN @Buffer TO *

1260 OUTPUT @A8530_control;"SING" ! TURN OFF FAST MUX MODE

1270 OUTPUT @A8530_control;"RECA8" ! PUT 8530A IN STANDARD STATE

1280 FOR N=0 TO 9

1290 OFF KEY N

1300 NEXT N

1310 WAIT 1

1320 ABORT 7

1330 CLEAR 7

1340 LOCAL @A8530_control ! PUT 8530A IN LOCAL

1350 PRINT USING "@"

1360 DISP ""

1370 SUBEXIT

1380 Build_table: ! USED FOR DATA CONVERSION

1390 !

1400 Exp_tbl(0)=2^(-15)

1410 FOR I=0 TO 126

1420 Exp_tbl(I+1)=Exp_tbl(I)+Exp_tbl(I)

1430 NEXT I

1440 Exp_tbl(128)=2^(-143)

1450 FOR I=128 TO 254

1460 Exp_tbl(I+1)=Exp_tbl(I)+Exp_tbl(I)

44

1470 NEXT I

1480 RETURN

1490 Setup_fastmux: !

1500 Setup=0

1510 ABORT 7

1520 CLEAR 7

1530 PRINT TABXY(1,30)," "

1540 PRINT " "

1550 PRINT " "

1560 OUTPUT @A8530_control;"RECA8" ! START IN KNOWN WORKING STATE

1570 WAIT 3

1580 OUTPUT @A8530_control;"HOLD;SINP" ! GO TO HOLD MODE, SINGLE POINT

1590 INPUT "ENTER FREQUENCY OF MEASUREMENT (IN GHz)",Freq

1600 OUTPUT @A8530_control;"OUTPERRO" ! CLEAR THE MESSAGE LINE

1610 ENTER @A8530_control;Report$

1620 OUTPUT @A8530_control;"CENT"&VAL$(Freq)&"GHz;SING" ! SET TO SELECTED FREQ, MAKE A CW

MEASUREMENT

1630 OUTPUT @A8530_control;"FASPARMTIME "&VAL$(Dwell_time) ! SET FAST MUX DELAY TIME (250 uS)

1640 OUTPUT @A8530_control;"FASMUXMODE 2;FASMD" ! SET UP FAST MUX MODE 2 (SEE O&P MANUAL FOR

OTHERS)

1650 OUTPUT @A8530_control;"OUTPERRO" ! CHECK FOR ERRORS DURING SET UP

1660 ENTER @A8530_control;Report$

1670 IF VAL(Report$)<>0 THEN

1680 PRINT TABXY(1,30),"THE FOLLOWING PROBLEM OCCURED DURING 8530A SETUP:"

1690 PRINT ""

1700 PRINT Report$

1710 DISP "RESOLVE PROBLEM AND CONTINUE ( OR EXIT )"

1720 FOR N=0 TO 4

1730 ON KEY N LABEL "CONTINUE" GOTO Setup_fastmux

1740 ON KEY N+5 LABEL "EXIT" GOTO Setup_failed

1750 NEXT N

1760 Wait_for_key:GOTO Wait_for_key

1770 END IF

1780 REPEAT ! WAIT FOR 8530A SRQ MASK BIT

1790 WAIT .01

1800 UNTIL BIT(SPOLL(716),2)

1810 TRIGGER @A8530_control ! DROPS 8530A INTO THE SELECTED FAST DATA MODE

1820 Setup=1 ! (FAST MUX MODE 2)

1830 Setup_failed: !

1840 PRINT TABXY(1,30)," "

1850 PRINT " "

1860 PRINT " "

1870 RETURN

1880 SUBEND

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