Making A Single Burst Measurement; Optimize Gsm Output Rf Spectrum Switching Measurement (N9071A Measurement Application); To Make Power Measurements On Multiple Bursts Or Slots Use Calculate:data<N>:Compress - Keysight N9000A Manual

RFBurst triggering depends on its establishment of a valid triggering reference level, based on previous bursts. If you only
have a single burst, the peak detection nature of this triggering function, may result in the trigger being done at the
wrong level/point generating incorrect data, or it may not trigger at all.

Making a Single Burst Measurement

To achieve consistent triggering and valid data for this type of measurement application, you must synchronize the
triggering of the DUT with the instrument. You should use the instrument's internal status system for this.
The first step in this process is to initialize the status register mask to look for the "waiting for trigger" condition (bit 5).
Use :STATus:OPERation:ENABle 32
Then, in the measurement loop:
1. Send query :STATus:OPERation:EVENt? to clear the current contents of the Operation Event Register.
2. Send query :READ:PVT? to initiate a measurement (in this example, for GSM Power versus Time) using the previous
setup. The measurement then waits for the trigger.
Make sure attenuation is set manually. Do not use automatic attenuation, as this requires an additional burst to
determine the proper attenuation level before the measurement can be made.
3. Create a small loop that polls the instrument for a status byte value of 128. Then wait 1 msec (or 100 ms if the display
is enabled) before checking again, to minimize bus traffic. Repeat these two commands until the condition is set, to
ensure that the trigger is armed and ready.
4. Trigger the DUT to send the burst.
5. Retrieve the measurement data.
Optimize GSM Output RF Spectrum Switching Measurement (N9071A Measurement
Application)
For ORFS (switching), setting the break frequency to zero (0) puts the instrument into a measurement setup where it can
use a direct time measurement algorithm, instead of an FFT-based algorithm. The non-FFT approach is faster.
However, remember that the break frequency for ORFS (modulation) measurements must be >400 kHz for valid
measurements, so, if you are making both types of measurements, you will need to change the break frequency.
To make Power Measurements on Multiple Bursts or Slots use
CALCulate:DATA<n>:COMPress?
The Calculate/Compress Trace Data Query is the fastest way to measure power data for multiple bursts/slots. (For details
of the command, see the Programming the Analyzer chapter of any X-Series Help file or Users & Programmers Reference
PDF.) There are two reasons for this:
1. It can be used to measure data across multiple, consecutive slots/frames with just one measurement, instead of a
separate measurement on each slot,
2. It can pre-process and/or decimate the data so that you only return the information that you need, which minimizes
data transfer to the computer.
Example: you want to do a power measurement for a GSM base station where you generate a repeating frame with 8
different power levels. Using the Waveform measurement, you can gather all the data with a single CALC:DATA:COMP?
acquisition.
SCPI Programming Fundamentals
Techniques for Improving Measurement Performance
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