Filter
Top Products
72 Chapter 2
Programming Fundamentals
Improving the Speed of Your Measurements
These two commands are repeated until the condition is set, so we
know that the trigger is armed and ready.
• Trigger your DUT to send the burst.
• Return the measurement data to your computer.
NOTE This process cannot be done by using with the current VXI plug-n-play
driver implementation. You will need to use the above SCPI commands.
When making power measurements on multiple
bursts or slots, use CALCulate:DATA[n]:COMPress?
The CALC:DATA:COMP? query is the fastest way to measure power
data for multiple bursts/slots. 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,
and 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.
For example: let’s say you want to do a power measurement for a GSM
base station where you generate a repeating frame with 8 different
power levels. You can gather all the data with a single
CALC:DATA:COMP? acquisition, using the waveform measurement.
With CALC:DATA2:COMP? MEAN,9,197,1730 you can measure the mean
power in those bursts. This single command will measure the data
across all 8 frames, locate the first slot/burst in each of the frames,
calculate the mean power of those bursts, then return the resulting 8
values.
NOTE For later version of firmware (after A.05.00) you can use equivalent
time values for the CALC:DATA:COMP? query. The command would
then be CALC:DATA2:COMP? MEAN,25us,526us,579.6us,8
Let’s set up the GSM Waveform measurement:
• :CONF:WAV? turns on the waveform measurement
• :WAV:BAND 300khz sets a resolution bandwidth of 300 kHz
• :WAV:SWE:TIME 5ms sets a sweep time of 5 milliseconds
• :WAV:BAND:TYPE FLAT selects the flat filter type
• :WAV:DEC 4;DEC:STAT ON selects a decimation of 4 and turns on
decimation. This reduces the amount of data that needs to be sent
since the instrument hardware decimates (throws some away).
• :INIT to initiate a measurement and acquire the data
• CALC:DATA2:COMP? MEAN,25us,526us,579.6us,8 to return the
desired data