Agilent Technologies E4406A VSA manual •Trigger your DUT to send the burst

NOTE

NOTE

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.

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.

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

72 Chapter 2