3 Spectrum Analyzer Mode
3.12 List Sweep Measurement (Remote Only)
3.12.3.11 Trigger Source
This command sets the source for the trigger that controls the start of each new
measurement point in the list. The other trigger command :TRIGger:SOURce, is used
to start the list .
The query form queries the analyzer for the values in the trigger source of the list
sweep.
When list trigger is set to BUS, the first measurement is taken immediately when the
INIT command is sent, and subsequent measurements are taken when the *TRG
command is sent. The measuring bit is set at the time when a new list point
measurement is initiated via *TRG and cleared when the measurement result of that
point is received. In other words, the measurement bit is set/reset at each point. An
example is shown as following:
1.
TRIG:SOUR IMM // this sets the first point trigger setting in the list sweep
2.
CONF:LIST // set to list sweep measurement
3.
LIST:FREQ 800e6, 810e6, 820e6 //set three point list frequency measurement
4.
LIST:TRIG:SOUR BUS // set list trigger to BUS
5.
INIT:IMM; *OPC? // Initiate one measurement and obtain the first point
acquisition as the first point is free run (in step (2))
6.
*TRG; *OPC? // trigger and obtain the 2nd point acquisition
7.
*TRG; *OPC? // trigger and obtain the 3rd point acquisition
8.
FETCH:LIST? // it should return the 3-point list of result
In the example above, the measuring “bit” is set at the starting of (5),(6) and (7) and
cleared when *OPC returns. The diagram below illustrates the measuring “bit” status
change vs. time:
Measuring “bit” status time line:
1942 Spectrum Analyzer Mode User's &Programmer's Reference
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