Fast Power Measurement On Power Ramps - Rohde & Schwarz R&S FSP Series Operating Manual

R&S FSP
'RMS measurement
query$ = query$ + ":CALC:MARK:FUNC:SUMM:SDEV:RES?"
'Standard deviation
status = viWrite(analyzer, query$, 120, retCnt)
status = viRead(analyzer, result$, 100, retCnt)
Print result$
END SUB
REM ************************************************************************
7.3.6

Fast Power Measurement on Power Ramps

A frequent task in mobile radio tests is measurement of a DUT at various power con-
trol levels at the highest possible speed. The R&S FSP offers two test functions for
this task, which can be used depending on the signal characteristics.
In the following, the two methods are presented by means of two examples.
7.3.6.1 Power Measurement with Multi-Summary Marker
The multi-summary marker function is suitable for measuring the power of a
sequence of pulses with the following characteristics:
•
•
•
The function uses the first pulse as a trigger signal. The power of the subsequent
pulses is determined exclusively via the timing pattern selected for the pulse
sequence. The function is, therefore, suitable for adjustments where the DUT output
power varies considerably and is not reliably above the trigger threshold.
The measurement accuracy is determined by the ratio of pulse duration to total
measurement time; this should not be below 1:50.
The function always uses TRACE 1 of the selected screen.
P
Trigger
Threshold
Time offset of
Trace start
Fig. 7.1 Block diagram illustrating signal processing by the R&S FSP
In the example below, a sequence of 8 pulses is measured with an offset of 50 µs of
the first pulse, 450 µs measurement time/pulse and 576.9 µs pulse period.
7.18
The pulses occur at identical time intervals, which is typical of GSM transmission
in slots, for example.
The level of the first signal is reliably above threshold.
The subsequent pulses may have any levels.
Measurement
Time
Period
first pulse
Remote Control – Programming Examples
More Complex Programming Examples
Measurement
Time
Period
Operating Manual 1164.4556.12 - 06
Measurement
Time
t