Remote Control - Commands R&S NRP-Z91
1168.8579.12 6.10 E-3
SENSe:FUNCtion[?] <sensor_function>
In contrast to other sensors, the R&S NRP-Z91 only implements the Continuous Average mode.
Therefore, the command SENSe:FUNCtion <sensor_function> only accepts the parameter
"POWer:AVG".
Table 6-3 Measurement mode "POWer:AVG"
<sensor_function> Description of the measurement mode
"POWer:AVG"
Continuous Average
In this mode, the average power of the measurement signal is asynchronously measured within
definable time intervals (sampling windows). The width of a sampling window is set with the
SENSe:POWer:AVG:APERture
command. The measurements are performed with chopper stabilization
to obtain more accurate measurement results with reduced noise and zero offset. Therefore, a single
measurement is always performed over two sampling windows
, the polarity of the detector output signal
being reversed for the second window. By taking the difference of the output signals, the effect of the
video path on noise and zero drif
t is minimized. When the averaging function is activated, the averaging
factor determines how often the described measurement cycle is repeated.
A measurement should be started with the command INITiate:IMMediate (once) or
INITiate:CONTinuous ON (continuously), the trigger source being set to IMMediate with the
TRIGger:SOURce command (asynchronous measurement).
The query always yields 1 for "POWer:AVG".
Default setting: "POWer:AVG"
SENSe:POWer:AVG:APERture[?] 10.0e–6 to 0.3
SENSe:POWer:AVG:APERture defines the time interval (sampling window); measured values are
continuously recorded in this interval. In manual operation, the default setting of 20 ms in conjunction
with the activated smoothing is sufficient in most cases.
Larger sampling windows are needed when the measurement shows fluctuations due to modulation. It
is then useful to adapt the size of the sampling window exactly to the modulation period, which yields
an optimally stable display. If the modulation period varies or is not precisely known, the Smoothing
function should also be activated (see command group SENSe:POWer:AVG:SMOothing). With
smoothing activated, approx. 5 periods within a sampling window are sufficient to reduce the
fluctuations caused by modulation to an acceptable degree; fluctuations are no longer perceptible with
more than 9 periods. With smoothing deactivated, the situation is considerably more unfavorable. In this
case, 300 instead of 5 periods are required, and the fluctuations do not disappear completely until there
are 3000 or more periods.
The query yields the currently set width of the sampling window in seconds.
Default setting: 0.02 [s]
SENSe:POWer:AVG:BUFFer:SIZE[?] 1 to 1024
SENSe:POWer:AVG:BUFFer:SIZE sets the buffer size for the buffered Continuous Average mode.
The query yields the current buffer size for the buffered Continuous Average mode.
Default setting: 1
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