R&S NRP-Z28/-Z98
Remote Control - Commands
1170.8966.12
6.13
E-4
SENSe:FUNCtion[?] <sensor_function>
SENSe:FUNCtion <sensor_function>
sets the sensor to one of the following measurement modes:
Table 6-3
Measurement modes
<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 drift 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).
"POWer:TSLot:AVG"
Timeslot Average
The average power of a definable number of successive timeslots within a frame structure with equal
spacing is measured. The width of one slot must be defined with
SENSe:POWer:TSLot[:AVG]:WIDTh
;
the number of slots is defined by
SENSe:POWer:TSLot[:AVG]:COUNt
. It is essential to define the
parameter
TRIGger:DELay
to ensure that the beginning of the first slot to be measured coincides with
the delayed trigger point. The measurement result is an array with the same number of elements as
timeslots. Each element represents the average power in a particular timeslot.
To minimize noise and zero offset, the measurement is performed with chopper stabilization. The
polarity of the detector output signal is therefore reversed from frame to frame. By subsequently taking
the difference of the output signals, the effect of the video path on noise and zero drift is reduced.
Time intervals that are to be excluded from the measurement can be set at the beginning and end of
each timeslot (see commands
SENSe:TIMing:EXCLude:STARt
and
SENSe:TIMing:EXCLude:STOP
).
A measurement is initiated with the command
INITiate:IMMediate
(once, irrespective of the number of
repetitions required for averaging) or
INITiate:CONTinuous ON
(continuously). The trigger source must
be set to
INTernal
or
EXTernal
with the
TRIGger:SOURce
command. After each occurrence of a
trigger event, the power is measured sequentially in all timeslots. Note that a trigger event must be
available for each frame.
"POWer:BURSt:AVG"
Burst Average
This mode is used to measure the average power of bursts. The time interval in which the average
power is measured starts when the power exceeds the trigger threshold and stops when the trigger
logic detects the end of the pulse. To prevent power drops due to modulation from being erroneously
interpreted as the end of a pulse, the user must define the dropout tolerance with
SENSe:POWer:BURSt:DTOLerance
.
To minimize noise and zero offset, the measurement is performed with chopper stabilization. The
polarity of the detector output signal is therefore reversed from burst to burst. By subsequently taking
the difference of the output signals, the effect of the video path on noise and zero drift is minimized.
In the
Burst Average
mode, only internal trigger events (from the signal) are evaluated (irrespective of
the setting of the
TRIGger:SOURce
parameter). The
TRIGger:DELay
parameter is also ignored, so
that the measurement interval begins exactly when the signal exceeds the trigger threshold.
Time intervals that are to be excluded from the measurement can be set at the beginning and at the
end of the measurement interval (see commands
SENSe:TIMing:EXCLude:STARt
and
SENSe:TIMing:EXCLude:STOP
).
