Configuring the RF signal
R&S
®
SMM100A
410
User Manual 1179.1341.02 ─ 05
"Serial Number"
Displays the serial number of the R&S NRP power sensor.
If the R&S
SMM100A does not detect a connected R&S NRPsensor,
you can assign the serial number manually.
"Add USBTMC Sensor"
Adds a detected R&S NRP sensor connected at the USB interface to
the list of sensors, including its device ID or name and its serial num-
ber.
Remote command:
7.12.4.3
NRP power viewer
The R&S
SMM100A features the power viewer function for measuring or monitoring
signals with R&S NRP power sensors.
About
The R&S
SMM100A can perform up to four power measurements simultaneously.
Depending on the signal characteristic (CW, AM, pulsed, etc.) or the parameter to be
measured (average, peak, etc...) a suitable R&S power sensor must be used.
About the measuring principle, averaging filter, filter length, and achieving stable
results
A sensor measures the average or peak RF power of the source continuously. The
measurement results are displayed in the "NRP Power Viewer" dialog.
The power viewer function uses
averaging filters
for getting a stable readout.
Measurement results could be interfered for instance by to much noise in your setup,
by a bad supression of harmonics or non harmonics or when you reach the sensitivity
level of your power sensor.
Measurements are continuously repeated in a predefined time window. The measure-
ment result is obtained by averaging the measured values for the last 2N time win-
dows. This approach is referred as a
two-step averaging process
.
The factor of 2 in the formula arises because the output signals from the microwave
detector are chopped at the same rate as the time windows to suppress low-frequency
noise. An independent measured value can only be obtained from two consecutive val-
ues.
The variable N in the formula indicates the
filter length
. The filter length then directly
influences the measurement time. The filter length can be selected automatically or it
can be manually set to a fixed value.
Depending on the R&S NRP power sensor type, the manual setting of the filter length
varies in resolution:
●
Resolution = 1 for the R&S NRPxx power sensor family
●
Resolution = 2
n
for R&S NRP-Zxx power sensors, with n = 1 to 16
Improving level performance
