R&S SMB100A Operating Manual page 171

®
R&S SMB100A
Sensor
Selects the R&S NRP-Z power sensor for power control.
Note: In remote control, the sensors are set up using the SENSe commands. The
remote measurement is triggered by the READ query which also provides the measure-
ment results.
The software version of the connected power sensor can be retrieved by means of the
remote control command :SENS:POW:TYPE?.
Use the "Setup >"
the sensor software.
Remote command:
[:SOURce<hw>]:POWer:SPC:SELect
State
Activates power control using the selected sensor.
The control loop periodically adjusts the generator output. After switching off, the run-
ning loop is completed.
Remote command:
[:SOURce<hw>]:POWer:SPC:STATe
Measured Level
Indicates the current reading of the sensor.
Zero - Power Sensors
Activates the auto zero function.
Zeroing calibrates the external power sensor by adjusting its reading at zero signal
power. For this purpose, the RF power source must be switched off or disconnected
from the sensor. If a Rohde & Schwarz power sensor receives an input power during
the zeroing process, it aborts zeroing and generates an error message. Zeroing takes
a few seconds, depending on the sensor model. Refer to the documentation of your
power sensor for more information.
Tips for zeroing
When to perform zeroing:
●
During warm up after switching on or connecting the instrument
●
After a substantial change of the ambient temperature
●
After fastening the power sensor module to an RF connector at high temperature
●
After several hours of operation
●
When low-power signals are to be measured, e.g. less than 10 dB above the lower
measurement limit.
●
Switch off the RF power source for zeroing, but do not disconnect it from the power
sensor. This proceeding keeps the thermal equilibrium, and the zeroing process
also compensates the noise that superimposes the measured signal (e.g. from a
broadband amplifier).
Remote command:
:SENSe<ch>[:POWer]:ZERO
Operating Manual 1407.0806.32 ─ 21
Chapter 5.2.3.5, "NRP-Z
on page 385
on page 324
Info/Update", on page 97 dialog to update
on page 384
Instrument Function
RF Block
156