R&S SMB100A Operating Manual page 185

®
R&S SMB100A
Remote command:
:SENSe<ch>:UNIT[:POWer]
Permanent Display State
Activates the permanent indication of the power measurement result in the upper right
corner of the block diagram. The instrument shows the type of sensor, the correspond-
ing connector, the measurement source and - if set - the offset.
It is possible to switch the permanent display active for several sensors. In this case,
the instrument indicates the values of the sensor with the lowest port number in the
display.
Remote command:
:SENSe<ch>[:POWer]:DISPlay:PERManent:STATe
Display Priority
Determines whether the instrument displays the measured average or the peak power
permanently on the screen.
To select the peak power display, it is required that the R&S NRP-Zxx sensor supports
this feature. On power-on or connecting a sensor the average power value is set by
default.
To enable the permanent display in the block diagram, select
State.
Remote command:
:SENSe<ch>[:POWer]:DISPlay:PERManent:PRIority
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).
Operating Manual 1407.0806.32 ─ 21
on page 324
Instrument Function
RF Block
on page 318
Permanent Display
on page 318
170