Rohde & Schwarz SMBV100A - Page 246

Instrument Function
R&S
®
SMBV100A
231Operating Manual 1176.8016.02 ─ 17
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 on page 588
Target Level
Specifies the nominal level expected at the input of the sensor. The signal generator
adjusts the output power accordingly, in order to meet the target value at the sensor
input, and thus the power required at the DUT.
Remote command:
[:SOURce<hw>]:POWer:SPC:TARGet on page 794
Limit - RF Level
Sets an upper limit for the RF output power.
You can use it to protect your DUT from damage due to high input power. If you enter
an RF level above this value, the instrument limits the output power to this specified
value, and generates a warning message.
However, the level indication in the status bar is not affected.
Note: The value is not affected by an instrument preset (PRESET key), *RST and the
"Save/Recall" function. It is influenced only by the Factory Preset and the factory value
is equal to maximum level.
Remote command:
[:SOURce<hw>]:POWer:LIMit[:AMPLitude] on page 789
Catch Range +/-
Sets the capture range of the control system.
Within the range:
Target Level +/- Catch Range
RF Block