Instrument Function
R&S
®
SMU200A
214Operating Manual 1007.9845.32 ─ 15
Source - Power Sensors
Selects the source for measurement.
"RF"
Measurement source is the RF signal of the generator. The RF frequency
is used as the measurement frequency of the sensor and the corre-
sponding correction factor is used.
In this mode the RF frequency of the generator is send to the sensor
automatically if changed.
If two sensors are connected, both sensor can be allocated the same
path, e.g. for measurements before and after the DUT.
For single path instruments, only selection RF A is offered.
"User"
Measurements source is any freely selectable source. The frequency is
entered manually under frequency (e.g. for measurement of amplifier
gain with 2 sensors).
SCPI command:
SENSe<ch>[:POWer]:SOURce on page 564
Frequency - Power Sensors
Source User only
Enters the frequency for measurement source "User".
SCPI command:
SENSe<ch>[:POWer]:FREQuency on page 562
Level Offset - Power Sensors
Activates and defines a level offset which is added to the measured value. This allows
e.g. an attenuator in the signal path to be taken into account. The offset is always entered
in dB, irrespective of the selected unit for result display.
SCPI command:
SENSe<ch>[:POWer]:OFFSet:STATe on page 563
SENSe<ch>[:POWer]:OFFSet on page 563
Filter Length - Power Sensors
Selects the filter length used for measurement. The filter length is the multiplier for the
measurement time and thus directly influence it.
The averaging filter is used to reduce fluctuations in the measured result to the extent
desired. Such fluctuations can be caused by inherent noise of the measuring instrument,
modulation of the measurement signal or beats from the superposition of adjacent car-
riers. A more stable display has to be traded off against longer measurements. The mea-
surement result is obtained from a two-stage averaging process.
Note: Longer measurements does not mean that it takes longer to display a new result,
but rather that it takes longer for the result to settle when the power changes.
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 windows.
The number N is the filter length, the factor of 2 arises because the output signals from
the microwave detector to suppress low-frequency noise are chopped at the same rate
as the time windows, which means that an independent measured value can only be
obtained from two consecutive values. As the filter length is the multiplier for the time
window it directly influences the measurement time.
RF Signal and Analog Modulations - RF Block
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