![Rohde & Schwarz FSH13 Скачать руководство пользователя страница 158](http://html.mh-extra.com/html/rohde-and-schwarz/fsh13/fsh13_operating-manual_1477832158.webp)
R&S FSH
Power Meter
Using a Directional Power Sensor
Operating Manual 1173.6275.12 - 30
143
Taking additional attenuation into account
When the directional power sensor is connected to a test point not directly but via a
cable, the influence of cable attenuation can be taken into account. For this purpose,
the cable attenuation for the measurement frequency in question is to be entered, i.e.
as a positive dB value if the power and matching are to be measured at the source and
the cable is connected between the source and the power sensor, and as a negative
dB value if the power and matching are to be measured at the load and the cable is
connected between the load and the power sensor. The directional power sensor then
corrects the power and matching values to produce the results that would have been
obtained if it had been directly connected to the test point.
► Press the AMPT key.
► Press the "Ref Offset" softkey.
The input field to enter the reference offset opens.
► Enter the offset you need.
The selected offset is displayed in the diagram header and is taken into account in
the power (level) and matching results.
If high powers are applied that exceed the maximum input level of the R&S FSH-Z14
or R&S FSH-Z44, a directional coupler or an attenuator has to be connected ahead of
the power sensor. In such cases, the coupling attenuation of the directional coupler or
the attenuation value of the attenuator are to be entered as positive dB values (see
above) into the R&S FSH to ensure true measured power readout. In both cases, a
termination or an attenuator of sufficient power-handling capacity has to be connected
to the power sensor at the load end. The matching readout is irrelevant in such case
since it is likewise corrected by taking into account the attenuation value of the
termination or attenuator.