Specifications

Setting and Using the Measurement Functions R&S FSH
1145.5973.12 4.40 E-10
Setting the reference level:
When selecting the reference level, ensure that the R&S FSH is not overdriven. As the power is
measured with a resolution bandwidth that is small in comparison with the signal bandwidth, the
R&S FSH may still be overdriven even though the trace is still within the measurement diagram. To
prevent the R&S FSH from being overdriven, the signal can be measured at the largest resolution
bandwidth possible using the peak detector. If this setting is selected, it is not possible for the trace to
exceed the reference level.
To simplify operation and to prevent incorrect measurements, the R&S FSH has an automatic routine
for setting the reference level.
¾ Press the LEVEL ADJUST softkey.
The R&S FSH starts the measurement of the optimal
reference level using a resolution bandwidth of 1 MHz,
a video bandwidth of 1 MHz and the peak detector.
During the measurement, the message "Adjusting level
for channel power measurement, please wait... " is
output.
The optimal reference level is then set.
Setting the channel bandwidth:
The channel bandwidth specifies the frequency range about the center frequency, over which the
R&S FSH performs the power measurement.
¾ Press the CHAN BW softkey.
The value entry box showing the current channel
bandwidth setting opens.
¾ Using the number keys enter a new channel
bandwidth and terminate the entry with the
appropriate unit, or
¾ Using the rotary knob or the cursor keys, change
the channel bandwidth and confirm with the
ENTER key or the CHANNEL BW softkey.
The R&S FSH automatically sets the appropriate span
for the channel bandwidth that has been entered (span
= 1.2 x channel bandwidth) to ensure that no incorrect
channel power measurements are made.
The minimum channel bandwidth that can be set is
8.33 kHz with R&S FSH3 models 1145.5850.03 and
1145.5850.13.
If you attempt to enter a smaller channel bandwidth,
the R&S FSH will automatically set 8.33 kHz and
output the message “Out of range”.
With the R&S FSH3 model 1145.5850.23 and with the
R&S FSH6, the minimum channel bandwidth is 833 Hz
at a span of 1 kHz.