Rohde & Schwarz FSH3 - Page 113

R&S FSH3 Setting and Using the Measurement Functions
The R&S FSH3’s LEVEL ADJUST routine will automatically determine the optimal reference level for
you.
¾ Press the LEVEL ADJUST softkey.
The R&S FSH3 starts the measurement to determine
the optimal reference level, using a resolution
bandwidth of 1 MHz, a video bandwidth of 1 MHz and
the peak detector. While the measurement is in
progress, the R&S FSH3 outputs the message
“Adjusting level for TDMA power measurement, please
wait... ".
The optimal reference level is then set.
Power readout:
The R&S FSH3 displays the measured power at the bottom of the measurement diagram (Power =
nn.n dBm). Usually the trace is not obscured. However, if the trace is in this area of the screen, the
power readout can be removed from the screen. Simply press the PWR DISP ON/OFF softkey. If the
softkey label is highlighted in green, the power readout is on.
Setting the trigger:
A trigger is usually required to perform power measurements on bursts. In the default setting, the
R&S FSH3 is configured to use the video trigger at 50 % of the Y scale on the measurement diagram.
Assuming that the burst on which the measurement is to be made crosses the 50 % point of the trigger,
the R&S FSH3 will trigger on the rising edge of the burst.
Should this not be the case, the trigger level must be adjusted so that the R&S FSH3 is triggered by the
burst edge. Otherwise no measurement will be performed.
If the DUT has a trigger facility, the external trigger can also be used for the measurement.
¾ Connect the DUT’s trigger output to the
R&S FSH3’s trigger input.
¾ Press the SWEEP key.
¾ Press the TRIGGER softkey.
¾ Select the EXTERN menu item (rising or falling
edge).
¾ Confirm your selection with the ENTER key or the
TRIGGER softkey.
Select the appropriate trigger delay to position the
burst in the measurement window.
¾ Press the DELAY... softkey.
¾ Using the rotary knob or the cursor keys, adjust the
trigger delay until the TDMA burst is inside the
vertical lines indicating the measurement range, or
¾ Using the number keys, enter the appropriate
trigger delay and terminate the entry with the
appropriate unit key.
1145.5973.12 4.39 E-6