User's Manual

TB8100 Calibration Kit User’s Manual Tuning the Receiver Front End 11
Tuning a K-Band, H-Band, or L-Band Receiver Front End
To tune the receiver front end, follow these steps.
1. Ensure you are already connected to the reciter (see “Connecting to a
Reciter Outside the Subrack” on page 5).
2. Select the Frequency Setup tab, and double-click Tune Receiver Front
End. The Tune Receiver Front End Wizard appears.
3. Connect the CTU’s noise source to the receiver input, turn the noise source
on, and then click Next.
4. Click Coarse (fast) and use the tuning tool to roughly adjust the front-end
helical filters on the receiver. As you do so, observe the graphical RSSI
readings across the lock band. Adjust first for maximum RSSI, and then for
flatness.
Note: As the response gets flatter, you may find it helpful to select a
more sensitive scale, so that you can see the graphical reading in
more detail.
Use the tuning tool as follows.
a. Insert the tuning tool into the first hole of the first set. You can start with
the hole on the left side and proceed along to the hole on the right, or
vice versa.
b. Tune each of the resonators in the first set once to give the best response.
c. Insert the tuning tool into the first hole of the second set. You can start
with the top hole and proceed down to the bottom hole, or vice versa.
d. Tune each of the resonators in the second set once to give the best
response.
e. Repeat this procedure as necessary to refine the response.
5. Once you have roughly tuned the front-end helical filters, click Fine
(slow). Repeat the above procedure to fine tune the front-end helical filters
until the response is flat in the middle of the lock band and not more than
-1 dB at the ends of the band.
Note: When using the Fine (slow) setting, you may notice a slight
delay as the reading from tuning the front-end helical filters takes
approximately one second to appear on the graph.
First set
Second set
UHF helical
filters: