How-To Guide
REV B — 22 Nov, 2021
1
Technical Service Bulletin 190425
RF Tuning Procedure for Transmitters Using Exact V2 Exciter
The Comark Exact exciter has a very capable / powerful non-linear digital pre-corrector con-
tained in it. Knowing how to set up and properly adjust this corrector is key to the best perfor-
mance and safe operation of a transmitter. Described below is a basic guide to allow a user to
accomplish the proper tuning adjustment of this corrector.
1. Overview Panel
First insure that the transmitter is properly connected to the output mask lter and load. Ensure
that you have RF output couplers in the path before and after the mask lter for transmitter feed-
back to the Exact exciter. Log into the Exact Exciter’s webpage and congure the correct output
modulation type, bandwidth, and frequency in the RF Output Parameters tab.
2. Basic Setup
On the rear panel there are 2 SMA connectors labeled FBA (Feed Back Amplier), and FBF
(Feed Back Filter).
The FBA signal should come from the transmitter output sample before the mask lter. This is
used for non-linear (shoulder) correction.
The FBF signal should come from the transmitter output sample after the mask lter. This is
used for linear (SNR) correction.
These signal levels should be in the range of -15 to -5 dBm.
3. Connecting Feedback Signals
Fig. 1 Rear panel