Comtech EF Data Radyne DM240XR, Installation And Operation Manual, Page: 217 / 222

DM240XR High-Speed Digital Modulator AutoEQ™ Interface Operation Guide
MN-DM240XR– Revision 12 D–11
D.9 Equalizer Calibration
For best AutoEQ equalization calibration it is recommended that the amplifier be run in its
linear range and not saturated
The AutoEQ™ RXRF Acquisition range is + 25 kHz from the programmed frequency and is not
programmable. To insure proper operation, the actual center frequency of the carrier should be
accurately measured with this measured value programmed into the AutoEQ™. This can be
accomplished by generation a CW (Carrier Wave) frequency with the modulator, and measuring
the downlink L-Band frequency with an accurate frequency counter or spectrum analyzer.
1. Reprogram the DM240XR Modulator output frequency to the proper operating frequency of
the Uplink system (if it was reprogrammed for Section 4.1 above) and the output power to the
system operating level. Connect the DM240XR Modulator output to the Uplink system.
Enable the modulator and adjust all uplink parameters as required for proper uplink
operation.
2. Measure the center frequency of the down converted modulated signal. Using the front panel
Menu, reprogram the AutoEQ™ to the center frequency of the down converted signal. The
AutoEQ™ programmed frequency must be 25 kHz of the measured frequency in
order to assure proper acquisition of the downlink signal. Connect the AutoEQ™ Input (J12)
to the earth Station L-Band Downlink System. The desired downlink carrier should be
typically between the range of -45 to -20 dBm.
3. Clear the events of the modulator by scrolling to <MONITOR> then down and over to
<PRESS CLEAR TO ERASE EVENTS> and press clear. Verify that the Event LED is now
off.
4. Using the Front Panel menu, scroll to “EQ CAL” and set it to “CALIBRATING”. This will
start the AutoEQ™ Calibration for the Satellite Link.