Comtech EF Data DM240XR - Manual (Page 191)

DM240XR High-Speed Digital Modulator AutoEQ™ Interface Operation Guide
MN-DM240XR– Revision 13 D–11
Figure 6. AutoEQ™ Ref Acq Set-up
For best results place the attenuator pad as close to the AutoEQ port (J12) as
possible.
9. Clear the events of the modulator by scrolling to then down and over to
CLEAR TO ERASE EVENTS> and press clear. Verify that the Event LED is now off.
10. Using the Front Panel menu, scroll to “EQ CALIBRATION” and set to “REF ACQ”
a. After a successful calibration the event log will display “REF ACQ SUCCESSFUL” upon
completion of this step. When the REF ACQ is complete, the “EQ CALIBRATION” will
revert to “NORMAL”.
11. Remove the interconnect cable installed in Step 8 above.
12. Verify through the event log that the system successfully calibrated the reference.
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 within + 25 kHz of the measured frequency in