Reverse Path Level Adjustment - ADC DIGIVANCE User Manual

3.4 Reverse Path Level Adjustment

The level of the composite RF signal that should be input to the antenna will vary depending
on the maximum acceptable DRU path loss per the system design. The design objective is for
the Digivance system to provide unity gain. Use the following procedure to adjust the RIU to
provide the required reverse path signal level at the antenna:
1. Determine the maximum acceptable DRU path loss per the system design specifications.
2. Determine the total gain provided by the DRU antenna and the donor antenna.
3. Determine the total cable loss that is imposed by the reverse path coaxial cable that links
the DHU to the RIU and the coaxial cable that links the RIU to the antenna.
4. Calculate the total gain that must be added by the RIU using the following formula:
RIU Gain = DRU path loss + Cable loss – DHU gain (10 dB) – Antenna Gain
The result should be negative which indicates that gain is required.
5. Using a small screwdriver, adjust the REV LEVEL ADJ rotary switches to insert the gain
required as determined in step 4. Refer to Figure 14 for a description of how the rotary
switches work and to Table 4 for the adjustment settings.
Note: The RIU provides a reverse path signal adjustment range of from +28 dB to +59 dB.
ADCP-75-114 • Issue C • June 2001
Page 21
© 2001, ADC Telecommunications, Inc.