ADC Digivance CXD, Operation Manual

Page: 68 / 74

ADCP-75-192 • Issue 2 • June 2007
Page 56
© 2007, ADC Telecommunications, Inc.
4.7 Gain Management and Fault Detection
This section outlines the concepts and performance objectives involved in the gain management
and fault detection (continuity) of the Digivance CXD/NXD system. This section breaks these
topics down into the following areas:
• Forward gain management
• Reverse Automatic Gain Control
• Forward delay management
• Reverse delay management
• Forward continuity
• Reverse continuity.
• PA Overpower Protection
• Hub Overpower Protection
4.7.1 Forward Gain Management
The Digivance CXD/NXD system has a compensation feature in the forward path to account for
changes in gain as a function of temperature. This feature applies on a per RAN basis and is
enabled by default. The operator can disable this feature if desired.
4.7.2 Reverse Automatic Gain Control
The Digivance CXD/NXD system autolimits any strong in-band signal which reaches the RAN
at a peak input level of greater than -38 dBm relative to the antenna port. The process does this
by monitoring A/D overflows and adding attenuation in the RDC when these overflow occur.
“AGC events” are logged on the CPU running the RDC process. Attenuation is backed out as
the signal strength subsides.
4.7.3 Forward Delay Management
Forward Delay Management (FDM) is a software function that is part of Tenant Processing and
whose responsibility is to equalize the path delays to all RANs in a simulcast group. The FDM
process is “enabled” in the Tenant OAM MIB (see Section 3, Sub-Section 7 Tenant
Configuration).
4.7.4 Reverse Delay Management
Reverse Delay Management (RDM) is a software function that is part of Tenant Processing and
whose responsibility is to equalize the path delays to all RANs in a simulcast group. The RDM
process is “enabled” in the Tenant OAM MIB (see Section 3, Sub-Section 7 Tenant
Configuration).