Squelch And Channel Access; Analog Signal Squelch & Access Operation - Futurecom PDR8000 Manual

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PDR8000® Portable Digital Repeater Product Planner
functionality is automatically curtailed when the link is restored (and if so configured, when
repeated audio is once again detected on the wireline interface).
6.6 S C A
QUELCH AND HANNEL CCESS
As PDR8000 monitors the receive frequency of its actively selected channel, it continuously
evaluates the signal being received in terms of several different attributes, including signal
strength, signal quality, and content. Based on whether the received signal passes the
provisioned acceptance criteria, the PDR8000 determines whether the received signal should
be accepted and processed (and thus repeated over-the-air and/or to the wireline connection).
This ensures that the PDR8000 only passes along traffic of sufficient quality, and intended for
the correct listeners.
In addition, PDR8000 can be configured to add certain access-control information to its
transmitted signals, to allow receiving units to decide whether that signal is intended for their
reception.
A variety of configuration parameters are available to tailor this behavior in order to achieve the
desired functionality. This operation, and the corresponding configuration parameters are
explained below. Note that the Squelch operation for Analog and Digital channels are found
below in 6.6.1 and 6.6.2. For a mixed-mode channel, both of these sections apply.
6.6.1 A S S & A O
NALOG IGNAL QUELCH CCESS PERATION
When evaluating an analog radio signal, PDR8000 can be configured to process the received
signal based on the Signal Strength (RSSI), Signal Quality (SINAD Equivalent) or both. The
determination of which of these criteria should be used is configured on a per-channel basis.
The RSSI threshold level can be set independently for each channel. If RSSI has been
configured as a receive criteria for a channel, then a common setting (across the active
Deployment Profile) is used to determine the measurement integration time (speed) and
hysteresis value for RSSI un-detect.
If Signal Quality is configured as a relevant receive criteria, the SINAD Equivalent On and Off
threshold values can be set independently for each channel. A common setting (across the
active Deployment Profile) is used to determine the measurement integration time (speed) for
this measurement.
Once PDR8000 determines that the received signal has passed the configured Signal Strength
and/or Signal Quality criteria, it next evaluates the signal contents to determine whether it
should further process the signal. This content analysis is based on configuration of whether
the PDR8000 should be additionally dependent on receiving sub-audible signalling on the
analog carrier. This signaling commonly takes the form of CTCSS (Continuous Tone-Coded
Squelch System; aka Motorola PL) or DCS (Digitally Coded Squelch: aka Motorola DPL).
Sophisticated configuration capability exists to set up the PL/DPL criteria using Access Code
Tables (see sections below).
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