User Manual

SGD-SB2025NT-TUM, Part 2
Jan 12 Page 80 RECEIVER VOTING
10.6 S QUELCH I NPUT (COR)
This is an optional input condition, since the RSSI input itself can be used to determine that the
receiver is active once the input signal has reached the minimum boundary value. However, use
of this input is strongly recommended to prevent false voting states if an RSSI voltage is used.
This condition can often occur, as the RSSI voltage output is likely to rise when invalid signals are
received (incorrect or no CTCSS) or from high level close frequency signals such as adjacent
channel interference.
To use this input for the “Squelch” or “COR” state requires that ‘Isolated Input #1’ be assigned to
‘Auto’ in the Setup configuration of the NI (see Section 5.2.2.4 – Isolated Inputs ). It is activated
by the application of a ground (0 V) to the input and when the RSSI signal from the receiver is
equal to or exceeds the minimum defined level the voting encode process will commence; i.e. Rx
squelch AND the minimum RSSI level are both required.