Tait TB8100 User Manual page 123

Subaudible
signaling
Gating logic
TB8100 Service Kit User's Manual
The Subaudible signalling area is joined to the second drop-down list box. This
indicates that the current signalling profile also provides an input into receiver
gating. For this input to be true, the received signal must carry the subaudible
signaling specified in the channel table. Alternatively, it must have the
subaudible signaling specified in one of the rows of the table in the current
signaling profile (and this row must specify the action 'Gate Receiver.') The
subaudible signalling input is combined with the resultant input of RSSI and/
or SINAD gating to give a mute/unmute decision.
Red lines and boxes show how the different gating criteria are to be combined
using Boolean logic.
Using the first drop-down list box, specify how the RSSI and SINAD gating
inputs are to be combined.
Option Description
AND Both RSSI and SINAD values must reach the required level for
the resultant input to be true.
OR Either RSSI or SINAD must reach the required level for the
resultant input to be true.
Select OR and set the RSSI level high (for example -100 dBm).
Tip:
This gives you quick gating when the signal level is high. When the
signal level is low, gating occurs based on SINAD. This is slower but
more immune to noise interference.
Using the second drop-down list box, specify how the above inputs are to be
combined with the input from the decoding of subaudible signalling.
Option Description
AND The RSSI and/or SINAD values must reach the required level
AND the correct subaudible signalling must be received before
the receiver unmutes.
OR Either the RSSI and/or SINAD must reach the required level OR
correct subaudible signalling must be received before the
receiver unmutes. This option means that the receiver can
unmute quickly to a signal with a high RSSI or more slowly to a
signal of lower strength that has valid subaudible signalling.
Interfering signals are unlikely to have a high RSSI.
Working with Channel Profiles 113