Inovonics FM SiteStreamer+ SOFIA 565, Инструкция по установке и эксплуатации, Страница: 25 / 40

— 23 —
Threshold On (dB):
is the set point that the program must drop
below to trigger an alarm. Moreover, the program level must
remain below this set point for the number of seconds pro-
grammed by the
Time On (Sec):
slider. For the alarm to reset,
the program level must re-attain a specified
Threshold Off (dB):
value and remain above that point for the number of seconds
set by the
Time Off (Sec):
slider.
In this example, the program must fall below –25dB for a full
60 seconds to trigger an alarm. Then when the program re-
turns, it must stay above –20dB for 30 seconds for the alarm to
reset.
Low Signal
This alarm is similar to the one just discussed for audio loss.
When
Mute:
is turned
On
, program audio at all outputs is
‘squelched’ (silenced) during the alarm interval. With an FM re-
ceiver, this keeps ‘interstation hiss’ from making a nuisance of
itself when the incoming signal is lost.
The
RSSI (dBuV):
grayed-out bargraph gives the level of the in-
coming RF carrier.
Threshold On (dBuV):
and
Threshold Off
(dBuV):
set points are programmed in much the same manner
as the audio-loss alarm example above.
RDS Alarm
There are two
Off
/
On
settings for RDS errors. Turning
RDS
Loss: On
delivers an alarm when the RDS subcarrier simply goes
missing. Setting
PI Error: On
gives an alarm when RDS is re-
ceived with a PI code mismatch.
RDS data transmitted with an analog-FM broadcast contains a PI
code unique to that station. A PI mismatch can signal a transla-
tor ‘hijacking’ by a radio hooligan, or the less sinister condition
of the expected signal going off-air and a distant on-channel
broadcast received in its place.
To enable the PI mismatch function, enter the station’s true PI
code in the
PI Code
: box. The code being received at the mo-
ment is shown as
Current
PI:
. Simply enter that
same hex value as shown
and then click
Save
.
There are no threshold settings for RDS alarms, and both RDS
loss and PI mismatch share the same
Time On (Sec):
and
Time
Off (Sec):
settings, which work the same way as the alarms al-
ready discussed.
RT Update
Not infrequently a station’s playout system will ‘stick’ while
sending RDS RadioText. RadioText is sent as a complete data
message, unlike the static or scrolling PS field that is transmit-
ted as a rapid succession of 8-character data blocks. This and
other complexities (the associated RT+ features, for example)
make the RadioText field more likely to cause problems than
other RDS functions when it misses an update.