Specifications

NOTE: The modified frequency and ON/OFF condition will not become effective until the
final operation of the Program/Execute switch described in the next paragraph. To
prevent interruption of other channels when a frequency change takes place, the 450
automatically mutes the carrier until the phase locked loop frequency synthesizer
has stabilized at the new frequency.
5. Operate the Program/Execute switch. The display will now show the Compressor or Expander
status (IN/OUT). If you wish to make a change, operate the vertical switch to toggle the
status. When the display indicates the desired condition, press the Program/Execute switch
a final time. At this time the changes you have made will become the new settings for the
channel.
3-5. ALARM INDICATIONS. - An alarm condition for either channel will:
1. Illuminate the alarm indicator,
2. Indicate the alarm status on the LCD display,
3. Cause a form C relay closure to appear at the terminal block on the rear of the shelf for
remote indication.
4. Mute the output of the channel (audio in the case of a receiver, or the subcarrier in a
transmitter). The left side of the LCD indicates alarms for channel A and the right side
for channel B.
Alarms are:
Transmitter :
CXR ALM if the carrier frequency deviates beyond predetermined limits.
AFC ALM if the synthesizer is out of lock.
CXR AFC if both alarms are present.
Receiver:
CXR ALM upon a drop in incoming carrier level beyond the squelch setting or the RF/IF section
of the receiver is defective.
AFC ALM if the incoming carrier is off frequency or if the frequency determining elements of the
receiver are defective.
CXR AFC if both alarms are present.
CAUTION
An annoying remote alarm can be disabled by turning the channel "off". If
this is done there will be no alarm condition active to remind maintenance
personnel there is a problem. The channel may be brought on-line by
someone unaware of the existing problem.
450 Operation Manual Rev A Page 18 8/26/99