Loss-of-Receive-Carrier Alarm

TM 11-5805-424-15/NAVSHIPS 0967-220-9013/TO 31W2-2G-41

input to amplifier IN-9. The high-level output from

(1) With input fsk signals applied, the output of

amplifier IN-9 activates 2-second delay Q11, Q12.

third input amplifier Q15 is applied through REC

CARRIER ALARM THRESHOLD resistor 1A1R11 to the

(a) If the input receive carrier is restored

level threshold, which provides a polar signal (+ 6 volts)

to amplitude detector Q7, Q8, Q9. The amplitude

within a 2-second interval, the amplitude detector

detector provides a low-level output that is inverted by

provides a low level to amplifier IN-10, turning off

amplifier IN-10, providing a high-level output (+ 6 volts)

ALARM indicator lamp 1A1DS2 as described in (1)

through amplifier IN-9. Amplifier IN-9 provides a low-

above.

level output to activate 2-second delay Q11, Q12

(adjustable by REC CARRIER ALARM TIME control

(b) If the input carrier is lost for more than 2

resistor 1A1R12), producing a low level for OR gate

seconds, 2-second delay Q11, Q12 times out, providing

GOB-1 (input interface and common alarm module) that

a high level (+ 6 volts ) to OR gate GOB-1 in the input

holds ALARM indicator lamp 1A1DS2 in the off

interface and carrier alarm module and causing ALARM

condition (b (1) above).

indicator lamp 1A1DS2 to be lighted (b(2)

(2) When the receive carrier is lost, the amplitude

detector provides a high-level output equivalent to no

output from the detectors to amplifier IN-10. The

resultant, inverted, low-level output provides a low-level

Change 3

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