Cable-to-Radio Circuits, Synchronous Mode

TM 11-5820-695-35

modem 1A12 are provided in paragraphs 2-5 and 2-6.

2304 kHz cable-to-radio clock input, cable digital

processor 1A12A4 generates the timing signal used in

b. Cable-to-Radio Circuits, Synchronous Mode. The

reformatting and retiming the pcm signal.

The

cable-to-radio circuits (fig. 2-1, lower section) of digital

reformatted and retimed pcm output (to radio) of cable

data modem 1A12 provide processing of the

digital processor 1A12A4 is applied to the modulator

pcm/orderwire/dc signal received from the cable system.

circuits of Transmitter, Radio T-1054/GRC-144 for

The pcm and orderwire signals are separated for

combining with the orderwire signal and subsequent

individual processing. The orderwire signal is applied to

radio transmission.

orderwire assembly 1A13. The pcm signal is processed

in digital data modem 1A12. Upon completion of

(4) Cable digital processor 1A12A4 also

processing, the pcm and orderwire (from 1A13) signals

includes a cable loopback function. When the CABLE

are applied to the modulator circuits of Transmitter,

LOOP TEST switch is in TEST position, cable digital

Radio T-1054/GRC-144.

processor 1A12A4 applies the cable sliced pcm signal

input (which is received by cable digital regenerator

(1) The pcm/orderwire/dc signal is applied to

1A12A2 from the cable system) to the radio-to-cable

cable digital regenerator 1A12A2 which separates the

circuits of digital data modem lA12 as a cable loopback

signals. The pcm signal is reshaped into a digital form

pcm signal. The radio-to-cable circuits loop the pcm

(fig 2-2A and B) and applied to cable control comparator

signal back to the cable system for system maintenance

1A12A3 as the cable sliced pcm signal.

The

purposes.

orderwire/dc signal is applied to transformer

1A12A12A1T1 (fig. 5-29). The orderwire signal is

(5) The cable-to-radio circuits also include an

coupled to the transformer secondary and applied to af

alarm monitoring capability.

Cable-to-radio fault

amplifier 1A12A6. The direct current path is maintained

conditions are detected in cable digital regenerator

through the primary of the transformer and other

1A12A2, cable control comparator 1A12A3, and cable

components of digital data modem 1A12 for subsequent

digital processor 1A12A4 and applied to alarm monitor

return to the cable system (para 2-6c). The cable

1A12A5. Alarm monitor 1A12A5 generates applicable

extracted orderwire signal is amplified by af amplifier

fault alarm signals that control digital data modem 1A12

1A12A6 and applied to orderwire assembly 1A13.

and fault indicators on meter panel assembly 1A15A8.

Alarm monitor 1A12A5 also generates an alarm

(2) Cable control comparator 1A12A3 functions

summary which is sent to the shelter summary alarm of

in conjunction with 4608 kHz vco 1A12A1 to develop a

Radio Set AN/GRC-144.

cable-to-radio data timing signal for internal use and for

use in cable digital processor 1A12A4. Cable control

b.1. Cable-to-Radio Circuits, Asynchronous Mode.

comparator 1A12A3 compares the phase of the cable

The discussion of b above applies also for the

sliced pcm input (which is at the cable bit rate of 2304

asynchronous mode, except as noted here (see fig. 2-

kilobits/second) with the phase of a 2304 kHz timing

1.1, lower section).

signal developed from the 4608 kHz cable-to-radio clock

(1) Voltage controlled oscillator 1A12A1 is not

input from 4608 kHz vco 1A12A1. If the pcm signal and

used. The cable-to-radio clock signal (4915.2 kHz) is

the 2304 kHz timing signal are not in phase, cable

generated in cable digital regenerator 1A12A13 and

control comparator 1A12A3 generates a correction

designated 1CTIM. It is extracted from the pcm timing

voltage (cable vco modulation) that is applied to

inherent in the signal by means of a crystal filter

1A12A1 and causes it to change the frequency (4608

resonant circuit.

kHz) output such that the phase of the 2304 kHz timing

(2) Cable control comparator 1A12A14 retimes

signal coincides with the phase of the pcm data. Thus,

the pcm signal and inverts signal 1CTIM to 1NCLK. The

cable control comparator 1A12A3 and 1A12A1 form a

pcm and 1NCLK signals are applied to 1A12A4

phase-locked loop that phase-locks the 2304 kHz cable-

to-radio clock output of cable control comparator

c. Radio-to-Cable Circuits.

The radio-to-cable

1A12A3 to the pcm data. The cable sliced pcm and the

circuits (fig 2-1 and 2-1.1, upper section) of digital data

phase-locked 2304 kHz cable-to-radio clock signals are

modem 1A12 provide processing of the pcm/orderwire

applied to cable digital processor 1A12A4 for retiming of

signal input from Receiver. Radio R-1467(P)/GRC-

the pcm signal.

144(V). The radio-to-cable circuits separate the pcm

signal and the orderwire signal.

The recovered

(3) Cable digital processor 1A12A4 retimes the

orderwire signal is applied to orderwire assembly 1A13

half-baud, cable pcm signal (fig. 5-32, waveform B) into

for further

a full-baud signal (fig. 5-32, waveform E). Using the

Change 6 2-8.2