Digital Data Modem 1A12 Cable-to-Radio Circuits Functional Block Diagram Description

TM 11-5820-695-35

the digital orderwire 32 kHz clock signal. The clock and

The functional relationships between the cable-to-radio

retimed CVDOW signals are routed to module A7.

plug-in components and chassis circuits in digital data

modem 1A12 are shown in figure 5-7 for the

(5) Alternate bits in the CVDOW signal are

synchronous mode and in figure 5-7.1 for the

DOW and DVOW.

Those bits have known

asynchronous mode.

Each plug-in component is

characteristics and are therefore detectable. The DOW

functionalized and the main signal paths (heavy lines

detector in digital orderwire demultiplexer 1A12A7

through each plug-in component and between plug-in

adjusts the phase of the 16 kHz clock so that the DOW

components) are shown. In addition the control and

and DVOW demultiplexer each operate on the proper

alarm functions are shown. The operation of the

sequence of alternate bits. The DOW and DVOW data

synchronous mode plug-in components is described m a

and timing signals are applied to line drivers and routed

through f and the operation of the asynchronous plug-in

to the local OCU and DLED.

components is described in a.1, b.1, and g.

2-5. Digital Data Modem 1A12 Cable-to-Radio Circuits

Functional Block Diagram Description (fig. 5-7

a. Cable Digital Regenerator lA12A2 (Synchronous

(1) The input signal to cable digital regenerator

1A12A2 is designated FRCX (pcm/ orderwire/dc) Since

the length of cable through which the signal is

transmitted may vary up to a maximum of one mile, a

cable simulation net

Change 6 2-10