Radio-to-Cable Circuits

TM 11-5820-695-35

(3) In module A4, the data signal is retimed.

digital traffic retimer 1A12A5. The data signal is then

The CVDOW signal from module Al is gain adjusted.

regenerated and retimed. A clock signal is extracted

The gain adjustment varies according to the data bit rate

from the data signal by the action of a phase lock loop

in effect and is controlled by the DATA RATE SEL (MB)

to generate the cable data timing signal. The retimed

switch. The data and digital orderwire signals are then

data and the clock signal are routed to module A3. The

combined in a linear sum amplifier and routed to the

regenerated data signal is also returned to module A8

transmitter modulator circuits.

for use in the orderwire extraction circuits. At module

A3 the data signal is descrambled and retimed.

(4) When operating in the analog orderwire

Descrambled data and timing are routed to module A4.

mode, the OW SEL switch is in the ANLG position. The

In A4 the data signal is retimed and the data and clock

transmit analog orderwire signal (AVOW) is applied to

signals are routed through line drivers to the local DGM.

digital orderwire retimer 1A12A6. In module A6 the

AVOW signal is level adjusted and transformer coupled

(2) When the LOOP TEST switch is placed in

to orderwire assembly 1A13. With the OW SEL switch

RADIO position, the radio loopback switch is enabled.

in ANTI' position, if the AVOW switch (1A12S2) is

The from radio data is then routed through the radio

placed in BYPASS position, an inhibit signal is applied

loopback switch to the transmitter circuits and returned

to the retiming circuit in module A4 and the data signal

to the remote radio site. The from radio data signal is

to the radio is cut off.

still processed as described in (1) above but the data

signal from the local DGM is cut off and not used.

(5) Module A4 contains an electronic switch

Orderwire signal processing is not affected.

(cable loopback) that is controlled by a front panel

manual switch (LOOP TEST, 1A12S3). When the

(3) In module A8, the amplified from radio data

LOOP TEST switch is placed in DGM position this

signal is passed through a low pass filter to remove high

switch is enabled. The data signal from the DGM is

frequency data component and is then applied to a

then routed through the cable loopback switch and

subtractor. The regenerated, retimed data signal from

returned to the D;M. This allows the local DCM to test

module A5 is passed through a low pass filter, a

the cable connection. For cable loopback mode, the

multiplier and an AGC circuit and then applied to the

data signal from the DC41 is still sent through the

subtractor circuit. In the subtractor circuit, the filtered

normal path to the transmitter. However, the from radio

data only signal from A5 is subtracted from the

data signal is cut off and not used. The orderwire signal

composite data/ orderwire signal leaving the orderwire

(digital or analog) is not affected by cable loopback

signal as the output. In analog orderwire mode, this is

mode; it is processed and routed in the normal manner.

the AVOW signal; it is routed through a low pass filter.

The output AVOW signal is sent to orderwire module

c. Radio-to-Cable Circuits. The from ratio signal

1A13. In digital orderwire mode, the output of the

subtractor is the CVDOW signal; it is sent to module A6.

consisting of the recovered data and orderwire signals is

applied to digital regenerator 1A12A8 (fig. 5-8.3).

(4) In digital orderwire retimer 1A12A6, the

phase detector extracts a timing signal from the

(1) The composite data/orderwire signal is

CVDOW signal in a phase lock loop to generate

amplified in module A8, then sliced. The balanced data

signal from module A8 is converted to TTL level in

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