Racal Instruments AN/TRC-207, Инструкция по эксплуатации и обслуживанию

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TO 31R2-2TRC207-1
5-1
CHAPTER 5 THEORY OF OPERATION
Section I. FUNCTIONAL SYSTEM(S) OPERATION
5-1 GENERAL
This section describes the theory of operation of the bi-directional repeater. From both technical and operational
standpoints, the bi-directional repeater is designed to be a component of a communications system. It must function in
conjunction with other system components (receiver-transmitters, base stations, and vehicle adapters) to perform
communication functions. However, it does not depend on other receiver-transmitters for its proper functioning or
performance. The bi-directional repeater operates in the 30-88, 136-174, and 403-470 MHz frequency bands,
retransmitting analog frequency modulation (FM), or 12 kbps or 16 kbps Continuously Variable Slope Delta Modulation
(CVSD) digitized voice. The transmitter output consists of a single channel frequency-modulated carrier. The transmitter
power output as measured at the antenna port is selectable at 2 or 10 watts. The bi-directional repeater is COMSEC
transparent and does not have internal COMSEC components. It can pass both encrypted and unencrypted traffic. The
bi-directional repeater provides extension of the communication range for base stations and receiver-transmitters by
providing a bi-directional receive/retransmit capability without the need to decrypt/encrypt the transmission. It is intended
to operate as a self-contained/stand-alone unit in an unprotected environment.
5-2 FUNCTIONAL SYSTEM(S) OPERATION
(See Figure 5-1.) Paragraphs 5-2.1 through 5-2.11 provide a limited system description of the bi-directional repeater. The
functional block diagram (Figure 5-1) shows the interrelationship between the main circuits of the bi-directional repeater.
5-2.1 +15V DC-DC Converter Circuit Card Assembly (CCA) (A1A1)
The +15V DC-DC converter CCA (A1A1) provides reg15 VDC to the repeater control CCA (A3) and both hand-
held receiver-transmitters. The DC-DC converter operates from a 10-32 VDC input.
5-2.2 Repeater Control/Audio Circuit Card Assembly (CCA) (A1A2)
The repeater control/audio CCA (A1A2) combines the signal control and the audio interface between the two receiver-
transmitters and provides the audio output and microphone input. The audio out function is active in both COMMS and
RETRANS modes; the microphone in (MIC IN) function is active only in COMMS mode. The assembly provides
reclocking of data when data format is received by the receive receiver-transmitter. It also automatically identifies
whether a 12 kbps or 16 kbps signal is received. This CCA contains timing circuits to control the push-to-talk (PTT) line
of the transmit receiver-transmitter. Timing circuitry is included to reduce the possibility of missing the initial data bits.
Received audio is routed to the microphone line of the transmit receiver-transmitter and the SQ/CTS, signal present line
of the receive receiver-transmitter is converted to the PTT line of the transmit receiver-transmitter. The repeater control
CCA passes both clear and encrypted signals.
5-2.3 Repeater Interface CCA (A1A3)
The Repeater Interface card contains no electronic components. Its purpose is to link certain parent board tracks to
control board tracks. The linked functions are the audio line, the microphone line, and some front panel control lines.
5-2.4 Parent Board Circuit Card Assembly (CCA) (A1A4)
This card provides the interconnection between the other circuit card assemblies and provides power to the receiver-
transmitters.
5-2.5 Control Panel (A1A5)
The control panel (A1A5) contains all operator controls and indicators. This card contains the power amplifier Automatic
Level Control (ALC) adjustments for both output power settings. The audio amplifier, microphone pre-amplifier, and
voltage regulator circuits on this card enable local operations.
5-2.6 RF Power Amplifier Assembly (A1A6)
The RF power amplifier (A1A6) amplifies the output of the transmit receiver-transmitter to 2 or 10 watts, measured at
the output of the diplexer, as determined by the setting of the POWER switch.