CHAPTER 2. FUNCTION OF EQUIPMENT

TM 11-5820-509-35

CHAPTER 2

FUNCTION OF EQUIPMENT

Except for RT-671/PRC-47, the other functional

2-1. System Applications

equipments are considered accessory items and these

a. Radio Set AN/PRC-47 provides singlesideband

are each discussed in the several optional

voice (usb only), continuous wave (cw) telegraphy, and

configurations as they effect the general theory. Since

frequency shift keying (fsk) teletypewriter modes of

the radio set is a compact, modularized, portable

ground radio communication in the high frequency (hf)

transceiver, many of the circuits and devices used for

spectrum from 2.000 to 11.999-MHz and is operationally

transmitting are also used for receiving. These circuits

compatible with the AN/TRC-75 and similar radio

are described as part of the applicable signal function

equipment. The radio set is a two-man team, pack-

and appear in the appropriate block diagram for that

transportable, transmitter-receiver that is contained in

function.

transportable carrying cases. It includes an antenna

system and all necessary accessory items for telegraph

and telephone operation but does not include an fsk

b. The discussion relating to the theory of

input/output device or teletypewriter machines. The

operation and the maintenance requirements for the

transmitter provides 100 watts peak-enveloppower (pep)

AN/PRC-47 include reference designators that describe

output when operating singlesideband, and when

the module, the circuit stage, and the component part of

equipped with a suitable blower/converter, such as CV-

the circuit being discussed in the equipment. These

2455/PRC-47, will provide 100 watts average power in

reference designators are assigned in accordance with

teletypewriter service.

The receiver provides a

MIL-STD-16B, and an understanding of this

minimum power output of 50 milliwatts from an input

identification method will assist in locating individual

signal of 2.0 microvolts for a 10-dB signal-plus-noise to

components within the overall equipment. For example,

noise ratio.

reference designator AIC1 refers to capacitor number

b. Radio Set AN/PRC-47

normally

one in modular assembly A8A1. Radio Receiver-

implemented for push-to-talk (ptt) operation. A field

Transmitter RT-671/PRC-47 (A8) contains the following

modification can be easily accomplished in Electrical

nomenclatured

subassemblies

and

associated

Equipment Chassis Ch-474/PRC-47 that converts the

components.

equipment for voice-operated transmit (vox) operation.

This vox option is implemented by strapping pin 11

REF DES

OFFICIAL NOMENCLATURE

(push-to-talk) to pin 20 (vox) at connector JI (Power

Audio Frequency Amplifier AM-3506/PRC-47

Supply PP3318/PRC-47, module A5). The discussion

Amplifier-Modulator AM-3507/PRC-47

below assumes that this option is implemented: In the

Signal Data Translator CV-1377A/PRC-47

absence of this modification, only push-to-talk (ptt)

Electrical Equipment Chassis CH-474/PRC-47

Power Supply PP-3518/PRC-47

operation is possible and reference to the vox mode and

Radio Frequency Oscillator 0-1032/PRC-47

to the circuit description for the vox amplifier and relay

Oscillator Control C-4311/PRC-47

driver stages may be ignored.

Panel Cover CW-647/PRC-47

2-2. Block Diagram Explanations

2-3. Overall Block Diagram

a. This section presents the general theory of

a. Figure 2-1 is an overall block diagram for Radio Set

operation for Radio Set AN/PRC-47 on a block diagram

AN/PRC-47 that shows the relationship between the

level.

The general theory first describes the

several modules of Radio Receiver-Transmitter RT-

relationships between the six major functional areas of

671/PRC-47 and the external accessory items. The RT-

the equipment. These areas are: the audio input

671/PRC-47 contains the electronics that provide

devices, the cw telegraph key, the audio output devices,

singlesideband voice, continuous wave (cw) telegraphy,

the external power sources, the antenna system, and

the Radio Receive Transmitter RT-671/PRC-47 (A8).

2-1