Chapter 2. FUNCTIONING OF EQUIPMENT - TM-11-5895-1141-340012

TM 11-5895-1141-34

CHAPTER 2

FUNCTIONING OF EQUIPMENT

Section I. FUNCTIONAL DESCRIPTION

SECTION CONTENTS

PAGE

General

Functional Description of Major Circuits

2-1. GENERAL

The C-10931(P)/FRC includes three major units:

a. Headset/Microphone Jack Panel

b. Audio Unit

c. Selector Unit

These units are housed in an aluminum chassis (fig. 1-1) and are removable from this chassis.

The system comprises a complete radio control operator's position with the capability of controlling from 1 to 8 radio

channels. This chapter contains first, a brief functional, block diagram description of the system operation, followed by a

more detailed theory of operation of the circuitry within the system.

2-2. FUNCTIONAL DESCRIPTION OF MAJOR CIRCUITS

What follows is a working description of the major blocks that constitute the radio channel control system. They are: dc

power distribution, transmitting circuits, keying and interlock circuits, receiving circuits, telephone interface, recorder-mixer

and monitor, and lamp display.

a. DC Power Distribution. Refer to figure 2-1 and figure FO-1. Power for the system is obtained from a regulated dc

power supply (not furnished) which delivers +24 vdc via pin A of connector J105 located in the rear of the audio unit to

power switch S101 and fuse F1201 located on the front panel of the microphone amplifier/lamp brightener module

assembly. The fuse holder XF1201 contains a built-in incandescent lamp DS1201 which glows if the fuse opens. From

the fuse, power is distributed to the voltage regulator in the microphone amplifier/lamp brightener assembly and the other

modules via connector J106. A filter consisting of choke L101 and capacitor C101 provides filtered 24 vdc to the headset/

microphone jack panel assembly as well as the amplifiers on all the modules. The output voltage of the lamp bus

regulator circuit is set by

2-0