GENERAL - TM-11-5820-670-300016

TM 11-5820-670-30

1-12. GENERAL.

This section contains information covering principles of operation of major electronic assemblies of

the receiver-transmitter, beginning with the receiver. Material is presented in functional block

diagram format, with supporting text which explains the operation of each electronic module in the

radio.

Details pertaining to operation of most individual components in each module are not discussed in this

section. instead, the text explains overall effect each module has on an incoming signal, and how the

module contributes to the operation of the radio. Individual circuit details are in the foldouts in the

back of this manual.

At the direct support maintenance level, electronic components within radio modules are not

replaced. Because of this maintenance approach, this section generally does not discuss the per-

formance of specific circuits and components such as diodes and transistors. In fact, it is not neces-

sary to understand how circuits in a module operate to effectively troubleshoot or aline it. However, it

is very important to know what a module actually does in order to perform signal checks at test points

for the purpose of testing, troubleshooting, or alining the module.

This section also explains the principles of operation of the control unit and discusses the flow of

signals between the control unit and the receiver-transmitter in various modes of operation.

To present the technician with an effective understanding of principles of operation, both simplified

and detailed signal flow of all operational modes is in this section. First, an overview or simplified

paragraph explaining signal flow for each mode is presented, followed by a detailed description of the

operation of the modules in the particular mode.

Certain modules in the radio set operate in more than one mode; therefore, these modules are

explained in paragraphs pertaining to the selected mode. This approach allows the technician to

follow the signal flow through the modules of the radio set in each mode without interruption.

Discussion of the radio set operating in the retransmit mode is limited to an explanation of the control

circuits when the radio is set for retransmit so as not to duplicate other areas of the manual. Explaining

the signal flow through the modules when the radio is set for retransmit is not necessary since the rf

flows through modules already discussed in the transmit and receive modes of operation.

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