Kenwood TS-811A Instruction Manual page 28

430 mhz all mode transceiver

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tem, voice synthesis, etc. and accepts

interface with

the sub CPU or an external personal computers.

The sub CPU

interrfaces with the main CPU or the

MODEM IC, ІС19, to handles digital signal code conver-

sion and control tone ON/OFF and other such opera-

tion.

DCS system control section

The processing of the digital control signal used in the

DCS system is performed by the sub CPU, the MODEM

process IC (IC19: MN6127A) and IC18 (/РС4558С).

In transmission, first, the data (digital code, call sign) for

the control signal is trnsferred to the sub CPU from the

main CPU.

In the sub CPU, logic trnasforms that data

to NRZ (None Return to Zero) code, which is then out-

put to IC19.

It is subject to MSK (Minimum Shift Key-

ing) modulation at IC19.

Subsequently, that output is

input to Q4 in the AF unit via pin ANI and is applied as

FM modulation.

In reception, the signal which was subject to FM detec-

tion at discriminatro L34 in the IF unit is input to IC18

from ріп RT. ІС18, an active filter, cuts off the high fre-

quency component of this signal and also amplifies it

up to the proper input levei for IC19, and it is then out-

put to IC19.

At C19, it is subject to MSK demodulation to NRZ code

and is output to the sub CPU, in which it receives the

reverse logic operation to that in transmission and is

transferred to the main CPU.