Kenwood AT-440, PS-50, SP-430, PS-430, MB-430 Circuit Description, FULL/SEMI BREAK-IN timing char t

TS-440S

FULL BREAK-I N

H

AL

BL

CIRCUIT DESCRIPTION

1

KEYING I N

C

D

E

L

H

L

H

L

KEYING OU T

F	L
G
	L
	H
H	L	CONTROL OU T
SEMI BREAK-IN, VO X
A	L	KEYIN G	I N
		VOX
	H
	L	CONTROL OU T
F	L
J	H	KEYING OU		T
		VOX

Fig . 9-3 FULL/SEMI BREAK-IN timing char t

The above timing charts show the timing for standby an d keying signals .

When an input from the CW key is supplied to point A as shown in the above figure during full break-in operation , the one-shot multi-vibrator and gate circuits generate con - trol (full) and delayed keying (full) signals . After the fun- damental timing signal, RL (12V) for reception an d transmission rises, the keying wave also rises, and whe n the key is off, RL falls according to the preset tim e constant .

Semi-break-in operation is synchronized to VOX . When a signal is supplied to point A, the VOX delay time multi -

ing the slide switch . The control signal is checked by the microcomputer to see whether transmission is to be per - formed . The control signal is then used to switch CRL i n the IF assembly unit and generate RL (12 V) . TXB (trans- mit B+) (8 .8 V) is generated, synchronized to RL . Th e receive control signal RXB (receive B+) (8 .8 V) turn s on/off, synchronized to the inverted TXB signal, that is, RL .

12 V

RL

8 .8 v

vibrator determines the VOX time constant . The input sig- nal is converted to a keying (semi) signal by the gate circuit .

TXB

RXB

8 .e v

These keying semi/full and control semi/full signals ar e converted to appropriate break-in VOX mode signals us -

Fig . 10 STANDBY keying timing char t

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