Kenwood TS-60S Service Manual page 17

50mhz all mode

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CIRCUIT DESCRIPTION

8. Encoder circuit

The encoder is a mechanical one. The waveforms

frequency step is made coarse t o ensure smooth tun-

of the encoder pulses are rectified by IC3 and IC4

ing and frequency change. The minimum frequency

(TC4S584F) in the LCD assembly, and the number of

step is 5 Hz (50 Hz in FM mode); the maximum. 200 Hz

pulses is counted by the hardware counter in the mi-

(2kHz in FM mode). The frequency step is changed

crocomputer. The rotational speed of the encoder is

continuously according to the speed of rotation. (Fig.

detected. When the encoder is turned slowly, the fre-

18)

quency step is made fine; when it is turned quickly, the

5 v

M37702M4A

ENCODER

DIGITAL UNIT

LCDASSY

Fig. 18 Encoder circuit

9. Busy signal

11. Beep

The level of the port is monitored in receive mode,

The beep signal is generated using the timer in the

and busy indication and busy stop are performed dur-

microcomputer. The menu enable data (beep onloff.

ing scanning.

mode beep, warning Morse) is recognized, and the

necessary code is output. A dot lasts about 40ms; a

10. Dimmer control

dash, about 120ms. The oscillation frequency is about

The dimmer is controlled in five steps (including

1.4kHz.

OFF). The lamp is turned on or off by pin 7 of IC2 of the

switch unit. The brightness of the dimmer lamp is

determined by pins 5 and 6 of IC2. (Fig. 19)

Fig. 19 Dimmer control circuit