Kenwood UD-300 Service Manual page 47

UD-300
CIRCUIT DESCRIPTION
Operating Mode Control
Electronic switches are used in the HA12157. Noise
reduction ON/OFF, C/B, and Multiplex ON/OFF signals
controlled by parallel data (DC voltage) and a switch
controlled by serial data are provided in the operating
mode.
Control Using Parallel Data
Dolby noise reduction and multiplex filter are controlled
by the input signal at pins@, @, and@.
MPX-OFF
Serial Data Format
An 8-bit shift register is used as the serial data format.
The shift register fetches CLK and DATA signals only
when the STB signal is high, then latches data at the
falling edge of the STB signal.
TAPE
SELECT 1
TAPE
SELECT 2
Ea Ae eae
| on | METAL NORMAL
TAPE L Twice normal speed selection
SPEED
Normal speed selection
METER Meter sensitivity improved by 20 dB
SENSITIVITY b
Meter sensitivity normal
INPUT
SELECT1
Mute
INPUT DAC5
SELECT 2 Enters the muting state when all bits are set high.
Playback mode selection R/L R-channel register selection
eee Control register selection Rees L | Volume register selection
* Whether to control the condition or volume control is judged by the
content of bit 7.
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