LC78625 Просмотр технического описания (PDF) - SANYO -> Panasonic

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производитель

LC78625

Compact Disc Player DSP

SANYO -> Panasonic 

LC78625E

7. CLV servo circuit; Pin 13: CLV+, pin 14: CLV–, pin 15: V/P

Code

$04

$05

$06

$07

COMMAND

DISC MOTOR START (accelerate)

DISC MOTOR CLV (CLV)

DISC MOTOR BRAKE (decelerate)

DISC MOTOR STOP (stop)

RES = L

q

The CLV+ pin provides the signal that accelerates the disk in the forward direction and the CLV– pin provides the

signal that decelerates the disk. Commands from the control microprocessor select one of the four modes accelerate,

decelerate, CLV and stop. The table below lists the CLV+ and CLV– outputs in each of these modes.

Mode

Accelerate

Decelerate

CLV

Stop

CLV+

H

L

Pulse output

L

CLV–

L

H

Pulse output

L

Note: * CLV servo control commands can set the TOFF pin low only in CLV mode. That pin will be at the high level at all other times. Control of the TOFF

pin by microprocessor command is only valid in CLV mode.

• CLV

mode

In CLV mode the LC78625E detects the disk speed from the HF signal and provides proper linear speed using several

different control schemes by switching the DSP internal modes. The PWM period corresponds to a frequency of 7.35

kHz. The V/P pin outputs a high level during rough servo and a low level during phase control.

Internal Mode

CLV+

CLV–

V/P

Rough servo (When determined to be under speed)

H

L

H

Rough servo (When determined to be over speed)

L

H

H

Phase control (PCK locked)

PWM

PWM

L

• Rough servo gain switching

Code

$A8

$A9

COMMAND

DISC 8 Set

DISC 12 Set

RES = L

q

For 8 cm discs, the rough servo mode CLV control gain can be set about 8.5 dB lower than the gain used for 12 cm

discs.

No. 5502-14/35

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