Pioneer DEH-3770MP User Manual download pdf (Page 12)

234

CX-3158

1.2.4 Spindle servo system

In the spindle servo system, the following seven modes are available:

1) Kick

Used to accelerate the disc rotation in the setting-up mode.

2) Offset

a. Used in the setting-up mode until the TBAL adjustment completes after the kick mode.

b. Used when the focus loop is unlocked during the play mode and until it is locked again.

In both cases, the mode is to keep the disc rotation near to the appropriate one.

3) Applicable servo

In the normal operation, the CLV servo mode is used.

The EFM demodulation block detects through WFCK/16 sampling whether or not the frame sync signal and the inter-

nal frame counter output are synchronized, and generates the status signal based on the sampling result, synchro-

nized or non-synchronized. If eight consecutive "non-sync" signals are obtained, the system senses the status as "non-

sync". If not, the system senses as "sync". In the applicable servo mode, the leading-in servo mode is automatically

selected at the non-sync status, and the normal servo mode is at the sync status.

4) Brake

Used to stop the spindle motor.

In accordance with the microcomputer's command, the brake voltage is sent out from the servo LSI. At this moment,

the EFM waveform is being monitored in this LSI. When the longest EFM pattern exceeds a certain cycle (or the rota-

tion slows down enough), a flag is set inside the LSI, and the microcomputer switches off the brake voltage. If a flag is

not set within a certain period, the microcomputer shifts the mode from the brake mode to the stop mode, and keeps

this for a certain period. In the eject mode, after the mode is shifted to the stop mode and a certain period passes, the

loaded disc is ejected.

5) Stop

Used when the power is turned on and during the eject mode. At this moment, the voltage through the spindle motor

is 0V.

6) Rough servo

Used when the carriage is moved (or in the carriage move mode such as long search).

By obtaining the linear velocity from the EFM waveform, "H" or "L" is applied to the spindle equalizer. In the test

mode, this mode is used for grating confirmation.

Fig.1.2.9 Block diagram of the spindle servo system

DIG.

PWM

UPD63763GJ

DSP

BLOCK

EFM

SIGNAL

SPEED ERROR SIGNAL

PHASE ERROR SIGNAL

SOP

SOM

BA5835FP

SPINDLE

MOTOR

107

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Pioneer DEH-3770MP User Manual Page 12

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