Sony S530D manual CLV PB Mode, Mds, Mdp

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CLV PB Mode

In the CLV PB mode, IC001, IC303 and IC802 are used to regulate the spindle motor speed. System Control IC202 issues a CLV run command to IC303. By this time, the disc has reached data output speed so IC303 can use the data to govern the spindle motor. RF output from IC001/pin 54 is processed by IC303. IC303 compares the RF input to internal CD or DVD references and produces MDS and MDP spindle motor correction pulses. The correction pulses vary the speed of the motor so the RF disc data is always output at a constant rate. This is called constant linear velocity.

The following waveform taken during DVD playback shows that the MDP (ch 2) signals are periodic pulses that keep the disc spinning forward. The MDS (ch 1) pulses provide incremental speed correction in the form of 3V or 0 V pulses to speed up or slow down the motor. The combined MDP + MDS voltage at IC802/pin 26 is shown in channel 3. The feed- back signal (ch 4) is only present during a drastic spindle motor speed change, so it remains at 3V during DVD playback.

P M 3 3 9 4 , F L U K E & P H I L I P S
ch1
T
ch2
1
ch3
ch4
2
3
CH1!2 . 00 V=
CH2!2 . 00 V=
C H 3 ! 2 0 0 m V ~
CH4!2 . 00 V= CHP MTB50 . 0us	ch1+

Motor Drive Signals

	Name	Location		Voltage/div.
Channel 1	MDS	IC303/pin 49		2Vp-p
Channel 2	MDP	IC303/pin 52		2Vp-p
Channel 3	Composite	IC802/pin 26	0.2Vp-p (AC coupled)
	drive
Channel 4	Feedback	IC701/pin 65		2Vp-p
Time base		50usec/div.