Clv Pb Mode - Sony DVP S530D Training Manual

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
c h 1
T
c h 2
1
c h 3
c h 4
2
3
C H 1 ! 2 . 0 0 V =
C H 2 ! 2 . 0 0 V =
C H 3 ! 2 0 0 m V ~
4 C H 4 ! 2 . 0 0 V = C H P M T B 5 0 . 0 u s
Motor Drive Signals
Name
Channel 1 MDS
Channel 2 MDP
Channel 3 Composite
drive
Channel 4 Feedback
Time base
c h 1 +
Location Voltage/div.
IC303/pin 49 2Vp-p
IC303/pin 52 2Vp-p
IC802/pin 26 0.2Vp-p (AC coupled)
IC701/pin 65 2Vp-p
50usec/div.
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