Sony S530D manual Photo Detectors, Te +, Tzc

Photo Detectors

The three beams of light are reflected from the disc and returned to the optical assembly. They land on the photodetectors within these three groups.

E F

AD

C B

G H

KHM - 220AAA

PHOTO DETECTORS

The voltages from these detectors are matrixed by RF Amplifier IC001 that follows (on the TK-51 board) into servo correction and disc identifica- tion signals.

51

Photo Detector Manufactured Signals

Photo	Signals	Purpose
Detectors	Produced
A – D	TE (DVD only)	TE – DVD tracking error
	FE, PI, Mirr., RF	FE – Focus error
	(eye pattern)	PI – “Pull In” is the analog sum of A-D
		detectors used to ID the disc and
		create MIRR.
		MIRR – mirror signal goes high (4V) if
		PI is above a threshold. MIRR is used
		to count tracks and ID the disc.
		RF – Audio and Video Data
E, F *	TE +, TZC	CD Tracking error, track count.
G,H *	TE –, TZC	CD Tracking error, track count

*In CD and older DVD players, there are only two outer tracking error detectors (E & F). In this new laser assembly, two outer detectors were added but they are not used in this player.

The extra detectors are to permit this laser assembly to read DVD-R discs in future players. This DVD player cannot play DVD-Recordable discs even though the laser has the ability to do so. Detectors E & F are added together and treated as one. G & H detectors are also added in the matrix / RF amp IC001 that follows (not shown).