Sony S530D manual Tracking Servo, Track Counting in Pause or Picture Jump

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Tracking Servo

The purpose of the tracking servo is to keep the laser beam positioned at the center of the disc’s data (stream). This is achieved mechanically by attaching a lightweight coil of wire to the laser’s objective (final) lens. This coil faces a stationary magnet. Voltage applied to the tracking coil moves the coil and its attached lens. The laser beam that passes through the center of the lens is moved with the lens from side to side.

The sources of the tracking coil signals are four detectors in the optical assembly base unit (E-H). These signals are matrixed by IC001 to make a tracking error (TE) signal. When the TE signal is connected to the tracking coil by IC701, the servo loop is complete and the servo is turned on. The laser beam is now locked to the stream of disc data.

Tracking Servo

The tracking servo in IC701 is turned on by IC202 after the second focus search while the disc is spinning. System Control IC202 must first com- municate with IC601, which relays that command to Servo IC701.

System Control IC202 Uses HGA IC601

IC202 sends a tracking servo on command using data on the parallel bus. The transfer of data must be supported by additional signals from IC202:

IC202 to IC601 Communications Signals

Signal

Active

Signal Present when

 

 

 

Chip Select (CS1 or CS4)

Low

IC202 and IC205 gets Vcc

 

 

 

Clock IC202/pin 5

Low

IC202 gets B+

 

 

 

Write IC202/pin 22

Low

IC202 and IC205 gets Vcc

 

 

 

Six Address lines HA 0-5

 

IC202 gets B+

 

 

 

16 Data lines HD 0-15

 

IC202 gets B+

 

 

 

65

HGA IC601 to Servo DSP IC701 Communications

IC601 controls many ICs. One of them is Servo DSP IC701. Communi- cations between these ICs use four control lines to transfer the address and data on the parallel bus:

IC601 and IC701 Communications

 

Name

From IC

When present

 

 

 

 

1.

Chip

System Control IC202

Power on/off, playback, tray

 

Select

 

open, close and start/stop.

 

 

 

 

2.

Read

System Control IC202

Always when powered on

 

 

 

 

3.

Write

System Control IC202

Completion of command

 

 

 

(PB, pause, pwr on/off)

 

 

 

 

4.

Interrupt

Servo IC701

Completion of command

 

 

 

(PB, pause, pwr on/off)

 

 

 

Address

Bi-directional

Always when powered on

 

 

 

Data

Bi-directional

Always when powered on

 

 

 

 

Servo IC701 turns on the tracking servo by completing the tracking servo loop. IC701 amplifies the tracking error signal input pin 69 and outputs it as a differential drive signal at pins 92 and 97.

Track Counting in Pause or Picture Jump

The new single DVD/CD laser still projects three light beams close to- gether on to the disc. However, the early electronics inside the optical assembly produce new tracking detector outputs (E-H) in addition to the standard A-D RF outputs. IC001 matrixes the E-H tracking outputs to produce:

TE = tracking error signal for the playback servo

TZC = tracking zero crossing signal from IC001/pin 32 to count tracks in pause or when approaching a disc destination.

Both of these signals are applied to IC701. When the tracking servo is turned on by IC202, IC701 is instructed to amplify (and LPF) the TE sig- nals from IC701/pin 69 and produce complementary signals at pins 92 and 97. The analog TZC signal at IC701/pin 20 is judged and sent to IC202 (via IC601) as digital track count information on the parallel bus. Driver IC801 just amplifies the input signal to drive the tracking coil.

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Contents Course DVD-02 Course Description and Troubleshooting Page Table of Contents Initial Sled Motor Drive Processing Laser Servo Test Mode KHM-220A DVD Optical BlockTroubleshooting Disc Identification Processing BlockVHS Introduction to the DTS Audio FormatDVD, LD DVD, LD, DTVCD/DVD Player What is DTS?What do I need to play the DTS surround format? Channel Receiver With DTS Decoder AC-3 DecoderCompression Can DVD movies contain both DTS and AC-3 audio tracks?How does DTS work? Adaptive Predictive Coding AdpcmCompression Block MultiplexerPacker Global Bit ManagementBoard Layout DVD Features DVPCommunications Block DiagramPower Supply Servo ControlBlock Diagram Video and Audio Processing ARP2Block Diagram Main Power Supply Power Supply BlockStandby Power Supply Power ConsumptionPower Supply Block Run Standby OscillatorStart Regulation ConceptStandby Oscillator Main Oscillator EnableRegulation Main Oscillator IC201 IC202 Communications Waveforms Power ControlPlug PcontPower Control Post Power on Check Power Control Parallel Data Communications BlockSerial Data Communications Block Interface IC201 Serial Data CommunicationsSerial Bus EEProm IC201Serial Data Communications Audio DSP IC501 Serial Data Communications Chip Select Line Parallel Data CommunicationsHGA IC601 Parallel Data Communication Communications from IC202 to Other ICs Communications from Another IC to IC202Parallel Data Communication Mechanism No Power Tray Removal From the BottomDisc Tray and Laser Platform Position Tilt Motor No Power Tray Removal From the TopSled Position Focus Coil LaserPower on Mechanical Sequence No Disc Power on Mechanical Sequence DVD Disc Page IC201 Turns On the Display Tray Motor DriveInterface Controller IC201 Recognizes the Tray Button IC201 Communicates with System Control IC202Tray Motor Drive Tray Position Switch Returns Information to IC201 Driver IC802 Translates the CommandIC202 Instructs Hybrid Gate Array IC601 Tray Motor Drive System Control IC202 uses HGA IC601 Initial Sled Motor DriveInitial Sled Movement HGA IC601 Instructs Servo DSP IC701Initial Sled Motor Drive Servo DSP IC701 Issues Analog Commands to Driver IC802 Sled Still Sled OutwardInitial Sled Motor Drive Sled Driver IC802 Sends Voltages to the Stepper Sled Motor Home Position DetectionSled Drive Mute/Inhibit Initial Sled Motor Drive HGA IC601 to Servo DSP IC701 Communications Laser ServoSystem Control IC202 and HGA IC601 Communications Servo DSP IC701 to RF Amplifier IC001 CommunicationsLaser Servo DVD Focus KHM-220A DVD Optical BlockCD Focus Three Laser Beams from One Laser Photo Detectors TE +, TZCPage Sacd Disc Type Disc IdentificationOperation Disc Identification Concept Search FocusServo Focus System Control IC202 to Servo IC701 Focus DriveFocus Search Communications System Control IC202 to HGA IC701Focus HGA IC601 to Servo IC701 SdcpsFocus Spindle Motor Kick ModeDVD Spindle Motor MDS CLV PB ModeMDP Spindle Motor Track Counting in Pause or Picture Jump Tracking ServoSystem Control IC202 Uses HGA IC601 Tracking Servo Sled Movement to Another Location IC Summary ChartSled Motor Drive PB Following the TrackSled Motor Drive PB Tilt to Mid Position Tilt ServoTilt UP ICs InvolvedTilt Servo Manually Driving the Tilt Motor Power OFFDVD Playback Tilt Servo Audio/Video Processing Block Process Blocks Processing RF Amp IC001Processing Flash ROM IC205 Video Process CH12O Converters IC902, IC905 IC907CH78O CH34OAudio Processing Test Mode Access Test ModeTests Test Mode Access Video Level Adjustment Additional Test ModeSelf-Diagnostic Function Customer Error Codes Clearing Emergency CodesPage Troubleshooting No Power onNo DVD OSD logo No DVD PB CD PB OKNo DVD DL PB other discs PB OK No Disc PB
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