Alignments(Not Applicable); Circuit Descriptions - Philips DVD580M Service Manual

8. Alignments
Not applicable.
9. Circuit description
9.1 System Block Diagram, Functions Of Circuit
Module And Signal Flow Of The Dvd Player
9.1.1 System Block Diagram
Control Keys
& VFD display
EEPROM Digital Decoder
SDRAM
Remote Receiver
FLASH Memory
Figure 9-1 System Block Diagram
Note: The system architecture in the frame above would be
remained the same in different design of DVD product.
9.2 Circuit Module Function And Signal Flow
• Disc Loader: The encoded digital signal storing in the Disc
(DVD, CD, VCD...) is to be picked up by the Disc loader
and transfer to the Digital Decoder for further processing.
The Loader is constructed by Optical pick-up, Driving
mechanism, Digital signal processor, and Servo controller.
• Optical pick-up unit includes Laser Diode and Lens, Light
to Electrical conversion circuit.
• Driving mechanism includes Disc loading mechanism,
Main Axis moving system, and the driving mechanism of
optical Pick-up unit.
• FLASH / EPROM memory is used to store the control
program.
• EEPROM is used to store the user information, such as
menu and function setup.
• The CPU loads the control program from the FLASH /
EPROM to control the hold system running.
• SDRAM is used to store the data stream, data renew and
data buffer.
• Digital decoder is functioned as data receiver and
selection, DVD data identification and data decryption,
Program data or system data de-multiplexing.
• Video Processor is used to import the data stream from
data buffer (SDRAM), hence perform the data decoding
and error correction, picture format conversion such as
Letterbox, Pan scan and Wide screen, and finally the
processed video data will be output to the NTSC / PAL
video encoder and other processing unit.
• Audio Processor: Digital audio data are fetched from
SDRAM and then to be decoded, the decoded data will be
loaded into the SDRAM buffer again, then to be switch to
Audio port or IEC-958 interface for further D to A
conversion.
Disc Loader Video Processor
Audio Processor
CPU
Power Supply
Units
CL 26532085_029.eps
Alignments
• VFD is used to display part of system information transfer
from CPU such as when loading the disc and playback
timing...etc.
• CPU is also responsible to the control signal from the
remote handset and performs the operation commanded
by the user.
• The Power supply unit provides to the system a stable
and continuous voltage and current for operation.
9.3 The Variance Of Hardware
• Variation A: DVD LOADER with mechanical structure,
Optical pickup system, Disc signal processor and Servo
controller.
• Variation B: DVD LOADER with mechanical structure,
Optical pickup system, the Disc signal processor and
Servo controller to be combined into decoder board.
• Variation C: Servo controller system is integrated into
Decoder IC chip set.
180702
9.4 Introduction Of Dvd Related Information
9.4.1 Format
• DVD Video: Normally Dual faces, used to store the Audio
and video program.
• DVD Audio: High definition Audio, the definition is double
higher than the Audio CD disc.
• DVD-ROM: Compatible with computer files format, used
for data storage.
• DVD-R: Similar to CD-ROM, can only be written once.
• DVD-RAM: Can be rewritten for 100k times.
• DVD-RW: Similar to DVD RAM, but can be rewritten more
than 1000 times.
9.4.2 Video Encoding
• MPEG1: Major technique include DCT (Discrete cosine
transformation), RLC (Run length coding), VLC (variable
length code), Motion compensation prediction (I, P, B
picture transmitting). The picture resolution and picture rate
are fixed.
• MPEG2: Same as MPEG1 but increase the data bit rate,
higher picture resolution. The picture definition is defined
as Main profile @ Main level.
• JPEG: Static picture with video compression coding
technique.
9.4.3 Digital Audio Coding
The audio processing technique applying in DVD movie is
Dolby Digital, DTS (Digital theater system, and MPEG2 audio
code). Different audio coding format provide different data
compression that is different amount of data will be transferred.
PCM (Pulse code modulation) use pulse with same amplitude
and pulse width to perform signal conversion.
9.4.4 Anti-pirate Copy Technique
• APS (Analogue protection system): Prevent pirate copy
from home use VCR --- Macro vision 7.0.
DVD580M 8. EN 45