PHILIPS DVD-R985 tm.pdf
(
2664 KB
)
Pobierz
dvdr985.qxd
Philips DVDR985
Technical Training Manual
Philips Service and Quality/Training
One Philips Drive
Knoxville, TN 37914-1810
P. O. Box 14810
PH: 865-521-4397
FAX: 865-521-4818
EMAIL: TECHNICAL.TRAINING@PHILIPS.COM
Introduction
DVD Basics
This Manual is intended for use by the Service
Technician. The first portion of this manual con-
tains a basic description of disc based data play-
back and recording technologies. Self
Diagnostics are included to aid in troubleshoot-
ing. Technical Descriptions of the circuitry is fol-
lowed by a Troubleshooting Section.
Philips with nine other manufacturers chose a
format specification for DVDR and RW on March
16, 2001. This new format uses Real Time
recording. Its recording is compatible with DVD-
Video, and DVD ROM. The data blocks use loss-
less linking. The physical layout matches very
closely that of DVD ROM. See
Figure 1
. It also
uses Direct Overwrite when a RW disc is used.
The DVDR985 is the forth in a line of DVD
recorders. The DVDR1500 was the first.
Recordings can be made from broadcast trans-
missions, and from other analog or digital
sources. The DVDRW format allows the user to
record and erase a disc many times. The record-
ed discs will play on most existing and future
DVD players. The DVDR985 has a connection
for DV or Digital camcorders via an I-Link or
Firewire connection. This connection technically
is called an IEEE 1394 connection. This machine
records on 4.7Gbyte DVD+R and DVD+RW
discs. This machine uses a real-time MPEG2
Variable Bit Rate, VBR, Video encoder. The
DVDR985 plays back DVD Video, Video CD,
Audio CD, CD-R, and CD-RW discs.
Laser Technology
CDs use a red laser created by a diode and lens
system often called a Light Pen. Refer to
Figure
2
. The narrow beam of light is focused onto the
reflective layer of a disc. At the instant that focus
is achieved, the disc is spun. The laser starts on
the innermost tracks of the CD and reads out-
ward. At the beginning of the disc is the Table of
Contents. At the bottom of the Light Pen are
Monitoring Diodes. The Monitoring Diodes pro-
vide information about focus and tracking. Data
is retrieved from the disc in the form of pulses of
Its many features include: Favorite Scene
Selection for easy editing, Index Picture Screen
for instant overview of contents, Digital Time
Base Correcter, Digital Audio output (DTS, AC-
3, MPEG, PCM), TruSurround for 3D sound,
Zoom + Perfect Still. It is Widescreen, 16:9
compatible, and has a Universal Remote
Control, 20 disc resume, Disc Lock, and One
Touch Recording.
Virgin Mode
The DVDR985, when first hooked up, needs to
get information from the user about what lan-
guage and what local broadcast system the
unit is going to operate with. Use the remote to
make those selections. The unit will not operate
until this process is completed. If you want the
recorder to start up in Virgin mode, unplug the
recorder. Plug the recorder in again while hold-
ing the STANDBY-ON button.
Fig
ure
1
–
DVD R
O
M
Di
s
c
1
Figure 2 – CD Laser Operation
light reflecting from the disc. The pulses are
created by Pits in the Reflective Layer of the
disc. The Pits reflect less light than the intact
surface of the Reflective Layer, called Lands.
Disc Mechanical Layout
The DVD and CD share much of their tech-
nology. We will start with CDs and work our
way to the DVD. The CD is a plastic disc
120mm in diameter, with a thickness of
1.2mm.
Refer to Figure 3
. It has a silver col-
ored Reflective Layer. The maximum playing
time for a music recording on a Compact
Disc, CD, is 74 Min.
The CD is less vulnerable to damage than an
analog record. That does not mean it does
not have to be treated with care. Dirt and
heavy scratches can interfere with playability.
Figure 3 – Mechanical Layout of a CD.
2
Figure 4 - The Disc
As shown in
Figure 4
, the CD is subdivided into
three parts: the Lead In Track, the Program
Area, and the Lead Out Area. These three sec-
tions together are considered the Information
Area. There is a hole in the center for holding
the disc. The disc is held between two equally
sized concentric rings. The rings have an inner
diameter of 29mm and an outer diameter of
31mm.
The production of a disc is a high tech process
explained in
Figure 5
. The process starts with
glass that is photo etched. The glass is silver
plated and is used as a form for a metal cast.
The metal cast is used to stamp a nickel Mother
Stencil. The Mother Stencil is used to stamp the
Son Stencil. Son Stencils are used to stamp the
foil of the discs. A protective layer and label are
added.
The Data on the disc is recorded on a spiral
shaped track with pits and lands. The reflective
side of the disc contains the tracks.
Read Process
The Servo circuit is responsible for focusing the
laser and moving the Light Pen to follow the spi-
raling tracks on the rotating disc. The digital High
Figure 5 - Creating a CD
3
Frequency information, HF, is demodulated and
stored in RAM. When the RAM is half full, the
data is fed out to the Digital to Analog
Converters. The speed of the rotating disc is
servo controlled to keep the RAM half full. The
analog signals are amplified and sent to the out-
put connectors.
A partially recorded disc’s Information Area has
four sections: a PCA/RMA area, a Lead In Area,
a Recorded Program Area, and a Recordable
Program Area. See
Figure 6
for the dimensions.
The PCA Area is the Power Calibration Area,
PCA. The RMA Area is the Recording
Management Area.
Figure 6 – A Partially Recorded Disc.
Record Once Technology
A fully recorded or finalized disc’s Information
Area has three sections: A lead in Area, the
Program Area, and the Lead Out Area. See
Figure 7
for the dimensions.
Disc Mechanical Layout
From an external point of view, a DVD is the
same as the CD. Recordable media creates the
need for three physical layouts. There are three
possible states of a disc: a blank disc, a partially
recorded disc, and a full or finalized disc. The
difference is in the way the Information Area is
divided. The Information Area of a blank disc
extends from 22.35 mm centered on the disc to
59 mm centered on the disc. Refer to
Figure 6.
The disc’s recordable layer contains major differ-
ences from that of a stamped disc. The blank
disc has a Pre-groove stamped into the record-
able layer of the disc. This is polycarbonant for
DVD+Rs and organic dye material for
DVD+RWs. This spiral Pre-groove is for the
Servo circuit to provide a mechanical reference
Figure 7 – Fully Recorded or Finalized Disc
4
Plik z chomika:
Marpor
Inne pliki z tego folderu:
PHILIPS VR666 668 768 967 969.pdf
(30036 KB)
PHILIPS DVD-R985 tm.pdf
(2664 KB)
Inne foldery tego chomika:
Grundig
Panasonic
Samsung
Thomson
Zgłoś jeśli
naruszono regulamin