Philips CDR880 - Introduction to CD Recording Systems; CD-Recording System Overview; CD-R;RW vs. Pre-recorded CDs; CD-Recording System Requirements

BASICS CDR/RW
1. Introduction
1.1. The CD-Recording system
The CD-Recording system consists of a CD-Recorder/player
and the exchangeable software carrier CD-Recording disc.
Most known CD systems, like CD-Audio, CD-ROM, CD-I
CD-ROM XA, Photo CD, Video CD are pre-recorded systems,
and lack the facility of recording as enjoyed by tape systems.
This CD-Recording system addresses this deficiency.
Dependant to the applied disc carrier two different solutions
are in use: CD-Recordable and CD-ReWritable.
CD-Recordable (CD-R), a so-called Write-Once principle, has
the advantage of full compatibility with all pre-recorded CD
systems.
CD-ReWritable is able to write, read and rewrite
CD-ReWritable discs (CD-RW). CD-RW discs have a lower
reflectance than standard CDs and therefore cannot be
played-back by all today's CD players.
Above that both recording disc systems can be split to a
Professional application (e.g. CD-ROM) and a Consumer
(Audio) application.
Both applications have their own CD-Recordable and
CD-ReWritable discs with appropriate logo, to comply with
copyright legislation in various countries. The Audio
CD-Recorder/player will only make recordings on CD-R and
CD-RW discs bearing the appropriate ‘Digital Audio’ logo.
These discs are subject to levies that are payable to the
relevant copyright protection associations.
Concerning the lower reflectance of Audio CD-RW discs:
For CD-Audio players, from production 1998 onwards, Philips
intends to extend all her future CD-Audio players so that they
will be able to play Audio CD-ReWritable discs.
With the introduction of the CD-R/RW Audio Recorder at the
end of 1997 both recording functions (Recordable and
ReWritable) are combined in one Audio CD-Recorder/player.
This description assumes the knowledge of the conventional
CD-Audio system.
1.2 The most important differences between CD-R/CD-RW
discs and pre-recorded CDs.
The main physical difference between CD-R/CD-RW disc
types and the pre-recorded CD is that the latter has no
recording layer; the information is permanently stamped in the
aluminium reflecting layer.
There is also a difference in terms of the data areas on the
disc. Compared with standard CDs, there is a CD-R/CD-RW
area that is located in front of the Lead-in Area. This
additional area is used to store data specific to the recor-
ding process and is divided into the Program Memory Area
(PMA) and the Program Calibration Area (PCA). In chapter 2.5
Data Organization these areas are explained in more detail.
As long as recordings are made on the disc the Lead-In Area
is not filled. At the moment the recording disc is converted
into a standard CD-format, the PMA information is recorded in
the Lead-tn Area. This process is called ‘Finalizing’, because
after this procedure no more recordings on this disc can be
made.
1.3. The requirements for the CD-Recording system
The most important requirement for the CD-Recording system
is to be compatible with the conventional CD-Audio system.
The CD-Recording system has an added advantage to make
an incremental recording. This means that a recording
session can be interrupted at any time, and can be continued
at a later time, possibly using a different recorder. The
successive parts of information are recorded sequentially on
the disc.
The Audio recorded disc is compatible with the CD-Audio
system.
This is only true for the fully recorded CD-R disc, which
means that the Lead-In Area has been recorded after the
recording of the last track of the disc (Finalizing). For
‘finalized’ CD-RW discs (reflection) adapted players will play
back these discs only.
The blank CD-Recording disc contains a sensitive layer of a
material which has a reflection decrease if an effect (called a
pit) is recorded by heating up the sensitive layer locally. The
requirements for the recorded signals as well as for the rest of
the disc parameters are basically the same as the CD-Audio
system.
In other words, the CD-Recording system is’ fully compatible
with the conventional CD-Audio system.
The Audio CD-Recorder/player is a CD-Audio player with the
following basic functions:
- It can play back a disc of the existing CD-disc standard,
so itis a player which is compatible with the Compact Disc
system.
- It makes recording on the recording disc according to
CD-Recordable or CD-ReWritable standard possible.
- It enables to play back a partially recorded disc.
- It records additional tracks on partially recorded disc.
- It makes a fixing up of a recorded disc to a compatible
disc of the existing CD-disc standard (Finalizing).
Other main parameters are:
- Recording/playing time is equal to normal CD
(max. about 74 minutes).
- Scanning velocity of the laser spot:
Constant Linear Velocity (CLV) is 1.2 to 1.4 m/s.
- Disc diameter is 120 mm.
- CIRC/EFM encoding.
- Track pitch is nominally 1.6 um. The Program Area is
recorded between 50 and max. 116 mm diameter.
- Audio encoding: 2 channel stereo, 16 bit quantization,
44.1 kHz sampling frequency.
- Data encoding: block encoding with approximate user
data transfer rate of 1.4 Mbit/s.
All these parameters are a contribution to guarantee the
exchangeability between all Compact Discs and
CD-Recording discs recorded on other CD-Recording players.
The CD-Recording disc has to meet with the mechanical and
optical specifications lay down in the CD-Recordable and
CD-ReWritable standard.
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