Philips CDR880 Service Manual page 52

6
BASICS CDR/RW
Apart from this time, ATIP contains:
- An approximate value of the laser recording power for the
disc.
- The last possible start time of the Lead Out Area (see
paragraph 2.5.5).
- The Disc Application Code, which distinguishes between
discs used for different applications:
1: 'Discs for restricted use'
(professional use).
2: 'Discs for unrestricted use'
(consumer use).
2.4 The requirements for the CD-Recording discs
2.4.1. The unrecorded (blank) disc
Most disc and signal parameters of the unrecorded
CD-Recording discs are identical to the corresponding
parameters for conventional CD. The main additional
requirements, related to the recording capability of the disc,
are in the write condition the optimum recording power and
the wavelength of the recording spot. The reflection in the
unwritten part should be approx. 70%.
2.4.2 The recorded disc
The recorded disc fulfils all requirements of conventional CD
system.
The main additional requirements, related to the recording
capability of the disc are in the read condition the normal
reading power and the wavelength of the recording spot.
The reflection of the land should be approx. 70% and the
written part (pit) should be approx. 30%. It is about this
reflection the CD-ReWritable disc is deviating from the
original standard. Updating of standard has been realized, CD
players have to be adapted accordingly.
2.5 Data Organization
The CD-R disc is divided into five different area's. This chapter
describes what the purpose of each area is, which data
should be recorded in it, and in what sequence the data
should be recorded. The five different area's, from inside to
outside diameter are (see figures 1 to 3 and 10):
- Power Calibration Area (PCA).
- Program Memory Area (PMA).
- Lead In Area.
- Program Area.
- Recordable User Area + Lead Out Area.
PCA
Test_Ares in Count_Ame PMA In_ Area
ee" © Ee,
Lit | Pha dd Wd HU |
Partition | 100 98 4321 98 531 | | |
Figure 11
Organization of the PCA, PMA and Lead In Area
On this disc there is an incrementally, partially recorded CD-R
disc. The hatched area's are recorded parts of the disc.
Since Incremental Recording (or interrupted recording,
see chapter 1.3 "The requiremenis for the CD-Recording
system") is possible, there are requirements for the linking of
the different successive recordings.
Also there are requirements for the synchronization between
the ATIP time in the groove, and the time encoded in the
recorded data.
To prevent misrecordings some hints are given at the end of
this chapter.
2.5.1 Power Calibration Area
The PCA is reserved for obtaining the exact optimum recor-
ding power for the disc. Using the exact laser recording power
improves system margins. At the start up of a recording
session, the recorder checks in its memory whether it has
already determined the exact power for this particular disc.
If not, the procedure for determining the exact power is
started.
The PCA is divided into two area's (see figure 11):
1: The Test Area, in which test recordings with different laser
powers can be done.
2: The Count Area, which is meant for fast and reliable read
out of the part of the Test Area that should be used next.
In total 99 testrecordings can be carried out per disc.
2.5.2 Program Memory Area
In case of Incremental Recording, it is necessary to have an
area in which the track data (e.g. start addresses) of the
already recorded tracks can be noted temporarily.
When a new recording session starts on a partially recorded
disc, all necessary data can be read from this PMA (see
figure 11).
The PMA may contain three types of data:
1: Track numbers with their start and stop times. This is the
temporary table of contents for the partially recorded disc.
2: Disc Identification. A six digit number can be noted in the
PMA to identify each individual disc. This identification
number can be used e.g. to avoid repeated fixing of the
optimum recording power (see paragraph 2.5.1 "Power
Calibration Area").
2.5.3 Lead In Area
The description of this area is basically the same as the one
used in conventional CD. It contains the Table of Contents of
the finalized recorded disc. Additionally, some extra informa-
tion like the identification of the disc might be encoded.
2.5.4 Program Area
This is the area where the Audio tracks have been recorded
(see figure 2 and 3). The specification of this area is basically
the same as the one used in conventional CD. Only the Copy
bit is used to indicate a first or higher generation copy of a
Copyright protected track.
2.5.5 Recordable User Area + Lead Out Area
The Recordable User Area is the remaining unrecorded
(blank) area of the disc where additional tracks can be
recorded (see figure 2). The Lead Out Area marks the end of
the Program Area. The specification is basically the same as
in conventional CD's.
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