Philips CDR880 - CD-Recordable;ReWritable Audio Recorder Overview; Recorder Block Diagram Explanation

BASICS CDR/RW
3 The CD-Recordable/ReWritable Audio Recorder
3.1. Blockdiagram of a CD-Recordable/ReWritable Audio
recorder
RECORDING
AID
bel LEVEL CONVERTER
CONTROL SAA7366
DIGITAL
INPUT SAMPLE RATE
COAXIAL CONVERTER
OPTICAL
DIGITAL ToA1315 DIGITAL
OUTPUT INPUT/OUTPUT
INTERFACE
COAXIAL
OPTICAL
D/A
CONVERTER
TDA1305
| pt osrapar | |
COMPACT DISC
ENCODER
TDA1371 CDR
CDRW
DRIVE
DISPLAY
KEY MASTER
IR-REMOTE uP
uP
OPTICAL
RECORDING
UNIT
CDM36
COMPACT DISC
DECODER
CD60
Figure 13
Blockdiagram of a CD-Recordable/ReWritable audio recorder
The Recording signal in above drawn simplified biockdiagram
is moving according to the following steps.
Starting at the analogue input side:
- the Analogue input signal to
- the RECORDING LEVEL CONTROL unit and then via
- the Analogue/DIGITAL CONVERTER the analogue signal
will be transformed into a digital signal (sample frequency
44.1 kHz) and this digital signal is forwarded via
- the General Digital Input (GDIN) to
- the Datapath bus (I78).
The digital input connects the electrical and optical signals
directly to the:
- the General Digital Input (GDIN) where via the internal
Sample Rate Converter the digital signal is adapted to the
CD sample frequency (44.1 kHz) and after that forwarded
to
- the Datapath bus.
Via the Datapath bus the digital signal is connected to
- the Compact Disc Encoder, which transforms the signal
into EFM format. The EFM signal is forwarded to
- CDR/CDRW Drive unit with optical recording unit (CDM
= CDMechanism). In recording mode, but also in play
mode this drive is controlled by
- control pProcessor (Servo microcontroller) which on its
turn is actuated by
- the Master pProcessor (System controller). This processor
co-ordinates all activities which are started by the user via
- the Front Keys and/or IR Remote control signals and the
results are displayed on Display unit. These activities are
processed by a slave pProcessor (user microprocessor)
on the display board and the slave pProcessor communi-
cates with the Master uP.
In Play mode the signal flows as follows:
- From CDR drive the EFM signal read from disc is
forwarded to
- Compact Disc Decoder and decoded digital signal is
forwarded via
- the Datapath bus (I7S) to
- Digital/Analogue Converter (Analogue output) or via
DOBM IEC958 format to
- Digital and Optical out connector.
Monitoring the audio recorded signal is only possible via the
electrical input circuits until Datapath bus and than the output
Circuit.
Notice that the recorded signal on the disc is not “monitored.
From each input signal there is immediately a digital
output signal available at digital out.
The blocks of blockdiagram of figure 14 are gathered in the
Basic Engine part with the CDM, servo drivers, Basic Engine
uProcessor (or Servo Processor), encoder, decoder and the
loader unit and the User part is consisting of input and output
datapath and User pProcessor (System controller) unit.
The Display part contains the keys & display with slave pP.
The I/O part contains the connectors on the connector board
and the Power supply supplies.
For servicing reasons the CDM Loader Module consisting of
loader, CDM, CDM board and Main board is treated as one
central repair module. Local repairs on component level can
be executed on Power supply, I/O connector and Display
boards. See next drawing fig. 14.
PHILIPS
Service disc systems