Philips CDR Mozart Service Manual page 54

GB 54 9. CDR Mozart
9.8 Supply Part
Input for the module is +5V and +12V by means of connector
1214.
• +12V is used to make -12V supply by means of 7202.
• -12V is used to make -8V (pos 7200) and -5V (pos 6202).
• -8V is used for supply of opamps in the audio main board
• -5V is used for KILL circuitry.
• +12V is used to make analog 8V supply (pos 7201). +8V
is used for opamp supply
• +5V analog is derived from +8VA (pos 6204) and used
for ADC, DAC and Potmeter.
9.9 Analog Back-End
9.9.1 Analog Out
IIS data from Mozart is converted to analog signals through
DAC 7311. All DAC_IIS signals are generated by Mozart.
Analog outputs from the DAC are differential, which means
that both + and - output contain the same signal but with a
phase shift of 180 degrees.
Mozart resets the DAC by means of RST_ADDA.
MUTE is high active and controlled by Mozart.
DAC_DEEPI is activated (high) by Mozart when IIS data has
pre-emphasis.
Masterclock (DAC_CLK16) is delivered by Mozart (16MHz)
Opamp 7300 acts as a differential amplifier and filters Digital
to Analog rubbish from the Audio frequency band.
Transistors 7303, 7304, 7309 and 7310 are used to kill the
audio output to prevent Power on/off "PLOPS".
After the Kill transistors, audio output goes to connector
1402.
The KILL circuit (pos 7404, 7307, 7308, 6315) ensure that
the kill transistors are activated at power on and power down.
9.9.2 Analog IN
Analog audio signal comes from connector 1402. After
buffering (pos7400) and divide by 3 (pos 3400/3403, 3405/
3408), signal is fed to pos7402 Digital potmeter.
The potmeter has a "H" and a "L" input (pin 11/10 and 8/7).
For correct functioning of the potmeter, the "L" inputs must be
half the supply voltage (+5V).
Opamp 7400 outputs a stable DC voltage of 2.5V as
reference voltage for the potmeter.
The potmeters attenuation is selectable via I
and can be set from 0 to -64dB. The attenuated signal is
output on pins 9 and 6. After an amplification by 3 (pos 7401),
signals go to analog switch 7301.
The switch is controlled by Mozart and selects the input for
the ADC. Input can be either external audio (POT_LEFT and
POT_RIGHT) or internal audio (from DAC, DAC_LEFT and
DAC_RIGHT).
The ADC converts the analog signal to digital and outputs
data on IIS. ADC also generates BCLK and WCLK.
RST_ADDA is the reset and generated by Mozart.
Masterclock (DAC_CLK16) is delivered by Mozart (16MHz)
9.9.3 Kill-Circuit
This circuit is necessary to avoid PLOP-sounds while
powering on/off the CDR player.
The Mozart can also steer the kill-circuit.
9.10 Sort Applications
The Mozart back-end can be used in different applications.
Herewith different audio outputs are used.
These outputs are combined to a separate I/O-board via
connectors.
Circuit Description
9.10.1 Mini/Micro
CDR-
device
CD
9.10.2 Separate
CDR-
device
2
C commands
CDR-
device
CD
With this type of application, connectors 1402(analogue) and
1203(digital) are combined to an I/O-board.
The Mozart has the possibility to export every incoming
signal(CDR or CD-device) to the outputs, this is valid
for IIS and EBU.
BLock Diagram Mini/Micro.
IIS
EBU
EBU
EBU coax
EBU ext
EBU Mozart
IIS
DAC
IIS
ADC
Figure 9-15
Single Deck
This type of application is the same as Mini/Micro, only it is a
single deck with a CDR-device.
Block Diagram Single Deck.
IIS
EBU
EBU
EBU coax
EBU ext
Mozart
IIS
DAC
IIS
ADC
Figure 9-16
Double Deck
This type of application has the same possibilities as the
single deck, only here we have an extra cd-player
which we can use for making internal copies on double
speed.
There is also a DJ-mode, where we export the IIS-bus of the
CDR-device to steer an external DAC, EBU is
exported via the same connector.
Analogue and digital signals of the cd-player are exported via
the Mozart to the I/O-board.
Block Diagram Double Deck.
IIS
EBU
EBU
EBU
EBU coax
EBU ext
EBU Mozart
IIS
DAC
IIS
ADC
Figure 9-17
Conn.
coax
Digital
1203
ext
Conn. Analogue
1402
CL 16532046_038.eps
040701
Conn.
coax
Digital
1203
ext
Conn. Analogue
1402
CL 16532046_039.eps
040701
To external DAC
Conn.
1215 for DJ-mode
Conn.
coax
Digital
1203
ext
Conn. Analogue
1402
CL 16532046_040.eps
040701