Sony DNW-A75 Maintenance Manual page 233

The inputted digital audio signals (CH1/2 and CH3/4) from the AUDIO INPUT (AES/EBU) connectors
(on the CP-335 board) are sent to the APR-40 board and decoded to serial digital audio data by the AES/
EBU decode block. The decoded signals are then sent to the audio processing block. By setting the setup
menu, the decoded data can be converted into the internal clock rate by a sample rate conversion block
and sent to the audio processing block.
The inputted SDI signal from the SDI INPUT connector is sent to the SDI-41 board and converted from
serial to parallel. After that, in the SDI Decode Process block, an SDI audio signal is converted into serial
digital audio data and extracted a control signal (channel status bit). The serial digital audio data is sent to
the audio processing block on the APR-40 board.
In the audio processing block, input signals for recording are selected from a 12-channel input signal
consisting of three lines (analog audio, AES/EBU, and SDI audio) described above, and REC gain
control, channel mix/mute control, and data delay control are performed in this case.
The audio recording data (four-channel) output from the audio processing block is sent to the ECC
encode block on the DPR-118 board.
Betacam SX PB system
The PB audio data that was ECC-decoded by the outer ECC decode block on the DPR-118 board is input
through a VAR x2 process block to the DSP block for audio processing.
In the DSP block, five-field sequence processing (in 525/60 mode only) and JOG/VAR control are carried
out. After that, the PB audio data is sent to the audio processing block on the APR-40 board as serial
digital audio data.
Analog Betacam PB system
A longitudinal audio (CH1 and CH2) PB signal is sent to the AU-260 board and fed through the PB
equalizer circuit and the PB amplifier to the Dolby C noise reduction block for Dolby noise reduction.
After that, the PB signal is sent to the APR-40 board as CH1 and CH2 of an analog Betacam PB audio
signal.
The C RF signal containing an AFM signal is sent from the DM-89 board to the AU-260 board. The C RF
signal is passed through a low-pass filter to extract the AFM signal. After the AFM signal is converted
from analog to digital, it is passed through the AFM TBC block and FM-demodulated by the AFM
demodulation block. The AFM TBC block corrects a time base.
The demodulated audio signal is sent through the noise reduction block to the APR-40 board as CH3 and
CH4 of the analog Betacam PB audio signal.
Output system
In the audio processing block on the APR-40 board, PB/EE signal selection control, PB gain control,
monitor output selection, and data delay control are performed. The four-line serial digital audio data for
SDI output, line output (analog), line output (AES/EBU), and monitor output is output from this block.
The serial digital audio data for SDI output is sent to the SDI-41 board and converted into the SDI audio
signal by the SDI Encode Process block. The converted data is then multiplexed with video data. The
resultant data is converted from parallel to serial and output from the SDI OUTPUT connector on the
connector panel as the SDI signal.
The serial digital audio data for line output (AES/EBU) is encoded to an AES/EBU format by an AES/
EBU encode block and output from the AUDIO OUTPUT (AES/EBU) connector (CP-335 board) on the
connector panel.
The audio signal data for line output (analog) and monitor output is oversampled by a digital filter and
converted from digital to analog. The data is then de-emphasized and output from the connector panel (on
the CP-278 and CP-301 boards).
After the audio signal data for monitor output is also de-emphasized, it is sent to the VR-223 board for
headphone output. The data is level-controlled on the VR-223 board, and then output.
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DNW-A75/A75P