Sony DNW-7 Maintenance Manual page 79

(3) Audio system
(AXM-14 board (1/2), CNB-1 board (1/2), TC-80
board (1/2), RX-26 board, MA-68 board and
AIF-8 board)
The audio system of the Betacam SX recorder has the
configuration of the four input channels and the two output
channels.
The CH-1 and CH-2 have the "AUDIO IN" switches
which select their input signals from either the LINE/MIC
input (rear input) signals coming from the XLR connectors
on the rear panel, or the camera MIC input signal (front
MIC input: CH-3) coming from the camera, or the wireless
audio input signal (CH-4) coming from the slot-in wireless
receiver, to be recorded on tape.
The selected input signal is A/D converted and sent to the
audio data processor as the AU A/D data (1/2 and 3/4).
The output signal from the audio data processor is D/A
converted. The CH-1 and CH-2 signals are output from
the 5-pin XLR connector.
The earphones and internal speakers have the "MONI-
TOR" switch which selects either CH-1, MIX, or CH-2
signal to be output the earphones and internal speakers.
DNW-7/90/90WS
(4) System control
(DVP-1 board (2/2), TC-80 board (2/2), KY-293
board, HN-224 board (1/2), and AXM-14 board
(2/2))
Among the captioned circuit boards of the system control
block, the DVP-1 board controls its peripheral boards and
the entire system, while the TC-80 board controls the
system unique to the machine such as time code, display,
and key panel.
. DVP-1 board (2/2)
The DVP-1 board (2/2) has the system control CPU that
is the center of the system control. A 16-bit CPU
operating on a clock speed of 20 MHz, is used for the
system control CPU because it handles large volumes of
data such as communication with digital processors.
Regarding communication, the interface of the DVP-1
board is established after the parallel bus is level-shifted
(from 5V 3.3 V) because the parallel bus interface
system such as digital processor ICs, operates on 3.3 V.
The serial interface system can be interfaced directly
with the SIO of the CPU. However, because the CPU
must establish serial communication with the SERVO
MPU and TC MPU in addition to the SIO. The SIO is
shared and is switched to either SCI (DPR) or SCI (SV)
or SCI (TC) by the SCI selector.
For the serial communication with the CT MPU, another
SIO is used for interface because the CT MPU uses the
different synchronization system against VTR. An I/O
expander covers an insufficient I/O port.
. TC-80 board (2/2)
The TC MPU on the TC-80 board (2/2) controls TC IC
(LTC reader and generator) while communicating with
the system control CPU in serial communication.
The TC MPU also controls the LCD module, key matrix,
and character generator via the I/O expander.
A backup power supply using a lithium battery is
provided to back up the generators and real-time data.
4-3