3-4
CCU-590/P/V1(E)
AU-295 Board
The AU-300 board D/A converts and outputs the MIC1/MIC2 signals demodulated and A/D converted on
the TR-133B board to the rear panel. It also A/D converts the PGM1/2 signals input from the rear panel,
and sends them to the TR-133B board. The board D/A converts the INCOM1/2 signals demodulated and
A/D converted on the TR-133B board, and then connects the external INCOM line and the front panel. It
also A/D converts the Panel INCOM, PROD, and ENG signals sent from the external, and then transfer
them to the PLD for digital signal processing.
Furthermore, the board functions for TALLY signaling system switchover and external interface.
MIC1/2 Output Circuit
This circuit converts the MIC1/MIC2 digital signals demodulated and A/D converted on the TR-133B
board to analog signals, and then amplifies and outputs them to the XLR-3 connector on the rear panel.
The MIC output level can be selected (0 dB or
_
20 dB) by S18 and S19 in this circuit.
PGM1/2 AUDIO Input Circuit
This circuit amplifies the analog PGM1/2 signals input from the D-sub 25pin connector on the rear panel,
and then A/D converts them and outputs the digital PGM1/2 signals to the TR-133B board.
The PGM1/2 AUDIO signals are converted from balanced to unbalanced signal by IC204 and IC205. The
input levels of the signals are selected (0 dB or
_
20 dB) by S200 and 201.
INCOM Switching Circuit
This circuit switches INCOM lines on the CA side and the CCU-590 front panel side. There are three
types of INCOM lines: PRODUCER line, ENGINEER line (external system), and PRIVATE line isolated
from the external system. The switching control signal is sent from the AT-155B board with IIC data, and
is input into the PLD IC105 that converts the INCOM signals with digital data.
External Interface Circuit
This circuit has three types of 2-channel interfaces with external INCOM systems, supporting 2W, 4W,
RTS, and Clear Com interfaces. These interfaces are selected by S204, S205, S206, and S207 according
to the system connected.
External TALLY Signal Input Circuit
This circuit can accept three types of TALLY signal input: contact input, 12 VDC input, and 5 VDC
input. These types of input can be selected independently for RED and GREEN TALLY signals by
switching S1, S2, S3, and S4. Even if actual input signal does not equal the setting, no failure will occur.
Furthermore, this circuit is compatible with any signal polarity for 12 VDC and 5 VDC inputs.
IC1, IC2, D8 to D13, Q8, Q9, and T1 compose a power circuit for the external TALLY input circuit only,
which is ground isolated by the transformer T1. The TALLY signal output is also electrically isolated by
the photocoupler PH1.
