Sony WLL-CA55, Руководство по обслуживанию

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1-7 (E)
WLL-CA55
1-5. Circuit Description
1-5-1. VPR-84 Board
The VPR board has the following functions:
. Converts digital or analog R/G/B signals from the
camera to a 4:2:2 SDI parallel signal, and transfers it to
the DPR board.
. A/D converts the 2-channel analog audio signal from the
APR board, and transfers it to the DPR board.
.
Interfaces the IIC serial communication with the camera
and the parallel communication with the microcomputer
on the IF board.
Video Signal
While this unit is connected to a BVP-E10/950 camera,
digital R/G/B signals of the camera are input to the PLD1
IC500. While this unit is connected to a BVP-550/570
camera, analog R/G/B signals from the camera are
clamped, A/D converted by IC309, IC310 and IC311, and
then input into the PLD1. The clamp voltage and the A/D
conversion bottom/top voltages are specified with the
electronic variable resistor IC214. IC214 is controlled by
the microcomputer on the IF board via PLD1.
Camera type (BVP-E10/950 or BVP-550/570) is distin-
guished with the “XC GND” signal of the 68-pin connec-
tor; GND or open. R/G/B signals of either type are selected
in the PLD1.
The sampling rate of selected R/G/B signals is changed
from 18 MHz to 13.5 MHz by the PLD1. The signals are
then converted to the 4:2:2 SDI parallel signal and trans-
ferred to the DPR board.
Audio Signal
The 2-channel analog audio signals sent from the APR
board are converted to a 24-bit serial digital signal (multi-
plexed with channels 1 and 2) by the A/D converter IC300,
and then transferred to the PLD1. The 24-bit serial digital
signal is converted to a 16-bit signal in the PLD1, and then
transferred to the DPR board in phase with the FS and
64FS signals.
27 MHz Reference Clock
The 27 MHz reference clock is generated by the 27 MHz
X’tal VCO X400.
While this unit is not in communication with the WLL-
RX55 receiver, the HD signal from the camera becomes
the reference. The HD-VAR signal from the PLD1 is
compared with the reference signal, and the phase error
controls the X400 oscillation frequency.
While this unit is in communication with WLL-RX55, the
control signal from WLL-RX55 controls the X400 oscilla-
tion frequency. The HD signal from the camera is com-
pared with the HD-VAR signal, and the phase error H-
CONT signal is transferred to the camera.
Control System
This board has functions to detect various camera modes
through the IIC serial communication and to inform the
camera of WLL-CA55 modes. IC211, IC212, IC215 and
IC503 are provided for the IIC interface. Such data are
received and sent from/to the microcomputer of the IF
board via the PIO IC206.
The PLD1 program data is stored in the flash memory
IC809. The PLD2 IC806 controls read/write operations of
the program data.