Sony BVP-550, Maintenance Manual

Page: 246 / 924

2-4 (E)
BVP-550
• Generates a 27-MHz clock signal required for the VTR
control.
The video signals that has thus been digital-processed, are
then converted to Y, R-Y and B-Y signals. Some signals
are output to the DA-88 board and the others are output via
the MB board as a digital video signal output at the same
time. The Y/C signals are generated from the Y, R-Y and
B-Y signals with a color encoder IC on the PR-211 board.
These signals, that were sampled at 36-MHz rate and
quantized by 10 bits, are digital-to-analog converted. And
the resultants are then output to the DA-88 board as a
monochrome signal for VF, wide-band luminance signal,
or modulated chroma signal. The monochrome signal for
VF has a zebra signal for level indication, and character
signal and center marker signal on it.
DA-88 board
The monochrome signal for VF (VF Y) sent from the PR-
211 board goes through a lowpass filter and is output to the
MB-602 board. The wide-band luminance signal Hi-Ys is
output via a lowpass filter to the IF-510 board. The
modulated chroma signal C goes through a black clamp
circuit and lowpass filter and is added to the Hi-Ys. The
resultant is output to the IF-510 board as a VBS signal.
The Y, R-Y and B-Y signals, that are input from the PR-
211 board as the digital video signals, are aligned in phase
with video signals in another channels by a digital delay
line. The resultant is digital-to-analog converted and is
then output via a lowpass filter to the IF-510 board. On the
other hand, an analog component signal is generated in
combination with the above-mentioned Hi-Ys signal, R-Y
and B-Y signals. The analog component signal is con-
trolled, on the level adjustment and reference signal
addition, by the AT-95 board according to equipment
connected to the camera (VTR or CCU). The analog
component signal is output to external equipment via the
68P interface connector .
IF-510 board
Input signals at the IF-510 board are as follows;
Signals from the DA-88 board: VF Y, VBS, Y, R-Y and B-Y
Signals from external equipment: Reference signal for
external synchronization, Return video signal
By combination with these signals, the IF-510 board
outputs the following signals.
•
VBS OUT signal
Output via a buffer amplifier to external equipment.
•
VBS OUT signal for RM
Output to an interface connector for a remote control unit
RM-P9. Using the setup menu, a character signal to
confirm the menu setting can be mixed to this signal.
• TEST OUT signal
With the signal select switch at the right top of the
camera, the above-mentioned VBS or the VF Y signal
can be selected as a TEST OUT signal output at the
TEST OUT connector.
•
VF OUT/MONI OUT signal
The same signal is output as the VF OUT signal and the
MONI OUT signal. One of the VF Y, VBS, or return
video or reference signal selected by S1 on the IF-510
board, is selected. The selected signal is mixed with a
center marker and safety-zone pulse, and is then output.
The VF OUT signal is output at the VF connector and
the MONI OUT signal is output at the 68P interface
connector.
•
R/G/B output signals
The Y, R-Y and B-Y signals are converted to the R, G
and B signals by a matrix circuit. The converted signals
are output at the 68P interface connector.
•
Y/R-Y/B-Y output signals for VF
These signals are for a color viewfinder. A character
signal and SKIN GATE signal are mixed with the above-
mentioned Y, R-Y and B-Y signals. The resultants are
output to the VF.
In addition, the IF-510 board is equipped with the
following circuits.
• HD/VD external sync circuit
When displaying the return video or reference signal on
the viewfinder screen, it is necessary to synchronize the
cursor signal with those signals. And a sync signal is
separated from those signals to generate the external HD
and VD signals, and the resultant is sent to the cursor
signal generation circuit on the PR-211 board.
• Peak-detects the G signal and outputs to the AT-95
board.
• Transmits the SKIN GATE signal from DA-88 board to
the CCU via the 68P interface connector.
2-4. Circuit Description