Sony BVH-2000, Operation And Maintenance Manual

Page: 339 / 505

5-7-7. SR-15 Board
1.
Outline
This board is configured with hardware in order to generate the
reference signal for the servo system. The BW/COLOR
REF
SYNC, H, V, and are detected
by the video signal supplied from the REF VIDEO INPUT or
the VIDEO INPUT connector.
z
o
I-
«
a:::
w
0...
o
LL
o
>-
a:::
o
w
I
I-
LO
The video signal is amplified about 2 volts by Q14 to Q16
and the signal is then supplied to the burst separator and the
sync separator. An outputs of the BURST/H separator IC9-5
and burst is from the separator
IC3 K-6 by way of delay monostable multivibrator IC3 I are
output to the burst separator IC3 H-8 so that the burst is
separated at the timing of the both signals.
BURST SEPARATOR
TP4
REF H
( IC3K-7)
..__------------- OV
TP23
H
+
BURST
( IC9-5)
IC31-13
TP25
SEP'ED
(IC3H-8)
The burst counter IC4 Land IC5 K counts the number of burst.
When the count during one field becomes 1024 or more, the
output ofIC5K-12(Q8)
goes "High" and the color signal input is
detected. Therefore the of detection is latched IC5L-13.
The burst counter is reset by the reset pulse at an interval of field
supplied
from IC4K-10.
SERVO SYSTEM
4.
REF SYNC Separator
A video signal with negative sync which is clamped by D8 is
supplied to the inverting input of IC16-6 and the envelope of
sync portion which is detected
IC5 and IC7 is to the
non-inverting input of IC16-6. Based on the relationship
between the both the video signal without fluctuation
can be obtained This signal is converted to TIL level by the
sync separator IC14-9 and output to the REF H separator and
the
V separator.
H,
E
V separator is with IC4J, and
The IC3H is output the REF V pulse at the timing correspond to
the trailing edge of the first equalizing
pulse of V SYNC. The
monostable multivibrator with about 50 microseconds
time constant is used as a REF H separator in order to reject the
The REF FRAME separator is configured with IC51 and IC4H.
The REF FRAME is detected by the relationship
between the
and separators.
REF SEP
REF SYNC
(IC3M-3 )
I C4J-1
1 C4J-3
IC4K-10
IC3H-ll
REF
V
(lC4K-7 )
{1' 3 -FIELD
TP20
REF H
2,4 -FIELD
REF FRAME SEP
IC51-1 {
2,4-FIElD
1,3 -F I ElD
1, -FIELD
REF FRAME {
(IC4H )
2,4-FIElD
1,3-FIElD
1 - FIELD
2,4-FI ElD
5-7-1
B VH -2000 (U /C) IPS/PM
BVH-2180( U/C)/PS/PM