Sony BVH-2000, Operation And Maintenance Manual

Page: 341 / 505

(5-7-7. SR-15 Board)
10. PAl/PAL-M 4-Field Detector
Detection of PAL 4- field will be judged whether the burst at 6th
line of the odd field is detected
Burst pulse from IC9-5, which is passed through the 4.55 MHz
ceramic filter, is again converted to the TTL level by IC14 and is
input to the burst counter IC5E. The burst counter IC5E starts
counting at the timing of 6th line of odd field, and after counting
5 pulses, the carry out (CO) is output. This signal is latched by
the H sync timing so that the PAL 4-field pulse is output.
Detection of PAL- M 4- field will be judged whether the burst at
8th line of the odd field is detected
. SECAM
Detector
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Detection of SECAM 4-field will be judged whether the
subcarrier DR at the 8th line of the odd field is detected.
The subcarrier (DR=4.40625 MHz, DB==4.25 MHz) from IC9-5
is converted as a level signals correspond to the frequency of DR
and DB by means of 4.55 MHz ceramic filter so that the only the
DR is detected and converted to a TTL level by the comparator
IC14. The DR pulse converted as a
is input to the flip-flop
IC4H-8 and the pulses correspond to the DR and
DB at an interval of SYNC is generated.
The counter IC4G counts this pulse and the carry out (CO) is
output when the counter counts 15 pulses. Flip-flop IC4F-6 is
output "Low/High"
pulses alternately at the timing of H SYNC
and if a incorrect polarity of alternation is detected, polarity will
be inverted forcibly at the timing of carry out (CO) from the
counter IC4G. This output is latched by the frame rate signal
from IC5F in order to perform 4-field detection.
SECAM 4-FI ELD DETECTOR
FIELD -1
REF SYNC
I C3M-3
BURST FLAG
T P2"S : I C 3 I -S
TP9
IC14-4
IC4H- 8
IC4G -IS(CO)
IC4F-6
IC3E- 13
FIELD-3
REF SYNC
IC3M-3
BURST FLAG
TP2S: IC31-S
TP9
I C14-4
IC4H-8
IC4G-1S(CO)
IC4F-6
IC3E-13
SERVO SYSTEM
PAL 4-FIELD DETECTOR
IEVEN FIELDI
REF SYNC
IC3M-3
IC3K-7
IC4H-5
IC5H-4lD+2)
IC5H -1110+3)
FIELD -3
IC5E -15(CO)
IC5F-12
IC3E-13
FIELD -1
IC5E-1S(COI "L'
IC5F-12
IC3E -13
1000
FIELDI
I 313 I 314 I 315 I 316 I 317 I 318 I 319 I 320 I 321 I 322 I 323 I
IC3K-7
IC4H-5
IC5H-4lD+2)
IC5H-1110+31
FIELD-2
IC 5E -15(COI
IC5F -12
IC3E -13
'·H;....~
---------------t-4I----
FIELD -4
IC5E-15(CO) .• L.:;.... ..
----------------\----41'-----
IC5F-12
IC3E-13 \·L;...." -+ _
5-7-1
BVH-2000(U/C)/PS/PM
BVH-2180(U/C)/PS/PM