Akai VS-2EGN - Page 42

2) CUE or REVIEW mode
1
! 1
L
CAPSTAN MOTOR
FG
LOLA
1c? ®
RESET PULSE
1C7
Fig. 7-40 Timing chart of 1/7 counter (CUE or REVIEW mode)
With CUE or REVIEW: H set to “H”, the (A) portion
goes to “H” while the (B) portion goes to “L”. To
implement the function of a 1/7 frequency divider,
the counter must be started and then reset instan-
taneously upon reception of the 7th input pulse. From
the binary counter timing chart, it can be seen that
resetting upon 7th input pulse can be done when IC7
(pin @) TRO, pin @) TRI and pin G)TR2) are at “H”,
3-2-3 NTSC MODE
The reference signal of the capstan servo phase control
is the 30 Hz switching pulse available from ICI pin QQ.
The comparison signal is a 30 Hz signal which is ob-
tained by dividing the frequency of the capstan motor
FG signal (570 Hz) by 19.
Since CUE or REVIEW in the NTSC system is 5 times
1) 1/19 counter
SERVO 12V
1/19 CAPSTAN
MOTOR FG
pee
| oom
and thus TRO, TR1 and TR2 are AND (D3, D4, Ds,
R73) so as for resetting.
Operation as the result of this frequency division is
shown in the timing chart, Fig. 7-40 C44 and R65 make
up an integration circuit which ensures a delay necessary
to attain the proper reset pulse width so as to avoid mal-
function of the counter.
faster, than the PLAY mode, the comparation signal in
CUE or REVIEW mode is a CTL signal obtained by di-
viding the frequency by five.
The 1/19 counter circuit, CTL pulse 1/5 counter circuit,
CTL pulse 1/5 counter circuit, capstan motor FG signal
1/5 counter circuit used in the NTSC mode alone are
described in the following sections.
REC 12V
ad
3 | CUE or REVIEW 7H
(ONLY PB MODE)
FROM CAPSTAN MOTOR FG
STOH:
Service Manual VS-2EGN
SERVO 12v
rer 39
fj-——<— cTL PuLse
Fig. 7-41 1/19 counter circuit
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