Akai VS-2EGN

5-9 AFT CONTROL
280 -— ==
MUTE ON Tie ra
@ orFja7oL | ot tt
ams 4
F-ON VIDEO JUDGE
F-OFF
MUTE ON 280p-4 p=
msi H 1 }
ore | 270! H
9 vee
CHANNEL,
CHANGED
@
MUTE ON f
OFF.
In
the
case
of
EE
signal
changes
and
changes
made
on
the
function
buttons
of
ON/OFF,
PRESET
SELECT,
and
PLAY/STOP,
the
front
processor
switches
the
Mute
out-
put
to
the
tuner
ON/OFF.
This
Mute
output
is
at
once
an
AFT
control
output
for
VT,
and
it
is
designed
so
that
Mute
ON
effects
AFT
OFF,
and
Mute
OFF
effects
AFT
ON.
1) Function key ON/OFF (Fig. 7-94 @)
When
the
function-ON
key
is
depressed,
the
last
channel
data
is
output
to
the
DAC,
Mute
is
switched
ON
in
270
ms,
and
video
judgement
is
performed
280
ms
after
AFT
ON
occurs.
When
non-video
signal
judgement
is
made,
this
operation
is
repeated
over
and
over
again.
(cycle
time:
550
ms)
Reason:
When
broadcast
of
a
preset
channel
has
completed,
if
AFT
is
left
ON,
...
is
drawn
in
a
strange
place
due
to
noise,
getting
away
from
this
may
not
be
possible
even
when
a
broadcast
begins.
(Same
as
VS-5)
VIDEO JUDGE
EE | PLAY STOP
if i
1
7 280r-4
i270 i
ms
4
VIDEO JUDGE
Fig. 7-94 AFT control
2) PRESET SELECT (Fig. 7-94(2))
Similar
to
1).
Mute
is
switched
ON
for
a
period
of
270
ms,
AFT
is
turned
on,
and
then
video
judgement
is
made
after
in
280
ms.
The
rest
is
the
same
as
1).
3) EE signal change (Fig. 7-94@))
When the mode ceases to be EE due to, say, PLAY,
Mute is applied to the tuner so as not affect the play-
back system. Mute is kept ON for a period of 270 ms
after
the
mode
is
returned
from
PLAY
to
EE,
AFT
is
switched ON, and video judgement is performed after
280 ms. The rest is the same as 1).
270 ms and 280 ms are longer than the times required
for VT to gain the corresponding potentials after VT
data is sent to DAC, and also longer than the time during
which the VIDEO DETECT signal is established after
AFT ON occurs. (Though both are set at the same time
during the programming, ‘H’ time is shorter than ‘L’
time due to the effect of C14.)
nn
Service
Manual
VS-2EGN
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