Akai VS-2EGN

3-6-3 AUTO DISCRIMINATION
The auto discrimination method in the EE mode differs
from that in the PB mode.
1) EE mode
In the EE mode, AFC (H SYNC) pulses between the
leading edge and the next leading edge of V SYNC are
counted, and the mode is judged to be 50 Hz when the
number of pulsis counted is more than the discrimina-
tion level of 288 and 60.Hz when the count is less than
288.
For the 50 Hz mode, 50 OS (06 port) is brought to LOW
and 60 OS (07 port) to HIGH.
Then, NT-L (RO port) is brought to HIGH, the discrimi-
nator acts on the input signal of K port (CK-1, SD-1, or
SD-2), and the mode is determined .
For the 60 Hz mode, 50 OS (06 port) is brought to
HIGH, and 60 OS (07 port) to LOW.
Then, NT-L (RO port) is brought to LOW, the discrimi-
nator acts on the input signal (CK-1 or CK-2) of K port
and the mode is determined.
50 Hz Mode 60 Fiz Mode
1 SECAM B/G NTSC 4.43
2 SECAM L NTSC 3.58
3 PAL B/G 60 Hz B/W
4 50 Hz B/W
Fig. 7-65 Discrimination priority
When two or more signal enter K port, the one of high-
est priority is favoured,
50-L | 60-L | NT-L | SD-1 | SD-2. | CK-1 SB-H | 4N-H | 3N-H | SLH |PAL/SB/4N-H | MODE
L H H H L L H L L L L SECAM B/G.
L H H L H L L L L H E SECAM L
L H H L L H L L L L H PAL B/G
L H H L L L L L L L L 50 Hz B/W
Fig. 7-66 Mode discrimination in 50 Hz mode
S0-L | 60-L | NT-L | CK-1 | CK-2 SB-H | 4N-H | 3N-H | SL-H | PAL/SB/4N-H MODE
H L L H L L H L 2 H NTSC 4.43
H L L H L L H L L NTSC 3.58
H L L L L Lie L L L 60 Hz B/W
Fig. 7-67 Mode discrimination in 60 Hz mode
2)
Playback
mode
3)
CUE
or
REVIEW
mode
In
the
playback
mode,
the
AFC
(H
SYNC)
pulses
occur-
CUE
or
REVIEW
mode
is
the
same
as
the
PB
mode
ex-
ing
during
the
period
of
the
Switching
pulse
from
one
cept
that
the
discrimination
levels
are
different.
trailing edge to the next trailing edge), are counted.
When the number of pulses is equal to or more than the
discrimination level of 576, the mode is judged to be
50 Hz. When the number of pulses is less than 576, the
mode
is
judged
to
be
60
Hz.
The
rest
is
the
same
as
the
EE mode.
Service Manual VS-2EGN
56