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Verfügbare Sprachen
Verfügbare Sprachen
1801 is AND
circuit which consists of two inputs (pins
(2) and (3) } and one output (pin a) ), and because
of its AND logic operation, the output becomes "'high"
level only when both inputs are in "'high'' level at a
time.
Usually when the unit is in PLAY
mode, the loading
motor
forward
rotation's
output
(from
pin
@)) of
1809) becomes
'"'low' level while the capstan mototr's
output (from pin 3) of 1809) becomes "'high'' level,
so that the transistor turns off to apply a "'high"' level
signal to pin (3) of 1801; if, under this state, the VS
3.
FV (False sync pulse) generator circuit
HAND SWITCHING
PULSE
PAUSE/STILL
1707: HD14538B
The
FV generator circuit (1707) includes two mono-
stable
multivibrators:
the head switching pulse is ap-
plied to each of the two multivibrators.
When the input Cp is at "'high" level (in VS or PAUSE/
STILL
mode), there appear two one-shot pulses each
at pin (9) and ®
meeting the rise or the fall of the
head switching pulse.
These pusles are AND-processed
by D725 and D726 to create a FV signal.
VS STILL
|
|
H.S-P.
|
|
|
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button is pushed, a "high"' level signal is applied to pin
(2) of 1801; now that both inputs at pins (2) and
are in '"'high'' level, the output from pin @) becomes
'"*high"' level.
But this does not hold true of the case where the unit
is in PAUSE
(or PLAY
STILL)
mode
or the tape is
being loaded.
In this case, the transistor turns on to
make the input to pin (3) of I801 be in "'low"' level, so
that even if the VS button is then pushed (to cause a
"high"
level signal at pin (2) of 1801), the output
from pin a) of 1801 is sure to become "'low'"' level.
Figure 35.
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