Technics ST-9038

crRcu¡T
FoR
srART
año sro
lN
AUTO
TUNING,
AN
P PULSE GENERATION
D ADJACENT
CIRCUITS
't
2.
2-1
Circuit
fcir
start
and
stop
pulse generation
during
auto tuning, and adjacent
cirouits
Station selector
step
scan
TR1'17
co I
lector
+B
tc919
TR 109
+B
Stop
signal
4 5
t,
+B
To sy nthesizer
D108
Ft1 43
Auto mono
,o
P
ink
no ise
s3-3
TR113
(
M uting)
to
"L"
level
,o{
þ
uo*n
t
AT button
2-1-1
Flip-flopcircuit
Start
The internal structure of 1C912
(SN74LS00)
in
the above circuit is a
flip-flop
circuit as shown
here.
@
Stop
To TR113
(Muting
controlsignal)
This
flip-f
lop c¡rcuit has
such a
characteristic
that the level
of
@changes
from
"H"
I
ptn
@
evel
and changes
from
"H"
to
@
"L"
or
l',L"
to
"H"
only when
pin
@
ot
Now,
let us
see what occurs when a signal enters
pin
t2-
7
1
1
D917
N
o)
o
1c912
SNT4LSOO
D919
D918
@
with
the circuit stabilized
as shown
t