Akai AA-1010

2. PRESET
TUNING
SYSTEM
l) Preset
Station
Selecrion
For preset
íatio.
selection,
there is a
mechanical
and an eleclrical
merhod.
These
are memory
equipme.t
and seiection
equipment
enabling
desÍed station
s€lection
beforehand
and selecting
thes€ pre-set
srations
by simply
d€pressing
the
respective
switches.
An ordinary
car redio,
etc. utilizes
a mechanical
station selection
system
wherein
mechanical
variation
is by
mea.s
of
a variable
condenser or
posilioning
ofa
dust corc inside
a coil.
Model
AA,1010L utilizes
an
electrical srálion
selection
system and
employs
the
varacror
tuner
explained in
a
previous
item.
2) An example
of a stllion
selection
system employ"
ing
a
varactor
tuner is
shown in Fig.
6. For skrion
selection, push
switches
are used for
s€lecuon
of voltage supply
to
the varactor
tun€r. However,
in
the
AA.10I0L, these station selection push
switches
are
puÍe
electronic system sensi.touch
3)
Sensi-touch
Employed
Preset Station
Selection
System Operation
The
circult shown
in
Fig.
7 is th€
conlrol voltage
genêratinS
pres€l
volume
and sensi-touch
circuir.
Fig. 8
sho'rrs the inside
of circuit sensi-touch
IC
FPCI009C
which
include the 4 channel
circuitry.
Terminals 14 thÍou8h 17
are the input teminals;
.erminals
@, @,
@,-a
@
arêthestation
selection output
terminals; and
terminals
O ,
@
,
@
,
and
O
are rhe pilot
outpul terminals.
When
channêl I sensor
electrode is louched,
voltage
is snpplied to
the IC as rhe input signal
through
fmger (body)
resistance at t€rminal
@
.
Then,
the impedance
is lowered
at IC station
selector output
terminal
@
and
current flows
ai
shown
by
the
arrow marks in Fig.
9. Consequ-
enlly, because
the supply voltage
10 the varactor
runer
diode is changed
by the dividing ratio
of
Rb and Rc, station selection
is
possible
by
m€ans
of setting the
pr€set
volumes
beforehand
accoÍdrng
to the deriÍed broadcarl
tÍequen.res.