Technics ST-9038 User Manual

PART
IT
i,
PLL
SYNTHESIZER
ü
1-5-5
Circuit
to
prevent
faulty
operation
B.
74L574
oö
LS192
861 C
Load
B
orrow
tn
ln
the illustration
at left,
an
OR
circuit is
located
between
74L5192
and
861
C.
The
description
is
given
in
the
following.
When
the
decimal
place
is zero
such
as 88.0, 89.0
. 107.0,
the emission
of
load
signal.during
variable
code frequency
division
causes
"0"
to
b€
preset.
The counting
operation
is as
follows:
I
-
2->1+0-+Q -+g-+g
I lt
I
ba
comparison
frequency
Also,
the
frequency
at
terminal
"o'
c
T
0
o
Here,
74LS192
is
to
produce
borrow
output
as a. However,
as
"0"
is
preset,
it again
produces
borrow
output
at
b
thus
causing
faulty
operation.
This
results
in the
emergen.ce
of a
problem
that
the received
frequency
does not
match
the
indicated
frequency.
Accordíngly,
such defective
operation
is
prevented
by
putting
in
Õ
=
"1"
through
the
OR
circuit
when
the
load
signal is
given,
that
is,
when
O
of 874LS74
equals
"0",
not
allowing
the
borrow
output
at b to
get
into
861c.
lncidqntally,
c
is
provided
for
cutting
"noise".
1-6
Crystal frequency
divider
Trim mer
Crystal
330
K
The
comparison
frequency,
the
reference
for
the
PLL,
is
produced
in
this
circuit.
When
a
jZ.B
MHz
crystal
oscillator
with
a
high
accuracy
of
r20
ppM
is
connected
between
@
and
@
of
ppDB6lC
to
perform
frequenc¡r
division
with
one
stage
of
F/F
and
a 9-bit
dívider:
12.8
MHz
12.8
MHz
=-
=1'FVt-l-
21
o
1024
t
''e
t\t
tL
The
frequency
output
ut
@
is
the reference
0
IS:
12.8 MHz
--;-
= 6.4
MHz
z
I
PÞ861C
This
can
be used to check
for
defective
operation
of the oscillator.
lncidentally,
330Ko
is
the
bias
resistor,
and
the
trimmer
is
provided
for
fine
adjustment
of
the
freq
uency.
.f
Standard
oscillator
F/F
9-b it
divider
I

Technics ST-9038 Specifications

General

Brand	Technics
Model	ST-9038
Category	Tuner
Language	English