For
the
pilot
tone
with
adjustable
phase,
the
signal
from
the
6th
shift
register
stage
(8108.12)
triggers
the
monostable
B112.
Its
delay
can
be
adjusted
between
2
us
and
4
us,
approximately,
by
means
of
R316
"bf",
corresponding
to
a
phase
shift
of
about
140
(>
100)
referred
to
the
pilot
tone.
The
divider
3113
II
is
again
used
to
generate
the
l9-kHz
squarewave
signal.
The
squarewave
signal
performs
several
functions.
It
synchronizes
the
phase
control
loop
in
the
SCA
modulator
option
(see
separate
manual)
via
C170.
After
limiting
with
G1
l25/Gl
126,
the
emitter
follower
T147
feeds
the
pilot
output
Sthl.3b
(c)
at
the
rear
of
the
stereoooder.
The
differential
amplifier
T145/
T146
delivers
the
sinewave
pilot
tone
to
the
summing
amplifier
via
the
l9—kHz
bandpass
filter
(L113
to
L114)
and
the
emitter
folTOWer
T144.
The
pilot
ampli—
tude
is
determined
by
the
current
flowing
through
T145/T146,
depending
on
the
pilot
mode
selected
with
8107.
It
is
preset
with
R314
in
the
pilot
mode
”on"
and
adjustable
by
means
of
R312
"AU"
on
the
front
panel
in
the
variable
pilot—
tone
mode;
there
is
no
output
in
the
pilot
mode
"off".
The
PLL
IC
B114
provides
external
synchronization
of
the
pilot
tone
via
the
input
Sthl.3a.
It
compares
the
offset
between
the
internal
pilot
frequency
at
pin
3
and
the
external
pilot
frequency
at
pin
14
and
then
delivers
a
DC
voltage
which
is
proportional
to
the
phase
difference.
With
appropriate
set-
ting
of
link
BRTO4,
this
DC
voltage
is
taken
to
the
tuning
circuit
T143/0163/
0164
of
the
crystal
oscillator
instead
of
the
internally
generated
DC
voltage
(R317/3318)-
4.5
AF
Generator
See
circuit
diagram
230.8518
S,
sheet
1.
The
AF
generator
is
designed
as
a
Wien
bridge
oscillator
and
operates
when
input
selector
5101
is
in
the
positions
L,
R,
L
=
R
and
L
=
—R.
The
frequency-determining
section
is
formed
by
the
series—connected
RC
high—
pass
and
lowpass
filters.
The
capacitors
C132
and
0133
are
fixed,
whilst
the
resistors
R181
and
R182
can
be
changed
to
set
the
desired
frequency
(see
section
5.3.2).
The
output
voltage
is
+6
dEm.
The
following
operating
modes
can
be
obtained
by
turning
input
selector
8101:
L:
a
signal
is
only
applied
to
the
left
channel,
whereas
the
input
of
the
right
channel
is
connected
to
O V
(chassis).
R:
a
signal
is
only
applied
to
the
right
channel.
R
38122
—
20
