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mixer ZI to produce the 10.
IF.
This IF signal ;s amplified by
Ul.
filtered and applied to
U2
which
is
IF
Amplifier and Demodulator
System.
The demodulated compos;
U2 is amplified by Q4 and
and filtered by a low overshoot,
ted low pass filter.
Either the output of this filter or
input from the rear
panel ;s supplied to composite driver ampli
er Q8, Q9,
QIO~
Qll and
012.
The output of this amplifier is 6V pp
@
100% and is used to drive
the stereo and
SeA
monitoring circui
.
Q6 and
lter C54, l16
C55 convert a 32KHz pulse
assembly to a 32KHz sine wave which is used to FM a 10.7MHz
(Q7
and associated circuitry) when the CAL pushbutton
is
Signal is
coupl
to
IF
amplifier and used to provide
calibrate signal.
The RF signal level vol
at U2 pin 13 is fed to voltage comparator
rcuit U3.
of this
Ie
are used to mute the monitor and
so
drive the RF
. and OK
1
The lO.7MHz si
1 from the IF filter FLI is also fed to mixer Z2
through
bu
it
;s mixed with the output of
2nd
L.O. Q13
and
014.
This L.O.
is
frequency swept
by
a sawtooth generator made up
of CRI4, Q16 a
U6.
e output of the sawtooth generator is also used
to sweep the
t
L.O. in
ECTRUM ANALYZER WIDE mode through 015.
The
455KHz ou
t
of mixer
;s fed through buffer 017 and Q18 to the
spectrum analyzer filter and logarithmic amplifier U4 and associated
circuitry.
The output of the
log
amp
is
AM demodul
and fed through
ive filter U5 to the SCOPE VERT jack and
AM Noise measurement
circuit.
5.
(Stereo Demodulator) Assembly
Composite signal is fed to
Ql
which drives
pilot filter.
The
19KHz is squared by U3 after passing through the
se
ust
t composed of Q3, 04 and the front panel PILOT
0
CAL control.
The
19KHz
re wave
is
used to lock PLL U4.
The output
U4
is
nominally
190KHz.
This signal is divided down to provide square waves of
@
0
0 ,
38KHz
@
180
0 ;
38KHz
@
90
0
and 19KHz
@
90
0 .
These signals are us
demodulated le
and
and also to provide GEN 0 calibration and
o
calibration signals.
demodulation is accomplished by c
Q10 and Ql1 and the resul
1
and right signals are amplifi
through Q17.
The
output
amplifiers is filtered and
u
to
the DISPLAY
also audio output amplifiers U10. U13
Q19 through 022.
and
audio is added in U1I to produce
vertical channel for the
and subtracted in U12 to
the horizontal channel
splay.
Choppers 07 and 08 are
composite signal.
The action
PILOT
0
null indication.
are wave at 90
0
along with
choppers and U2 produces the
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