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Page 58
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ee ae |
tn
hb
et
=
-
SUppréesses
unwanted
aqjacent sign is and ma
the Receiver more selective,
es
The signal from the crystal filter is fed to the
control grid of the first IF amplifier tube V3,
The amplified signal from V3 is coupled through
capacitor C31
to the control grid of the second
IF amplifier tube, V4,
From the plate of tube V4 the IF signal is coupled
through
capacitor
C39
to the
detector,
Crystal
diodes
CR&3
and
CR4
detect
the
audio
Foes,
MAS
Wet
eS
=
Aaa!
modulation from the IF signal,
AVC AND ANL CIRCUITS
With the AVC {automatic volume control) switch
turned on, some of the signal from the plate of
tube V4 is rectified by crystal diodes CRi and
CR2, This DC voltage, which increases or de-
cee eee
me
eee the
bE. mm fee eek
teen
Tne
tae fn hen
als
CLleastdS
Willl
UIC
TIPU
SIPMeAL
Le Yel,
LO Lou
A
ta
the control grid of tubes V1, V3, and V4, This
AVC
voltage controls the amount of amplification
of these tubes, providing a more constant signal
level at the speaker,
With the ANL
(automatic noise limiter) switch
turned on, diodes CR5
and CR6
are connected
into the circuit, These diodes,
which limit the
peaks of the AF signal, clip off the noise pulses
such as static and ignition noise, that are often
present on the signai,
The signal from the plate of second IF ampli-
fier tube V4 is coupled through capacitor C47
grid of product getector tube
V5B
the
a USB signal, the Mode
switch i
no:
Ss
osition,
This
turns
on
produc
et
hee,
wee
pee SM
=] ed
stage V5B and BFO (beat frequency oscillator)
stage V5A. The BFO is tuned by coil L18 to the
carrier
frequency
necessary
for
proper
SSB
(single sideband)
or CW detection, For an LSB
signal the
Mode
switch is placed in the LSB
position,
The
BFO
is then
tuned
to a lower
ee
ee
ee
ee
a
a
ne
s
A
ee
re |
frequency
by capacitors
C46
and C49
Product
detertor
fue
V5B
mixes
the
single
sideband
or CW
The
audio
signal
from
the AM
detector
or
product
detector
is coupled
through
resistor
R53
and
capacitor C51 to the control grid of
first
audio
amplifier
tube
V6A.
V6A
ampli-
fies
the
signal
and then
couples
it through
capacitor
C52
io the
control
grid of audio
output tube V6B, The signal is amplified by tube
V6B
and
then
eounled
throuch
audic
output
waves
Sn
Od
oe
ee
od
transformer
T2 to the speaker or headphones,
Capacitor C56 provides high frequency feedback
for distortion cancellation, and stability.
POWER SUPPLY
The power supply is a full-wave rectifier, con-
csictinge
of
dindseac«c
CR?
and
CRA
and
nower
Dawes,
bers
MAUMEE
Wall
MM
Wet,
EE
Be
transformer
T3, The DC voltage is filtered by
resistors
R49, R50, R51, and R52 and capac-
itors C57, C58, C59, C60, and C61,
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