SS-100
AND
SS-200 AMPLIFIERS
-
Both
the
SS-100
and SS-200
external
linear
amplifiers use
special high
power
bipolar
matched
transistors
and
they
are
stud
mounted
to large heat
sinks. These amplifiers are
broadband
(3
to
30
MHz)
and
are capable
of
excellent
linearity
(third
order
IMD
products
better than
-3Odb).
VOX
CONTROL
-
The
VOX
circuit utilizes
an integrated circuit feed-
back
amplifier and
three bipolar transistors
Q103, Ql04
and
Ql05.
The
integrated
circuit
amplifies
the audio
received from the MIC
PRE AMP and
is
adjusted
for
proper
leve1 by the VOX GAIN
control.
The
VOX
CONTROL transistor
Ql03
provides
further arnplification of
the VOX
signal-
but
it also
provides
the adjustments for ANTI-VOX
an.l
delay
(for
both voice
and CW). When
VOX
operation is
not
ser€cted by the VOX
-
PTT
switch,
the VOX
CONTR0L transistor
Q103
is turned off and transistor
Ql04
is operated
directly
from the
rnicrophone
push-to-ta1k
circuit.
Transistor
Q105
provides
transmit
relay
switching
voltage. It
should
be noted that separate
controls
are used for CW and voice delay adjustments.
KEYER
-
The
keyer circuit
is
a bipolar transistor switch
Q201
that
operates frorn the external
key or
keyer
and controls the on/off
operation of
the
transmit
mixer
(XMIT
MIX)
stage.
The design of
the keyer
provides
for
shaping
of
the
rise and fal1
characteristics
of the CW wave.
This
is
done
to
rninimize
keyed bandwidth
and
still
perrnit
clean and
crisp keying
at
high CW speeds.
The
shaper
circuit
also
provides
a
smoothing effect to
minimize the effects
of
contact
bounce.
SIDETONE OSCILLATOR
-
The
sidetone
oscillator
is
an RC
phase
shift
type
using one
bipolar
transistor
q409.
It
is
enabled
and keyed
in
the
CW
mode only. Its output is
filtered to
produce a
good
clear
note
that
is
connected
to the speaker
audio anplifier.
The level
of output
is
adjustable from the back
panel
and the
frequency is
internal-ly
controlled
by the
RC constants.
CARRIER
OSCILLATOR
.
Although
the
carrier oscillator
circuit was
described
earlier in
this
section,
it should
be
noted here
that
the carrier oscillatorrs output
frequency is shifted
upward
approxirnately 800
Hz from the nornal 5.500
MHz when
transmitting
CW. This
is
done to al1ow the
frequency of
the
carrier oscillator
to
fa1l
within the
passband
of
the crystal filter.
28-
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