CIRCUIT DESCRIPTION
4,ll
When the 350 kHz (2.35 MHz) side band marker is ori,
the 31.15 MHz oscillator, 98, output mixed with
The preceding paragraph, 4.10, described marker
31.5 MHz in FET, Q9, produces a 350 kHz difference
circuits in general.
The circuits described below
frequency emphasized by L21, C33 and mixed with the
are the specific markers of the model
2001A and 63.0 MHz birdy marker in 910. C37, 38, 39 and L23
20018.
are a low pass filter which attenuates higher side
bands.
4
U
1
M66-59,5/1090/?4,5
MHz
This module contains
two single frequency markers
(59.5 MHz and 1090 MHz) and a side band circuit at
4.5 MHz.
The 59.5 MHz marker frequency is obtained from a
29.75 MHz crystal oscillator circuit
(Ql). The 2nd
harmonic is tuned by L4, C6 and coupled into a
tuned mixer circuit consisting of L5, C8 and
CR1.
Birdies from this mixer are coupled through a low
pass filter consisting of L6 and
C10.
If
the side
band oscillator is on, 4.5 MHz CW is coupled into
the mixer through
C11. C10 is tuned to emphasize
the 4.5 MHzvideo, providing side band marker video
of about the same amplitudeas the 59.5 MHz marker.
Operationof the 1090 MHz marker is the same except
for the harmonic generation section.
A
54.5 MHz
oscillator is doubled by CR3-CR4 and
Lll-C21 tunes
to 109 MHz.
45 amplifies harmonicsof 109 MHz, and
545 MHz is selected by
L12-C25. 545 MHz is coupled
to the mixer diode CR5 where its 2nd harmonic is
emphasized by the sweep sample tuning circuit L13-
C27,
whichis tuned to the desired marker frequency
of 1090 MHz. L18 couples 4.5 MHz from Q8 through
C30 and
C29 to produce the 4.5 MHz side bands.
This module contains a single frequency marker
63.0
MHzand two side band circuits+.gand?.35 MHz.
The 63.0 MHz marker frequency is obtained from 31.5
MHz crystal oscillator circuit
91, the output of
which is doubled by
42 and 3,
and coupled to the
tuned FET mixer circuit consisting of L7, C8 and
44. Birdies from this mixer are coupled through
63.0 MHz marker size control R12 to the low pass
filter
C11,
12 and L10 and then to the marker amp-
lifier module.
4,11,3 M6H-5,
20,
30
MHz
Circuit functions for these markers are labeled on
the M6H schematics.
A
tuned Colpitts oscillator with
fhecrystal operating at its thirdovertone frequency
in a series resonant mode drives a harmonic genera-
tor
42.
The
CW
comb is mixed with sweep sample in
CR1 and theresultant birdiesareamplifiedbyQ3 and
Q4, and coupled through
theSIZEcontro1 R15 to pin
3 of the module.
This module contains a
1
MHz harmonic marker and a
side band 200 kHz marker generator.
A
1
MHz series crystal oscillator consisting of 91,
Q2 and 43 drives a harmonic generator, consisting
ofQ4and Q5,to nrnduce a CWcomb. The comb is mixed
with a sweep
sampfe in CR2 to produce birdies, which
are then amplified by a video amplifier consisting
of Q6, Q7 and
48. The marker birdies are coupled
through
Q9 topin7 providing the
1
MHz marker out-
put.
A
low pass filter, comprised of L7, L8, L9
and associated capacitors attenuate the 1MHzoscil-
lator
signal, and any side band video frequencies
higher than 500 kHz. This side band video is also
used to produce 200 kHz markers by mixing with the
CW comb
from
412, in CR4 and CR5, when 200 kHz
B+
is applied.
The
switchat pin 8 suppliesBtto the 200 kHz mark-
er circuits and
if
the
1
MHz switch is not on, acti-
vates the
1
MHz section through diode CR3, while
disabling the
1
MHz birdy output through Q9. The
1
MHz oscill ator provides a clock for
IC1
connected
as a
5:l frequency divider to produce a 200 kHz
CW output. The first and second harmonics are
coupled through
Q12 into the 200 kHz mixer CR4-CR5.
The 200 kHz
siqnal and all video frequencies above
40 kHz are then attenuated by a low pass filter
he
900 kHz (+.9
MHZ)
side band frequency is ob- 112-~15. The birdy is then amplified by Q13 and
tained from a 32.4 MHz crystal oscillator, Q5, the coupled through the SIZE control R38 to pin
11
of
Output of which is mixed with the 31.5 MHz signal the module, broviding the 200
HZ
marker output.
in the FET mixer,
46.
C21 couples the output to
the 900 kHz tuned mixer L15,
~27'and 97 where'
it
is
mixed with the 63.0 MHz birdy.
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4.11
The
preceding paragraph, 4.10, described
marker
circuits
in
general.
The
circ~fts
described
below
are the specific markers of the
model
2001A
and
2001B.
4.11.1
M66-S9.S/1090/±4.5
MHz
This
module
contains
two
single frequency markers
(59.5
MHz
and
1090
MHz)
and
a side
band
circuit
at
4.5
MHz.
The
59.5
MHz
marker
frequency
is
obtained
from
a
29.75
MHz
crystal
oscillator
circuit
(Q1).
The
2nd
harmonic
is
tuned
by
L4,
C6
and
coupled into a
tuned
mixer
circuit
consisting of
L5,
C8
and
CR1.
Birdies
from
this
mixer are coupled through a
low
pass
filter
consisting ofL6
and
ClO.
If
the side
band
oscillator
is
on, 4.5
MHz
CW
is
coupled into
the
mixer
through
C11.
C10
is
tuned to emphasize
the 4.5
MHz
video, providing side
band
marker
video
of about the
same
amplitude as the 59.5
MHz
marker.
Opera
t f
on
of the
1090
MHz
rna
rker
is
the
same
except
for the
harmonic
generation section. A 54.5
MHz
oscillator
is
doubled
by
CR3-CR4
and
L11-C21
tunes
to
109
MHz.
Q5
amplifies
harmonics
of
109
MHz,
and
545
MHz
is
selected
by
L12-C25.
545
MHz
is
coupled
to the
mixer
diode
CR5
where
its
2nd
harmonic
is
emphasized
by
the
sweep
sample
tuning
circuit
L13-
C27,
which
is
tuned
to the desired
marker
frequency
of
1090
MHz.
L18
couples 4.5
MHz
from
Q8
through
C30
and
C29
to
produce
the 4.5
MHz
side bands.
4.11.2
M66-63/±.9/±.35
MHz
This
mOdule
contains a single frequency
marker
63.0
MHz
and
two
side
band
circuits:!:.. 9
and:!:..
35
MHz.
The
63.0
MHz
marker
frequency
is
obtained
from
31.5
MHz
crystal
oscillator
circuit
Q1,
the output of
which
is
doubled
by
Q2
and
3,
and
coupled to the
tuned
FET
mixer
circuit
consisting of
L7,
C8
and
04.
Birdies
from
this
mixer
are coupled through
63.0
MHz
marker
size control
R12
to the
low
pass
filter
C11,
12
and
L10
and
then to the
marker
amp-
1
ifi
er
modul
e.
The
900
kHz
(+.9
MHz)
side
band
frequency
is
ob-
tained
from
a 32.4
MHz
crystal
oscillator,
Q5,
the
output of
which
is
mixed
with the 31.5
MHz
signal
in the
FET
mixer,
06.
C21
couples the output to
the
900
kHz
tuned
mixer
L15,
C27
and
Q7
where
it,_is
mixed
with the 63.0
MHz
birdy.
CIRCUIT DESCRIPTION
When
the
350
kHz
(+.35
MHz)
side
band
marker
is
on,
the 31.15
MHz
oscillator,
Q8,
output
mixed
with
31.5
MHz
in
FET,
09,
produces
a
350
kHz
difference
frequency
emphas
i
zed
by
L21,
C33
and
mi
xed
with the
63.0
MHz
birdy
marker
in
010.
C37,38,
39
and
L23
are a
low
pass
filter
which
attenuates higher side
bands.
4.11.3
M6H-5
1
20
1
30
MHz
Circuit functions for these
markers
are labeled
on
the
M6H
schematics. A
tuned
Colpitts
oscillator
with
the crystal operating
at
its
third overtone frequency
in a
series
resonaht
mode
drives a
harmonic
genera-
tor
02.
The
CW-comb
is
mixed
with
sweep
sample
in
CR1
and
the
resultant
birdiesareamplifiedbyQ3
arid
04,
and
coupled through
the-SIZE
control
R15
to pin
3 of the
module.
4.11.4
M66H-.2/1
MHz
This
module
contains a 1
MHz
harmonic
marker
and
a
side
band
200
kHz
marker
generator.
A 1
MHz
series
crystal
oscillator
consisting of 01,
02
and
Q3
drives a
harmonic
generator, consisting
of
04
and
05, to
prnduce
a
CW
comb.
The
comb
is
mi
xed
with a
sweep
sample
in
CR2
to
produce
birdies,
which
are then amplified
by
a
video
amplifier consisting
of
06,
Q7
and
08.
The
marker
birdies are coupled
through
09
to pin 7 providing the 1
MHz
marker
out-
put. A
low
pass
filter,
comprised
of
L7, L8,
L9
and
associated capacitors attenuate the 1 MHzoscil-
lator
signal,
and
any
side
band
video frequencies
higher than
500
kHz.
This
side
band
video
is
also
used
to produce
200
kHz
markers
by
mixing
with the
CW
comb
from
Q12,
in
CR4
and
CR5,
when
200
kHz
B+
is
applied.
The
switch
at
pin 8
suppl
ies
B+
to the
200
kHz
mark-
er
circuits
and
if
the 1
MHz
switch
is
not on,
acti-
vates the 1
MHz
section through diode
CR3,
while
disabling the 1
MHz
birdy output through 09.-
The
1
MHz
oscillator
provides a clock for IClconnected
as a 5:1 frequency divider to
produce
a
200
kHz
CW
output.
The
first
and
second
harmonics
are
coupled through
012
into the
200
kHz
mixer
CR4-CR5.-
The
200
kHz
signal
and
all
video
frequencies
above
40
kHz
are then attenuated
by
a
low
pass
filter
L12-L15.
The
birdy
is
then amplified
by
013
and
coupled through the
SIZE
control
R38
to pin
11
of
the
module,
providing the
200
kHz
marker
output.
4-9
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