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SECTION
I
INTRODUCTION
1.1
PURPOSE OF THE EQUIPMENT
The
Model 144
HF
Sweep
Generator
is
a
precision
0.0005
Hz
to
10
MHz
source of
sine, triangle,
square, positive
pulse,
and
negative pulse
waveforms.
.
.each
with
variable
amplitude,
dc
offset,
and symmetry. Frequency
range
selec-
tion
is
provided
in
10
decades,
with
a
vernier control
per-
mitting
adjustment
of
approximately
1%
of the selected
range.
Maximum
output amplitude
is
30
V
p-p
into
an
open
circuit
(15
V
p-p
into
50 ohms)
with
a
60
dB
calibrated step
attenuator
and
a
20
dB
vernier
attenuator
(80
dB
overall)
allowing
signal levels as
low
as 1.5
mV
p-p.
Both
the
output
waveform
and
the
dc
offset are
attenuated
by
the
60 dB
calibrated step attenuator.
Six operational
modes
(continuous,
triggered, gated,
con-
tinuous sweep,
triggered
sweep, and
sweep and
hold), plus
tone
burst
capability, are
provided
by
the
Model
144.
The
main
output can be
internally
swept
over
a
1000:1
ratio
at
sweep
speeds
from 10
/lxs
to
100 seconds—
or
it
can be
frequency modulated, dc
programmed,
or externally
swept
over the
1000:1
ratio
by
applying an
external control
signal
to the front panel
VCG
IN connector.
A
single
cycle of
output, or
one
full
sweep
of the output, can be obtained
if
an
external
trigger
is
applied
to
the front panel
TRIG
IN
connector.
In
addition to the 50S7
main output and
a
separate
rear
panel
SYNC
output, the
Model 144
also
has
a
front panel
SWP/GCV
output.
When
the
main output
is
not
internally
swept,,
the
sawtooth output
of the
internal
sweep
generator
appears
at
the
SWP/GCV
OUT
connector.
When
the
main
output
is
internally
swept,
a
GCV
output
proportional to
the instantaneous
frequency
of the
main
generator
will
appear
at
the
SWP/GCV
OUT
connector. This
GCV
output
(Generator-Controlled-Voltage)
can be used
to drive
X-Y
recorders or the
vertical
and
horizontal deflection
circuits
of
oscilloscopes,
video monitors,
etc.
Varying the
triangle
symmetry
produces
a
sawtooth
or
"ramp"
signal
with
a
rise
or
fall
time
as
steep
as
50
nano-
seconds
at a recurring
rate
of
1
MHz.
Pulse
outputs
as
narrow
as
50
nanoseconds, with
repetition rates
as
high
as
1
MHz
(on-off
ratios
as great
as
19:1),
can be generated
in
either polarity.
Even
the
sine
wave symmetry
may
be
varied
over
this
1:19
to 19:1
range
if
desired.
When
the
output
symmetry
is
not
1:1,
the indicated
output frequency
must
be
divided
by
approximately
10.
With
this
instrument
it
is
possible to
simultaneously
pro-
gram
or
sweep
the
output
frequency,
select
the
output
symmetry
desired,
and manually
vary the
dc
offset.
This
capability,
coupled with
the
variety of
waveforms
available
and
precision
output amplitude
control,
makes
the
Model
144
an extremely
versatile
instrument.
1.2
GENERAL
PHYSICAL DESCRIPTION
Weighing approximately 9
pounds
(13
pounds
when
shipped)
the
Model 144
is
8-1/2
inches wide,
5-%
inches
high,
and
11-y2
inches
deep.
Housed
in
a
compact,
ruggedized,
portable
case,
the
Model 144
is
normally shipped with
a
10-foot, 3-wire,
detachable
line
cord
and one copy
of
this
instruction
manual.
1.3
SPECIFICATIONS
1.3.1 Versatility
WAVEFORMS
Selectable
sine
^
,
square
""jj
,
triangle
,
positive
pulse
,
and
negative pulse
u-
.
Symmetry
of
all
out-
puts continuously
adjustable
from
1:19
to 19:1.
Varying
triangle
symmetry
produces sawtooth
/\
or
/A
out-
put.
Separate
SWP/GCV OUTput
and
separate
SYNC
OUTput
with
variable
symmetry
as
described below.
OPERATING
FREQUENCY RANGE
0.0005
Hz
to
10
MHz
in
the following
ranges:
X.001
0.0005
Hz
to
.01
Hz
X.01
0.005
Hz
to
0.1
Hz
X.1
0.05
Hz
to
1
Hz
XI
0.1
Hz
to
10
Hz
X10
0.1
Hz
to
100
Hz
X100
1
Hz
to
1
kHz
X1K
10
Hz
to
10
kHz
X10K
100
Hz
to
100
kHz
X100K
1
kHz
to
1
MHz
X1M
10
kHz
to
10
MHz
Note:
When
symmetry
control
is
used,
indicated
frequency
is
divided
by
approximately
10.
1-1
12/70
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