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In
example
1,
the
dial
is
set
at
5 and 0
volts
VCG
input
voltage
is
applied.
Extend
a
straight
line
from
5
(dial
setting)
through
0
volts
(VCG
voltage).
The
result
is
an
output frequency
of
5
(multiplied
by
the range
multiplier).
The
generator can
be
made
to
free
run
in
this
mode
at
certain settings of
the
trigger
level
control.
By
resetting
the
trigger
level
control,
normal
gated operation
can be
re-established.
In
order to
set
the generator
at
.01
x
the range
multiplier
(1/1000
of the
range)
the following procedure
is
to be
followed:
a)
Using the frequency
dial
and
a
counter
or
oscillo-
scope,
set
the generator
frequency
to
0.1
x
the
range
multiplier.
b)
By
rotating
the
vernier
counter-clockwise, decrease
the
frequency
to
.01
x the range
multiplier.
As
can
be
seen
from
the
nomograph,
a
+5
volt
VCG
input
vwll
then cause the frequency
to
increase to
the
maximum
of
10
X the range
(an increase
from
.01
to 10;
i.e.,
1000:1).
2.5.3
Operation
as a
Triggered
Generator
1.
Select
the
desired
waveform
using
the
waveform
selector switch.
2.
Set the generator
mode
switch to
trig.
3.
Adjust the
generator to the desired
frequency
(or
width)
using the range switch
and
the
main
frequency
dial.
4.
Apply
a
signal
to the Trig
In
BNC.
Note:
The
SWP/GCV
ouqiut
may
be used
as
a trigger
source.
In this
case the
sweep time
control
determines
the repetition
rate
of the
triggered
output
signal,
and
the
trigger
level
dial
control
sets
the width, or dura-
tion,
of the
output
signal.
2.5.4
Gated
or
Tone
Burst Operation
With
the generator adjusted
as
in
trigger
operation above,
change
the
mode
control to the gated position.
The
gen-
erator
output
will
then be a
burst of
signals.
The
duration
of the burst
is
adjustable
by
the
trigger
level
control,
refer
to Figure
2-5.
BURST
REPETITION
RATE
2.5.5
Operation
as a
Sweep
Generator
Three sweep
modes
are available
with
the
Model
144,
continuous with sweep,
trigger
with
sweep and sweep and
hold.
The
operation
of these
modes
can be
visualized
by
the graphs
shown
in
Figure
2-6.
These
graphs
plot
the
output frequency
of the generator
as
a function of
time
in
the three
different
sweep modes.
GENERATOR
FREQUENCY
Figure 2-6
-
Generator
Sweep Modes
These
modes
together
with
the
GCV
output
can be
used,
to accurately adjust the
sweep
limits
over
a preselected
frequency
range.
The
set-up
procedure
shown
in
Figure
2-7
utilizes
an
oscilloscope,
however
an
X-Y
recorder or a
counter could be used
in
a similar
manner.
2-7
1/74
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