Wavetek 132 Instruction Manual page 12

sired
amplitude with
OUTPUT VERNIER
(dB)
control.
'Operation
as
a
Random
FM
Source
Before
using the generator
as
a
random
FM
source,
please
note the
following.
4.
Select desired
SEQUENCE LENGTH
by depres-
sing
appropriate push button.
5.
Select noise
amplitude by
setting
OUTPUT
ATTEN
(dB) control to
appropriate attenuation
position
and
fine adjusting noise to desired
amplitude with
OUTPUT VERNIER
(dB) con-
trol.
The frequency
of the generator
is
being
varied or
modulated by
a
changing
voltage
in
the
same
way
as
described
in
"Operation
as a
Voltage Controlled Gen-
erator."
However,
instead of using
a
dc ramp, or ac
signal,
a
random
analog voltage
is
used.
When
the
FM
push button
is
depressed, the analog noise
is
injected
internally into
the
VCG
circuit;
therefore, the
modu-
lation
is
created
by
random
noise.
The S/N
—
N/S
(dB)
knob controls ths
msximum amount
of frscjusncy
deviation, since
it
controls the
amplitude of the
noise.
Bandwidth
of the
FM
signal
is
controlled
by
the
NOISE
FREQ HZ
control.
Using the generator
in
the
FM
mode may
be accomplished as follows:
1.
Select the desired signal
waveform
by
setting
function selector to
/
\y
,
/
\/
,
or Hu
•
2.
Set frequency
dial
and
FREQ
HZ
range multi-
plier
for desired center
output frequency.
3.
Depress
MODE
— FUNC
and
FM
push buttons.
4.
Select the
bandwidth by
setting
NOISE
FREQ
HZ
control to desired range
and
fine
adjusting
frequency by turning the noise frequency
Hz
vernier control.
5.
Select desired
SEQUENCE LENGTH
by
depres-
sing
appropriate push button.
6.
Select
signal
frequency deviation
by
setting
S/N
—
N/S
(dB) controi to appropriate attenua-
tion position
and
fine
adjusting attenuation to
desired deviation with
S/N
—
N/S
vernier control.
7.
Select
output
signal
amplitude by
setting
OUT-
PUT
ATTEN
(dB) control to
appropriate
atten-
uation position
and
fine adjusting
signal
to de-
sired
amplitude with
OUTPUT VERNIER
(dB)
control.
Operation
as a Digital
or
Analog Noise Source
1.
Set function
selector to
digital
or analog
noise
position.
2.
Depress
MODE — FUNC
push button.
3.
Select clock
frequency
for
digital
or
bandwidth
for analog noise by
setting
NOISE
FREQ
HZ
control to desired range
and
fine adjusting
fre-
quency by
turning the noise
frequency
Hz
ver-
nier control.
Connect
Signal
and
Chassis
Grounds
The
instrument
is
shipped
from the factory with the
signal
ground
floating
above
chassis
ground,
unless
otherwise
specified.
A
common
signal/chassis
ground
can be obtained
as follows:
1.
2
.
3.
Remove power
cord.
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and remove
panel.
Solder
a
jumper
wire
between the ground
lugs
(green wires) of the
SYNC OUT
connector and
the
power connector
(Figure 2-4).
ADD
POWER
JUMPER CONNECTOR
J1
Figure
2-2.
Common
Ground Connection Diagram
Converting
Output Impedance
to
600
Ohms
Unless otherwise
specif
ied,
this
instrument
was shipped
with
50
ohm
output impedance, but can be converted
to
600
ohm
output
if
needed. Place
a
550^2
resistor
in
series
with the wire
leading
from the center tap of
the
50^2
OUT
BNC
and the attenuator control.
9