Wavetek 132 Instruction Manual page 9

amplitude remains constant,
thus giving
cali-
brated 0 to
—50
dB
signal-to-noise ratios. In
the
N/S mode,
the
signal
is
attenuated with the
noise
remaining unchanged, thus
giving noise-
to-signal ratios
from 0
to
—50
dB.
The
steps for
this
control
are
indicated
in
black
numerals on
the front panel.
14.
S/N
—
N/S (dB) Vernier
—
Allows
a
calibrated
fine
adjustment of the
S/N
—
N/S
(dB) step
at-
tenuator
(
13).
This control
is
continuously
vari-
able over
at least a
10
dB
range.
When
added
to
the coarse control
(13), this
amount
equals the
total
S/N
or
N/S
ratio.
Approximate
values ot
attenuation
are indicated
in
red
numerals on
the
front panel.
15,
NOISE
FREQ HZ
—
This range control
selects
the clock frequency, or bandwidth
for
the
digi-
tal,
or analog
noise, respectively.
When
using the
digital
noise function, clock frequencies
from
160
Hz
through
1.6
MHz
(indicated
in
black
numerals and
letters
on
the front panel) are
available.
When
using
analog noise or the S/N,
N/S modes,
the
bandwidth
of the analog noise
may
be
selected
from
10
Hz
to
100 kHz
(in-
dicated
in
red numerals
and
letters
on
the front
panel). In
the
FM
mode,
this
control
establishes
the
bandwidth
of the analog noise used
for fre-
quency
modulation. There
are
four detent
posi-
tions
with an overlapping
vernier control
(16).
With
the vernier
in
the
full
cw
position,
the
clock frequency,
or
bandwidth,
is
equal
to
the
value printed
to the right of
the detent mark.
16,
NOISE
FREQ HZ
Vernier
—
As mentioned
in
number
15,
this
control provides
a
continuous,
fine control
between
the detent positions of
the coarse
control.
When
in
the
full
cw
position,
the clock frequency, or bandwidth,
is
equal
to
the value appearing
at
the
right
of the detent
mark.
As
the
knob
is
rotated ccw, the clock
frequency, or bandwidth,
is
decreased.
In
the
full
ccw
position,
the actual value
will
be
at
least
10:1 (and
as
much
as
100:1) lower than
the value
to the right
of the detent mark.
17.
VCG
IN
—
This connector allows
external volt-
age control of function generator frequency.
Up
to
1000:1 frequency change
may
be
obtained.
A
positive voltage increases
frequency and
a
negative voltage decreases frequency. Refer
to
"Operation
as a
Voltage Controlled Generator."
SEQUENCE LENGTH
18.
2
10
—
1
—
Depressing
this
push button
will
provide 1,023 counts of the selected clock
fre-
quency,
or
bandwidth, determined by
the
NOISE
FREQ
HZ
controls (15
and
16), for
generation of
a digital,
or analog noise pattern.
At
the
end
of each sequence, the pattern
is
automatically
repeated.
19.
2
15
—
1
—
Depressing
this
push button
will
provide 32,767 counts
of the selected clock
frequency, or
bandwidth, determined by
the
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generation of
a digital,
or analog noise pattern.
At
the
end
of
each sequence, the
pattern
is
automatically repeated.
20.
2 20
—
1
—
Depressing
this
push button
will
provide 1,048,575 counts of the selected clock
frequency, or
bandwidth, determined by
the
NOISE
FREQ HZ
controls (15
and
16), for
generation of
a digital,
or
analog
noise pattern.
At
the end of each sequence, the
pattern
is
automatically repeated.
REAR PANEL
21.
DC OFFSET —
This
control adjusts the
±5
V
base
line
above
or
below ground
(±2.5
V
offset
into
50^2
load).
The
OFF
position gives
normal
vertical
symmetry. Peak amplitude
is
limited
by
the
dynamic
range of the amplifier output.
22.
FUNCTION SYNC —
This connector provides
a
synchronizing
signal
output
at
the
same
fre-
quency
of the main
generator; that
is,
at
the
same frequency
as
the
sine,
triangle
or square
wave.
The
amplitude
is
greater
than
1
V
peak
to
peak
square
wave
into
open
circuit at
600^2
output impedance.
23.
NOISE
SYNC —
This connector provides
a
syn-
chronizing output
signal for
monitoring the
dig-
ital
or
analog
noise.
A
sync
signal
is
generated
at
the beginning of each
repetitive cycle for the
selected sequence length of
digital
or
analog
noise.
24.
NOISE
CLOCK
—
This connector provides an
external output of the
basic
clock frequency
used
to
generate the
digital
sequence and
analog
noise.
6