Wavetek 132 Instruction Manual page 17

3,
Using
a
comparator,
set
the
positive
peak
to the
center of the scope.
Switch
the
comparator
to
the negative peak and
adjust
R121
so that
the
negative
peak
equals the positive peak.
Triangle
Amplitude
1.
Set frequency
dial
for
2.0 (XI
K
range)
and
function
selector to
•
2.
Connect
oscilloscope,
with peak
mV
plug-in, to
tab of switch
SW3B,
as illustrated
under "Square
Wave
Amplitude Symmetry."
3.
Adjust
R56
on main board
for positive
peak
at
'
-i
o
r
.
.- 1
4.
- -f-rr
\ r t ,
„
.. .
t
,
.
*
.
i_ t
• «
V
\J
I
LD —%J |||V
\3CC
onciu
t /
4.
Adjust
R59
for negative
peak
at
—1
.25
V
±5 mV.
Negative Peak
Positive
Peak
Output
Amplifier
y/
1.
Connect
oscilloscope to
50^2
OUT
connector
with 50^2
terminator loaded
at
oscilloscope
(
1
j_j
function).
2.
Set
FREQ
HZ
selector for
X1K
(FREQ VER-
NIER
fully
cw) and frequency
dial
at 2.0.
3.
Turn
OUTPUT VERNIER
(dB)
fully
ccw.
4.
Adjust
R150
for
amplitude
symmetry
about
ground.
5.
Set
FREQ HZ
selector for
XI
M
(2.0
dial
setting).
6.
Turn
OUTPUT VERNIER
(dB) fully
cw.
7.
Adjust
C64
to
provide
a flat
square
wave
with
100 nanosecond
rise
time.
First
VCG
Null
y/
1.
Connect
oscilloscope to
50&2
OUT
connector.
2.
Set
FREQ
HZ
selector to
XI
K.
Set frequency
dial
to
0.02
and
turn
FREQ VERNIER
to
CAL
position.
3.
Short and open
VCG
IN
to
signal
ground
(out-
side
of
BNC
connector) while monitoring
out-
put frequency
variation.
Adjust R11
for mini-
mum
frequency change
using
X20
horizontal
magnification
on
oscilloscope.
Time Symmetry y/
1.
Connect
unit
and
oscilloscope,
with dual chan-
nel
plug-in
set
for alternate display, as
shown
in
Figure
4-1
2.
Set
FREQ
HZ
selector for
X100K
with
FREQ
VERNIER
in
CAL
position
(
r
|_j
function).
3.
Set
frequency
dial
to
0.02
to
provide 2
kHz
display
on
oscilloscope.
4.
Adjust
R28
for time
symmetry
with frequency
dial set
to 0.02.
5.
Turn
FREQ VERNIER
fully
ccw
and
adjust
R22
for
time
symmetry.
NOTE
Interaction occurs
between
R
28 and
R22.
Repeat
steps
4 and 5
until
1% symmetry
accuracy
is
met.
(On
oscilloscope
1%
—
1
cm
at 0.1 (isec
with
X
10 horizontal
magni
fication.
6.
Check
for
waveform time
symmetry
at
the 0.2
and
2 frequency
dial settings.
7.
Check
to assure
FREQ HZ
selector
is
set
to
X100K
position with
FREQ VERNIER
turned
fully
ccw.
8.
Turn frequency
dial
fully
cw.
9.
Check
frequency
ratio
from
top range
setting to
1/1000
of range (not
dial setting).
10.
Adjust R8,
if
necessary, for
slightly greater
than
1000:1
ratio.
MODEL
132
50
OHM
SCOPE
TERM
50
OHM
O—
—
6
o X
>
OUT
(NORMAL)
-OCH.
B
(INVERTED)
Trigger:
Internal
Time
Base:
Display: Alternate
50
microseconds/
cm
for
1/100
of
200 kHz
500
microseconds/
cm
for
1/1000
of
200 kHz
Figure
4-1
Time Symmetry
Measurement
for
Test Setup
14