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1 4 . S W E E P
M U L T I P L I C A T I O N
C A T I O N )
T h e apparent magnification of the delayed s w e e p is deter-
mined by the values set by the A and B S W E E P T I M E / D I V
controls.
1 . Apply a signal to the INPUT jack and set the vertical
MODE to the channel to be used, adjusting V O L T S / D I V
for an easily observed display of the w a v e f o r m and the
other controls if necessary.
2. Set the A S W E E P T I M E / D I V so that several cycles of the
waveform are displayed. Depress the HOLD O F F control
to ( A F T E R D E L A Y ) .
W h e n the HORIZ M O D E is set to INT, the magnified por-
tion of the waveform will appeared intensified on the C R T
display.
3. Use the D E L A Y T I M E M U L T to shift the intensified por-
tion of w a v e f o r m to correspond with the section to be
magnified for observation. Use the B S W E E P T I M E / D I V
to adjust intensified portion to cover the entire portion
to be magnified.
4. S e t the HORIZ M O D E to either A L T or B and use the •
POSITION and T R A C E S E P A R A T I O N controls to adjust
the display for easy v i e w i n g .
5. Time measurements are performed in the same manner
from the B s w e e p as w a s described above for A s w e e p
time measurements.
The apparent magnification of the intensified w a v e f o r m
section is the A S W E E P T I M E / D I V divided by the B
S W E E P T I M E / D I V .
Using the formula:
The apparent magnification
of the intensified w a v e f o r m
Intensity modulation area
Fig. 4 5
[EXAMPLE]
In the example, the A S W E E P T I M E is 2 ps and the B S W E E P
T I M E is 0 . 2 us. (See Fig. 4 5 )
Substituting the given value:
Apparent magnification ratio =
3 2
( M A G N I F I -
_ A S W E E P TIME/DIV setting
b S W E E P TIME/DIV setting
A S w e e p
B S w e e p
2 x 1 Q ~
6
= 1 0
0 . 2 x 1 0 - 6
With the above magnification, if the magnification ratio is
increased, delay jitter will occur.
T o achieve a stable display, set the B M O D E to T R I G and
used the triggered mode of operation.
1 . Perform the above steps 1 through 3 .
2 . Pull the HOLD OFF control to activate B T R I G ' D function.
3. Set the HORIZ MODE to either A L T or B. T h e apparent
magnification will be the same as described above.
1 5 .
A P P L I C A T I O N O F X - Y O P E R A T I O N
*
Phase Shift Measurement
A method of phase measurement requires calculations bas-
ed on the Lissajous patterns obtained using X - Y operations.
Distortion due to non-linear amplification also can be dis-
played.
A sine w a v e input is applied to the audio circuit being test-
ed. T h e same sine w a v e input is applied to the vertical in-
put of the oscilloscope, and the output of the tested circuit
is applied to the horizontal input of the oscilloscope. T h e
amount of phase difference between the t w o signals can
be calculated from the resulting w a v e f o r m .
To make phase measurements, use the following procedure.
1 . Using an audio signal generator with a pure sinusoidal
signal, apply a sine w a v e test signal at the desired test
frequency to the audio network being t e s t e d .
2. Set the signal generator output for the normal operating
level of the circuit being t e s t e d . If desired, the circuit's
output may be observed on the oscilloscope. If the test
circuit is overdriven, the sine w a v e display on the oscil-
loscope is clipped and the signal level must be reduced.
3. Connect the channel 1 probe to the output of the test
circuit.
4. Select X - Y operation by placing the T R I G MODE s w i t c h
in the X - Y position.
5. Connect the channel 2 probe to the input of the test
circuit.
(The input and output test connections to the vertical and
horizontal oscilloscope inputs may be reserved.)
6. Adjust the channel 1 and 2 gain controls for a suitable
viewing size.
7. Some typical results are s h o w n in Fig. 4 7 .
If the t w o signals are in phase, the oscilloscope trace is
a straight diagonal line. If the vertical and horizontal gain
are properly adjusted, this line is at a 4 5 ° angle. A 9 0 °
phase shift produces a circular oscilloscope pattern.
Phase shift of less (or more) than 9 0 ° produces an ellip-
tical oscilloscope pattern. T h e amount of phase shift c a n
be calculated from the oscilloscope trace a s shown in Fig.
5 7 .
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