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14. PULSE JITTER MEASUREMENT
Pulse jitter can be measured as follows:
(1) Normal Procedures
1 )
Apply the signal to the input connector. Select the chan-
nel to be used with the V E R T I C A L MODE.
Adjust each control for normal s w e e p display. T h e n ,
adjust the V O L T S / D I V control to obtain proper w a v e -
form display. Especially, the trigger-related controls
must be carefully adjusted for stable display. S e t the
A S W E E P T I M E to C A L .
2)
Select A INT B of the H O R I Z O N T A L MODE s w i t c h e s .
Set the B S O U R C E to A F T . D . Adjust the D E L A Y P O S I -
TION so that the pulse to be measured is intensity-
modulated.
3)
Adjust the B S W E E P T I M E / D I V so that the whole por-
tion where jitters are produced is intensity-modulated.
4)
Select B of the H O R I Z O N T A L MODE s w i t c h e s . Meas-
ure the horizontal deviation of the jittered pulses. Time
of jitters can be determined by multiplying this horizon-
tal distance by B S W E E P T I M E / D I V setting.
Pulse jitter =.
Horizontal distance of jitters (div)
x
B
S W E E P T I M E / D I V setting
P u l s e j i t t e r
Fig. 52
[EXAMPLE]
In the example s h o w n in Fig. 5 2 , the jitter width is 1.6
divisions. If B S W E E P T I M E / D I V setting is 0 . 2 fis.
Pulse jitter = 1.6 (div) x 0 . 2 (fis) = 0 . 3 2 fis
(2) Cursor Measurement Procedures
1)
Display the w a v e f o r m to be measured on the C R T a c -
cording to items 1) to 3) of the normal procedures.
2)
Select B of the H O R I Z O N T A L MODE s w i t c h e s . Also
select the AT cursor mode.
3)
Adjust the AREF cursor to the left of the t w o points to
be measured and the ^ c u r s o r to the right.
4 )
Measured value is displayed following AT in the upper
right of the C R T .
I R E F c u r s o r
F i g .
15. Sweep Magnification
The apparent magnification of the delayed s w e e p operation
depends on setting of the A and B S W E E P T I M E / D I V
controls.
1)
Apply the signal to the input connector. Select the chan-
nel to be used with the V E R T I C A L M O D E . Adjust each
control for normal s w e e p display. Adjust the V O L T S /
DIV to obtain proper w a v e f o r m display.
2)
Adjust the A S W E E P T I M E / D I V to display several c y -
cles of w a v e f o r m on the C R T . T h e n , set the B S O U R C E
s w i t c h to A F T . D . By selecting then A INT B of the
H O R I Z O N T A L M O D E s w i t c h e s , the part to be magni-
fied is intensity-modulated and displayed brilliantly.
3)
Move the intensity-modulation part to the part to be
magnified with the D E L A Y P O S I T I O N . Adjust the B
S W E E P T I M E / D I V so that the whole part to be magni-
fied is intensity-modulated.
4)
Select A L T or B of the H O R I Z O N T A L M O D E s w i t c h e s .
Move the waveform to an easy-to-see position with the
• POSITION and T R A C E S E P controls.
5)
Time measurement can be executed under the condi-
tion where the B s w e e p trace is displayed in the same
manner as the A s w e e p . Setting of the B S W E E P
T I M E / D I V is the s w e e p ratio for this measurement.
To find the apparent magnification of the magnified
w a v e f o r m , divide A S W E E P T I M E / D I V setting by B
S W E E P T I M E / D I V setting.
Apparent magnification of s w e e p ratio
A S W E E P T I M E / D I V setting
=
B S W E E P T I M E / D I V setting
M e a s u r e d v a l u e
c u r s o r
5 3
37
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