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17. PULSE WIDTH MEASUREMENT USING
DELAYED SWEEP
High-accuracy pulse width can be measured in the same
manner a s the time measurement.
1 )
Apply the pulse signal to the input connector. Select
the channel to be used w i t h the V E R T I C A L MODE.
2)
Adjust each control for normal s w e e p display. Adjust
the V O L T S / D I V , V A R I A B L E , and t POSITION so that
the pulse w a v e f o r m can be easily observed and the
center horizontal graduation line is in the center of am-
plitude of the pulse. Set the A S W E E P T I M E to C A L .
3)
Rotate the A S W E E P T I M E / D I V to display the part to
be measured. 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 , and set the B S O U R C E s w i t c h to
A F T . D . Adjust the B S W E E P T I M E / D I V to minimize the
intensity-modulation
4)
Adjust the D E L A Y POSITION so that the intensity-
modulation part is in contact w i t h the center horizon-
tal graduation line. Make a record of a measurement
displayed following D E L A Y in the upper right of the
C R T .
5)
Adjust the D E L A Y POSITION so that the trailing edge
of the pulse is intensity-modulated in contact with the
center horizontal graduation line. Determine the pulse
width by subtracting the first measurement from the
second measurement.
Pulse width —
2nd measurement
1 s t s e t t i n g
[ E X A M P L E ]
In the example s h o w n in Fig. 5 6 , if the first measure-
ment
is 0 . 9 3 2 us, the
1 1 . 1 4 4 ps, and A S W E E P T I M E / D I V setting is 2 fis.
Pulse width = 1 1 . 1 4 4 - 0 . 9 3 2 = 1 0 . 2 1 2 / i s
18. FREQUENCY MEASUREMENT USING
DELAYED SWEEP
Since frequency is a reciprocal of a period, it can be deter-
mined by measuring time of one c y c l e .
1)
Measure the period in the time measurement procedures
using the delayed s w e e p mentioned above.
2)
Calculate a reciprocal of the measured period to deter-
mine frequency a s follows:
Frequency =
Period
part.
- 1st measurement
1 s t m e a s u r e m e n t
2nd
2nd
Fig. 56
second measurement
-
1 s t s e t t i n g -
[ E X A M P L E ]
Supposing the measured period is 4 0 . 2 0 /is in the e x -
ample s h o w n in Fig. 5 7 ,
Frequency =
19. PULSE REPETITION TIME MEASUREMENT
The pulse repetition time can be measured accurately us-
ing the delayed s w e e p operation.
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 / D I V control to obtain proper
m e a s u r e m e n t
display.
2)
Rotate the A S W E E P TIME/DIV to display more than t w o
cycles of w a v e f o r m .
s e t t i n g
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 ,
and set the B T R I G G E R I N G S O U R C E s w i t c h to A F T . D .
Set the B S W E E P T I M E / D I V to a s fast value as possible.
3)
Adjust the D E L A Y P O S I T I O N so that the intensity-
modulation part coincides w i t h the first pulse.
Select A L T of the H O R I Z O N T A L MODE s w i t c h e s , and
adjust the B s w e e p trace to an easy-to-see position with
the T R A C E S E P control.
4)
Adjust the pulse to a proper vertical graduation line with
the D E L A Y P O S I T I O N , and make a record of the meas-
urement displayed following D E L A Y in the upper right
of the C R T .
5)
Adjust the second pulse to the same vertical gradua-
is
tion line as in the above item with the D E L A Y POSITION.
The pulse repetition time can be determined by subtract-
ing the first measurement from the second meas-
urement.
Repetition time =
2nd measurement — 1 s t measurement
Fig. 57
- = 2 4 . 8 8 kHz
4 0 . 2 0 X 1 0 "
6
w a v e f o r m
-2nd
s e t t i n g
39
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