[EXAMPLE]
For
the example, the horizontal distance is 4.0 divisions.
The
SWEEP
TIME/DIV is 2
/*s.
(See Fig. 23)
Substituting the given value:
Risetime
= 4.0 (div) x 2 (jts) = 8/xs
Risetime
and
falltime
can be measured by making use of
the alternate step 3 as described below as well.
4. Use the POSITION control to set the 10% point to
coincide
with
the center vertical graduation line and
measure
the horizontal distance to the point of the in-
tersection of the waveform
with
the center horizontal
line. Let this distance be D
t
.
Next
adjust the waveform
position
such
that
the 90% point coincides
with
the ver-
tical centerline and measure the distance
from
that
line
to the intersection of the waveform
with
the horizontal
centerline. This distance is D
2
and the
total
horizontal
distance
is then D
t
plus D
2
for use in the above relation-
ship
in calculating the risetime or falltime.
Using
the formula:
Risetime
= (D
x
+ D
2
) (div) x
(SWEEP
TIME/DIV
setting)x"x 10 MAG" value
1
(1/10)
Rise
time
Fig.
24
[EXAMPLE]
For
the example, the measured D
x
is 1.8 divisions while D
2
is
2.2 divisions. If
SWEEP
TIME/DIV is 2 /is we use the
following relationship. (See Fig. 24)
Substituting the given value:
Risetime
= (1.8 + 2.2) (div)x2 (/ts) = 8/ts
TIME DIFFERENCE MEASUREMENTS
This
procedure is useful in measurement of
time
dif-
ferences
between two signals
that
are synchronized to one
another but skewed in time.
Procedure:
1.
Apply the two signals to CH1 and CH2 INPUT
jacks.
Set
the vertical MODE to DUAL choosing either ALT or
CHOP
mode.
Generally for low frequency signals CHOP is chosen
with
ALT used for high frequency
signals.
2.
Select the faster of the two signals as the
SOURCE
and
use
the VOLTS/DIV and
SWEEP
TIME/DIV to obtain an
easily
observed display.
Set
the VARIABLE control to CAL position.
3.
Using the w POSITION control set the waveforms to the
center of the CRT display and use the POSITION
control to set the reference signal to be coincident
with
a
vertical graduation line.
4. Measure the horizontal distance between the two
signals
and multiply this distance in divisions by the
SWEEP
TIME/DIV setting.
If " x 10 MAG" is being used multiply this again by
1/10.
Using
the formula:
Time = Horizontal distance (div) x
(SWEEP
TIME/DIV
setting) x " x 10 MAG" value"
1
(1/10)
[EXAMPLE]
For
the example, the horizontal distance measured is 4.4
divisions.
The
SWEEP
TIME/DIV is 0.2 ms. (See Fig. 25)
Substituting the given value:
Time = 4.4 (div) x 0.2 (ms) = 0.88 ms
23
Adjust
to
the vertical
scale
with
o
POSITION
Rise
time
Fig.
23
Adjust 90%
point
to
the center
and measure
D
2
.
Adjust 10%
point
to the center
and
measure
Dj.
-
Reference signal
Comparison
signal
Time
difference
Ffg.
25
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