Table of Contents
Advertisement
(21 Cursor measurement
1 . In the same w a y as the ordinary measurement, adjust
waveforms to be measured to an easy-to-observe posi-
tion.
2. Set the cursor mode to A T .
3 . Adjust the A R E F cursor to the left edge of the pulse
signal to be measured, and the A cursor to the right
edge.
4 . Measured value is displayed in the upper right part on
the screen posterior to A T .
REF cursor
Fig. 24
8. PULSE RISETIME AND FALLTIME
MEASUREMENTS
(1) Ordinary measurement
For risetime and falltime -measurements, the 1 0 % and
9 0 %
amplitude points are used as starting and ending
reference points.
Procedure:
1 . Apply a signal to the INPUT jack. Set the vertical MODE
to the channel to be used.
Use
the V O L T S / D I V
and V A R I A B L E to
waveform peak-to-peak height to five divisions.
2. Using the • POSITION control and the other controls,
adjust the display such that the waveform is centered
vertically in the display. Set the S W E E P TIME/DIV to as
fast a setting as possible consistent with observation of
both the
1 0 % and 9 0 % points.
V A R I A B L E control to C A L position.
3 . Use the
POSITION control to adjust the 1 0 % point
to coincide with a vertical graduation line and measure
the distance in divisions between the 1 0 % and 9 0 %
points on the waveform. Multiply this by the S W E E P
TIME/DIV and also by 1/10, if " x 10 M A G " mode w a s
used.
Measured value
cursor
adjust
the
Set the
S W E E P
NOTE: T h e graticule on the C R T includes the 0 , 1 0 , 9 0 ,
and 1 0 0 % lines assuming that 5 divisions corres-
pond to 1 0 0 % . Use them as a reference for a c -
curate measurements.
Using the formula:
Risetime = Horizontal
distance (div) x ( S W E E P
setting) x " x 10 M A G " value"
Adjust to the vertical scale
with •*> POSITION
Rise time
Fig. 2 5
[EXAMPLE]
For the example, the horizontal distance is 3 . 3 divisions.
The S W E E P TIME/DIV is 2 (ps/div). (See Fig. 2 5 )
Substituting the given value:
Risetime = 3 . 3 ( d i v ) x 2 (jts/div) = 6.6/iS
Risetime and falltime can be measured by making use of
the alternate step 3 as described below as well.
4 . Use the o
POSITION control to set the 1 0 % 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
.position such that the 9 0 % 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
distance is then D
plus D
x
ship in calculating the risetime or falltime.
Using the formula:
Risetime = (D, + D
) (div) x (SWEEP TIME/DIV
2
setting) x " x 10 M A G " value"
T I M E / D I V
1
( 1 / 1 0 )
. Next adjust the waveform
t
and the total horizontal
2
for use in the above relation-
2
1
(1/10)
23
Advertisement
Table of Contents
