Rise-Time And Fall-Time Measurements - Tektronix 7B80 Instruction Manual

Operating Instructions-7B80
9. Determine the frequency of the displayed waveform ob-
tained in steps 1 through 8 by taking the reciprocal of the
period of 1 cycle.
Example: Assume that the period of the displayed wave-
form is 0.7 millisecond.
Using the formula:
Frequency
=
1
Period
Substituting values:
Frequency
=
1
=
1.43 kilohertz
0.7 ms
Rise-Time and Fall-Time Measurements
Perform the following procedure to measure the rise time
and fall time of a displayed waveform:
1. Install the time-base unit in a mainframe horizontal
compartment (either A or B horizontal in a four-compart-
ment mainframe).
2. Connect the signal to be measured to the vertical unit
input.
RISE TlME
10
9
1'
FALL TlME
1
1985-11
3. Set the mainframe horizontal- and vertical-mode switch-
e s to display the time base and the vertical unit. (Check
that the time base VARIABLE (CAL IN) control is pushed
in and the HOLD OFF control is in the MIN position.)
Fig. 1-7. Measuring the rise time and fall time of a displayed wave
form.
4. Set the TRIGGERING switches and LEVEL control for
a stable display (see General Operating lnformation for
selecting proper triggering).
or falling portion of the waveform that is 10% and the
point that is 90% of the total display amplitude (see Figure
1-7).
5. Set the vertical deflection factor and position control
for a vertically-centered display with an exact number of
divisions of amplitude.
NOTE
6. Set the TIMEIDIV switch and POSITION control to dis-
play the rising or falling portion of the waveform within the
center 8 graticule divisions a s shown in Figure 1-7 (see
General Operating lnformation in this section for discussion
of timing measurement accuracy).
The left edge of the oscilloscope graticule is
scribed with 0, 10,90, and 100% lines for con-
venience when measuring rise time or fall time.
To use this feature, adjust the vertical deflection
factor and position control to fit the display be-
tween the 0 and 100% graticule lines. Then
measure the horizontal distance between the
points where the waveform crosses the 10% and
90% graticule lines.
7. Determine rise time or fall time by measuring the hori-
zontal distance in divisions between the point on the rising
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