Rise Time; Frequency - Tektronix 2213A Instruction Manual

3. Adjust the TRIGGER LEVEL control to obtain a stable
display.
4. Set the SEC/DIV switch to display one complete pe­
riod of the waveform. Ensure that the SEC/DIV Variable
control is in the CAL detent.
5. Position the display to place the time-measurement
points on the center horizontal graticule line (see Figure 4-5).
6. Measure the Horizontal distance between the time-
measurement points.
7. Calculate time duration using the following formula:
horizontal
distance
Time (division)
Duration = _________________________ __
magnification factor
EXAMPLE: The distance between the time measurement
points is 8.3 divisions (see Figure 4-5), and the SEC/DIV
switch is set to 2 ms per division. The X I0 Magnifier is
off (knob in).
Substituting the given values:
Time Duration = 8.3 div x 2 ms/div = 16.6 ms
Figure 4-5. Time duration.
SEC/DIV
x switch
setting
Operating Procedures— 221

Frequency

The frequency of a recurrent signal can be determined
from its time-duration measurement as follows:
1. Measure the time duration of one waveform cycle us­
ing the preceding "Time Duration" measurement procedure.
2. Calculate the reciprocal of the time-duration value to
determine the frequency of the waveform.
EXAMPLE: The signal in Figure 4-5 has a time duration
of 16.6 ms.
Calculating the reciprocal of time duration:
Frequency = ----- — - — = — —--------- = 60 Hz
time duration

Rise Time

Rise-time measurements use the same methods as time
duration, except that the measurements are made between
the 10% and 90% points of the low to high transition of the
selected waveform (see Figure 4-6) Fall time is measured
between the 90% and 10% points of the high to low transi­
tion of the waveform.
1. Preset instrument controls and obtain a baseline
trace.
2. Apply an exact 5-division signal to either vertical-
channel input connector and set the VERTICAL MODE
switch to display the channel used.
Figure 4-6. Rise time.
3A Operators
16.6 ms
4-5