Tektronix 5441 Instruction Manual page 33

Operating Information-54411~5441
This product can be converted to frequency by taking the
reciprocal of the period (see application of Determining
Frequency).
Time Period Measurement
To measure the time (period) between two points on a
waveform, use the following procedure.
1. Connect the signal to the vertical input connector, se-
lect either ac or dc input coupling, and set the VoltsIDiv
switch to display about four divisions of the waveform.
2. Set the time-base triggering controls to obtain a sta-
ble display. Set the SecIDiv switch to the fastest sweep rate
that will permit displaying One cycle of the waveform in less
Fig. 2-8. Measuring time duration (period) between points on a
than eight divisions (some non-linearity may occur in the first
waveform.
and last graticule divisions of display). Refer to Fig. 2-8.
I
Horizontal
I
distance
-f
I I
2. Take the reciprocal of the period to determine the
3. Adjust the vertical Position control to move the points
frequency.
between which the time measurement is made to the center
horizontal line. Adjust the horizontal Position control to cen-
ter the time-measurement points within the center eight divi-
sions of the graticule.
EXAMPLE: The frequency of the signal shown in Fig.
2-8, which has a period of 0.5 ms, is:
1
Frequency
=
-
=
-
=
4. Measure the horizontal distance between the time
2 kHz
period 0.5 ms
measurement points. Be sure the variable SecIDiv control is
in the Cal position.
5. Multiply the distance measured in step 4 by the set-
ting of the SecIDiv switch.
Risetirne Measurement
Risetime measurements employ basically the same tech-
niques as the time-period measurements.
he
main differ-
EXAMPLE: Assume that the horizontal distance be-
ence is the points between which the measurements is
tween the time-measurement points is five divisions and the
made. The following procedure gives the basic method of
SecIDiv switch is set to .1 ms. Use the following formula.
measuring risetime between the 1O0/0 and 90% points of the
horizontal SecIDiv waveform.
Period
=
distance X switch
=
(5) (0.1 ms)
=
0.5 ms
(divisions) setting
1. Connect the signal to the input connector.
The period is 0.5 ms.
Determining Frequency
The time measurement technique can also be used to
determine the frequency of a signal. The frequency of a peri-
odically recurrent signal is the reciprocal of the time duration
(period) of one cycle. Use the following procedure.
1. Measure the period of one cycle of the waveform as
described in the previous application.
2. Set the VoltsIDiv switch and variable VoltsIDiv control
to produce a display exactly five divisions in amplitude.
3. Center the display about the center horizontal line
with the vertical Position control.
4. Set the time-base triggering controls to obtain a sta-
ble display. Set the SecIDiv switch to the fastest sweep rate
that will display less than eight divisions between the 10%
and 9O0/0 points on the waveform (see Fig. 2-9).
REV MAY 1982