Keysight U1281A Guide De L'utilisateur page 93

Measuring duty cycle
The duty cycle (or duty factor) of a repetitive pulse train is the ratio of the positive or
NOTE
negative pulse width to the period expressed as a percentage, as shown in Figure 2-32.
The duty cycle function is optimized for measuring the on or off time of logic and switching
signals. Systems such as electronic fuel injection systems and switching power supplies are
controlled by pulses of varying width, which can be checked by measuring duty cycle.
1 To measure duty cycle, position the rotary switch on one of the functions allowing
frequency measurements shown in Table 2-15.
2 Press
points and read the display.
Figure 2-34
The duty cycle percentage of the input signal is shown in the primary display. The voltage
or ampere value of the signal is shown in the secondary display. The bar graph does not
indicate duty cycle but indicates the voltage or ampere value of the input signal.
The pulse polarity is displayed to the left of the duty cycle value.
pulse and
hold
Press
Press
than 1 second to exit the frequency measurement function.
Keysight U1281A/U1282A User's Guide
until the measurements are displayed as a percentage (%). Probe the test
Hz
Save
Duty cycle display
indicates a negative pulse. To change the polarity being measured, press and
for more than 1 second.
to scroll through the frequency, pulse width, and duty cycle measurements.
Hz
Save
to scroll back to the frequency measurement mode, and hold
Hz
Save
Making Measurements
indicates a positive
for more
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