Duty Cycle

Duty cycle is defined as the ratio of positive pulse width to the period. This is the percentage of the period that the positive pulse width occupies, or (+ Pulse Width/Period) x (100). Therefore, duty cycle is displayed as a percentage (%). The measurement can be restricted to a region. Two pairs of annotation labels are placed on the waveform. The first pair identify the rising and falling edges of the positive pulse width (+ Pulse Width), and the second pair identify the period between consecutive rising edges. This measurement is available for measurement of single-valued waveforms only.

The time between the edges of the waveform used for the duty cycle measurement is taken at the middle threshold crossings. The lower and upper threshold levels do not directly affect the period measurement. However, the lower and upper threshold levels are used to determine whether or not a waveform edge is valid for the measurement.

This measurement is not compatible with PAM signals.

Configurable Measurement Parameters

This measurement is affected by the following settings (choose Measure > Thresholds...):

To measure

  1. Click the toolbar's Time tab.
  2. Click the toolbar's More buttons to locate the Duty Cycle button.
  3. Click the button.
  4. Select the Region in which to make the measurement:
    • Displayed Waveform — is what you see in the waveform window (which can be a zoomed-in view of the complete waveform).
    • Entire Waveform — specifies the complete waveform.
    • Region N — If regions are enabled for the selected signal, you can select one of those regions.
  5. Select the number of Occurrences to measure per acquisition:
    • Measure One — makes one measurement per acquisition using edges closest to the timebase reference.
    • Measure All — makes as many measurements per acquisition as possible using all edges in the acquisition. In this case, the measurement closest to the timebase reference is the "current" measurement (and is the one with annotations).
  6. Select the Edge Direction to specify the edge on which to start the measurement:
    • Rising — the cycle(s) on which the measurement is made begin with a rising edge.
    • Falling — the cycle(s) on which the measurement is made begin with a falling edge.

SCPI Command

:MEASure:HORizontal:DCYCle