Duty cycle

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In telecommunication and electronics, the term duty cycle has the following meanings:

The duty cycle D is defined as the ratio between the pulse duration (

τ

) and the period (T) of a rectangular waveform

In a periodic phenomenon, the ratio of the duration of the phenomenon in a given period to the period.

duty cycle $D = \frac{\tau}{T} \$

where

D is the so-called duty cycle;

τ

is the duration that the function is non-zero;

Τ

is the period of the function.

For example, in an ideal pulse train (one having rectangular pulses), the duty cycle is the pulse duration divided by the pulse period. For a pulse train in which the pulse duration is 1 μs and the pulse period is 4 μs, the duty cycle is 0.25. The duty cycle of a square wave is 0.5, or 50%.

For another example, for a piece of electrical equipment, like an electric motor, the period for which it may be operated without deleterious effects, such as from overheating.

The ratio of (a) the sum of all pulse durations during a specified period of continuous operation to (b) the total specified period of operation.

In a continuously variable slope delta (CVSD) modulation converter, the mean proportion of binary "1" digits at the converter output in which each "1" indicates a run of a specified number of consecutive bits of the same polarity in the digital output signal.

Pulse-width modulation (PWM) is used in some music synthesizers to vary the duty-cycle of an oscillator during the performance, which has a subtle effect on the tone colors obtained.

This article contains material from the Federal Standard 1037C (in support of MIL-STD-188), which, as a work of the United States Government, is in the public domain.