In an ideal pulse train, i.e., one having rectangular pulses, the ratio of the pulse duration to the pulse period. Note: For example, the duty cycle is 0. 25 for a pulse train in which the pulse duration is 1 s and the pulse period is 4 s. 2. 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. 3. 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. 4. In a periodic phenomenon, the ratio of the duration of the phenomenon in a given period to the period. Note: In a piece of electrical equipment, e. G. , an electric motor, the period for which it may be operated without deleterious effects, e. G. , from overheating.