Pulse Modulation

Pulse modulation involves modulating a carrier that is a train of regularly recurrent pulses. The modulation might vary; the amplitude, pulse amplitude modulation (PAM); the duration,  pulse width modulation (PWM); the presence of the pulses, pulse code modulation (PCM); the time delay between pulses in a sequence, pulse position modulation (PPM); or the relative density of the pulses, pulse density modulation (PDM). Although pulse modulation transmits digital instead of analog signals, the modulating wave is continuous.
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Noun
1. modulation that imposes a signal on a train of pulses
(hypernym) modulation
(hyponym) pulse-time modulation