PWM

Pulse Width Modulation. An analog synthesis technique in which an low-frequency oscillator or some other modulation source is applied to vary the length of time a pulse wave remains in its high state (i.e., its width). This varies the amplitudes of the fundamental frequency and lower harmonics, with an effect similar to sweeping a lowpass filter. Used by video laser disc systems, and sometimes as an intermediate stage between sampling and A/D conversion. Better than PCM in that it only uses one bit and produces no quantizationing noise floor. It does, however, have attendant sampling errors: jitter and aliasing. See Appendix C…

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