Variable pulse-width modulation with zero D.C. average in each period

Pulse-width modulation (PWM) finds wide use in many applications including motor control, communication systems, music synthesizers, power supplies, class-D and digital amplifiers, among others. The Fourier series expansion of each period of a pulse waveform includes an additive term that is a function of the pulse width in that period. As the pulse width is varied, this additive term varies, which can be problematic in many applications. In an embodiment, a single-pulse per period pulse width modulated waveform comprising a zero d.c. term in each period regardless of pulse width is generated. In various realizations these waveforms may be generated by electronic circuitry without the use of capacitive coupling or may be generated by algorithms. Further aspects include “through-zero” pulse width modulation and zero-centered asymmetric triangle waveforms and use in instrumentation for measurement of a phase angle of an exogenous system or phenomena.