DIGITAL-TO-ANALOG CONVERSION USING PULSE-WIDTH MODULATION

Pulse width modulation (PWM) has found application in various situatio ns where efficient delivery of high power is required. In this paper i ts use in the conversion of signals from digital to analogue represent ations is addressed, i.e. as a digital-to-analogue converter (DAC), an d it is shown that there are many advantages in using PWM over convent ional DAC methods and that high resolution and accuracy can be achieve d. One advantage is that, provided a suitable output stage can be prov ided, a complete, high-power, high-resolution digital-to-analogue powe r converter can be constructed. Because this work was motivated by the author's interest in digital audio, such a device has come to be know n as a digital (power) amplifier. The article describes PWM, particula rly in its digital forms, and shows how to make it practical for use a s a DAC. This involves various digital signal processing stages prior to the final modulator. Results are presented from simulations and fro m demonstrator hardware.