This chapter provides an insight to the theory on high-speed PWM and its usage in generating analog waveform. The high-speed PWM output, combined with an analog filter can be used to generate analog output signals, i.e. a digital to analog converter (DAC). A digital pulse train with a constant period (fixed base frequency) is used to generate an analog signal. Different analog levels can be generated by varying the duty cycle (and thereby the pulse width) of the digital signal. If a high analog level is needed, the duty cycle is increased and vice versa. The analog waveform considered in this application note is Sine Wave.