What is the difference between pulse code modulation and pulse width modulation?
Pulse Code Modulation consists of a sequence of digital values of the signal taken at a specific rate to suit the application. The original signal can be practically reconstructed to recover the signal by applying them to a DAC. Pulse Width Modulation consists of maintaining a fixed amplitude pulse high for a time that is proportional to the instantaneous amplitude of the signal. For example, a sine wave 0V is set to 50% duty cycle. Then scale positive peak MAX for about 95%, allowing negative part of sine wave to be between 50% and 5% See Links for more info.