Non-linear analogue-to-digital conversion through PWM

A method for finding non-linear functions digitally is described. The design is based on pulse width modulating (PWM) the analogue signal by applying a specially shaped reference waveform in the modulator. The number of pulses of a high frequency clock entering in a binary counter during the high state period of the PWM will provide a digital number proportional to the first, square, cubic or forth order root at the input voltage. Exponential form functions also can be found digitally.