Measurement of voltage for A=D converter - involving digital comparison with reference voltage produced by low pass filtering square waves interactive approximation

摘要

A method of measuring a voltage involves digital comparison with a variable reference voltage and min. of the difference voltage by iterative approx.. The reference voltage is generated by low pass filtering of a pulse width modulated square wave voltage of constant period and amplitude. For iterative approx., the reference voltage is varied using interval staging until min. variation is detected before comparator switching. The low pass filter (2) has a digital input and an analogue output. The comparator (3) produces a digital output. USE/ADVANTAGE - For measurement and digitisation of analogue electrical voltgages. Efficient.