Analogue to digital converter

摘要

An analogue to digital converter comprises a comparator, an up/down counter and a pulse width modulator. The analogue input to the comparator initially causes the counter to count up. The counter output is the converted digital word. The word is used to vary the modulation duty cycle of the modulator output which is compared with the analogue input to the comparator. When the modulator output exceeds the analogue input, the comparator output changes and the counter counts down, maintaining a digital output from the counter at the value of the converted analogue signal.