An analog-to-digital converter employs a capacitor circuit for integrating a sample of an input signal during a predetermined interval of time and, thereafter, the capacitor is discharged at a predetermined rate until the integration voltage is equal to that of a reference. The discharge time serves...http://www.google.fr/patents/US4999632?utm_source=gb-gplus-shareBrevet US4999632 - Analog to digital conversion with noise reduction
