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1. (CA2068215) ANALOG TO DIGITAL CONVERSION WITH NOISE REDUCTION

Office : Canada
Application Number: 2068215 Application Date: 14.12.1990
Publication Number: 2068215 Publication Date: 16.06.1991
Grant Number: Grant Date: 01.06.1999
Publication Kind : C
Prior PCT appl.: Application Number:US1990007503 ; Publication Number: Click to see the data
IPC:
H03M 1/52
H03M 1/06
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
M
CODING, DECODING OR CODE CONVERSION, IN GENERAL
1
Analogue/digital conversion; Digital/analogue conversion
12
Analogue/digital converters
50
with intermediate conversion to time interval
52
Input signal integrated with linear return to datum
H ELECTRICITY
03
BASIC ELECTRONIC CIRCUITRY
M
CODING, DECODING OR CODE CONVERSION, IN GENERAL
1
Analogue/digital conversion; Digital/analogue conversion
06
Continuously compensating for, or preventing, undesired influence of physical parameters
CPC:
H03M 1/0658
H03M 1/004
H03M 1/52
Applicants:
Inventors: PARKS, ROBERT A.
Priority Data: 451,212 15.12.1989 US
Title: (EN) ANALOG TO DIGITAL CONVERSION WITH NOISE REDUCTION
(FR) CONVERSION ANALOGIQUE-NUMERIQUE A BRUIT ATTENUE
Abstract: front page image
(EN) An analog-to digital converter (10) employs a capacitor circuit (12) for integrating a sample of an input signal (20) during a predetermined interval of time and, thereafter, the capacitor (42) is discharged at a predetermined rate until the intergration voltage is equal to that of a reference. The discharge time serves as a measure of the amplitude of the input signal. A measurement interval is established which is equal to an integral number of cycles of each of the possible values of frequency of the A.C. excitation. The signal integration interval has a duration less than or approximately equal to the shortest period of the A.C. exitation, this being the period of the highest frequency A.C. excitation. The signal integration is repeated periodically at each third half-cycle of the highest frequency excitation so that the total integration time experienced during positive half cycles is equal to that experienced during negative half cycles of any of the plurality of excitation frequencies. This cancels the effect of noise due to signal polarity.


Also published as:
EP0505496WO/1991/009470