Patent ID: 6308139
Filing Date: 2001-10-23
Classification: G01R

Abstract:
A method of determining an effective value of a periodic electric test signal, comprising:sampling with a sampling device and an analog-digital converter the periodic electric test signal during a sampling interval to produce M samples, wherein M is an odd number, wherein the sampling interval corresponds to at least two periods of the periodic electric signal, and wherein N samples of the M samples correspond to a first one of the at least two periods of the periodic electric signal;squaring and adding the samples up to and including the Nth sample to produce a resulting total;multiplying the first resulting total by two and dividing by M to produce a second resulting total;adding to the resulting total a correction factor to produce a third resulting total, wherein the correction factor corresponds to a square of a subtotal obtained from one-quarter of the Nth sample and three-quarters of the (N+1)th sample;dividing the third resulting total by M to produce a fourth resulting total;extracting a square root of the sum of the second and fourth resulting total to produce the effective value of the periodic test signal; andproviding the effective value at an output.