Estimator of amplitude and frequency of a noisy-biased sinusoid from short bursts of samples

Abstract

The amplitude or frequency of a sinusoidal signal represented as sample values S.sub.1, S.sub.2, S.sub.3, S.sub.4 is estimated by computing a triplet of differences x.sub.1, x.sub.2, x.sub.3, where x.sub.1 is a difference between S.sub.2 and S.sub.1, x.sub.2 is a difference between S.sub.3 and S.sub.2, and x.sub.3 is a difference between S.sub.4 and S.sub.3. An indication of the estimate of the amplitude or frequency is computed as a ratio of algebraic functions of the differences x.sub.1, x.sub.2, x.sub.3. The amplitude is computed as the square root of a first ratio of algebraic functions, and the frequency is computed as an arc-cosine function of a second ratio of algebraic functions. Preferably the ratio is evaluated by a division operation computed as a polynomial approximation, and the square root function and the arc-cosine function are also computed as a polynomial approximation. Preferably ratios computed from a plurality of triplets are averaged together to give more accurate estimates. Preferably any ratio having a denominator value that has a magnitude less than a threshold value is excluded from the average of the ratios, so that the average will not be corrupted by any inaccurate result that could be obtained when dividing by a relatively small number. The method can be used for compensating a parasitic capacitance, or for monitoring the health of a plurality of signals in an electronic circuit.

Dependencies are inferred from the claim text.