Applies peak interpolation methods, specified with the Interpolation property, to get a better estimate of the peaks closest to the frequencies in the Freqs. Freqs parameter will be updated with new values and cplxEst will hold the complex results. The value of the Freq can be the frequency of the closest frequency bin in the frequency spectrum depending on the interpolation method. cplxEst returns the complex value spectral bin at the specified frequency, if peak interpolation was TInterpolationMethod.imNumeric. Alternatively the result of cplxEst is simply zero. freqIdx contains the indexes in the spectrum for Freqs on output. When interpolation is active, the indexes will correspond to the closest spectral line and its content can be discarded. 

The vectorized variant of this method is roughly 10x faster than the single frequency overload, provided that Freq.Length is large enough. When Freq.Length is 10 then speed up is about 3x and when it is 100, the speed up is about 10x.

ApproximateComplexEst Method