Comments on the extension of waveshapes. A critical note on the "quasi-continuous" frequency spectrum.

Recently a method is described to calculate from one extended pressure and one extended flow pulse a quasi-continuous fourier spectrum instead of the non continuous spectrum obtained by the usual Fourier analysis. We have tested this method, mathematically starting with the well-known formulae, and by means of computer calculations. We have proven that the graphs of modulus and phase of input impedance based on extended waves go through the points found from the not extended waves. The “extra” information, the result at interpolated frequencies, depends on the start of sampling.