interpolate.fft {spectral}

interpolates data using the Fourier back transform

Description

There are two ways to interpolate data from a given spectrum. Frist, one can do zero padding to cover n new data points. Or, secound the complex amplitude with the associated frequency is taken and evaluated at given points xout. Doing that for all frequencies and amplitudes will give the interpolation. The result is compared to linear approximation for didactic reasons.

Usage

interpolate.fft(y, x = NULL, n = NULL, xout = NULL)

Arguments

y

numeric data vector to be interpolated

x

numeric data vector with reference points

n

number of new points

xout

a vector new points

Value

A list with a x and y component is returned. The e99 value evaluates the error of the interpolation with respect to linear approximation with the approx() function.