Interpolation and Resampling

interpolate(v, n) Returns an interpolated version of the vector v with n times as many points as v.

multirate(v, n, m, [f]) Returns a version of multichannel signal v resampled by a factor of n/m, using the optional argument f as the lowpass interpolating filter.

resample(v, m, n) Returns a vector obtained from v by n-fold interpolation and then sampling every mth point.

Arguments:

• v is a vector or matrix of real or complex numbers representing the samples of a signal. If v is a matrix, each column is processed individually. For resample, data must be real.
• n is an integer, the upsampling/interpolation factor. For resample and interpolate, n ≥ 2.
• m is an integer, downsampling/decimation factor. For resample, m ≥ 2.
• f, (optional) is a vector of FIR lowpass filter coefficients used between upsampling and downsampling. Default filter has length 32, gain n, windowed with a Hanning taper, with cutoff .45 times the min(1/n,1/m).