1-D interpolation using FFT method
y = interpft(x,n)
y = interpft(x,n,dim)
If length(x) = m, and x has sample interval dx, then the new sample interval for y is dy = dx*m/n. Note that n cannot be smaller than m.
If X is a matrix, interpft operates on the columns of X, returning a matrix Y with the same number of columns as X, but with n rows.
Interpolate a triangle-like signal using an interpolation factor of 5. First, set up signal to be interpolated:
y = [0 .5 1 1.5 2 1.5 1 .5 0 -.5 -1 -1.5 -2 -1.5 -1 -.5 0]; N = length(y);
Perform the interpolation:
L = 5; M = N*L; x = 0:L:L*N-1; xi = 0:M-1; yi = interpft(y,M); plot(x,y,'o',xi,yi,'*') legend('Original data','Interpolated data')