DOUBLEN Interpolates a time series to double its length. Y=DOUBLEN(X) for a column vector X of length M, returns the interpolation of X to length 2M. M must be even. For matrix X of size M x N, each column is interpolated to length 2M, and Y is size 2M x N. The interpolated vector Y may be considered to be of the same duration, but with twice the sample rate, as the original vector. In the interpolated vector, all frequencies higher than the original Nyquist are set to zero. DOUBLEN uses the frequency-domain zero padding algorithm of Mallat (1999), second edition, Section 4.5.4. 'doublen --t' runs a test. 'doublen --f' generates a sample figure. _________________________________________________________________ This is part of JLAB --- type 'help jlab' for more information (C) 2004--2015 J.M. Lilly --- type 'help jlab_license' for details