% Lancoz filter lowpass
% [tlow,xlow,xhi]=lowpass(t,x,om,ns);

function [tlow,xlow,xhi]=lowpass(t,x,om,ns);
h1=lanczos(ns,om);
xx=conv(h1,x);
nn=length(h1);
n=length(xx);
xlow=xx(nn:n-nn+1);
tlow=t(ns+1:length(t)-ns);
xlow=xlow;
xhi=x(ns+1:length(x)-ns)-xlow;