function y=upsample(x)
%  y=upsample(x)
% bandlimited interpolation to 2048 samples
	L=length(x);
	M=2048;
	if L < M
		y=zeros(1,M);
		k=fix(M/L);
		y(k*[0:L-1]+ceil(k/2))=x;
		X=fft(y);	L2=fix(L/2);
		X=X.*[ones(1,L2),zeros(1,M-2*L2),ones(1,L2)];
		y=k*real(ifft(X));
	else
		y=x;
	end