% EMD_SAMPLING.M%% P. Flandrin, Mar. 13, 2003 - modified Mar. 2, 2006%% computes and plots an error measure in the EMD% estimation of a single tone%% produces Figure 3 in%% G. Rilling, P. Flandrin and P. Gon鏰lves% "On Empirical Mode Decomposition and its algorithms"% IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing% NSIP-03, Grado (I), June 2003N = 256;% # of data samplest = 1:N;tt = fix(N/4):fix(3*N/4);Nf = 257;% # of tested fequenciesf = logspace(-log10(2*Nf),-log10(2),Nf);x = cos(2*pi*f'*t);se = zeros(1,Nf);kmin = 65;for k = kmin:Nf-1		y = x(k,:);			sy = sum((y(tt)).^2);		imf = emd(y);	se(k) = sqrt(sum((imf(1,tt)-y(tt)).^2)/sy);	[k size(imf)]				endplot(log2(f(kmin:Nf-1)),max(log2(se(kmin:Nf-1)),-60),'o-')axis([-8 -1 -16 0])xlabel('log_{2}(frequency)')ylabel('log_{2}(error)')hold onplot([-8 -1],[-14 0],'r')gridhold off