[Pe,F] = pwelch(e(ntrW-20000:ntrW),[],[],2048,Fs);
plot(F,10*log10(Pd(:,1)*Fs),'b',F,10*log10(Pe(:,1)*Fs),'r');
axis([0 2000 -25 30]);
xlabel('Frequency [Hz]');
% ylabel('Amplitude [dB]');
ylabel('Power Spectrum Estimate [dB]');
title('Spectra of the Original and Attenuated Noise');