Threshold value of Noisy Signal???

Signal1= 0.5*[ sin(2*pi*f1(1)*t)+sin(2*pi*f2(1)*t)];

r1= Signal1+ randn(size(t)); % Random noise signal

R1= fft(r1, 512); % fft of S1

p= R5.* conj(R5)/512; % power spectrum

f= 1000*(0:256)/512; % frequency scale

[Image Analyst]

This later post is just a repeat of your earlier post, http://www.mathworks.com/matlabcentral/answers/225975-i-am-trying-to-find-a-threshold-value-for-separation-of-the-noise-components-and-the-signal-compon except this one has far less information. Also, it did not even answer the questions I gave in your original question, so that's probably why no one is answering. Make it easy for us to help you, not hard . http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer