HOW DO I GET FREQUENCY AND PHASE ANGLE FROM A WAVE SIGNAL

If i have a wave signal data collected at site as below, how can i get the frequency and phase angle from it?

Arrival Time: 0, 0.00013, 0.00025, 0.00038, 0.0005

Amplitude: 0.060643, 0.083724, 0.004865, 0.038468, 0.11925

[Azzi Abdelmalek]

can you tell us which function represent your signal ? when i ploted your signal , i did'nt find it sinusoidal

[Ron]

im so sorry about that..actually, the data consists of 800 points..but i only put here the first 5 points..

But i already sent the complete data to your email.Kindly check your email. Thank you very much for your attention. i really appreciate it. For your information, i just started learning matlab a week ago by myself. im looking forward for the solution.

[Walter Roberson]

Please do not send people files without asking them first.

[Ron]

Walter Robertson, im sorry.it will not happen again in the future.Thanks for the reminder.

Answer 1

[Walter Roberson]

As your times are not uniform, you need a non-uniform discrete fft, sometimes abbreviated nfft and sometimes nufft and sometimes other things.

There does not appear to be any MATLAB routine or any MATLAB File Exchange routine for nfft, but see

http://www.mathworks.com/matlabcentral/newsreader/view_thread/320379

http://www.mathworks.com/matlabcentral/newsreader/view_thread/283117

Answer 2

[Azzi Abdelmalek]

%your signal don't contain just one frequency

num=xlsread('FileName');t=num(:,1);y=num(:,2);
Y=fft(y);
[wc,w0,a0,ak,bk,c0,ck]=get_harmonics(Y,t(2)-t(1),2)
%the ck contains your frequencies
% wc contains the pulses (rd/s)
stem(wc,abs(ck))  %your Amplitude spectrum
stem(wc,angle(ck))  % your phase spectrum
% get get_harmonics on

http://www.mathworks.com/matlabcentral/fileexchange/37654-get-harmoniques-of-a-real-signal

[Walter Roberson]

Azzi, in your FEX routine, what is the input argument "pas" ? It does not appear to be documented. It appears to be something like a frequency.

[Walter Roberson]

Ron's question implies that the signals are arriving at irregular times, but you seem to be skipping the times in this analysis.

[Azzi Abdelmalek]

Walter, pas is a sample time, and you are right it is not constant. maybe we can interpolate to have a constant sample time. I don't know why the sample time is changing?

pas=min(abs(diff(t)));
t1=min(t):te:max(t);
y1=interp1(t,y,t1)
Y=fft(y);
[wc,w0,a0,ak,bk,c0,ck]=get_harmonics(Y,pas,2)