fft error: Not enough input arguments.

Someone can help me in this code for know de heart frequency.

function homoFreq(y,Fs,nfft) 

% x is input signal 

% nfft is number of fft points 

Fs = 16000;%sampling rate 

% subplot(2,1,1),plot(x); 
% title('Waveform'), xlabel('Time (ms)'), ylabel('Amplitude'); 

[y,Fs]=wavread('*.wav'); %* is for file name

t=((1:length(y))-1)/Fs;

figure();
plot(t,y); %only for check

ht=fft((y.*hamming(length(y))),nfft); %nfft point -----> fft error in this line

freqAxis=Fs/2*length(ht)/Fs; 

f=(0:freqAxis)*Fs/length(ht); 
% subplot(2,1,2); 

spec = 20*log10(abs(ht(1:length(f)))); 

plot(f,spec);ylim([-50 35]); 

title('Spectrum'), xlabel('Frequency'),ylabel('Log Magnitude'); 

[pks,locs] = findpeaks(spec); 

for m = 5:5,  

      differ(m-4) = locs(m)-locs(m-1);  

      %finding the difference between 5th... 
      %and 4th peak of the spectrum     

end 

pitchFreq = mean(differ)*Fs/nfft; 

fprintf('Pitch Frequency in Frequency Domain = %gHz\n', pitchFreq)

[Walter Roberson]

What does

which -all fft

report?

[Fernando]

This function read a heart-beat sound with Fs=16000, format .wav, and determines the heart rate.

I am developing work to the chair of theory of signs at the university, and i find this code in a website, and dicided use it for improve my work, but it didn´t work.

I need to confess that i am new in matlab.

The report in matlab is:

>> homoFreq

Error using homoFreq (line 12)

Not enough input arguments.

Answer 1

[Walter Roberson]

You need to invoke

homoFreq([], [], NFFT)

where NFFT is the number of points you want to use for the fft.

[Fernando]

So, is nfft relative to sampling rate?

[Dr. Seis]

He is simply suggesting you replace "NFFT" with the number of points you want to use. For example:

homeFreq([],[],1024)

The number you replace NFFT with depends on if you want to truncate "y", keep "y" the same length, or pad "y" with zeros until its length is equal to NFFT.

[Fernando]

I think that understand what you suggest.

Thanks a lot.

Answer 2

[Dr. Seis]

When you run the function as "homFreq" (with no input arguments) from the command line (or from the editor) you aren't defining "nfft" before it is being called at line 12.