need help in this matlab question!!!!!!!!!!!

[vjfaisal]

hi
please help in these concepts , as it is not cleared from the help of matlab.

what is the difference b/w freqz and fft commands in matlab.

and kkindly tell me, which command is used at which moment.....




best regards

 

[Sal]

HI

In fact they are very different,
while freqz can be used only to determine the frequency response of "digital filters" and their arguments are components of a digital filter, the fft is algorithm to get the numerical calculation of the Fourier transform which is employed in a more widely range of topics. freqz may use the fft to get its job done.

Sal

 

[matrixanov]

Hi
I just want to add that you will obtain the same resault if you use freqz to compute the spectrum of a digita signal, but i use freqz in this case because it returns the freqency axis in addition to the complex spektrum
example
if you want to calculate the spectrum of x with sampling freqency Fs[Hz] and plot it

[H f]=freqz(x,1,Fs,N)
plot(f,abs(H))

where
N is the length of FFT
f is the frequencies vektor (0 to Fs/2) Hz

regards

 

[bulx]

Just to add that, when you are talking about a filter, the frequency domain info refers to the filter characteristics, and when you are talking about a signal, the same thing refers to the spectral component of the signal.
-b

 

[vjfaisal]

please giv me the justified answer