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

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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
 

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
 

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
 

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
 

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