frequency estimation

i make fmcw radar and the output of mixer will be connected to the mic socket in my labtop then i use simulink to calculate range of target so i acquire data from mic port then passed to lpf then i calculate fft then i want to no the frequency which the max(abs(fft))to calculate range and the i try to make a radar scope in matlab and pass the extracted data from sikulink model to it so i have a big problem that it is how i can calculate frequency of a signal in simulink model?

Answer 1

[Honglei Chen]

If you have Signal Processing Blockset or DSP System Toolbox, you can use the FFT block

http://www.mathworks.com/help/toolbox/dsp/ref/fft.html

[mohamed al-asklany]

fft give me amplitude spectrum i need to get freq in array to calculat range

[Honglei Chen]

f = (0:NFFT-1)*Fs/NFFT-Fs/2

[mohamed al-asklany]

can not understand this equation and where i can write it in simulink?