how to make a smooth sepectrum??

Hi guys,

I have been using the below code to make a loglog fft plot.

But i want to make a smooth spectrum, which goes through the fft plot??

I have also uploade a picture, which shows a fft plot with smooth spectrum.

Thanks in advance!

Fs = 1;                  % sample frequency (Hz)
N = length(A1);          % number of samples
y = fft(A1);
f = (0:N-1)/Fs;          % frequency range
power = abs(y).^2/N;     % power of the DFT
figure(5)
bin_vals = [0 : N-1];
fax_Hz = bin_vals*Fs/N;
N_2 = ceil(N/2);
loglog(fax_Hz(1:N_2),(X_mags(1:N_2)))

Answer 1

[Ameer Hamza]

See smoothdata(): https://www.mathworks.com/help/releases/R2020a/matlab/ref/smoothdata.html. Pass the X_mags vector through smooth data to get a smooth profile. Similarly, you can also try low to use a low-pass filter: https://www.mathworks.com/help/signal/ref/lowpass.html on the fft data.