I want to do a comparison of power spectral density of BFSK, 4FSK and 8FSK by using matlab
"fskmod".Following is the code:
M = 2; freqsep = 32; nsamp = 4; Fs = 64; x = randint(1000,1,M); % Random signal y = fskmod(x,M,freqsep,nsamp,Fs); % Modulate. ly = length(y); % Create an FFT plot. freq = [-Fs/2 : Fs/ly : Fs/2 - Fs/ly]; Syy = 10*log10(fftshift(abs(fft(y)))); plot(freq,Syy)
With this configuration, I get a very good spectrum but when I change nsamp to 8 or any other value,multiple lobes start to appear between two frequencies. The confusion is in the understanding of the relation of nsamp and frequency separation. Could any one solve this confusion???