plot a signal in the freq domain
3 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
Hello!! I am trying to plot this function X= m*((sin(pi*f/2*m)*sin(pi*f/n))/pi*f*cos(pi*f/2*m))^2;
that is in the freq domain, but when I get the plot is empty. This function is the theorically spectrum of a BOC modulation, so I guess that I can not do fft or pwelch or stuff like that, so I dont know how to plot it in the f domain. I thought is gonna be samething easy as
for f=1:100:100000;
X= m*((sin(pi*f/2*m)*sin(pi*f/n))/pi*f*cos(pi*f/2*m))^2;
end
plot(f,X)
but is not working I will appreciate a lot is someone can give me a hint Thanks in advance Nicolas
2 Commenti
Risposta accettata
Dr. Seis
il 7 Mar 2012
If the code is setup exactly the way you say above, then there is only one element in "f" and one element in "X". You need to do something like this instead:
% Define m and n
f = 1:100:100000;
X = zeros(size(f)); % Preallocate
for ii=1:numel(f)
X(ii)= m*((sin(pi*f(ii)/2*m)*sin(pi*f(ii)/n))/pi*f(ii)*cos(pi*f(ii)/2*m))^2;
end
Or... skip the for loop
X = m*((sin(pi*f/2*m).*sin(pi*f/n))/pi.*f.*cos(pi*f/2*m)).^2;
Then
plot(f,X)
3 Commenti
Dr. Seis
il 8 Mar 2012
You are using "f" inside your sinc and sin functions, but I think you meant to use "a(f)" instead.
Più risposte (1)
Thomas
il 7 Mar 2012
try the following:
define m and n;
m=1;
n=1;
format long
for f=1:100:100000;
X=[X m*((sin(pi*f/2*m)*sin(pi*f/n))/pi*f*cos(pi*f/2*m))^2];
end
plot(f,X)
Vedere anche
Categorie
Scopri di più su Get Started with Signal Processing Toolbox in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!