plot a signal in the freq domain
3 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
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 Kommentare
Akzeptierte Antwort
Dr. Seis
am 7 Mär. 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 Kommentare
Dr. Seis
am 8 Mär. 2012
You are using "f" inside your sinc and sin functions, but I think you meant to use "a(f)" instead.
Weitere Antworten (1)
Thomas
am 7 Mär. 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)
Siehe auch
Kategorien
Mehr zu Get Started with Signal Processing Toolbox finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!