Aliasing
aliasFreq.m
function [ f_alias ] = aliasFreq( f_sampling, f_noise)
%aliasFreq calculates the aliasing frequency f_alias for
% a real noise frequency f_noise.
% http://tnotes.de/Aliasing
f_max = f_sampling / 2;
f_alias = mod(f_noise,f_sampling);
if (f_alias>f_max)
f_alias = f_sampling - f_alias;
end
end
%aliasFreq calculates the aliasing frequency f_alias for
% a real noise frequency f_noise.
% http://tnotes.de/Aliasing
f_max = f_sampling / 2;
f_alias = mod(f_noise,f_sampling);
if (f_alias>f_max)
f_alias = f_sampling - f_alias;
end
end
aliasFreqCan.m
function [ f_cadi_arr ] = aliasFreqCan( f_sampling, f_noise, N)
%aliasFreqCan calculates aliasing frequency candidates for
% a observed noise frequency f_noise in a estimated spectrum.
% The candidates are the frequencies of possible noise sources.
% http://tnotes.de/Aliasing
f_max = f_sampling / 2;
f_cadi_arr = [];
f_d = f_max - f_noise;
for k=1:2:N
f_r = f_max * k;
f_cani = f_r - f_d;
f_cadi_arr = [f_cadi_arr; f_cani];
f_cani = f_r + f_d;
f_cadi_arr = [f_cadi_arr; f_cani];
end
end
%aliasFreqCan calculates aliasing frequency candidates for
% a observed noise frequency f_noise in a estimated spectrum.
% The candidates are the frequencies of possible noise sources.
% http://tnotes.de/Aliasing
f_max = f_sampling / 2;
f_cadi_arr = [];
f_d = f_max - f_noise;
for k=1:2:N
f_r = f_max * k;
f_cani = f_r - f_d;
f_cadi_arr = [f_cadi_arr; f_cani];
f_cani = f_r + f_d;
f_cadi_arr = [f_cadi_arr; f_cani];
end
end
Examples
>> aliasFreq(200, 2134) ans = 66 >> aliasFreq(200, 220) ans = 20 >> aliasFreq(200, 320) ans = 80 >> aliasFreqCan(40,10,10) ans = 10 30 50 70 90 110 130 150 170 190 >>
Siehe auch • • •