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Commit fa921b9c authored by Martin Hudlicka's avatar Martin Hudlicka
Browse files

Deleted

parent 317a3028
function Hrrc = F_freqSqrtRaisedCosine(Tsym, alpha, deltaT, N)
% This function generates the frequency response of a root raised cosine
% filter using the definition in the following reference:
% M. Joost, "Theory of Root-Raised Cosine Filter," published online at
% www.michael-joost.de/rrcfilter.pdf
% See Section 5.2.1 of IEEE P1765 document: Filter the Baseband Signals
% INPUTS:
% Tsym: Symbol duration in ns, inverse of symbol rate
% alpha: Root raised cosine filter rolloff
% deltaT: Point spacing in ns, inverse of sample rate
% N: Total number of points
% OUTPUTS:
% Hrrc: Transfer function of the root-raised cosine filter
% The Hrrc is defined in three frequency ranges
% At lower frequencies, f < f1, constant spectrum
% For frequencies, f1 > f > f2, root raised cosine function
% At higher frequencies, f > f2, zero
% Calculate the frequencies f1 and f2:
f2 = ((1.0 + alpha) / 2.0) / double(Tsym); % Maximum filter frequency
f1 = ((1.0 - alpha) / 2.0) / double(Tsym); % Start of rolloff
deltaF = 1.0 / (double(N) * deltaT); % Frequency spacing
ns = floor(f2 / deltaF); % Set of frequencies in the passband of the filter
Ntotal = 1 + 2 * ns;
Hrrc = complex(zeros(Ntotal,1));
B = sqrt(Tsym);
% Create the filter values
k = 0;
for kFreq = -ns:ns
Freq = double(kFreq) * deltaF;
k = k + 1;
if abs(Freq) <= f1
Hrrc(k) = B;
elseif abs(Freq) <= f2
Hrrc(k) = (B / sqrt(2.0)) * sqrt(1.0 + cos(pi * (Tsym/alpha) * ((abs(Freq) - f1))));
end
end
end
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