jens
b31f3e7435
git-svn-id: http://moon:8086/svn/matlab/trunk@153 801c6759-fa7c-4059-a304-17956f83a07c
36 lines
922 B
Matlab
Executable File
36 lines
922 B
Matlab
Executable File
% [h] =fir_rrc(fa,Tsym,Alpha,N)
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function [b,k,delay] =fir_rrc(fa,Tsym,Alpha,N)
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if rem(N,2),
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delay = (N-1)/2;
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else
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delay = N/2;
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end
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n = ((0:N-1)-delay)/fa;
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ind1 = find(n == 0);
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if ~isempty(ind1),
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b(ind1) = - sqrt(2./Tsym) ./ (pi.*fa) .* (pi.*(Alpha-1) - 4.*Alpha );
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end
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ind2 = find(abs(abs(8.*Alpha.*n./Tsym) - 1.0) < sqrt(eps));
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if ~isempty(ind2),
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b(ind2) = sqrt(2./Tsym) ./ (2.*pi.*fa) ...
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* ( pi.*(Alpha+1) .* sin(pi.*(Alpha+1)./(4.*Alpha)) ...
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- 4.*Alpha .* sin(pi.*(Alpha-1)./(4.*Alpha)) ...
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+ pi.*(Alpha-1) .* cos(pi.*(Alpha-1)./(4.*Alpha)) ...
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);
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end
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ind = 1:length(n);
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ind([ind1 ind2]) = [];
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nind = n(ind);
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b(ind) = -4.*Alpha./fa .* ( cos((1+Alpha).*2.*pi.*nind./Tsym) + ...
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sin((1-Alpha).*2.*pi.*nind./Tsym) ./ (8.*Alpha.*nind./Tsym) ) ...
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./ (pi .* sqrt(1./(2./Tsym)) .* ((8.*Alpha.*nind./Tsym).^2 - 1));
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b = sqrt(2./Tsym) .* b;
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k=0.5*fa*Tsym;
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