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function Comp_Coef = iqimbal2coef(Amp_Imb_dB, Ph_Imb_Deg)
// This function returns the I/Q imbalance compensator coefficient for given amplitude and phase imbalance.
// Calling Sequence
// COMP_COEF = IQIMBAL2COEF(AMP_IMB_DB, PH_IMB_DEG)
// Description
// COMP_COEF = IQIMBAL2COEF(AMP_IMB_DB, PH_IMB_DEG) returns the I/Q imbalance
// compensator coefficient for given amplitude and phase imbalance.
// Comp_Coef is a scalar or a vector of complex numbers.
// AMP_IMB_DB and PH_IMB_DEG are the amplitude imbalance in dB
// and the phase imbalance in degrees and should be of same size.
// Examples
// [a_imb_db,ph_imb_deg] = iqcoef2imbal([4 2 complex(-0.1145,0.1297) complex(-0.0013,0.0029)])
// disp(a_imb_db,'amplitude imbalance in dB =')
// disp(ph_imb_deg,'phase imbalance in degrees=')
// Comp_Coef = iqimbal2coef(a_imb_db, ph_imb_deg)
// disp(Comp_Coef,'Compensator Coefficients=')
// Bibliography
// http://in.mathworks.com/help/comm/ref/iqimbal2coef.html
// See also
// iqcoef2imbal
// Authors
// Pola Lakshmi Priyanka, IIT Bombay//
//*************************************************************************************************************************************//
//Input argument check
[out_a,inp_a]=argn(0);
if (inp_a > 2) | (out_a > 1) then
error('comm:iqimbal2coef: Invalid number of arguments')
end
if ( or(Comp_Coef==%nan) | or(Comp_Coef==%inf))
error('comm:iqimbal2coef: Input arguments should be finte')
end
if ( size(Amp_Imb_dB) ~= size(Ph_Imb_Deg) ) then
error('comm:iqimbal2coef: Input arguments should be of same size')
end
Comp_Coef = complex(zeros(size(Amp_Imb_dB)));
for i = 1:length(Amp_Imb_dB)
Igain = 10^(0.5*Amp_Imb_dB(i)/20);
Qgain = 10^(-0.5*Amp_Imb_dB(i)/20);
angle_i = -0.5*Ph_Imb_Deg(i)*%pi/180;
angle_q = %pi/2 + 0.5*Ph_Imb_Deg(i)*%pi/180;
K = [Igain*cos(angle_i) Qgain*cos(angle_q); ...
Igain*sin(angle_i) Qgain*sin(angle_q)];
R = inv(K);
w1r = (R(1,1)+R(2,2))/2;
w1i = (R(2,1)-R(1,2))/2;
w2r = (R(1,1)-R(2,2))/2;
w2i = (R(2,1)+R(1,2))/2;
w1 = w1r + complex(0,1) * w1i;
w2 = w2r + complex(0,1) * w2i;
Comp_Coef(i) = w2/w1;
end
endfunction
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