Subversion Repositories iqcorrection

library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

use ieee.std_logic_unsigned.all;

use ieee.math_real.all;

architecture IQGainPhaseCorrection_integer of IQGainPhaseCorrection is

        --signal declarations

begin

    correction : process (clk) is

        variable x1_real : real := 0.0;

        variable y1_real : real := 0.0;

        variable reg_1x1 : real := 0.0;

        variable y2      : real := 0.0;

        variable mu_1    : real := 0.000244;

        variable mu_2    : real := 0.000122;

        variable x1y2    : real := 0.0;

        variable reg_1   : real := 0.0;

        variable reg_2   : real := 1.0;

        variable y3      : real := 0.0;

                begin

                if clk'event and clk = '1' then

                           --get I and Q, and convert them back to real values. 

                           x1_real := real(to_integer(x1));

                           x1_real := x1_real / ((2.0**31.0)-1.0);

                           y1_real := real(to_integer(y1));

                           y1_real := y1_real / ((2.0**31.0)-1.0);

                           --phase error estimate, step size set to 0.000244

                           --which is achieved with an arithmetic shift right by 12.

                           y2 := y1_real - reg_1 * x1_real;

                           reg_1 := reg_1 + mu_1*x1_real*y2;

                           --phase_error <= reg_1;

                           --gain error estimate, step size set to 0.000122

                           --which is achieved with a shift right by 13.

                           y3 := y2 * reg_2;

                           reg_2 := reg_2 + mu_2 * ((x1_real * x1_real) - (y3*y3));

                end if;

        end process;

end IQGainPhaseCorrection_integer;