library ieee;use ieee.std_logic_1164.all;use ieee.math_real.all;use ieee.numeric_std.all;use work.normal_distribution_random_noise.all;--by MEP 22 February 2011--usage:--these are functions, which means they can be on the right-hand side--of an assignment. These functions create an I and Q sample.--The arguments are --a natural number standing for the index of the sample,--a real number that provides a way to have many samples per period,--a real number standing for the standard deviation of the normally distributed noise added to the sample,--a real number standing for the amplitude of the signal,--a natural number indicating the width of the vector holding the returned value,--a real number indicating the gain error of Q with respect to I,--and a real number indicating the phase error of Q with respect to I----create_I_sample(n_dat, freq, sgma, amplitude, return_width);--create_Q_sample(n_dat, freq, sgma, amplitude, return_width, e1, a1);--package create_sample is function create_I_sample( n_dat : integer; freq : real; sgma : real; amplitude : real; return_width : natural) return signed; function create_Q_sample( n_dat : integer; freq : real; sgma : real; amplitude : real; return_width : natural; --x1_tb'LENGTH e1 : real; --gain error a1 : real) --phase error return signed; end package create_sample;package body create_sample is function create_I_sample( n_dat : integer; freq : real; sgma : real; amplitude : real; return_width : natural) --x1_tb'LENGTH return signed is variable local_x1 : real; variable int_x1: integer; variable returned_x1 : signed(return_width downto 0); begin local_x1 := amplitude*sin(2.0*math_pi*(real(n_dat))*freq) + random_noise(sgma); --report "local_x1 inside CREATE_I_SAMPLE function is " & real'image(local_x1) & "."; --AGC scaling. Scaling factor is maximum value the signal can take. local_x1 := local_x1/(1.11); --report "local_x1 after AGC inside CREATE_I_SAMPLE function is " & real'image(local_x1) & "."; int_x1 := integer(trunc(local_x1*((2.0**31.0)-1.0))); --scaled --report "integer version of x1 inside CREATE_I_SAMPLE function is " & integer'image(int_x1) & "."; returned_x1 := (to_signed(int_x1, return_width+1)); return returned_x1;end function; function create_Q_sample( n_dat : integer; freq : real; sgma : real; amplitude : real; return_width : natural; --x1_tb'LENGTH e1 : real; --gain error a1 : real) return signed is variable local_y1 : real; variable int_y1: integer; variable returned_y1 : signed(return_width downto 0); begin local_y1 := amplitude*(1.0 + e1)*cos(2.0*math_pi*(real(n_dat))*freq + a1) + random_noise(sgma); --report "local_y1 first created CREATE_Q_SAMPLE function is " & real'image(local_y1) & "."; --AGC scaling. Scaling factor is maximum value the signal can take. local_y1 := local_y1/(1.11); --report "local_y1 after AGC inside CREATE_Q_SAMPLE function is " & real'image(local_y1) & "."; int_y1 := integer(trunc(local_y1*((2.0**31.0)-1.0))); --scaled --report "integer version of y1 inside CREATE_Q_SAMPLE function is " & integer'image(int_y1) & "."; returned_y1 := (to_signed(int_y1, return_width+1)); return returned_y1; end function;end package body create_sample;

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