Subversion Repositories all_digital_fm_receiver

LIBRARY ieee;

USE ieee.std_logic_1164.all;

USE IEEE.numeric_std.ALL;

ENTITY loop_filter IS

-- Declarations

 port ( CLK             : in std_logic;

                        RESET   : in std_logic;

                        C                       : in signed(7 downto 0);

                        D1              : out signed(11 downto 0);

                        D2              : out signed(11 downto 0)

                );

END loop_filter  ;

ARCHITECTURE behavior OF loop_filter  IS

signal E : signed(11 downto 0);

signal dtemp : signed(11 downto 0);

begin

process(CLK, RESET)

begin

        if (RESET='1') then

            D1 <= (others => '0');

                                                D2 <= (others => '0');

                                                E <= (others => '0');

                                                dtemp <= (others => '0');

        elsif rising_edge(CLK) then

                                                dtemp <=  (C(7)&C(7)&C(7)&C&'0') + dtemp - E;

                                                E <= dtemp(11)&dtemp(11)&dtemp(11)&dtemp(11)&dtemp(11 downto 4);

                                                D1 <= dtemp;

                                                D2 <= dtemp(11 downto 4)&"0000";

          end if;

end process;

END behavior;