16阶滤波器.vhd

清华大学Altera FPGA工程师成长手册（光盘视频）

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity filter16 is
port ( clock	: in	std_logic;
	din0x	: in	std_logic_vector( 7 downto 0);
	coef0x	: in	std_logic_vector( 7 downto 0);
	result	: out	std_logic_vector(15 downto 0) );
end;
architecture str of filter16 is
component filter
port (clock	: in	std_logic;
	din0x	: in	std_logic_vector( 7 downto 0);
	coef0x	: in	std_logic_vector( 7 downto 0);
	din4x	: out	std_logic_vector( 7 downto 0);
	coef4x	: out	std_logic_vector( 7 downto 0);
	   result	: out	std_logic_vector(15 downto 0) );
end component;
signal coef4x,din4x,coef8x,din8x,coef12x,din12x,coef16x,din16x:std_logic_vector(7 downto 0);
signal r0x,r4x,r8x,r12x :std_logic_vector(15 downto 0);
begin
	filter_i0:filter port map(clock,din0x,coef0x,din4x,coef4x,r0x);
	filter_i1:filter port map(clock,din4x,coef4x,din8x,coef8x,r4x);
	filter_i2:filter port map(clock,din8x,coef8x,din12x,coef12x,r8x);
filter_i3:filter port map(clock,din12x,coef12x,din16x,coef16x,r12x);
	process(clock)
	begin
		if rising_edge(clock) then
			result <= r0x + r4x + r8x + r12x;
		end if;
	end process;
end;