convolutional_encoder.vhd

扩跳频通信在QUARTUS7.0开发环境下的VHDL源程序及总体框图实现

library ieee;
use ieee.std_logic_1164.all;

entity convolutional_encoder is
port(
	clk:in std_logic;
	data:in std_logic;
	notready:in std_logic;
	datai_1:out std_logic;
	dataq_1:out std_logic;
	control:buffer std_logic);
end;

architecture encoder_arch of convolutional_encoder is
	signal shift:std_logic_vector(8 downto 0);
	signal nextcount:std_logic_vector(3 downto 0);
begin

process(clk,notready)
begin
	if notready='1' then
		shift<="000000000";
	elsif clk'event and clk='1' then
		shift(0)<=shift(1);
		shift(1)<=shift(2);
		shift(2)<=shift(3);
		shift(3)<=shift(4);
		shift(4)<=shift(5);
		shift(5)<=shift(6);
		shift(6)<=shift(7);
		shift(7)<=shift(8);
		shift(8)<=data;
	end if;
end process;

process(notready,clk,control)
begin
	if notready='1' then
		nextcount<="0000";
	elsif clk'event and clk='1' then
		if control='1' then
			nextcount<="0000";
		else
			case nextcount is
			when "0000"=>nextcount<="0001";
			when "0001"=>nextcount<="0011";
			when "0011"=>nextcount<="0010";
			when "0010"=>nextcount<="0110";
			when "0110"=>nextcount<="0111";
			when "0111"=>nextcount<="0101";
			when "0101"=>nextcount<="0100";
			when "0100"=>nextcount<="1100";
			when "1100"=>nextcount<="1101";
			when "1101"=>nextcount<="1111";
			when "1111"=>nextcount<="1110";
			when "1110"=>nextcount<="1010";
			when "1010"=>nextcount<="1011";
			when "1011"=>nextcount<="1001";
			when "1001"=>nextcount<="1000";
			when "1000"=>nextcount<="0000";
			when others=>nextcount<="XXXX";
			end case;
		end if;
	end if;
end process;

process(notready,nextcount)
begin
	if notready='1' then
		control<='0';
	elsif nextcount="1111" then
		control<='1';
	end if;
end process;

process(shift)
begin
	datai_1<=shift(8) xor shift(7) xor shift(6) xor shift(5) xor shift(3) xor shift(1) xor shift(0);
end process;

process(shift)
begin
	dataq_1<=shift(8) xor shift(6) xor shift(5) xor shift(4) xor shift(0);
end process;

end encoder_arch;