有關音樂程式的頻率計算問題

p123315427 · 發表於 2011-6-18 22:20:15

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

---- Uncomment the following library declaration if instantiating
---- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;
entity musicmusic is
  port( inclk    :  in    std_logic;       --Clock Signal
      spk    :  buffer  std_logic; --speaker driver
   reset :in std_logic;
   L1,L2    : in std_logic);
end  musicmusic ;
--------------------------------------------------------------------------------------
architecture behave of  musicmusic  is
  signal tone       :  std_logic_vector(10 downto 0);
  signal tone_count  :  std_logic_vector(10 downto 0);
  signal tone_index  :  integer range 0 to 19;
  signal clk10_count :  std_logic_vector(17 downto 0);
  --signal time       :  integer range 0 to 500;
  signal clk       :  std_logic;
  signal clk10    :  std_logic;
  signal se1 :  integer range 0 to 63;
  signal se2 :  integer range 0 to 160;
  signal se3 :  integer range 0 to 35;
-------------------------------------------------------------------------------------
  begin
  PROCESS(inclk)  --generate 2Mhz clock signal
   variable cnt1 : INTEGER RANGE 0 TO 39;
BEGIN
   IF inclk='1' AND inclk'event THEN
      IF cnt1=39 THEN cnt1:=0;
         ELSE
         IF cnt1<30 THEN clk<='1';
            ELSE clk<='0';
         END IF;
         cnt1:=cnt1+1;
      END IF;
   END IF;
END PROCESS;
-------------------------------------------------------------------------------------
process(clk)  --generate 10hz clock signal
begin
   if(clk'event and clk='1') then
      clk10_count<=clk10_count+1;
      if(clk10_count=16#3ff#) then
         clk10<=not clk10;
      end if;
   end if;
  end process;
-------------------------------------------------------------------------------------
  process(clk10)
begin
   if reset='0' then
   se1<=0;
se2<=0;
se3<=0;
tone_index<=0;
elsif(clk10'event and clk10='1') then
----------------------------------------------------------------------
  process(tone_index)
begin
   case tone_index is
      when 0=>tone<="11111111111"; --no output
      when 1=>tone<="01100000101"; --773--1
      when 2=>tone<="01110010000"; --912--2
      when 3=>tone<="10000001100"; --1036--3
when 4=>tone<="10000111111"; --1087--4
      when 5=>tone<="10010101101"; --1197--5
      when 6=>tone<="10100001010"; --1290--6
      when 7=>tone<="10101011100"; --1372--7
      when 8=>tone<="10110000010"; --1410--High 1
      when 9=>tone<="10111001000"; --1480--High 2
      when 10=>tone<="11000000110";  --1542--High 3
      when 12=>tone<="11000110000";  --1584--High 4
      when 13=>tone<="11010000100";  --1668--High 5
when 16=>tone<="10001111111";  --1151--High #4
when 17=>tone<="10011110100";  --1766--High #5
when 18=>tone<="10111100110";  --1510--High #2
      when others=>tone<="11111111111"; --others:no output

   end case;
  end process;

  -------------------------------------------------------------------------------------
  process(clk) --control the frequence of the speaker
begin
   if(clk'event and clk='1') then
      if(tone_count=16#7ff#) then
         tone_count<=tone;
         if(tone<2047) then
            spk<=not spk;
         end if;
      else
         tone_count<=tone_count+1;
      end if;
   end if;
  end process;

end behave;

中 do 的773頻率是如何算出來的??
那是用多少HZ去算的??
希望有公式給個解答

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[問題求助] 有關音樂程式的頻率計算問題