Polyphase_filter_vhdl/mult_blk.vhd

LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
USE ieee.numeric_std.ALL;
USE work.POLY_FIR_PKG.ALL;

ENTITY MULT_BLK IS
  PORT(i_clk    : IN  std_logic;
       i_data   : IN  vect_fir_data_in;
       i_coeffs : IN  vect_fir_coeffs_in;
       o_data   : OUT vect_mult_data_out
       );
END MULT_BLK;

ARCHITECTURE Mult_Path OF MULT_BLK IS

  SIGNAL data_mult_signed : vect_mult_data_out_signed;
  SIGNAL coeffs_signed    : vect_mult_coeffs_signed;
  SIGNAL data_signed      : vect_data_mult_in_signed;


BEGIN

  -- purpose: wiring: cast the i_data and i_coeffs into signed
  cast : FOR i IN 0 TO cst_nb_coeffs_subfilter_in-1 GENERATE
    data_signed(i)   <= signed(i_data(i));
    coeffs_signed(i) <= signed(i_coeffs(i));
  END GENERATE cast;



  -- purpose: calculate and send cast result to output
  mult : PROCESS(i_clk)
  BEGIN
    IF rising_edge(i_clk) THEN
      FOR i IN 0 TO cst_nb_coeffs_subfilter_in-1 LOOP
        data_mult_signed(i) <= data_signed(i) * coeffs_signed(i);
        o_data(i) <= std_logic_vector(unsigned(data_mult_signed(i)));
      END LOOP;
    END IF;
  END PROCESS;

END Mult_Path;