Subversion Repositories astron_filter

-------------------------------------------------------------------------------
-- Author: Harm Jan Pepping : pepping at astron.nl: 2012
-- Copyright (C) 2012
-- ASTRON (Netherlands Institute for Radio Astronomy) <http://www.astron.nl/>
-- P.O.Box 2, 7990 AA Dwingeloo, The Netherlands
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program.  If not, see <http://www.gnu.org/licenses/>.
--
-------------------------------------------------------------------------------
 
library ieee, common_pkg_lib;
use IEEE.std_logic_1164.all;
use common_pkg_lib.common_pkg.all;
 
package fil_pkg is
 
  -- Parameters for the (wideband) poly phase filter. 
  type t_fil_ppf is record
    wb_factor      : natural; -- = 1, the wideband factor
    nof_chan       : natural; -- = default 0, defines the number of channels (=time-multiplexed input signals): nof channels = 2**nof_chan 
    nof_bands      : natural; -- = 1024, the number of polyphase channels (= number of points of the FFT)
    nof_taps       : natural; -- = 16, the number of FIR taps per subband
    nof_streams    : natural; -- = 1, the number of streams that are served by the same coefficients.
    backoff_w      : natural; -- = 0, number of bits for input backoff to avoid output overflow
    in_dat_w       : natural; -- = 8, number of input bits per stream
    out_dat_w      : natural; -- = 16, number of output bits per stream
    coef_dat_w     : natural; -- = 16, data width of the FIR coefficients
  end record;
 
  constant c_fil_ppf : t_fil_ppf := (1, 0, 1024, 16, 1, 0, 8, 16, 16);
 
  -- Definitions for fil slv array (an array can not have unconstraint elements, so choose sufficiently wide 32 bit slv elements)
  subtype  t_fil_slv_arr is t_slv_32_arr;    -- use subtype to ease interfacing to existing types and to have central definition for filter components
  constant c_fil_slv_w   : natural := 32;    -- match slv width of t_fil_slv_arr
 
  -- Record with the pipeline settings for the filter units. 
  type t_fil_ppf_pipeline is record
    -- generic for the taps and coefficients memory
    mem_delay             : natural;  -- = 1
    -- generics for the multiplier in in the filter unit
    mult_input            : natural;  -- = 1
    mult_product          : natural;  -- = 1
    mult_output           : natural;  -- = 1                   
    -- generics for the adder tree in in the filter unit
    adder_stage           : natural;  -- = 1
    -- generics for the requantizer in the filter unit
    requant_remove_lsb : natural;  -- = 1
    requant_remove_msb : natural;  -- = 0
  end record;
 
  constant c_fil_ppf_pipeline : t_fil_ppf_pipeline := (1, 1, 1, 1, 1, 1, 0);
 
end package fil_pkg;
 
package body fil_pkg is
end fil_pkg;