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;