-------------------------------------------------------------------------------
-- Copyright (c) 2003 Mentor Graphics Corporation
--
-- This model is a component of the Mentor Graphics VHDL-AMS educational open 
-- source model library, and is covered by this license agreement. This model,
-- including any updates, modifications, revisions, copies, and documentation 
-- are copyrighted works of Mentor Graphics. USE OF THIS MODEL INDICATES YOUR 
-- COMPLETE AND UNCONDITIONAL ACCEPTANCE OF THE TERMS AND CONDITIONS SET FORTH
-- IN THIS LICENSE AGREEMENT.  Mentor Graphics grants you a non-exclusive 
-- license to use, reproduce, modify and distribute this model, provided that:
-- (a) no fee or other consideration is charged for any distribution except 
-- compilations distributed in accordance with Section (d) of this license 
-- agreement; (b) the comment text embedded in this model is included verbatim
-- in each copy of this model made or distributed by you, whether or not such 
-- version is modified; (c) any modified version must include a conspicuous 
-- notice that this model has been modified and the date of modification; and 
-- (d) any compilations sold by you that include this model must include a 
-- conspicuous notice that this model is available from Mentor Graphics in its
-- original form at no charge.
--
-- THIS MODEL IS LICENSED TO YOU "AS IS" AND WITH NO WARRANTIES, EXPRESS OR 
-- IMPLIED.  MENTOR GRAPHICS SPECIFICALLY DISCLAIMS ALL IMPLIED WARRANTIES OF 
-- MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  MENTOR GRAPHICS SHALL
-- HAVE NO RESPONSIBILITY FOR ANY DAMAGES WHATSOEVER.
-------------------------------------------------------------------------------
-- File       : e_NthOrderPoly.vhd
-- Author     : Mentor Graphics
-- Created    : 2002/05/21
-- Last update: 2003-05-20
-------------------------------------------------------------------------------
-- Description: Nth-degree S-domain polynomial transfer function, with 
-- electrical connections. 
-------------------------------------------------------------------------------
-- Revisions  :
-- Date        Version     Author              Description
-- 2002/05/21  1.0         Mentor Graphics     Created 
-- 2003/04/15  1.1         Mentor Graphics     Added z-domain architecture 
-------------------------------------------------------------------------------

library IEEE;
use IEEE.math_real.all;
use IEEE.electrical_systems.all;

entity e_NthOrderPoly is
  generic (
    --  User may add comma-separated generic values into num and den 
    --  arrays. These values represent the transfer function
    --  coefficients in ascending powers of s (s0, s1, s2, etc).
    --  The size of num and den vectors is defined by the number of 
    --  comma-separated coeffs.

    num   : real_vector := (314.0, 0.0);  -- Numerator coeffs. in rad/s
    den   : real_vector := (314.0, 1.0);  -- Denominator coeffs. in rad/s
    k     : real        := 1.0;           -- Normalizing gain
    Fsmp  : real        := 10.0e3;  -- For z-dmn only: Sample frequency (in Hz)
    init_delay  : real  := 0.0;     -- For z-dmn only: Initial Delay (real)
    z_num : real_vector := (0.0314, 0.0314);  -- For z-dmn only: num coeffs.
    z_den : real_vector := (2.0314, -1.9686)  -- For z-dmn only: den coeffs.
    );
  port (
    terminal input  : electrical;
    terminal output : electrical);
end entity e_NthOrderPoly;
-------------------------------------------------------------------------------
-- Transfer Function:
--
--               a0 + a1s + a2s^2 ...
-- Vo(s) = K * ------------------------ Vin(s)
--               b0 + b1s + b2s^2 ...
-------------------------------------------------------------------------------
architecture s_dmn of e_NthOrderPoly is
  quantity   vin across input to electrical_ref;
  quantity   vout across iout through output to electrical_ref;
begin
  vout == k*vin'ltf(num, den);          -- S-domain transfer function
end architecture s_dmn;

-- Z Domain Implementation
-------------------------------------------------------------------------------
-- Transfer Function:
--
--             a0 + a1z^(-1) + a2z^(-2) + ...
-- H(z) = K * ------------------------------- 
--             b0 + b1z^(-1) + b2z^(-2) + ...
-------------------------------------------------------------------------------
architecture z_dmn of e_NthOrderPoly is
  quantity vin across input to electrical_ref;
  quantity vout across iout through output to electrical_ref;
  constant T : real := 1.0/Fsmp;
begin
  vout == k*vin'ztf(z_num, z_den, T, init_delay); -- Z-domain transfer function
end architecture z_dmn; 

-------------------------------------------------------------------------------
-- Copyright (c) 2003 Mentor Graphics Corporation
-------------------------------------------------------------------------------