-------------------------------------------------------------------------------
-- Copyright (c) 2002 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 
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-- notice that this model has been modified and the date of modification; and 
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-- THIS MODEL IS LICENSED TO YOU "AS IS" AND WITH NO WARRANTIES, EXPRESS OR 
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-------------------------------------------------------------------------------
-- File       : PressureConstant.vhd
-- Author     : Mentor Graphics
-- Created    : 2002-05-21
-- Last update: 2003-05-13
-------------------------------------------------------------------------------
-- Description: Ideal Hydraulic Constant Pressure Source
--              Includes Frequency Domain Settings
-------------------------------------------------------------------------------
-- Revisions  :
-- Date        Version     Author              Description
-- 2002-05-21  1.0         Mentor Graphics     Created
-------------------------------------------------------------------------------
--
--    ...Model Summary
--
--    This model represents an ideal constant pressure source. Its
--    characteristics are such that the specified pressure is applied across
--    from port1 to port2 and flow rate is such that the specified pressure
--    level is maintained.
--    There is also the capability for modeling small signal characteristics
--    using the "ac_mag" and "ac_phase" GENERIC values. 
--    The polarity of the flow rate is consistant with the general convention 
--    where the value is positive when the "flow" is through from port1 to
--    port2.
-------------------------------------------------------------------------------
library IEEE;
use IEEE.MATH_REAL.all;
use IEEE.fluidic_systems.all;

entity PressureConstant is

  generic (
    level    : pressure;               -- Constant value [N/m**2]
    ac_mag   : pressure := 1.0;        -- AC magnitude [N/m**2]
    ac_phase : real := 0.0);           -- AC phase [degrees]

  port ( terminal port1, port2 : fluidic);

end entity PressureConstant;

architecture ideal of PressureConstant is
-- Declare Through and Across Branch Quantities
  quantity p across flow through port1 to port2;
-- Declare quantity in frequency domain for AC analysis
  quantity ac_spec      : real spectrum ac_mag, math_2_pi*ac_phase/360.0;

begin

  if domain = quiescent_domain or domain = time_domain use
    p == level;
  else       --      if DOMAIN = FREQUENCY_DOMAIN use
    p   == ac_spec;
  end use;

end architecture ideal;
-------------------------------------------------------------------------------
-- Copyright (c) 2002 Mentor Graphics Corporation
-------------------------------------------------------------------------------