-- Copyright (C) 2000-2002 The University of Cincinnati.  
-- All rights reserved. 

-- This file is part of VESTs (Vhdl tESTs).

-- UC MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
-- SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
-- OR NON-INFRINGEMENT.  UC SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY
-- LICENSEE AS A RESULT OF USING, RESULT OF USING, MODIFYING OR
-- DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.

-- By using or copying this Software, Licensee agrees to abide by the
-- intellectual property laws, and all other applicable laws of the U.S.,
-- and the terms of this license.

-- You may modify, distribute, and use the software contained in this
-- package under the terms of the "GNU GENERAL PUBLIC LICENSE" version 2,
-- June 1991. A copy of this license agreement can be found in the file
-- "COPYING", distributed with this archive.

-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

-- ---------------------------------------------------------------------
--
-- $Id: double_tuned.ams,v 1.1 2002-03-27 22:11:19 paw Exp $
-- $Revision: 1.1 $
--
-- ---------------------------------------------------------------------

--************************************************************************
-- Structural Model of a DOUBLED TUNED TRANSFORMER 
-- VHDL-AMS implementation
-- Developed at Distributed Processing Laboratory
-- University of Cincinnati
--************************************************************************

--************************************************************************
--
--	             ________________________________
-- 	    V_in    |                                |           
--	      o-----|--------            ------------|---o  V_out         
--	            |  |     |          |      |     |	
--	            |  |     |          |      |     |	
--	            |  |     |          |      |     |
--	            |  |     >rp      rs<      |     |
--	            |  |     >          <     ---    |
--	      FM    | _|_    | .        |     ---    |  FM & AM Signal
--	    Signal  | ___   ( )        ( )     |Cs   |
--	            |  |    ( )  ||    ( )     |     |
--	            |  |Cp  ( )  ||    ( )     |     |
--	            |  |     | Lp    Ls |      |     |
--	      o-----|--------            ------------|---o V_out_gnd      
--	  Vin_gnd   |________________________________|
--
--************************************************************************

PACKAGE electricalSystem IS
NATURE electrical IS real ACROSS real THROUGH ground reference;
FUNCTION SIN (X : real ) RETURN real;
FUNCTION COS (X : real ) RETURN real;
FUNCTION EXP  (X : real ) RETURN real;
FUNCTION SQRT (X : real) RETURN real;
END PACKAGE electricalSystem;

------------------------------------------------------------------------------
----------------------  TUNED TRANSFORMER ------------------------------------
------------------------------------------------------------------------------

USE work.electricalSystem.all;

ENTITY FM_2_AM_Converter IS
generic (freq_fm : real := 1.0);
port (terminal Signal_in, Signal_out : electrical);
END FM_2_AM_Converter;

ARCHITECTURE behav OF FM_2_AM_Converter IS

  CONSTANT  k :real:=0.4;
  CONSTANT lp :real:=1.0e-3;
  CONSTANT ls :real:=1.0e-3;
  CONSTANT rp :real:=10.0;	
  CONSTANT rs :real:=10.0;	

--> Q = 2*PI*Freq*L/R 		: for 10.7 MHz -> q=6723     

  terminal temp1,temp2: electrical;

  quantity v_rp across i_rp through Signal_in to temp1;
  quantity v_rs across i_rs through temp2     to Signal_out;
  
  quantity V_cp across i_cp through Signal_in  to ground;
  quantity V_cs across i_cs through Signal_out to ground;
   	
  QUANTITY V_lp ACROSS i_lp Through temp1 to ground;
  quantity v_ls across i_ls through temp2 to ground;

  quantity m : real ;         -- mutual inductance;


BEGIN    --  behavior

  brk : break i_lp => 0.0, i_ls => 0.0,v_cp=>0.0,v_cs=>0.0;

  mutual : m == k * sqrt(lp*ls);
  voltp : v_lp == lp * i_lp'dot + m * i_ls'dot;
  volts : v_ls == ls * i_ls'dot + m * i_lp'dot;

  i_cp == (25.331/(freq_fm*freq_fm))*v_cp'dot;   -- cal. using the value of Inductance
  i_cs == (25.331/(freq_fm*freq_fm))*v_cs'dot;   -- as 1.0e-3.
				     	  	 -- modify this if u want to use another	
  v_rp == rp *i_rp;	              	         -- value of Lp and ls	
  v_rs == rs *i_rs;				 -- c =1/(2*PI*F)*(2*PI*F)*L

END behav;

------------------------------Test Waveforms-----------------------

--> FM  wave generator 
----------------------

use work.electricalsystem.all;

ENTITY fm_source IS
generic(c_freq:real:=100.0e6;		-- carrier frequency
	s_freq:real:=25.0e3;		-- modulating(signal) frequency 
	 V_fm :real:=1.0		-- Peak voltage of FM signal
       );
PORT(TERMINAL fm_out,fm_gnd : electrical);
END fm_source;

ARCHITECTURE fm_behavior OF fm_source IS

quantity V_fm_signal across i_fm_signal through fm_out to fm_gnd;

BEGIN

--- the max. freq. deviation is 75.0Khz for FM Signal. 

  V_fm_signal == (V_fm*sin((2.0*22.0/7.0*c_freq*real(time'pos(now))*1.0e-15)+(75.0e3/s_freq*sin(2.0*22.0/7.0*s_freq*real(time'pos(now))*1.0e-15))));

END ARCHITECTURE fm_behavior;

--------------------------------  TEST BENCH --------------------------

use work.electricalSystem.all;

entity test is
end test;

architecture structure of test is

  terminal t1,t2,t3 : electrical;

--> Component Declarations

component fm_source is
generic(c_freq:real:=100.0e6;		-- carrier frequency
	s_freq:real:=25.0e3;		-- modulating(signal) frequency 
	  V_fm:real:=1.0		-- Peak Voltage of FM Signal	
       );
PORT( TERMINAL fm_out,fm_gnd : electrical);
end component;
for all: fm_source use entity work.fm_source(fm_behavior);

component FM_2_AM_Converter IS
generic (freq_fm : real := 1.0);
port (terminal Signal_in, Signal_out : electrical);
end component;
for all : FM_2_AM_Converter use entity work.FM_2_AM_Converter(behav);

quantity v_out across i_out through t2 to ground;

begin  

   FM_AM : FM_2_AM_Converter generic map(freq_fm=>10.7816e6)
 		       	     port map(t1,t2);

   fm_ip : fm_source         generic map(10.7e6,10.0e3,1.0)
			     port map(t1,ground);
   
  resout : v_out == i_out * 1.0e6;

end structure;

------------------------------  NOTES -------------------------------------
--	It is a tuned transformer with the resonant freq. slighty higher 
--	than the carrier freq.
--
--	Q = 2*PI*Freq*L/Rl		BandWidth = F_carrier/Q
--	F_carrier = 1/2*PI*sqrt(L*C)    
--
--	Tune the Transformer to a frequency of   (All quantities in MHz)
--		( F_carrier + 0.075 + 0.005 + Band_width ) 
--			       |	
--			       |	
-- 			       *-> Max Deviation	
----------------------------------------------------------------------------