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-- Copyright (C) 2002 Morgan Kaufmann Publishers, Inc
-- This file is part of VESTs (Vhdl tESTs).
-- VESTs 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 2 of the License, or (at
-- your option) any later version.
-- VESTs 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 VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
library ieee_proposed; use ieee_proposed.electrical_systems.all;
library ieee; use ieee.math_real.all;
entity PLL is
generic ( Fp : real := 20.0e3; -- loop filter pole freq [Hz]
Fz : real := 1.0e6; -- loop filter zero freq [Hz]
Kv : real := 100.0e3; -- VCO gain [Hz/V]
Fc : real := 1.0e6 ); -- VCO center freq [Hz]
port ( terminal input, lf_out, vco_out : electrical );
end entity PLL;
----------------------------------------------------------------
architecture behavioral of PLL is
quantity v_in across input to electrical_ref;
quantity v_lf across i_lf through lf_out to electrical_ref;
quantity v_vco across i_vco through vco_out to electrical_ref;
-- internal quantities and constants
-- multiplier
quantity mult : real;
-- loop filter (Lag)
constant wp : real := math_2_pi * fp; -- pole freq in rad/s
constant wz : real := math_2_pi * fz; -- zero freq in rad/s
constant num : real_vector := (1.0, 1.0 / wz); -- numerator array
constant den : real_vector := (1.0, 1.0 / wp); -- denominator array
-- VCO
quantity phi : real; -- used in VCO equation
constant Kv_w : real := math_2_pi * Kv; -- change gain to (rad/s)/V
constant wc : real := math_2_pi * Fc; -- change freq to rad/s
begin
if domain = quiescent_domain use
phi == 0.0; -- initialize phi
else
phi'dot == wc + Kv_w * (v_lf); -- calculate VCO frequency
end use;
mult == v_in * v_vco; -- multiplier output
v_lf == mult'ltf(num, den); -- loop filter output
v_vco == cos(phi); -- VCO output
end architecture behavioral;
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