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Diffstat (limited to 'testsuite/vests/vhdl-ams/ashenden/compliant/frequency-modeling/lowpass.vhd')
-rw-r--r-- | testsuite/vests/vhdl-ams/ashenden/compliant/frequency-modeling/lowpass.vhd | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/testsuite/vests/vhdl-ams/ashenden/compliant/frequency-modeling/lowpass.vhd b/testsuite/vests/vhdl-ams/ashenden/compliant/frequency-modeling/lowpass.vhd new file mode 100644 index 000000000..e553f1752 --- /dev/null +++ b/testsuite/vests/vhdl-ams/ashenden/compliant/frequency-modeling/lowpass.vhd @@ -0,0 +1,170 @@ + +-- 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 + +-- not in book + +library ieee_proposed; use ieee_proposed.electrical_systems.all; + +entity resistor is + generic ( res : resistance ); + port ( terminal p1, p2 : electrical ); +end entity resistor; + +architecture ideal of resistor is + quantity v across i through p1 to p2; +begin + v == i * res; +end architecture ideal; + + +library ieee_proposed; use ieee_proposed.electrical_systems.all; + +entity capacitor is + generic ( cap : resistance ); + port ( terminal p1, p2 : electrical ); +end entity capacitor; + +architecture ideal of capacitor is + quantity v across i through p1 to p2; +begin + i == cap * v'dot; +end architecture ideal; + +-- end not in book + + +library ieee; use ieee.math_real.all; +library ieee_proposed; use ieee_proposed.electrical_systems.all; + +entity lowpass is + generic ( gain : real := 1.0; -- gain for 'dot, 'ltf, and 'ztf + fp : real := 10.0; -- pole in Hz for 'dot, 'ltf, and 'ztf + Fsmp : real := 10.0e3 ); -- sample frequency for ztf + port ( terminal input: electrical; + terminal output: electrical ); +end entity lowpass; + +---------------------------------------------------------------- + +architecture RC of lowpass is + + constant cap : real := 1.0e-6; + constant res : real := 1.0 / (math_2_pi * cap * fp); + +begin + + assert false + report "gain is ignored in architecture RC" severity note; + assert false + report "Fsmp is not used in architecture RC" severity note; + + R : entity work.resistor(ideal) + generic map( res => res ) + port map( p1 => input, p2 => output ); + + C : entity work.capacitor(ideal) + generic map( cap => cap ) + port map( p1 => output, p2 => electrical_ref ); + +end architecture RC; + +---------------------------------------------------------------- + +architecture dot of lowpass is + + quantity vin across input to electrical_ref; + quantity vout across iout through output to electrical_ref; + constant wp : real := fp * math_2_pi; -- pole in rad/s + constant tp : real := 1.0 / wp; -- time constant + +begin + + assert false + report "Fsmp is not used in architecture dot" severity note; + + vin == (vout + tp * vout'dot) / gain; + +end architecture dot; + +---------------------------------------------------------------- + +architecture ltf of lowpass is + + quantity vin across input to electrical_ref; + quantity vout across iout through output to electrical_ref; + constant wp : real := fp * math_2_pi; -- pole in rad/s + constant num : real_vector := (0 => wp); + constant den : real_vector := (wp, 1.0); + +begin + + assert false + report "Fsmp is not used in architecture ltf" severity note; + + vout == gain*vin'ltf(num, den); + +end architecture ltf; + +---------------------------------------------------------------- + +architecture z_minus_1 of lowpass is + + quantity vin across input to electrical_ref; + quantity vout across iout through output to electrical_ref; + quantity vin_sampled : real; -- sampled input + quantity vin_zm1, vout_zm1 : real; -- z**-1 + constant Tsmp : real := 1.0 / Fsmp; -- sample period + constant wp : real := fp * math_2_pi; -- pole in rad/s + constant n0 : real := Tsmp * wp; -- z0 numerator coefficient + constant n1 : real := Tsmp * wp; -- z-1 numerator coefficient + constant d0 : real := Tsmp * wp + 2.0; -- z0 denominator coefficient + constant d1 : real := Tsmp * wp - 2.0; -- z-1 denominator coefficient + +begin + + vin_sampled == gain*vin'zoh(Tsmp); + + vin_zm1 == vin_sampled'delayed(Tsmp); + + vout_zm1 == vout'delayed(Tsmp); + + vout == vin_sampled * n0 / d0 + n1 * vin_zm1 / d0 - d1 * vout_zm1 / d0; + +end z_minus_1; + +---------------------------------------------------------------- + +architecture ztf of lowpass is + + quantity vin across input to electrical_ref; + quantity vout across iout through output to electrical_ref; + constant Tsmp : real := 1.0 / Fsmp; -- sample period + constant wp : real := fp * math_2_pi; -- pole in rad/s + constant n0 : real := Tsmp * wp; -- z0 numerator coefficient + constant n1 : real := Tsmp * wp; -- z-1 numerator coefficient + constant d0 : real := Tsmp * wp + 2.0; -- z0 denominator coefficient + constant d1 : real := Tsmp * wp - 2.0; -- z-1 denominator coefficient + constant num : real_vector := (n0, n1); + constant den : real_vector := (d0, d1); + +begin + + vout == gain*vin'ztf(num, den, Tsmp); + +end ztf; |