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diff --git a/testsuite/vests/vhdl-ams/ashenden/compliant/frequency-modeling/opamp_2pole.vhd b/testsuite/vests/vhdl-ams/ashenden/compliant/frequency-modeling/opamp_2pole.vhd
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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;  use ieee.math_real.all;
+library ieee_proposed;  use ieee_proposed.electrical_systems.all;
+
+entity opamp_2pole is
+  port ( terminal in_pos, in_neg, output : electrical );
+end entity opamp_2pole;
+
+----------------------------------------------------------------
+
+architecture dot of opamp_2pole is
+
+  constant A : real := 1.0e6;                      -- open loop gain
+  constant fp1 : real := 5.0;                      -- first pole
+  constant fp2 : real := 9.0e5;                    -- second pole
+  constant tp1 : real := 1.0 / (fp1 * math_2_pi);  -- first time constant
+  constant tp2 : real := 1.0 / (fp2 * math_2_pi);  -- second time constant
+  quantity v_in across in_pos to in_neg;					
+  quantity v_out across i_out through output;
+
+begin
+
+  v_in == (tp1 * tp2) * v_out'dot'dot / A
+          + (tp1 + tp2) * v_out'dot / A + v_out / A;
+
+end architecture dot;
+
+----------------------------------------------------------------
+
+architecture ltf of opamp_2pole is
+
+  constant A : real := 1.0e6;		   -- open loop gain
+  constant fp1 : real := 5.0;		   -- first pole (Hz)
+  constant fp2 : real := 9.0e5;		   -- second pole (Hz)
+  constant wp1 : real := fp1 * math_2_pi;  -- first pole (rad/s)
+  constant wp2 : real := fp2 * math_2_pi;  -- second pole (rad/s)
+  constant num : real_vector := (0 => wp1 * wp2 * A);
+  constant den : real_vector := (wp1 * wp2, wp1 + wp2, 1.0);
+  quantity v_in across in_pos to in_neg;
+  quantity v_out across i_out through output;
+
+begin
+
+  v_out == v_in'ltf(num, den);
+
+end architecture ltf;