resistor.cpp

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/*
 * resistor.cpp - resistor class implementation
 *
 * Copyright (C) 2003, 2004, 2005, 2006, 2008 Stefan Jahn <stefan@lkcc.org>
 *
 * This 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, or (at your option)
 * any later version.
 *
 * This software 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 this package; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 * $Id$
 *
 */

#if HAVE_CONFIG_H
# include <config.h>
#endif

#include "component.h"
#include "resistor.h"

using namespace qucs;

resistor::resistor () : circuit (2) {
  type = CIR_RESISTOR;
}

void resistor::initSP (void) {
  initModel ();
  allocMatrixS ();
}

void resistor::calcSP (nr_double_t) {
  // calculate S-parameters
  nr_double_t z = getScaledProperty ("R") / z0;
  setS (NODE_1, NODE_1, z / (z + 2));
  setS (NODE_2, NODE_2, z / (z + 2));
  setS (NODE_1, NODE_2, 2 / (z + 2));
  setS (NODE_2, NODE_1, 2 / (z + 2));
}

void resistor::calcNoiseSP (nr_double_t) {
  // calculate noise correlation matrix
  nr_double_t r = getScaledProperty ("R");
  nr_double_t T = getPropertyDouble ("Temp");
  nr_double_t f = celsius2kelvin (T) * 4.0 * r * z0 / sqr (2.0 * z0 + r) / T0;
  setN (NODE_1, NODE_1, +f); setN (NODE_2, NODE_2, +f);
  setN (NODE_1, NODE_2, -f); setN (NODE_2, NODE_1, -f);
}

void resistor::calcNoiseAC (nr_double_t) {
  // calculate noise current correlation matrix
  nr_double_t r = getScaledProperty ("R");
  if (r > 0.0 || r < 0.0) {
    nr_double_t T = getPropertyDouble ("Temp");
    nr_double_t f = celsius2kelvin (T) / T0 * 4.0 / r;
    setN (NODE_1, NODE_1, +f); setN (NODE_2, NODE_2, +f);
    setN (NODE_1, NODE_2, -f); setN (NODE_2, NODE_1, -f);
  }
}

void resistor::initModel (void) {
  /* if this is a controlled resistor then do nothing here */
  if (hasProperty ("Controlled")) return;

  nr_double_t T  = getPropertyDouble ("Temp");
  nr_double_t Tn = getPropertyDouble ("Tnom");
  nr_double_t R  = getPropertyDouble ("R");
  nr_double_t DT = T - Tn;

  // compute R temperature dependency
  nr_double_t Tc1 = getPropertyDouble ("Tc1");
  nr_double_t Tc2 = getPropertyDouble ("Tc2");
  R = R * (1 + DT * (Tc1 + Tc2 * DT));
  setScaledProperty ("R", R);
}

void resistor::initDC (void) {
  initModel ();
  nr_double_t r = getScaledProperty ("R");

  // for non-zero resistances usual MNA entries
  if (r != 0.0) {
    nr_double_t g = 1.0 / r;
    setVoltageSources (0);
    allocMatrixMNA ();
    setY (NODE_1, NODE_1, +g); setY (NODE_2, NODE_2, +g);
    setY (NODE_1, NODE_2, -g); setY (NODE_2, NODE_1, -g);
  }
  // for zero resistances create a zero voltage source
  else {
    setVoltageSources (1);
    setInternalVoltageSource (1);
    allocMatrixMNA ();
    voltageSource (VSRC_1, NODE_1, NODE_2);
  }
}

/* The calcDC() function is here partly implemented again because the
   circuit can be used to simulate controlled non-zero resistances. */
void resistor::calcDC (void) {
  nr_double_t r = getScaledProperty ("R");

  // for non-zero resistances usual MNA entries
  if (r != 0.0) {
    nr_double_t g = 1.0 / r;
    setY (NODE_1, NODE_1, +g); setY (NODE_2, NODE_2, +g);
    setY (NODE_1, NODE_2, -g); setY (NODE_2, NODE_1, -g);
  }
}

void resistor::initAC (void) {
  initDC ();
}

void resistor::calcAC (nr_double_t) {
  calcDC ();
}

void resistor::initTR (void) {
  initDC ();
}

void resistor::calcTR (nr_double_t) {
  calcDC ();
}

// Initialize computation of MNA matrix entries for HB.
void resistor::initHB (void) {
  initModel ();
  nr_double_t r = getScaledProperty ("R");
  setVoltageSources (1);
  setInternalVoltageSource (1);
  allocMatrixMNA ();
  voltageSource (VSRC_1, NODE_1, NODE_2);
  setD (VSRC_1, VSRC_1, -r);
}

// properties
PROP_REQ [] = {
  { "R", PROP_REAL, { 50, PROP_NO_STR }, PROP_NO_RANGE }, PROP_NO_PROP };
PROP_OPT [] = {
  { "Temp", PROP_REAL, { 26.85, PROP_NO_STR }, PROP_MIN_VAL (K) },
  { "Tc1", PROP_REAL, { 0, PROP_NO_STR }, PROP_NO_RANGE },
  { "Tc2", PROP_REAL, { 0, PROP_NO_STR }, PROP_NO_RANGE },
  { "Tnom", PROP_REAL, { 26.85, PROP_NO_STR }, PROP_MIN_VAL (K) },
  PROP_NO_PROP };
struct define_t resistor::cirdef =
  { "R", 2, PROP_COMPONENT, PROP_NO_SUBSTRATE, PROP_LINEAR, PROP_DEF };