//DISCRETE_CLASS_DESTRUCTOR(_name)
//~discrete_dst_sallen_key_node() { }
// discrete_base_node
//DISCRETE_RESET(dst_sallen_key)
public override void reset()
{
discrete_op_amp_filt_info info = (discrete_op_amp_filt_info)custom_data(); //DISCRETE_DECLARE_INFO(discrete_op_amp_filt_info);
double freq = 0;
double q = 0;
switch ((int)DST_SALLEN_KEY__TYPE)
{
case DISC_SALLEN_KEY_LOW_PASS:
freq = 1.0 / (2.0 * M_PI * std.sqrt(info.c1 * info.c2 * info.r1 * info.r2));
q = std.sqrt(info.c1 * info.c2 * info.r1 * info.r2) / (info.c2 * (info.r1 + info.r2));
break;
default:
fatalerror("Unknown sallen key filter type\n");
break;
}
calculate_filter2_coefficients(this, freq, 1.0 / q, DISC_FILTER_LOWPASS, ref m_fc);
set_output(0, 0);
}
//DISCRETE_STEP(dst_op_amp_filt)
public void step()
{
//DISCRETE_DECLARE_INFO(discrete_op_amp_filt_info)
discrete_op_amp_filt_info info = (discrete_op_amp_filt_info)custom_data();
double v_out = 0;
double i;
double v = 0;
if (DST_OP_AMP_FILT__ENABLE() != 0)
{
if (m_is_norton != 0)
{
v = DST_OP_AMP_FILT__INP1() - OP_AMP_NORTON_VBE;
if (v < 0)
{
v = 0;
}
}
else
{
/* Millman the input voltages. */
i = m_iFixed;
switch (m_type)
{
case DISC_OP_AMP_FILTER_IS_LOW_PASS_1_A:
i += (DST_OP_AMP_FILT__INP1() - DST_OP_AMP_FILT__INP2()) / info.r1;
if (info.r2 != 0)
{
i += (m_vP - DST_OP_AMP_FILT__INP2()) / info.r2;
}
if (info.r3 != 0)
{
i += (m_vN - DST_OP_AMP_FILT__INP2()) / info.r3;
}
break;
default:
i += (DST_OP_AMP_FILT__INP1() - m_vRef) / info.r1;
if (info.r2 != 0)
{
i += (DST_OP_AMP_FILT__INP2() - m_vRef) / info.r2;
}
break;
}
v = i * m_rTotal;
}
switch (m_type)
{
case DISC_OP_AMP_FILTER_IS_LOW_PASS_1:
m_vC1 += (v - m_vC1) * m_exponentC1;
v_out = m_vC1 * m_gain + info.vRef;
break;
case DISC_OP_AMP_FILTER_IS_LOW_PASS_1_A:
m_vC1 += (v - m_vC1) * m_exponentC1;
v_out = m_vC1 * m_gain + DST_OP_AMP_FILT__INP2();
break;
case DISC_OP_AMP_FILTER_IS_HIGH_PASS_1:
v_out = (v - m_vC1) * m_gain + info.vRef;
m_vC1 += (v - m_vC1) * m_exponentC1;
break;
case DISC_OP_AMP_FILTER_IS_BAND_PASS_1:
v_out = (v - m_vC2);
m_vC2 += (v - m_vC2) * m_exponentC2;
m_vC1 += (v_out - m_vC1) * m_exponentC1;
v_out = m_vC1 * m_gain + info.vRef;
break;
case DISC_OP_AMP_FILTER_IS_BAND_PASS_0 | DISC_OP_AMP_IS_NORTON:
m_vC1 += (v - m_vC1) * m_exponentC1;
m_vC2 += (m_vC1 - m_vC2) * m_exponentC2;
v = m_vC2;
v_out = v - m_vC3;
m_vC3 += (v - m_vC3) * m_exponentC3;
i = v_out / m_rTotal;
v_out = (m_iFixed - i) * info.rF;
break;
case DISC_OP_AMP_FILTER_IS_HIGH_PASS_0 | DISC_OP_AMP_IS_NORTON:
v_out = v - m_vC1;
m_vC1 += (v - m_vC1) * m_exponentC1;
i = v_out / m_rTotal;
v_out = (m_iFixed - i) * info.rF;
break;
case DISC_OP_AMP_FILTER_IS_BAND_PASS_1M:
case DISC_OP_AMP_FILTER_IS_BAND_PASS_1M | DISC_OP_AMP_IS_NORTON:
v_out = -m_fc.a1 * m_fc.y1 - m_fc.a2 * m_fc.y2 +
m_fc.b0 * v + m_fc.b1 * m_fc.x1 + m_fc.b2 * m_fc.x2 +
m_vRef;
m_fc.x2 = m_fc.x1;
m_fc.x1 = v;
m_fc.y2 = m_fc.y1;
break;
}
/* Clip the output to the voltage rails.
* This way we get the original distortion in all it's glory.
*/
if (v_out > m_vP)
{
v_out = m_vP;
}
if (v_out < m_vN)
{
v_out = m_vN;
}
m_fc.y1 = v_out - m_vRef;
set_output(0, v_out);
}
else
{
set_output(0, 0);
}
}
//DISCRETE_CLASS_DESTRUCTOR(_name)
//~discrete_dst_op_amp_filt_node() { }
// discrete_base_node
//DISCRETE_RESET(dst_op_amp_filt)
public override void reset()
{
discrete_op_amp_filt_info info = (discrete_op_amp_filt_info)custom_data(); //DISCRETE_DECLARE_INFO(discrete_op_amp_filt_info)
/* Convert the passed filter type into an int for easy use. */
m_type = (int)DST_OP_AMP_FILT__TYPE() & DISC_OP_AMP_FILTER_TYPE_MASK;
m_is_norton = (int)DST_OP_AMP_FILT__TYPE() & DISC_OP_AMP_IS_NORTON;
if (m_is_norton != 0)
{
m_vRef = 0;
m_rTotal = info.r1;
if (m_type == (DISC_OP_AMP_FILTER_IS_BAND_PASS_0 | DISC_OP_AMP_IS_NORTON))
{
m_rTotal += info.r2 + info.r3;
}
/* Setup the current to the + input. */
m_iFixed = (info.vP - OP_AMP_NORTON_VBE) / info.r4;
/* Set the output max. */
m_vP = info.vP - OP_AMP_NORTON_VBE;
m_vN = info.vN;
}
else
{
m_vRef = info.vRef;
/* Set the output max. */
m_vP = info.vP - OP_AMP_VP_RAIL_OFFSET;
m_vN = info.vN;
/* Work out the input resistance. It is all input and bias resistors in parallel. */
m_rTotal = 1.0 / info.r1; /* There has to be an R1. Otherwise the table is wrong. */
if (info.r2 != 0)
{
m_rTotal += 1.0 / info.r2;
}
if (info.r3 != 0)
{
m_rTotal += 1.0 / info.r3;
}
m_rTotal = 1.0 / m_rTotal;
m_iFixed = 0;
m_rRatio = info.rF / (m_rTotal + info.rF);
m_gain = -info.rF / m_rTotal;
}
switch (m_type)
{
case DISC_OP_AMP_FILTER_IS_LOW_PASS_1:
case DISC_OP_AMP_FILTER_IS_LOW_PASS_1_A:
m_exponentC1 = RC_CHARGE_EXP(info.rF * info.c1);
m_exponentC2 = 0;
break;
case DISC_OP_AMP_FILTER_IS_HIGH_PASS_1:
m_exponentC1 = RC_CHARGE_EXP(m_rTotal * info.c1);
m_exponentC2 = 0;
break;
case DISC_OP_AMP_FILTER_IS_BAND_PASS_1:
m_exponentC1 = RC_CHARGE_EXP(info.rF * info.c1);
m_exponentC2 = RC_CHARGE_EXP(m_rTotal * info.c2);
break;
case DISC_OP_AMP_FILTER_IS_BAND_PASS_1M | DISC_OP_AMP_IS_NORTON:
if (info.r2 == 0)
{
m_rTotal = info.r1;
}
else
{
m_rTotal = RES_2_PARALLEL(info.r1, info.r2);
}
goto case DISC_OP_AMP_FILTER_IS_BAND_PASS_1M; //[[fallthrough]];
case DISC_OP_AMP_FILTER_IS_BAND_PASS_1M:
{
double fc = 1.0 / (2 * M_PI * std.sqrt(m_rTotal * info.rF * info.c1 * info.c2));
double d = (info.c1 + info.c2) / std.sqrt(info.rF / m_rTotal * info.c1 * info.c2);
double gain = -info.rF / m_rTotal * info.c2 / (info.c1 + info.c2);
calculate_filter2_coefficients(this, fc, d, DISC_FILTER_BANDPASS, ref m_fc);
m_fc.b0 *= gain;
m_fc.b1 *= gain;
m_fc.b2 *= gain;
if (m_is_norton != 0)
{
m_vRef = (info.vP - OP_AMP_NORTON_VBE) / info.r3 * info.rF;
}
else
{
m_vRef = info.vRef;
}
break;
}
case DISC_OP_AMP_FILTER_IS_BAND_PASS_0 | DISC_OP_AMP_IS_NORTON:
m_exponentC1 = RC_CHARGE_EXP(RES_2_PARALLEL(info.r1, info.r2 + info.r3 + info.r4) * info.c1);
m_exponentC2 = RC_CHARGE_EXP(RES_2_PARALLEL(info.r1 + info.r2, info.r3 + info.r4) * info.c2);
m_exponentC3 = RC_CHARGE_EXP((info.r1 + info.r2 + info.r3 + info.r4) * info.c3);
break;
case DISC_OP_AMP_FILTER_IS_HIGH_PASS_0 | DISC_OP_AMP_IS_NORTON:
m_exponentC1 = RC_CHARGE_EXP(info.r1 * info.c1);
break;
}
/* At startup there is no charge on the caps and output is 0V in relation to vRef. */
m_vC1 = 0;
m_vC1b = 0;
m_vC2 = 0;
m_vC3 = 0;
set_output(0, info.vRef);
}
