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Add L-pad 1st series attenuator

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The output of the L-pad attenuator is unmatched. The output impedance is shown in a QLineEdit.
The output impedance is shown in a box. The derivation of the design equations will be provided separately in the pull request
This commit is contained in:
andresmmera 2024-05-14 18:39:44 +02:00
parent 6fd8531d71
commit dcef098439
5 changed files with 91 additions and 0 deletions
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63
qucs-attenuator/attenuatorfunc.cpp
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@ -135,6 +135,17 @@ int QUCS_Att::Calc(tagATT *ATT)
ATT->PR3 = ATT->PR1;
break;
}
case L_PAD_1ST_SERIES:
L = pow(10, -ATT->Attenuation / 10);
// Design equations
ATT->R1 = -ATT->Zin*(L-1)/(sqrt(L)+1);// Series resistor
ATT->R2 = -ATT->Zin*(L + sqrt(L))/(L - 1); // Shunt resistor
ATT->R3 = ATT->R2*(ATT->R1+ATT->Zin)/(ATT->R1+ATT->R2+ATT->Zin);//Output impedance
// Power dissipation
ATT->PR1 = ATT->Pin*(1-sqrt(L));// Series resistor
ATT->PR2 = ATT->Pin*L*(1-L)/(L+sqrt(L));// Shunt resistor
break;
}
return 0;
@ -558,6 +569,58 @@ QString* QUCS_Att::createSchematic(tagATT *ATT, bool SP_box)
}
*s += "</Paintings>\n";
break;
case L_PAD_1ST_SERIES:
*s += QString("<R R1 1 255 130 -35 -45 0 0 \"%1 Ohm\" 1 \"26.85\" 0 \"0.0\" 0 \"0.0\" 0 \"26.85\" 0 \"US\" 0>\n").arg(QString::number(ATT->R1, 'f', 1));
*s += QString("<R R2 1 330 200 -15 60 0 1 \"%1 Ohm\" 1 \"26.85\" 0 \"0.0\" 0 \"0.0\" 0 \"26.85\" 0 \"US\" 0>\n").arg(QString::number(ATT->R2, 'f', 1));
*s += "<GND * 1 330 230 0 0 0 0>\n";
if (SP_box)
{
// S-parameter simulation block
//-----------------------------
// Resistor attenuators are broadband ckts, so it's pointless to ask the user to input the analysis freq sweep. Let's do a wideband
// sweep and then the user can modify that in the schematic
*s += "<.SP SP1 1 140 350 0 83 0 0 \"lin\" 1 \"50 MHz\" 1 \"3 GHz\" 1 \"200\" 1 \"no\" 0 \"1\" 0 \"2\" 0 \"no\" 0 \"no\" 0>\n";
// Equations
*s += "<Eqn Eqn1 1 360 350 -32 19 0 0 \"S21_dB=dB(S[2,1])\" 1 \"S11_dB=dB(S[1,1])\" 1 \"S22_dB=dB(S[2,2])\" 1 \"yes\" 0>\n";
// Input term
*s += QString("<Pac P1 1 50 200 18 -26 0 1 \"1\" 1 \"%1 Ohm\" 1 \"0 dBm\" 0 \"1 GHz\" 0 \"26.85\" 0>\n").arg(ATT->Zin);
*s += "<GND * 1 50 230 0 0 0 0>\n";
// Output term
*s += QString("<Pac P1 1 460 200 18 -26 0 1 \"1\" 1 \"%1 Ohm\" 1 \"0 dBm\" 0 \"1 GHz\" 0 \"26.85\" 0>\n").arg(ATT->Zout);
*s += "<GND * 1 460 230 0 0 0 0>\n";
}
*s += "</Components>\n";
*s += "<Wires>\n";
*s += "<285 130 350 130 \"\" 0 0 0 \"\">\n";
*s += "<140 130 225 130 \"\" 0 0 0 \"\">\n";
*s += "<330 130 330 170 \"\" 0 0 0 \"\">\n";
if (SP_box)
{ // Additional wiring because of the input/output ports
// Input port
*s += "<50 130 50 170 \"\" 0 0 0 \"\">\n";
*s += "<50 130 140 130 \"\" 0 0 0 \"\">\n";
// Output port
*s += "<460 130 460 170 \"\" 0 0 0 \"\">\n";
*s += "<460 130 350 130 \"\" 0 0 0 \"\">\n";
}
*s += "</Wires>\n";
*s += "<Diagrams>\n";
*s += "</Diagrams>\n";
*s += "<Paintings>\n";
*s += QString("<Text 160 60 12 #000000 0 \"%1 dB L-pad 1st Series Attenuator\">\n").arg(ATT->Attenuation);
if (!SP_box)
{// If the SP simulation box option is activated, then the input and output ports are attached.
// Thus, it doesn't make sense to have a text field indicating the input/output impedance
*s += QString("<Text 50 122 10 #000000 0 \"Z1: %1 Ohm\">\n").arg(ATT->Zin);
*s += QString("<Text 360 122 10 #000000 0 \"Z2: %1 Ohm\">\n").arg(ATT->Zout);
}
*s += "</Paintings>\n";
break;
}
return s;

1
qucs-attenuator/attenuatorfunc.h
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@ -19,6 +19,7 @@
#define REFLECTION_TYPE 3
#define QW_SERIES_TYPE 4
#define QW_SHUNT_TYPE 5
#define L_PAD_1ST_SERIES 6
#define C0 299792458
#define PI 3.141592653589793238462643383279502884197169399375105820974944592307816406286

BIN
qucs-attenuator/bitmaps/L_pad_1st_series.png Normal file
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26
qucs-attenuator/qucsattenuator.cpp
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@ -89,6 +89,7 @@ QucsAttenuator::QucsAttenuator()
ComboTopology->insertItem(4, "Reflection attenuator");
ComboTopology->insertItem(5, "Quarter-wave series");
ComboTopology->insertItem(6, "Quarter-wave shunt");
ComboTopology->insertItem(6, "L-pad 1st series");
connect(ComboTopology, SIGNAL(activated(int)), SLOT(slotTopologyChanged()));
topoGrid->addWidget(ComboTopology, 1,0,1,2);
@ -582,6 +583,31 @@ void QucsAttenuator::slotTopologyChanged()
QSpinBox_Freq->show();
Combo_FreqUnits->show();
break;
case L_PAD_1ST_SERIES:
pixTopology->setPixmap(QPixmap((":/bitmaps/L_pad_1st_series.png")));
LabelImp1->setText("Z0:");
LabelImp2->hide();
QSpinBox_Zout->hide();
LabelImp2_Ohm->hide();
LabelR2->setText("R2:");
LabelR3->show();
LabelR3->setText("Zout:");
LabelR4->hide();
lineEdit_R3->show();
lineEdit_R4->hide();
LabelR4_Ohm->hide();
LabelR3_Ohm->show();
lineEdit_R3_Pdiss->hide();
ComboR3_PowerUnits->hide();
lineEdit_R4_Pdiss->hide();
ComboR4_PowerUnits->hide();
R_Check->hide();
Check_QW_CLC->hide();
Label_Freq->hide();
QSpinBox_Freq->hide();
Combo_FreqUnits->hide();
break;
}
adjustSize();
slotCalculate();

1
qucs-attenuator/qucsattenuator.qrc
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@ -9,5 +9,6 @@
<file>bitmaps/qw_shunt.png</file>
<file>bitmaps/qw_shunt_CLC.png</file>
<file>bitmaps/qw_series_CLC.png</file>
<file>bitmaps/L_pad_1st_series.png</file>
</qresource>
</RCC>