{
"metadata": {
"name": "Chapter_15"
},
"nbformat": 2,
"worksheets": [
{
"cells": [
{
"cell_type": "markdown",
"source": [
"<h1>Chapter 15: Active Filters<h1>"
]
},
{
"cell_type": "markdown",
"source": [
"<h3>Example 15.1, Page Number: 491<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"%matplotlib inline"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"",
"Welcome to pylab, a matplotlib-based Python environment [backend: module://IPython.zmq.pylab.backend_inline].",
"For more information, type 'help(pylab)'."
]
}
],
"prompt_number": 1
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"",
"f0=15*10**3; #center frequency in hertz",
"BW=1*10**3;",
"Q=f0/BW;",
"if Q>10:",
" print('narrow band filter, Q = %d'%Q)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"narrow band filter, Q = 15"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"source": [
"<h3>Example 15.2, Page Number: 494<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"",
"R2=10*10**3;",
"R1=0.586*R2; #FOR BUTTERWORTH RESPONSE",
"print('R1 in ohms =%d'%R1)",
"print('5.6kilo ohm will be ideally close to maximally flat butterworth response')"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"R1 in ohms =5860",
"5.6kilo ohm will be ideally close to maximally flat butterworth response"
]
}
],
"prompt_number": 3
},
{
"cell_type": "markdown",
"source": [
"<h3>Example 15.3, Page Number: 496<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"",
"import math",
"R_A=1*10**3;",
"R2=1*10**3;",
"R_B=R_A;",
"R=R_A;",
"C_A=0.022*10**-6;",
"C_B=C_A;",
"C=C_A;",
"f_c=1/(2*math.pi*R*C); #critical frequency",
"R1=0.586*R2; #for butterworth response",
"print('critical frequency in hertz =%f'%f_c)",
"print('value of R1 in ohms = %d'%R1)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"critical frequency in hertz =7234.315595",
"value of R1 in ohms = 586"
]
}
],
"prompt_number": 4
},
{
"cell_type": "markdown",
"source": [
"<h3>Example 15.4, Page Number: 498<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"",
"import math",
"f_c=2860.0;",
"R=1.8*10**3;",
"C=1/(2*math.pi*f_c*R);",
"R2=R;",
"R1=0.152*R2; #BUTTERWORTH RESPONSE IN FIRST STAGE",
"R4=R;",
"R3=1.235*R4; #BUTTERWORTH RESPONSE IN SECOND STAGE",
"C=C*10**8",
"print('capacitance in farads = %f *10^-8'%C);",
"print('R1 in ohms for butterworth response in first stage = %.1f'%R1)",
"print('R3 in ohms for butterworth response in second stage = %d'%R3)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"capacitance in farads = 3.091588 *10^-8",
"R1 in ohms for butterworth response in first stage = 273.6",
"R3 in ohms for butterworth response in second stage = 2223"
]
}
],
"prompt_number": 5
},
{
"cell_type": "markdown",
"source": [
"<h3>Example 15.5, Page Number: 500<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"",
"import math",
"f_c=10*10**3; #critical frequency in hertz",
"R=33*10**3; #Assumption",
"R2=R;",
"C=1/(2*math.pi*f_c*R);",
"R1=0.586*R2; #for butterworth response",
"C=C*10**10",
"print('Capacitance in Farads = %f * 10^-10'%C)",
"print('R1 in ohms taking R2=33kilo-ohms = %d'%R1)",
"R1=3.3*10**3; #Assumption",
"R2=R1/0.586; #butterworth response",
"print('R2 in ohms taking R1=3.3kilo-ohms = %f'%R2)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Capacitance in Farads = 4.822877 * 10^-10",
"R1 in ohms taking R2=33kilo-ohms = 19338",
"R2 in ohms taking R1=3.3kilo-ohms = 5631.399317"
]
}
],
"prompt_number": 6
},
{
"cell_type": "markdown",
"source": [
"<h3>Example 15.6, Page Number:503<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"",
"import math",
"R1=68.0*10**3;",
"R2=180.0*10**3;",
"R3=2.7*10**3;",
"C=0.01*10**-6;",
"f0=(math.sqrt((R1+R3)/(R1*R2*R3)))/(2*math.pi*C);",
"A0=R2/(2*R1);",
"Q=math.pi*f0*C*R2;",
"BW=f0/Q;",
"print('center frequency in hertz = %f'%f0)",
"print('maximum gain = %f'%A0)",
"print('bandwidth in hertz = %f'%BW)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"center frequency in hertz = 736.134628",
"maximum gain = 1.323529",
"bandwidth in hertz = 176.838826"
]
}
],
"prompt_number": 7
},
{
"cell_type": "markdown",
"source": [
"<h3>Example 15.7, Page Number: 504<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"",
"import math",
"R4=1000.0;",
"C1=0.022*10**-6;",
"R7=R4;",
"C2=C1;",
"R6=R4;",
"R5=100.0*10**3;",
"f_c=1/(2*math.pi*R4*C1); #critical frequency in hertz for each integrator",
"f0=f_c #center frequency",
"Q=(1+(R5/R6))/3;",
"BW=f0/Q;",
"print('center frequency in hertz = %f'%f0)",
"print('value of Q = %f'%Q)",
"print('bandwidth in hertz = %f'%BW)"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"center frequency in hertz = 7234.315595",
"value of Q = 33.666667",
"bandwidth in hertz = 214.880661"
]
}
],
"prompt_number": 8
},
{
"cell_type": "markdown",
"source": [
"<h3>Example 15.8, Page Number: 507<h3>"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"",
"import math",
"R4=12.0*10**3;",
"C1=0.22*10**-6;",
"R7=R4;",
"C2=C1;",
"R6=3.3*10**3;",
"Q=10;",
"f0=1/(2*math.pi*R7*C2);",
"R5=(3*Q-1)*R6;",
"print('center frequency in hertz = %f'%f0)",
"print('R5 in ohms = %d'%R5)",
"print('Nearest value is 100 kilo-ohms')"
],
"language": "python",
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"center frequency in hertz = 60.285963",
"R5 in ohms = 95700",
"Nearest value is 100 kilo-ohms"
]
}
],
"prompt_number": 9
}
]
}
]
}