{
 "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
    }
   ]
  }
 ]
}