{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 5: ADC and DAC"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_1,pg 491"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# output voltage\n",
"\n",
"import math\n",
"# Variable declaration\n",
"Vref=12.0 #ref. voltage\n",
"n =4.0 #no. of binary weighted resistors\n",
"n1=3.0 #input-1\n",
"n2=1.0 #input-2\n",
"\n",
"#Calculations\n",
"Vo=-(Vref/2**n)*(2**n1+2**n2)\n",
"\n",
"#Result \n",
"print(\"output voltage:\")\n",
"print(\"Vo = %.1f V\"%Vo) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"output voltage:\n",
"Vo = -7.5 V\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_2,pg 491"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# voltage division ratio and feedback resistor\n",
"\n",
"import math\n",
"# Variabe declaration \n",
"# serie arm resistance = 10k, since the divider arm resistance Rsh=2Rse \n",
"# therefore for straight binary code, one should have section voltage ratio as Vos/Vis=0.5\n",
"\n",
"#Vo/Vref=0.5\n",
"Rse=10*10**3 #series resistance(Rsh/2)\n",
"\n",
"#Calculation\n",
"Rf=0.5*(16*Rse)/15 #feedback resistor\n",
"\n",
"#Result\n",
"print(\"voltage section ratio = 0.5\")\n",
"print(\"\\nfeedback resistor:\")\n",
"print(\"Rf = %.2f k-ohm\"%(Rf/1000)) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"voltage section ratio = 0.5\n",
"\n",
"feedback resistor:\n",
"Rf = 5.33 k-ohm\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_3,pg 492"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# output voltage\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Rse = 1*10**3 #series resistance\n",
"Rsh = 2*10**3 #shunt resistance\n",
"Vref= 5.0 #ref. voltage\n",
"n1 = 0 #input-1\n",
"n2 = 3 #input-2\n",
"Ro=0.22*10**3 #load resistance\n",
"\n",
"#Calculations\n",
"Vo=(Vref*(2**n1+2**n2)/16)*(Ro/(Ro+Rsh))\n",
"\n",
"#Result\n",
"print(\"output voltage:\")\n",
"print(\"Vo = %.3f V\"%(math.floor(Vo*1000)/1000)) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"output voltage:\n",
"Vo = 0.278 V\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_4,pg 492"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# find count\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Vref=5.0 #ref. voltage\n",
"t=1*10**-3 #sawtooth wave time\n",
"f=100*10**3 #clock frequency\n",
"Vi=1 #input voltage\n",
"\n",
"#Calculations\n",
"N=((t*f*Vi)/Vref) #count\n",
"\n",
"#Result\n",
"print(\"count = %d\"%N)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"count = 20\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_5,pg 492"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# find integrator output voltage\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Tu=1*10**-3 #wave time\n",
"Vi=0.2 #input voltage\n",
"t=4*10**-3 #integration time constant(1/RC)\n",
"\n",
"\n",
"#Calculation\n",
"V1=((Vi*Tu)/t) #integrator output voltage\n",
"\n",
"#Result\n",
"print(\"integrator output voltage:\")\n",
"print(\"V1 = %.2f V\"%V1) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"integrator output voltage:\n",
"V1 = 0.05 V\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_6,pg 493"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# find rise in output voltage and charging time\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Tz=0.6*10**-3 #discharge time\n",
"Vref=1 #ref. voltage\n",
"t=4*10**-3 #integrator time const.\n",
"Vi=0.2 #input voltage\n",
"#Calculations\n",
"Vk=((Vref*Tz)/t) #rise in output integrator\n",
"Tu=Vref*(Tz/Vi) #charging time\n",
"\n",
"#Result\n",
"print(\"Rise in integrator output:\")\n",
"print(\"Vk = %.2f V\\n\"%Vk)\n",
"print(\"charging time:\")\n",
"print(\"Tu = %.0f msec\"%(Tu*1000)) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rise in integrator output:\n",
"Vk = 0.15 V\n",
"\n",
"charging time:\n",
"Tu = 3 msec\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_7,pg 493"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# find count of counter\n",
"\n",
"import math\n",
"#Variable declaration\n",
"Vref=1 #ref. voltage\n",
"Vi=0.2 #input voltage\n",
"n=15 #no. of counts before reset(n+1)\n",
"\n",
"#Calculations\n",
"N=((n+1)*Vi)/Vref #no.of counts over charging time\n",
"\n",
"print(\"No of counts over charging time:\")\n",
"print(\"N = %.1f = %d(approx.) \"%(N,N)) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"No of counts over charging time:\n",
"N = 3.2 = 3(approx.) \n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_8,pg 493"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# find input voltage\n",
"\n",
"import math\n",
"Nx=2**6 #6 bit counteer register\n",
"Vref=2.2 #ref. voltage\n",
"N=32.0 #SAR output\n",
"\n",
"#Calculations\n",
"Vi=(N/(Nx+1)*Vref) #input voltage\n",
"\n",
"#Result\n",
"print(\"Input Voltage:\")\n",
"print(\"Vi = %.2f V\"%Vi) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Input Voltage:\n",
"Vi = 1.08 V\n"
]
}
],
"prompt_number": 14
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_9,pg 493"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# conversion number\n",
"\n",
"import math\n",
"#Variable declaration\n",
"n=3 #3-bit ADC\n",
"Vref=2.2 #ref.voltage\n",
"Vi=1 #input voltage\n",
"\n",
"#Calculations\n",
"N=(((2**n)-1)*Vi)/Vref #SAR output\n",
"\n",
"#Result\n",
"print(\"SAR conversion no.:\")\n",
"print(\"N = %.2f \"%N) "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"SAR conversion no.:\n",
"N = 3.18 \n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example5_10,pg 493"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# signal to noise ratio\n",
"\n",
"import math\n",
"#Variable declaaration\n",
"n = 3.0 #3-bit ADC\n",
"\n",
"#Calculations\n",
"SbyN=(((2**(n-1)*12**0.5)/2**0.5)) #S/N ratio\n",
"\n",
"#Result\n",
"print(\"S/N ratio:\")\n",
"print(\"SbyN = %.3f\\n\"%SbyN) \n",
"print(\"This produces an error due to noise nearly 10%\")"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"S/N ratio:\n",
"SbyN = 9.798\n",
"\n",
"This produces an error due to noise nearly 10%\n"
]
}
],
"prompt_number": 14
}
],
"metadata": {}
}
]
}