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{
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{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter -6 Digitally Controlled Frequency Synthesizers"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.1 - Page 180"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from numpy import pi\n",
"import math\n",
"from fractions import Fraction \n",
"# Given data\n",
"R1= 15*10**3 # in \u03a9\n",
"C1= 0.01*10**-6 # in F\n",
"C2= 10*10**-6 # in F\n",
"R2= 3.6*10**3 # in \u03a9\n",
"Vpos= 12 # in V\n",
"Vneg= -12 # in V\n",
"f_out= 1.2/(4*R1*C1) # free running frequency in Hz\n",
"f_out= f_out*10**-3 # in kHz\n",
"print \"The free running frequency = %0.f kHz\" %f_out \n",
"f_L= 8*f_out/(Vpos-(Vneg)) #Lock-range in kHz\n",
"print \"Lock-range of the circuit = \u00b1 \", Fraction(f_L).limit_denominator(100), \"kHz\" \n",
"f_L= f_L*10**3 # in Hz\n",
"f_C= math.sqrt(f_L/(2*pi*R2*C2)) # Hz\n",
"print \"Capture-range of the circuit = \u00b1 %0.2f Hz\" %f_C"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The free running frequency = 2 kHz\n",
"Lock-range of the circuit = \u00b1 2/3 kHz\n",
"Capture-range of the circuit = \u00b1 54.29 Hz\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.2 - Page 185"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Given data\n",
"f_out_max= 200 # in kHz\n",
"f_lowest= 1 # in Hz\n",
"# Frequency of reference oscillator,\n",
"f_ref_os= 2.2*f_out_max # in kHz\n",
"print \"The frequency of reference oscillator = %0.f kHz\" %f_ref_os\n",
"# Formula used : f_lowest= f_ref_os/2**n\n",
"n= round(math.log(f_ref_os*10**3/f_lowest, 10)/math.log(2,10))\n",
"print a\n",
"print \"The number of bits required = %0.f\" %n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The frequency of reference oscillator = 440 kHz\n",
"19.0\n",
"The number of bits required = 19\n"
]
}
],
"prompt_number": 26
}
],
"metadata": {}
}
]
}
|
