| 1 | #!/usr/bin/python -tt
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| 2 | #
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| 3 | # Dominik Neise, Werner Lustermann
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| 4 | # TU Dortmund, ETH Zurich
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| 5 | #
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| 6 | import numpy as np
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| 7 |
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| 8 | class SignalGenerator(object):
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| 9 | """ Signal Generator
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| 10 | generates signals for testing several helper classes like:
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| 11 | * fir filters
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| 12 | * signal extractors
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| 13 | """
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| 14 |
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| 15 | def __init__(self, option_str = 'len 100 noise 3', name = 'SignalGenerator'):
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| 16 | """ initialize the generator
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| 17 | sets default signal to generate
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| 18 | """
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| 19 | self.option_str = option_str.lower()
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| 20 | self.options = make_options_from_str(option_str)
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| 21 | self.parse_options()
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| 22 | self.name = name
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| 23 |
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| 24 | def parse_options(self):
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| 25 | o = self.options #shortcut
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| 26 | if 'len' in o:
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| 27 | self.npoints = int(o['len'][0])
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| 28 | else:
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| 29 | self.npoints = 100
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| 30 | if 'noise' in o:
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| 31 | self.sigma = float(o['noise'][0])
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| 32 | else:
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| 33 | self.sigma = 1
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| 34 | if 'bsl' in o:
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| 35 | self.bsl = float(o['bsl'][0])
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| 36 | else:
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| 37 | self.bsl = -0.5
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| 38 |
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| 39 | if 'step' in o:
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| 40 | self.step_height = float(o['step'][0])
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| 41 | self.step_start = int(o['step'][1])
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| 42 | self.step_stop = int(o['step'][2])
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| 43 |
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| 44 | if 'triangle' in o:
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| 45 | self.pulses = []
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| 46 | # append 1st pulse to list of pulses
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| 47 | self.pulses.append( ( float(o['triangle'][0]) , float(o['triangle'][1]), int(o['triangle'][2]), int(o['triangle'][3]) ) )
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| 48 | number_of_pulses_after_1st = (len(o['triangle'])-4)/2
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| 49 | for i in range(number_of_pulses_after_1st):
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| 50 | self.pulses.append( ( float(o['triangle'][2*i+4]) , float(o['triangle'][2*i+5]), int(o['triangle'][2]), int(o['triangle'][3]) ) )
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| 51 |
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| 52 | if 'spike' in o:
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| 53 | self.spikes = []
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| 54 | for i in range(len(o['spike'])/2):
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| 55 | self.spikes.append( ( int(o['spike'][2*i]), float(o['spike'][2*i+1]) ) )
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| 56 |
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| 57 | def __call__(self, option_str = ''):
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| 58 | if option_str:
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| 59 | self.option_str = option_str.lower()
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| 60 | self.options = make_options_from_str(self.option_str)
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| 61 | self.parse_options()
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| 62 |
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| 63 | signal = np.zeros(self.npoints)
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| 64 | signal += self.bsl
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| 65 | signal += np.random.randn(self.npoints) * self.sigma
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| 66 | if 'step' in self.options:
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| 67 | signal[self.step_start:self.step_stop] += self.step_height
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| 68 | if 'triangle' in self.options:
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| 69 | for pulse in self.pulses:
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| 70 | pos = pulse[0]
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| 71 | height = pulse[1]
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| 72 | rise = pulse[2]
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| 73 | fall = pulse[3]
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| 74 | start = pos - rise
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| 75 | stop = pos + fall
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| 76 | signal[start:pos] += np.linspace(0., height, rise)
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| 77 | signal[pos:stop] += np.linspace(height, 0. , fall)
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| 78 | if 'spike' in self.options:
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| 79 | for spike in self.spikes:
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| 80 | signal[spike[0]] += spike[1]
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| 81 | return signal
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| 82 |
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| 83 | def __str__(self):
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| 84 | s = self.name + '\n'
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| 85 | s += 'possible options and parameters\n'
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| 86 | s += ' * len: number of samples (100)\n'
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| 87 | s += ' * noise: sigma (1)\n'
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| 88 | s += ' * bsl: level (-0.5)\n'
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| 89 | s += ' * step: height, start, end\n'
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| 90 | s += ' * triangle: pos height risingedge, fallingedge [pos height ...]\n'
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| 91 | s += ' * spike: pos height [pos height ...]\n'
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| 92 |
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| 93 | s += 'current options are:\n'
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| 94 | for key in self.options.keys():
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| 95 | s += key + ':' + str(self.options[key]) + '\n'
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| 96 | return s
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| 97 |
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| 98 |
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| 99 | # Helper function to parse signalname and create a dictionary
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| 100 | # dictionary layout :
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| 101 | # key : string
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| 102 | # value : [list of parameters]
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| 103 | def make_options_from_str(signalname):
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| 104 | options = {}
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| 105 | for word in (signalname.lower()).split():
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| 106 | if word.isalpha():
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| 107 | current_key = word
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| 108 | options[current_key] = []
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| 109 | # if word.isdigit():
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| 110 | else:
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| 111 | options[current_key].append(word)
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| 112 | # else:
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| 113 | # print '-nothing'
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| 114 | return options
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| 115 |
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| 116 | def _plotter(signal, text):
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| 117 | x=range(len(signal))
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| 118 | ax = plt.plot(x, signal, 'b.', label='signal')
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| 119 | plt.title('test of SignalGenerator with option string:\n' + text)
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| 120 | plt.xlabel('sample')
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| 121 | plt.legend()
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| 122 | plt.grid(True)
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| 123 | plt.show()
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| 124 |
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| 125 | if __name__ == '__main__':
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| 126 | import matplotlib.pyplot as plt
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| 127 | """ test the class """
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| 128 | myGenerator = SignalGenerator('len 400 noise 0.3 bsl -2.5 triangle 50 10.2 10 100 65 10 150 20 180 10 250 10 spike 100 50. 20 50 21 49')
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| 129 | sig = myGenerator()
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| 130 | print myGenerator
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| 131 | _plotter(sig, myGenerator.option_str)
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