58 lines
1.6 KiB
Python
58 lines
1.6 KiB
Python
import numpy as np
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import matplotlib.pyplot as plt
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stimulusrate = 500. # the eod frequency of the fake fish
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currentchirptimes = [0.0]
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chirpwidth = 0.014 # ms
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chirpsize = 100.
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chirpampl = 0.02
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chirpkurtosis = 1.
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p = 0.
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stepsize = 0.00001
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inch_factor = 2.54
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time = np.arange(-0.05, 0.05, stepsize)
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signal = np.zeros(time.shape)
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ampl = np.ones(time.shape)
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freq = np.ones(time.shape)
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ck = 0
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csig = 0.5 * chirpwidth / np.power(2.0*np.log(10.0), 0.5/chirpkurtosis)
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for k, t in enumerate(time):
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a = 1.
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f = stimulusrate
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if ck < len(currentchirptimes):
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if np.abs(t - currentchirptimes[ck]) < 2.0 * chirpwidth:
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x = t - currentchirptimes[ck]
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g = np.exp(-0.5 * (x/csig)**2)
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f = chirpsize * g + stimulusrate
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a *= 1.0 - chirpampl * g
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elif t > currentchirptimes[ck] + 2.0 * chirpwidth:
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ck += 1
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freq[k] = f
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ampl[k] = a
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p += f * stepsize
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signal[k] = a * np.sin(6.28318530717959 * p)
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fig = plt.figure(figsize = (20/inch_factor, 12/inch_factor))
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ax1 = fig.add_subplot(211)
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plt.yticks(fontsize=18)
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ax2 = fig.add_subplot(212, sharex=ax1)
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plt.setp(ax1.get_xticklabels(), visible=False)
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ax1.plot(time*1000, signal, color = 'royalblue', lw = 1)
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ax2.plot(time*1000, freq, color = 'royalblue', lw = 3)
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ax1.set_ylabel("field [mV]", fontsize = 22)
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ax1.yaxis.set_label_coords(-0.1, 0.5)
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ax2.set_xlabel("time [ms]", fontsize = 22)
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ax2.set_ylabel("frequency [Hz]", fontsize = 22)
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ax2.yaxis.set_label_coords(-0.1, 0.5)
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plt.xticks(fontsize=18)
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plt.yticks(fontsize=18)
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fig.tight_layout()
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#plt.show()
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plt.savefig('stimulus_chirp.png')
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