62 lines
2.1 KiB
Python
62 lines
2.1 KiB
Python
import numpy as np
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def create_chirp(
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eodf=500,
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chirpsize=100,
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chirpduration=0.015,
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ampl_reduction=0.05,
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chirptimes=[0.05, 0.2],
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kurtosis=1.0,
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duration=1.0,
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dt=0.00001,
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):
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"""create a fake fish eod that contains chirps at the given times. EOF is a simple sinewave. Chirps are modeled with Gaussian profiles in amplitude reduction and frequency ecxcursion.
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Args:
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eodf (int, optional): The chriping fish's EOD frequency. Defaults to 500 Hz.
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chirpsize (int, optional): the size of the chrip's frequency excursion. Defaults to 100 Hz.
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chirpwidth (float, optional): the duration of the chirp. Defaults to 0.015 s.
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ampl_reduction (float, optional): Amount of amplitude reduction during the chrips. Defaults to 0.05, i.e. 5\%
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chirptimes (list, optional): Times of chirp centers. Defaults to [0.05, 0.2].
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kurtosis (float, optional): The kurtosis of the Gaussian profiles. Defaults to 1.0
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dt (float, optional): the stepsize of the simulation. Defaults to 0.00001 s.
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Returns:
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np.ndarray: the time
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np.ndarray: the eod
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np.ndarray: the amplitude profile
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np.adarray: tha frequency profile
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"""
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p = 0.0
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time = np.arange(0.0, duration, dt)
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signal = np.zeros_like(time)
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ampl = np.ones_like(time)
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freq = np.ones_like(time)
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ck = 0
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csig = 0.5 * chirpduration / np.power(2.0 * np.log(10.0), 0.5 / kurtosis)
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#csig = csig*-1
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for k, t in enumerate(time):
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a = 1.0
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f = eodf
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if ck < len(chirptimes):
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if np.abs(t - chirptimes[ck]) < 2.0 * chirpduration:
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x = t - chirptimes[ck]
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gg = np.exp(-0.5 * np.power((x / csig) ** 2, kurtosis))
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cc = chirpsize * gg
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# g = np.exp( -0.5 * (x/csig)**2 )
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f = chirpsize * gg + eodf
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a *= 1.0 - ampl_reduction * gg
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elif t > chirptimes[ck] + 2.0 * chirpduration:
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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 * dt
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signal[k] = -1 * a * np.sin(2 * np.pi * p)
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return time, signal, ampl, freq
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