Generate texture stimuli

This shows how to generate texture coherence stimuli.

import matplotlib.pyplot as plt
import numpy as np

from expyfun.stimuli import play_sound, texture_ERB

fs = 24414
n_freqs = 20
n_coh = 18  # very coherent example

# let's make a textured stimilus and play it
sig = texture_ERB(n_freqs, n_coh, fs=fs, seq=("inc", "nb", "sam"))
play_sound(sig, fs, norm=True, wait=True)

This stim will have successive tones separated by 1.45 ERBs

Let’s look at the time course

t = np.arange(len(sig)) / float(fs)
fig, ax = plt.subplots(1)
ax.plot(t, sig.T, color="k")
ax.set(xlabel="Time (sec)", ylabel="Amplitude (normalized)", xlim=t[[0, -1]])
fig.tight_layout()

And now the spectrogram:

fig, ax = plt.subplots(1, figsize=(8, 2))
img = ax.specgram(sig, NFFT=1024, Fs=fs, noverlap=800)[3]
img.set_clim([img.get_clim()[1] - 50, img.get_clim()[1]])
ax.set(xlim=t[[0, -1]], ylim=[0, 10000], xlabel="Time (sec)", ylabel="Freq (Hz)")
fig.tight_layout()

And the long-term spectrum:

fig, ax = plt.subplots(1)
ax.psd(sig, NFFT=16384, Fs=fs, color="k")
xticks = [250, 500, 1000, 2000, 4000, 8000]
ax.set(xlabel="Frequency (Hz)", ylabel="Power (dB)", xlim=[100, 10000], xscale="log")
ax.set(xticks=xticks)
ax.set(xticklabels=xticks)
fig.tight_layout()