Easily plot an audio signal as a continuous waveform and (optionally) save to a file. Uses matplotlib for plotting and saving the figure, pathlib for path handling, and numpy for sine generation. I use this snippet all the time to plot signals and inspect outputs of an audio system. Feel free to treat it as a template: copy, paste & tweak accord…

plot_signal.py

import numpy as np
import matplotlib.pyplot as plt
from pathlib import Path


IMG_OUTPUT_PATH = Path('img')
SAVE_PARAMS = {'dpi': 300, 'bbox_inches': 'tight', 'transparent': True}


def plot_signal(signal, time=None):
    plt.rcParams.update({'font.size': 20})
    COLOR = '#ef7600'

    samples_count = signal.shape[0]

    plt.figure(figsize=(12,6))
    if time is None:
        xlim = [0, samples_count]
        plt.plot(signal, COLOR, linewidth=3)
        plt.xlabel('samples')
    else:
        xlim = [time[0], time[-1]]
        plt.plot(time, signal, COLOR, linewidth=3)
        plt.xlabel('time [s]')
    plt.hlines(0, xlim[0], xlim[1], 'k')
    plt.ylabel('amplitude')
    plt.xlim(xlim)
    plt.yticks([-1, 0, 1])

    ax = plt.gca()
    ax.spines['top'].set_visible(False)
    ax.spines['right'].set_visible(False)
    ax.spines['bottom'].set_visible(False)


def plot_signal_and_save(signal, output_path, time=None):
    plot_signal(signal, time)
    # plt.show() # closes the figure
    output_path.parent.mkdir(parents=True, exist_ok=True)
    plt.savefig(output_path, **SAVE_PARAMS)
    plt.close()


def main():
    frequency = 440
    sample_rate = 44100
    length_seconds = 5
    time = np.arange(length_seconds * sample_rate) / sample_rate
    sine = np.sin(2 * np.pi * frequency * time)
    plot_signal_and_save(sine[:1000], IMG_OUTPUT_PATH / 'sine_signal.png', time[:1000])


if __name__ == '__main__':
    main()