Python 中电信号的示波器动画

Question

晚上好，我是Python新手。我正在尝试处理保存在文件中的信号npy。
该文件包含一个电信号，我想像在实验室中使用示波器一样查看该信号，因此我想生成一个动画来显示信号如何随时间变化。
这是我的尝试：

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

signal = np.load('signal.npy')

fig = plt.figure()

def animation(i):
    plt.cla()
    plt.plot(signal)
    # what to do here?

anim = FuncAnimation(fig, animation, frames = len(signal), interval = 10)
plt.show()

我不知道在动画功能中要做什么。
预先感谢并抱歉我的英语

Answer 1

由于我无法访问您的信号数据，因此我生成了我的信号数据以运行动画。用你的随机信号替换我的随机信号。
查看信号相对于时间的基本代码可能是这样的：

# import
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

# signal generation
N = 10001
stop = 100
time = np.linspace(0, stop, N)
A = 1/4*np.cos(2*np.pi*(np.abs(time - stop/2)/stop)) + 1
f = np.concatenate((1*np.ones(int(N/4)), 2*np.ones(int(N/2) + 1), 1*np.ones(int(N/4))))
signal = A * np.sin(2*np.pi*f*time) + 0.05*np.random.randn(N)

# figure preparation
fig, ax = plt.subplots(1, 1, figsize = (8*0.9, 6*0.9))
displayed_period = int(2*f.min())
span = int(N/stop/f.min())

def animation(i):
    # delete previous frame
    ax.cla()

    # plot and set axes limits
    ax.plot(time[span*i: 1 + span*(i + displayed_period)],
            signal[span*i: 1 + span*(i + displayed_period)])
    ax.set_xlim([time[span*i], time[span*(i + displayed_period)]])
    ax.set_ylim([1.1*signal.min(), 1.1*signal.max()])

# run animation
anim = FuncAnimation(fig, animation, frames = int(len(time)/span - 1), interval = 10)
plt.show()

这给出了这个动画：

解释

就我而言，信号是正弦波，其幅度和频率随时间变化（加上一些噪声）。我选择在每帧中查看信号的两次完整振荡，因此我设置

displayed_period = int(2*f.min())

确保至少看到两次完整的振荡。然后我必须定义一帧和以下帧之间通过 x 轴的时间量，所以我设置：

span = int(N/stop/f.min())

话虽这么说，当您运行代码时，该animation函数会被多次调用，每次i计数器都会增加1。因此，您可以使用此计数器对time和signal数组进行切片：time[span*i: 1 + span*(i + displayed_period)]。
通过这种方式，您可以绘制许多displayed_period完整的振荡，并且对于每一帧，您可以按元素滚动 x 轴span。
您必须根据信号属性设置displayed_period和span才能获得类似的结果。

如果您想要像示波器一样进行一些自定义，请检查以下代码：

# import
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

# signal generation
N = 10001
stop = 100
time = np.linspace(0, stop, N)
A = 1/4*np.cos(2*np.pi*(np.abs(time - stop/2)/stop)) + 1
f = np.concatenate((1*np.ones(int(N/4)), 2*np.ones(int(N/2) + 1), 1*np.ones(int(N/4))))
signal = A * np.sin(2*np.pi*f*time) + 0.05*np.random.randn(N)

# color definition
black = '#0F110D'
grey = '#3B3D3A'
yellow = '#FFFF21'

# figure preparation
fig, ax = plt.subplots(1, 1, figsize = (8*0.9, 6*0.9))
displayed_period = int(2*f.min())
span = int(N/stop/f.min())

def animation(i):
    # delete previous frame
    ax.cla()

    # set background color and plot
    ax.set_facecolor(black)
    ax.plot(time[span*i: 1 + span*(i + displayed_period)],
            signal[span*i: 1 + span*(i + displayed_period)],
            color = yellow)

    # plot axes lines
    ax.hlines(y = 0,
              xmin = 0,
              xmax = stop,
              lw = 2,
              colors = grey)
    ax.vlines(x = time[int(span*i + (1 + span*displayed_period)/2)],
              ymin = 1.1*signal.min(),
              ymax = 1.1*signal.max(),
              lw = 2,
              colors = grey)

    # set grid, axes limits and ticks
    ax.grid(which = 'major',
            ls = '-',
            lw = 0.5,
            color = grey)
    ax.set_xlim([time[span*i], time[span*(i + displayed_period)]])
    ax.set_ylim([1.1*signal.min(), 1.1*signal.max()])
    plt.tick_params(axis = 'both',
                    which = 'both',
                    bottom = False,
                    left = False,
                    labelbottom = False,
                    labelleft = False)

# run animation
anim = FuncAnimation(fig, animation, frames = int(len(time)/span - 1), interval = 10)
anim.save('oscilloscope.gif', writer = 'imagemagick')
plt.show()

我没有改变功能，只是改变了动画的方面：