45、STM32F4 微控制器：模拟音频信号处理与数字控制入门

STM32F4 微控制器：模拟音频信号处理与数字控制入门

1. STM32F4 微控制器模拟音频信号处理

1.1 信号处理代码片段

在处理模拟音频信号时，有如下代码用于文件写入和绘图：

file.write(str(a3[x+1]))
file.write(", ")
file.write("\n")
for x in range(5):
    file.write(str(b4[x]))
    file.write(", ")
for x in range(4):
    file.write(str(a4[x+1]))
    file.write(", ")
    file.write("\n")
for x in range(5):
    file.write(str(b5[x]))
    file.write(", ")
for x in range(4):
    file.write(str(a5[x+1]))
    file.write(", ")
    file.write("\n")
file.write("};")
file.close()

fig = plt.figure()
ax = fig.add_subplot(1, 1, 1)
ax.semilogx(w1, 20 * np.log10(np.maximum(abs(h1), 1e-5)))
ax.axis((10, 48000, -100, 10))
ax.semilogx(w2, 20 * np.log10(np.maximum(abs(h2), 1e-5)))
ax.semilogx(w3, 20 * np.log10(np