线性调频信号的脉冲调频测速代码

A：以下是一个用于生成线性调频信号并利用脉冲调频技术测速的Python代码：

import numpy as np
import matplotlib.pyplot as plt

def chirp_signal(duration, freq_start, freq_end):
    t = np.linspace(0, duration, duration*44100, endpoint=False)
    k = (freq_end - freq_start) / duration
    freq = freq_start + k * t
    signal = np.sin(2 * np.pi * freq * t)
    return signal

def pulse_compress(signal, pulse_width):
    N = len(signal)
    pulse = np.ones(pulse_width)
    signal = np.concatenate((np.zeros(pulse_width//2), signal, np.zeros(pulse_width//2)))
    compress_len = N + pulse_width - 1
    compress = np.zeros(compress_len)
    for i in range(compress_len):
        compress[i] = np.sum(signal[i:i+pulse_width] * pulse)
    return compress

duration = 2 # 2秒
freq_start = 1000 # 1kHz
freq_end = 4000 # 4kHz
pulse_width = 50 # 50个采样点，即1.1毫秒

signal = chirp_signal(duration, freq_start, freq_end)
compress = pulse_compress(signal, pulse_width)

plt.plot(signal)
plt.plot(compress)
plt.show()

在这个代码中，我们使用`chirp_signal`函数生成了一个线性调频信号，并使用`pulse_compress`函数对信号进行脉冲压缩处理。最后用Matplotlib画出了原始信号和压缩后的信号。