利用matlab软件设计并仿真下面的无线通信系统。模拟信源为单音频信号。模拟调制方式为ASK。信道为多径信道（仿真中2径），信道中噪声为加性高斯白噪声。采用相干解调接收。画出了解调器输出端性能曲线与点信噪比SNR的关系。(Matlab software is used to design and simulate the following wireless communication systems. The analog source is a single tone signal. The analog modulation mode is ASK. The channel is multipath (2 paths in simulation), and the noise in the channel is additive Gauss white noise. Coherent demodulation reception. Draw the relationship between the output curve of the regulator and the signal to noise ratio (SNR).)