在matlab上实现2ASK信号的调制，以及相干解调，并给出调制/解调后的信号波形。主程序名为ASKmod.m，调用子程序为T2F.m、F2T.m、 和LPF.m。-To achieve in matlab 2ASK signal modulation, and coherent demodulation, and given modulation/demodulation of signal waveform. Main program, called ASKmod.m, call subro