在发送端，模拟信号经过抽样、量化、编码变为数字信号，再经过码形变换等过程送到信道上。到了接收端，首先进行码型反变换，再由接收设备把数字信号还原为模拟信号。我们能看到信号在接收端和发送端之间传输时，始终采用数字信号的形式。下面我们就来看一看数字信号的传输。 At the sending end, the analog signal is sampled, quantized and encoded into a digital signal, which is then sent to the channel through a process such as code conversion. To the receiving end, the first anti-pattern conversion, and then by the receiving device to restore the digital signal into an analog signal. We can see that the signal always takes the form of a digital signal when it is transmitted between the receiving end and the sending end. Let’s take a look at the digital signal transmission.