关键词：传感器；通信系统；发射器；编码器
摘 要：Communication is the action of transmitting and eventually receiving another message in response, as in an exchange of e-mails, for example. In a technical approach, one may say that communication is the process that involves the transmission and reception of messages between a source and an addressee receiver, in which information transmitted through physical resources or equipment, and technological devices are coded at source and decrypted at the destination using agreed systems of signs or sound symbols, written or iconographic. Schematically (Figure 15.1), there are five elements in any communication system, namely, an emitter, an encoder, a transmission channel, a decoder, and a receiver. The encoder handles the message, so it passes through the channel, and the decoder carries out the reverse process. In order to be practical and safe, the construction of a communication system may rennire other comnonents.