Tiêu đề 15. COMMUNICATION SYSTEMS.pdf ✅

Communication means transmission of information. Everyone experiences the need to impart or receive Information continuously in the surrounding and for this , we speak, listen, send message by a messenger, use coded signaling methods through smoke or flags or beating of drum etc. and these days we are using telephones, TV, radio, satellite communication etc. Propagation Of Light Every communication system has three essential elements – (i) transmitter (ii) medium/ channel (iii) receiver Transmitter converts the message signal into an electric signal and transmits through channel. The receiver receives the transmitted signal and reconstructs the original message signal to the end user. There are two basic modes of communication: (i) point-to-point and (ii) broadcast. In point-to-point communication mode, communication takes place over a link between a single transmitter and a single receiver as in telephony. In the broadcast mode, there are a large number of receivers corresponding to a single transmitter. Radio and television are most common examples of broadcast mode of communication. Basic terminology Used in Electronic Communication systems: (i) Transducer. Transducer is the device that converts one form of energy into another. Microphone, photo detectors and piezoelectric sensors are types of transducers. (ii) Signal - Signal is the information converted in electrical form. Signals can be analog or digital. Sound and picture signals in TV are analog. It is defined as a single-valued function of time which has a unique value at every instant of time. CHAPTER – 15 COMMUNICATION SYSTEMS COMMU NICATION SYSTEMS