Introduction to Communication Systems

Introduction to Communication Systems:

Bandwidth Requirement in Communication System : It is reasonable to expect that the frequency range i.e., Bandwidth Requirement in Communication System for a given transmission should depend on the Bandwidth occupied by the modulation signals themselves. A high-fidelity audio signal requires a range of 50 to 15,000 Hz, but a bandwidth of 300 to 3400 Hz is adequate for a telephone conversation. When a carrier has been similarly modulated with each, a greater bandwidth will be required for the high-fidelity (hi-fi) transmission. At this point, it is worth noting that the transmitted Bandwidth not be exactly the same as the bandwidth of …


Need of Modulation in Communication System : Until the process of superimposing a low-frequency (long-wave) voice information component on a high-frequency (short-wave) carrier signal was perfected, the most widely used form of communications was a system based on the transmission of a continuous-wave (CW) signal. With this system, the signal was interrupted periodically (Morse code) to produce a coded message. The CW system required tremendous training and expertise on the part of the persons involved in transmitting and receiving the messages, and therefore the field was limited to a few experts. With the development of Need of Modulation, a whole new era …


Principles of Communication Systems : In a broad sense, the term Principles of Communication Systems refers to the sending, receiving and processing of information by electronic means. Communications started with wire telegraphy in the eighteen forties, developing with telephony some decades later and radio at the beginning of this century. Radio communication, made possible by the invention of the triode tube, was greatly improved by the work done during World War II. It subsequently became even more widely used and refined through the invention and use of the transistor, integrated circuits and other semiconductor devices. More recently, the use of satellites and …