1.1 Terminology used in electronic communication system

  Communication Systems

• Transducer: Any device that converts one form of energy into another is known as transducer.
• Signal: Information converted in electrical form and suitable for transmission is known as signal. Signal can either be analog or digital.
• Noise: It refers to the unwanted signals that tend to disturb the transmission and processing of message signals in a communication system.
• Transmitter: A transmitter processes the incoming message signal so as to make it suitable for transmission through a channel and subsequent reception.
• Receiver: A receiver extracts the desired message signals from the received signals at the channel output.
• Attenuation: The loss of strength of a signal while propagating through a medium is known as attenuation.
• Amplification: It is the process of increasing the strength of a signal using some suitable electronic circuit.
• Range: It is the largest distance between a source and a destination upto which the signal is received with sufficient strength.
• Bandwidth: It refers to the frequency range over which an equipment operates or the portion of the spectrum occupied by the signal.
• Modulation: It is the phenomenon of superimposing the low frequency message signal (called the modulating signal) on a high frequency wave (called the carrier wave).
• Demodulation: The process of retrieval of information from the carrier wave at the receiver is known as demodulation. Demodulation is the reverse process of modulation.
• Repeater: A repeater is the combination of a receiver and a transmitter.