Analog Modulation

• Published in: Introduction to Analog and Digital Communication pp. 3 - 27
• Main Authors: Bhagyaveni, M. A., Kalidoss, R., Vishvaksenan, K. S.
• Format: Book Chapter
• Language: English
• Published: Routledge 2016
• Edition: 1
• Subjects: Source Encoder; Lower Sideband; Sideband Amplitude; Message Signal; Sideband Modulation; Sideband Power; Discrete Memoryless Source; PWM; Time Domain Representation; Source Decoder; Continuous Time Signal; Modulating Signal; Sideband Signals; Channel Encoder; DSB; Modulation Index; PWM Signal; Frequency Spectrum; Phase Angle; Receiver Side; Carrier Power; TDMA Technique; Carrier Signal; Discrete Time Signal
• ISBN: 9788793379336; 8793379331
• DOI: 10.1201/9781003338673-2

The term "communication" is transfer of information from one place to another or between individuals. A transmitter block is divided into source, source encoder, channel encoder, and modulator. Similarly a receiver block is divided into demodulator, channel decoder, source decoder, and detector. Audio signals are known to occupy the frequency range from 20 Hz to 20 kHz in the same frequency band. At the receiver side, picking up particular user signals is possible, since all the user frequencies are occupied in the same frequency band. Transmitting antenna size should be at least one quarter of wavelength of transmitting signal to ensure efficient transmission of the signal. The channel may be a wired medium or wireless medium one. A message signal is a low-frequency signal, while a carrier signal is a high-frequency signal. Message and carrier signals are needed for doing modulation. The output of the modulator is modulated signal.