Analog & Digital Modulation Techniques: An Overview (original) (raw)

A Comparative Study of Various Digital Modulation Techniques

Digital communication is a transfer of information from source to destination in the form of discrete signals. These signals are manipulated by electronic circuits (analog or digital) for making it possible to transmit and receive the data or information. Digital transmission is the physical transfer of data over a point-to-point or point-to-multipoint communication channel such as copper wires (guided and unguided channels), optical fibres, wireless communication channels, and storage media. The data is represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal. In communication systems, the noise is an error or undesired random disturbance of a useful information signal, introduced before or after the detector and decoder. The noise is a summation of unwanted or disturbing energy from natural and sometimes man-made sources. If we transmit the baseband signals directly, the signals from different transmitters will get mixed up and the information will be lost. Because of these reasons, we use the technology of modulation, for transmitting message signals effectively for long distances Modulation is the process of varying one or more properties of a high frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted. The main goal of modulation today is to squeeze as much data into the least amount of spectrum possible. That objective, known as spectral efficiency, measures how quickly data can be transmitted in an assigned bandwidth expressed in terms of bits per second per Hz (b/s/Hz). Multiple techniques have emerged to achieve and improve spectral efficiency. There are various analog and digital modulation techniques used to transmit the signals. Due to various advantages of digital signals over analog signals, digital modulation techniques are preferred widely. This paper presents a brief study of different digital modulation methods and their uses for a particular application.

Studying the process of analogue and digital modulation

Studying the process of analogue and digital modulation, 2017

The study of communication systems is largely based on signals and systems theory. An important objective in modulation is to produce a signal whose frequency range is suitable for transmission over the communication channel to be used. This paper presents an approach for studying the process of the main types of modulations of low and higher order. By using of computer simulations in MATLAB environment different types of modulation can be deep analyzed. It can be used for educational purposes in engineering education.

A New Modulation Method for Digital Communication

IEEE Conference, 2007

We present the design of a transmitter and a receiver for digital communication system that uses function modulation (fm) method. The design covers both orthogonal and non-orthogonal analytic functions. The design is based on the concept of software radio on a general purpose Digital Signal Processor (DSP). A numerical method for generating the waveforms required for the fm system is presented. Experimental results on real environment, demonstrating the feasibility of the concept, are also discussed.

MODULATION METHODS EMPLOYED IN DIGITAL COMMUNICATION : An Analysis

2012

The concept of modulation is a key factor in commun ication, because without an appropriate modulation method or scheme, getting an expected th roug put in such a communication effort would be impossible to achieve. Communication engineers and researchers have not relented in trying to find the best modulation methods aimed at achieving an expected t hroughput, bandwidth/power efficiency, low error performance, etc in digital communication networks. Digital modulation is preferred to the analogue mo dulation due to their error-free capability.Moreso, this cho i e of digital modulation is dependent on the type of communication network that is to be established. Ho wever, trade-offs must be made between the bandwidt h efficiency, power efficiency and the cost of implem ntation of such a network. This paper focuses onsome methods usually employed in the process of modulation in digital communicati on networks. Specifically, binary phase shift keying, quadrature phase shift keying, eigh...

Simulation of Digital Modulation Techniques Using MATLAB

International Journal of Advanced Research in Computer Science and Electronics Engineering, 2012

In Digital modulation the message signal is in the digital form and the carrier wave is in sinusoidal form. In this technique the Amplitude, Frequency or Phase of carrier varies according to message (Baseband) signal. There are various type of digital modulation technique like Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), Frequency Shift Keying (FSK), Quadature Phase Shift Keying (QPSK), Differential Phase Shift Keying (DPSK) and other digital demodulation technique.