Overmodulation overmodulation is a condition that occurs when an excessive intelligence signal overdrives an am modulator making %m 100% because e i e c modulated carrier amplitude reach value greater than double of unmodulated value it produces a distortion known as sideband splatter, which results on transmission at frequencies outside. Amplitude modulation in hindi communication system youtube. In this case the rotor blades pass through a turbulent boundary layer that extends over about onefourth of. Ppt amplitude modulation powerpoint presentation free. Modulation is the process of varying one or more properties of a highfrequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted. Find powerpoint presentations and slides using the power of, find free presentations research about amplitude modulation and demodulation ppt. This type of modulation technique is used in electronic communication.
Amplitude modulation is a very basic form of modulation, and although its simplicity is one of its major advantages, other more sophisticated systems provide a number of advantages. Essentially an amplitude modulated wave consists of a radio frequency carrier a sine wave at one frequency, typically in the radio frequency portion of the spectrum. Principles of communication modulation tutorialspoint. It is often called as am and is commonly used in transmitting a piece of information through a radio carrier wave. Fm signals have the same peak frequency deviation, then when mt is a sinusoidal signal set such that the pm and note. When we take the pulse digital modulation, we use a periodic sequence of rectangular pulses as the carrier signal. Basic concepts of modulation three kinds of modulations modulation is the process of facilitating the transfer of information over a medium. Pulse digital modulation is also used in both analog and digital communications. Modulation techniques pwm and pulse code modulation. View amplitude modulation research papers on academia. Pulse amplitude modulation is the basic form of pulse modulation. In amplitude modulation or am, the carrier signal has its amplitude.
The frequency of the carrier signal is usually much greater than the highest frequency of the input message signal. Communication is achieved over a transmitter and a receiver through signals. Multiple choice questions and answers on amplitude modulation. Introduction what is communication transmitter channel receiver a communication system process of conveying message or information transmitter modifies the message signal into a form which is suitable for transmission over channel which is achieved by modulation information source. Today communication is the heart of the technology. No information is lost, but the energy is redistributed in the frequency domain. Pm and digital modulation s p where 2 is the pkpk phase change in one symbol duration, t for digital signals the modulation index. Pulse amplitude modulation is one of the kinds of modulation techniques used in signal transmission. Up tp 93% off launching official electrical technology store shop now. The basic theory and equations behind amplitude modulation are relatively straightforward and can be handled using straightforward trigonometric calculations and manipulation.
The pulse may take any real voltage value that is proportional to the value of the original waveform. In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that of the message signal being transmitted. Amplitude modulation am radio is a commonplace technology today, and is standard in any type of commercial stereo device. This shout can be heard only up to a certain distance. But we are getting ahead of ourselves, as we have not yet even defined what am is.
Before we study in detail about pam lets know the concepts of. Farshad lahouti january 20, 2003 winter 2003 uw, ece 318 lecture notes 2 information source signal modulator propagation channel signal demodulator information destination analog communication system analog signals may be transmitted directly via carrier modulat ion over. The carrier amplitude is constant and the phase variation of the signal contains the information. The modulation concept, baseband signal, bandpass signal, message signal, carrier signal, modulated signal, modulation, types of modulation, amplitude modulation am, angle modulation, frequency modulation fm, phase modulation pm breaking news. Pulse amplitude modulation is the simplest form of modulation. Amplitude modulation introduction amplitude modulation is the simplest and earliest form of transmitters am applications include broadcasting in medium and highfrequency applications, cb radio, and aircraft communications basic amplitude modulation the information signal varies the instantaneous amplitude of the carrier am characteristics am is a nonlinear process sum and. To extend the range of sound, we need to transmit it through a medium other than air, such as a phone. A free powerpoint ppt presentation displayed as a flash slide show on id. Operation of varying amplitude, frequency or phase of carrier signal accordingly with the instantaneous amplitude of the message signal is called modulation modulation adding information to a carrier signal. In singlechannel efield sensing, the carrier we transmit is m, the sensed value is a, and the noise is n vectors. For a perfect modulation, the value of modulation index should be 1, which implies the percentage of modulation should be 100%. Basic concept of modulation the information source typically a low frequency signal referred to as the baseband signal carrier a higher frequency sinusoid example.
In this modulation, the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the modulating signal. Amplitude modulation is mostly used in the form of electronic communication. To heterodyne means to mix to frequencies together so as. In this modulation, the amplitude of the carrier signal varies in accordance with the message signal, and other factors like phase and frequency remain constant. The carrier frequency, fc, should be larger than the highest spectral component. Amplitude modulation a1 49 you will see in this experiment, and in others to follow, that there is no problem in generating an am signal with a depth of modulation exceeding 100%, and without any rf distortion whatsoever. Because of the low cost of the parts necessary to implement am transmission and the simplicity of the underlying technology, using amplitude modulations is a cheap and effective way to perform many tasks that require wireless communication.
Apr 18, 2020 chapter amplitude modulation and demodulation, ppt, adc, semester, engineering computer science engineering cse notes edurev is made by best teachers of computer science engineering cse. View and download powerpoint presentations on amplitude modulation and demodulation ppt. What is modulation 2 modulation in the modulation process, some characteristic of a highfrequency carrier signal bandpass, is changed according to the instantaneous amplitude of the information baseband signal. Frequency modulation fm phase modulation pm click on the links given above to know more. Amplitude modulation and demodulation ppt xpowerpoint. Principles of communication modulation a signal can be anything like a sound wave which comes out when you shout. Amplitude modulation a carrier signal is modulated only in amplitude value the modulating signal is the envelope of the carrier the required bandwidth is 2b, where b is the bandwidth of the modulating signal since on both sides of the carrier freq.
An example is a rotor operating in a very uneven inflow, such as the rotor operating near a wall that was discussed in chapter 10. In india, radio broadcasting is done through amplitude modulation. These signals carry the information through modulation. Amplitude modulation an overview sciencedirect topics. Amplitude modulation am is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. Chapter amplitude modulation and demodulation, ppt, adc. The message signal is, for example, a function of the sound to be reproduced by a. Modulation presented by nidhi baranwal mca 6th sem 2. This document is highly rated by computer science engineering cse students and has been viewed 2851 times. It was the earliest modulation technique used to transmit voice by radio. Quadrature amplitude modulation is widely used for carrying many digital signals, everything from wifi to mobile phone communications and very much more. As given is the problem the modulation is sinusoidal this is also called tone modulation. Amplitude modulation a continuouswave goes on continuously without any intervals and it is the baseband message signal, which contains the information.
In this video, i have explained amplitude modulation by following outlines. Amplitude modulation with modulation factor 1 or 100%. Modulation is defined as the process of modifying a carrier wave radio wave. Amplitude modulation occurs when the source level on a rotating blade varies significantly with position. Accordingly it is worth looking at some of the disadvantages of amplitude modulation. Amplitude modulation am is the technique in which the amplitude peaktopeak voltage of the carrier wave is varied as a function of time in proportion to the strength of the data signal. In pulse width modulation, there are different types of modulation for analog and digital as shown below. In the context of radio communications, near the end of the 20th century, few modulated signals contain a significant component at carrier frequency. Television broadcasting is done with amplitude modulation for video signals and frequency modulation for audio signals. Amplitude modulation is a process by which the wave signal is transmitted by modulating the amplitude of the signal. The various parts of this lab unit will be used to explore and verify the operation of the two am modulation methods using four different am modulating circuits. If the received carrier phase is assumed to be constant, each of the seven reference values will have to be shifted only.