Amplitude shift keying ask teknik modulasi ini disebut juga sebagai onoff keying ook. If the amplitude of the high frequency carrier wave is varied in accordance with the instantaneous amplitude of the modulating signal, then such a technique is called as amplitude modulation. Pulse amplitude modulation pam, quadrature amplitude modulation qam 12. Amplitude modulation how is amplitude modulation abbreviated. What is modulation modulation in the modulation process, some characteristic of a high frequency carrier signal bandpass, is changed according to the instantaneous amplitude of the information baseband signal.
In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that of the message signal being transmitted. This question is illdefined a signal doesnt use quadrature modulationdemodulation, transmittersreceivers do. Demonstration of amplitude modulation using matlab. The frequency as well as the duty cycle and the amplitude can be changed instantaneously. In general, video modulation means that a higher frequency carrier wave is modified according to the original video signal. Amplitude modulation free download as powerpoint presentation. 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.
In this code, it is considered the default value of ma equal to 1 for hundred percent modulation. How to make a circuit of amplitude modulation using. The pwm generator can generate pulse width modulation signals in real time. Ppt amplitude modulation powerpoint presentation free to view id. Modulation is the process of putting information onto a high frequency carrier for transmission frequency translation. May 09, 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. Design and implementation of amplitude modulator and demodulator introduction communication is the most important needs from the very beginning of civilization. To be exact, this modulation is named amsc supressed carrier, for a reason that i will clarify a bit later. Basic concept of modulation the information source typically a low frequency signal referred to as the baseband signal carrier a higher frequency sinusoid example.
Amplitude modulation an interactive demo which enables you to both see and hear the result of multiplying a sine wave with a cosine amplitude envelope. Am signals can be received by a crystalpowered radio set, that. The signal can travel long distances, and appear in faraway places, because of the earths ionosphere. The message signal is, for example, a function of the sound to be reproduced by a. For a perfect modulation, the value of modulation index should be 1, which implies the percentage of modulation should be 100%.
The middle graph shows the modulated carrier, where is the message signal and is the modulation factor. How do i make a circuit of amplitude modulation using transistor. This is a power point presentation with embedded audio explanation for each slide, the graphic images are self explanatory. Actually, am modulation creates two copies of the original signal, one at 20003000hz band and another at 30004000hz. The adobe flash plugin is needed to view this content. This is further divided into amplitude and angle modulation.
Video modulation is a strategy of transmitting video signal in the field of radio modulation and television technology. Sep 07, 2018 the bandwidth required for am system is twice the maximum frequency component of the modulating signal, which is an analogue signal. The code for amplitude modulation am with control of modulation index ma has been developed using matlab according to conventional theory. This strategy enables the video signal to be transmitted more efficiently through long distances. Modulation theory 4 a sine wave is represented as follows ct ac cos2. The intensity of the amplitude modulation can be controlled by increasing or reducing the amplitude of the timevarying modulator relative to its dc offset. The idea is simple, though the notion that it can be used to modulate signals for transmission was hardly obvious before its discovery. Amplitude modulation synthesis is a counterintuitive method of creating harmonic content. The bandwidth required for am system is twice the maximum frequency component of the modulating signal, which is an analogue signal. 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. Amplitude modulation definition is modulation of the amplitude of a radio carrier wave in accordance with the strength of the audio or other signal. For simplicity, the amplitude of the carrier signal and the amplitude of the message signal are both kept equal to 1. In its basic form, amplitude modulation produces a signal with power concentrated at the carrier frequency and in two adjacent sidebands. Tunable amplitude and phase modulation in terahertz regime using transverse stratified configuration.
Amplitude modulation am, variation of the amplitude of a carrier wave commonly a radio wave in accordance with the characteristics of a signal, such as a vocal or musical sound composed of audiofrequency waves. This document is highly rated by computer science engineering cse students and has been viewed 2878 times. Which one statement is right about amplitude modulation, amplitude changes according to modulating voltage or amplitude. Bpsk, qpsk, msk frequency shift keying, fsk quadrature amplitude modulation, qam. Modulation techniques there are three basic types of digital modulation techniques known as. Pulse amplitude modulation signal free download at rocket. 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. Download demonstration of amplitude modulation for free. Why modulation is used suitable for signal transmission distanceetc multiple signa. At 100% modulation, the power efficiency of am is 33. 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. The basic theory and equations behind amplitude modulation are relatively straightforward and can be handled using straightforward trigonometric calculations and manipulation. B 2b carrier component together with the message definition.
Amplitude modulation am radio is a commonplace technology today, and is standard in any type of commercial stereo device. The instantaneous amplitude overall signal power varies depending on the instantaneous amplitude of the modulating data. Remove this presentation flag as inappropriate i dont like this i like this remember as a favorite. Chapter amplitude modulation and demodulation, ppt, adc. Modulation presented by nidhi baranwal mca 6th sem 2. Pulse amplitude modulation signal free download at. Amplitude modulation definition of amplitude modulation by. Amplitude modulation article about amplitude modulation by. Modulation makes my voice to exchange band from 0 to 20004000hz. One can clearly follow the complexity involved in the modulation process. Amplitude modulation simple english wikipedia, the free. An example of a message signal mt waveform for amplitude modulation of the message signal mt amplitude modulation amplitude modulation an example of message energy spectral density.
The signal can travel long distances, and appear in faraway places, because of the earths ionosphere amplitude is the height of a wave. Amplitude shift keying ask frequencyshift keying fsk phaseshift keying psk amplitude shift keying ask is a form of modulation that represents digital data as variations in the amplitude of a carrier wave. The technical way to describe the am process involves an initial oscillator called the carrier, which is what gets heard in the traditional way, while the second. The highest frequency of the modulating data is normally less than 10 percent of the carrier frequency. Chapter 3 pulse modulation chapter 3 pulse modulation 3.
Amplitude modulation is the process of changing the amplitude of a relatively high frequency carrier signal in proportion with the instantaneous value of the modulating signal information. In continuouswave modulation, a high frequency sine wave is used as a carrier wave. The carrier frequency remains constant during the modulation process but that its amplitude varies in accordance with the modulating signal. Amplitude modulation am is a method of impressing data onto an alternatingcurrent ac carrier waveform. Ppt quadrature amplitude modulation qam transmitter powerpoint presentation free to download id. Energy spectrum of the am modulated message signal. Pam pulse amplitudo modulation pwm pulse width modulation ppm pulse posision modulation pcm pulse code modulation delta modulation pengembangan dari pcm 3. Amplitude modulation, usually shortened to am, is a simple way to send a radio signal. Amplitude modulation study findings how am affects people. How do i add two different amplitude and same frequency signal and different amplitude and different ac signal source in series and parallel. Notice that the sine wave will move up and down as the dc is varied, its mean value equalling the dc value. Modulation of a radio wave can be performed by varying one or more of its signal componentsamplitude, frequency, or phasewhile keeping its other signal components constant.
When the modulator has a dc offset, the carrier frequency will remain present in the output sound, along with sidebands at frequencies determined by the sum and the difference of the. Set g so that the sinewave peaks just fall to zero. Each sideband is equal in bandwidth to that of the modulating signal and is a. Am is the oldest method of broadcasting radio programs. 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. An interactive demo which enables you to both see and hear the result of multiplying a sine wave with a cosine amplitude envelope. A carrier wave is modulated changed by adding audio. Both amplitude and frequency modulated radio signals nowadays use quadrature modulation and demodulation as a mean to transfer and receive radio signals. A couple of common types of modulation are amplitude modulation and frequency modulation.
Demonstration of amplitude modulation and demodulation using matlab. Types of modulation 6 flynnkatz 7810 analog modulation amplitude modulation, am frequency modulation, fm double and single sideband, dsb and ssb digital modulation phase shift keying. As the name suggests amplitude modulation or am does exactly what it says on the tin, meaning the amplitude of an audio signal is modulated by another signal. The combined signal is transmitted over a frequency. 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. 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 2. Demonstration with professor sandy hill from the university of massachusetts at amherst. Ppt pulse amplitude modulation pam powerpoint presentation free to download id. Introduction modulation is the process by which some characteristics of a carrier is varied in accordance with a modulation wave. The purpose of the modulator is to convert discrete amplitude serial symbols bits in a binary system ak to analogue output pulses which are sent over the channel.
Ppt modulator powerpoint presentation free to download. You can save 4 memory presets and the software supports multiple sound cards. Pulse modulation is yet another form of modulation, without a carrier, in which pulses with precisely known characteristics are transmitted and details can be learned. Ppt teknik modulasi pada komunikasi data powerpoint. There are no amplitude scales shown, but you should be able to deduce the depth of modulation 1 by inspection. The second disadvantage is that almost twothirds of the power is used by th. Continue reading to learn about amplitude modulation in the modular domain. Wind turbine amplitude modulation and planning control study. An amplitude modulated signal has the original carrier signal at the output, as well as the new. Ppt amplitude modulation powerpoint presentation free. Amplitudeshift keying ask frequencyshift keying fsk phaseshift keying psk amplitudeshift keying ask is a form of modulation that represents digital data as variations in the amplitude of a carrier wave.
Amplitude modulation article about amplitude modulation. Pradeep kshetrapal, tutorials point india private limited. Amplitude modulation definition of amplitude modulation. Amplitude modulation am this type of modulation is called amplitude modulation and denoted by and is given by. 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. In amplitude modulation am, auditory or visual information is impressed on a carrier wave by varying the amplitude of the carrier to match the fluctuations in the audio or video signal being transmitted. Ppt quadrature amplitude modulation qam transmitter. Tunable amplitude and phase modulation in terahertz regime using transverse stratified. Amplitude modulation am is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. Ppt modulator powerpoint presentation free to download id. Why modulation is used suitable for signal transmission distanceetc. Amplitude modulation that results in two sidebands and a carrier is often called double sideband amplitude modulation dsbam.
94 996 175 13 119 342 1138 57 1133 900 730 901 193 1331 400 1011 243 359 165 799 824 1425 222 1229 1379 565 907 102 545 658 1265 725 152 323 821 804 1455 1051 1010 170 61 1221 851 980 1205 982 499