Slow light of an amplitudemodulated gaussian amg pulse in cesium vapor is demonstrated and studied, since the appropriate amplitude modulation to a single pulse can enrich its spectrum and even. Pulse amplitude modulation pam, quadrature amplitude modulation qam 12. In this lecture we will study amplitude modulation and a device which can be used as an amplitude modulator. Radio waves can carry audio, video, and digital information over great distances by using changes in a carrier waves amplitude, frequency, or phase to represent the information being transmitted. Demonstration with professor sandy hill from the university of massachusetts at amherst. There are many ways in which amplitude modulation can be generated and a variety of circuits that can be used. Pulse amplitude modulation has some applications, but it is not used by itself in data communication. Commutator determines the synchronization and sequence of the channels signals to be sampled. Amplitude and phase can be modulated simultaneously and separately, but this is difficult to generate, and especially difficult to. In fm, the amplitude of the modulating carrier is kept constant while its frequency is varied by the modulating message signal. Gallager lectures on nyquist theory, pulse amplitude modulation pam, quadrature amplitude modulation qam, and frequency translation. The following figures explain the pulse amplitude modulation. Pdf use of pulse amplitude modulated pam fluorometry. The amplitude of the analog signal is sampled at uniform intervals and each sample is quantized to its nearest.
Each one of these digits, though in binary code, represent the approximate amplitude of the signal sample at that instant. Instead of a pulse train, pcm produces a series of numbers or digits, and hence this process is called as digital. Principles of communication systems 20022003 8 chapter 7. Such require ments impact the choice of continuoustime waveform that the discrete sequence is modulated onto. The continuous wave modulation techniques are further divided into amplitude modulation and angle modulation. The pulse amplitude modulated signal, will follow the amplitude of the original signal, as the signal traces out the path of the whole wave. Dec 05, 2014 amplitude modulation modulated signal. Winter 2003 uw, ece 318 lecture notes 3 modulation. Chapter 4 pulse modulation final modulation sampling. Lecture 39 pulse modulation schemes pwm and ppm youtube. Lec 21 mary pam pulse amplitude modulation ii youtube. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect.
The process by which some characteristics of a carrier signal i. Before we study in detail about pam lets know the concepts of modulation. Pulse amplitude modulation pulse code modulation sampling. Next topic pulse code modulation pulsecode modulation pcm is used to digitally represent sampled analog signals. So lets start with pulse amplitude modulation pam here we will. Use of pulse amplitude modulated pam fluorometry for in situ measurements of photosynthesis in two red sea faviid corals article pdf available in marine biology 14. Ppt amplitude modulation powerpoint presentation free.
Up next angle modulated systemsa conceptual video lecture duration. Theory of amplitude modulation representation of am power relations in the am wave singlesideband techniques amplitude modulation. Lec 21 principles of communicationii mary pam pulse amplitude modulation ii iit kanpur. The modulating signal can then theoretically be recovered exactly by filtering the pulseamplitudemodulated signal with an ideal lowpass filter.
Pdf slow light of an amplitude modulated gaussian pulse. Process by which a property or a parameter of a signal is varied in proportion to a second signal. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. In practical applications, pulseamplitudemodulation pam fluorometry in conjunction with the saturation pulse method has been particularly successful. Analogue modulation amplitude modulation v c t v c cos c t, peak amplitude v c, carrier frequency c radians per second. Pulse amplitude modulation is a technique in which the amplitude of each pulse is controlled by the instantaneous amplitude of the modulation signal. Sampling theorem determines the necessary conditions which allow us to change an analog signal to a discrete one.
Feb 12, 2014 pulseamplitude modulation, acronym pam, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. And all of these follow, in a very straightforward way, from the modulation property for the fourier. Amplitude, frequency, pulse modulation electronics. In the next lecture well consider the same set of notions related to discrete time, and also a concept referred to as pulse amplitude modulation. Amplitude modulation am in am, the modulating signal the message signal mt is impressed on to the amplitude of the carrier. Hence, the position of these pulses is proportional to the width of the pwm pulses. Pulse amplitude modulation pam theory of and its applications. Ii, 2018 2 cw vs pulse modulation in amplitude modulation and angle modulation, some parameter of sinusoidal carrier wave is varied continuously in accordance with the message signal. Digital modulation in communications systems an introduction. The course serves as an introduction to the theory and practice behind many of todays communications systems. Click here to visit our frequently asked questions about html5 video.
Digital carrier modulation lecture topics eye diagrams pulse. Oct 03, 2017 watch the complete video lecture and written content about pulse modulation and pulse modulation techniques like pulse amplitude modulation pam, pulse width modulation pwm pulse duration modulation pdm, pulse position modulation ppm and pulse code modulation pcm. A two bit modulator pam4 will take two bits at a time and will map the signal amplitude to one of four possible levels, for example. Amplitude and phase can be modulated simultaneously and separately, but this is difficult to generate, and especially difficult to detect. This means that their ratio is unity at the output of the adder, which forces m to a magnitude of exactly unity. The pulse amplitude modulated signal, will follow the amplitude of the original signal, as.
Slow light of an amplitude modulated gaussian amg pulse in cesium vapor is demonstrated and studied, since the appropriate amplitude modulation to a single pulse can enrich its spectrum and even. We use modulation technique to alter signals in time and frequency to accomplish desired objectives. These signals carry the information through modulation. The original waveform amplitude is quantized with a resulting loss of information. Modulated signal some parameter of the carrier amplitude, frequency, phase is varied in accordance with the baseband signal xt t xf f modulator baseband carrier modulated signal 5 flynnkatz 7810. The ideal modulated signal should have a minimum euclidean distance of 2. The am generator, or exciter, as such a low power source of modulated signal is often called, is now set up. Communication is achieved over a transmitter and a receiver through signals. However, it is the first step in another very popular conversion method called pulse code modulation. Today communication is the heart of the technology. Pulse amplitude modulation pam, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. Autoplay when autoplay is enabled, a suggested video will automatically play next.
Ppt amplitude modulation powerpoint presentation free to. Watch the complete video lecture and written content about pulse modulation and pulse modulation techniques like pulse amplitude modulation pam, pulse width modulation pwm pulse duration modulation pdm, pulse position modulation ppm and pulse code modulation pcm. Pdf slow light of an amplitude modulated gaussian pulse in. The depth of modulation, defined below, can be adjusted with the adder gain control g. Figure 242 shows three typical waveforms in which the pulse amplitude is varied by the amplitude of the modulating signal. The transmission bandwidth required by dsb sc is b t2b. Next topic pulse code modulation pulse code modulation pcm is used to digitally represent sampled analog signals. In early am transmitters the amplitude modulator circuit was a key element of the transmitter. This is the simplest and oldest form of modulation. Department of electrical and computer engineering chapter outline pulse modulation pulse code modulation line coding introduction to digital modulation. 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. Cahn, combined digital phase and amplitude modulation communication systems, ire transactions on communications systems, vol. Sampling theorem and pulse amplitude modulation pam reference stremler, communication systems, chapter 3. The pulse may take any real voltage value that is proportional to the value of the original waveform.
Winner of the standing ovation award for best powerpoint templates from presentations magazine. Baseband signal may use shaped pulses, so cosine amplitude varies. It is a modulation system in which the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the signal at the instant of sampling. Surendra prasad, department of electrical engineering,iit delhi. Amplitude modulated systems amplitude modulation based solved problems are covered in this video lecture. It requires that the amplitude of the dc a part of at is equal to the amplitude of the ac part a.
So our focus in todays lecture will be on sinusoidal amplitude modulation in continuous time. Gallager gives 24 video lectures on the principles of digital communications. Analog communication pulse modulation tutorialspoint. Electronics and communication ece lecture videos gate and ies. Our new crystalgraphics chart and diagram slides for powerpoint is a collection of over impressively designed datadriven chart and editable diagram s guaranteed to impress any audience. Fourier transforms and their application to pulse amplitude modulated signals phil lucht rimrock digital technology, salt lake city, utah 84103 last update. Amplitude, frequency, pulse modulation electronics engineering test questions 1 in ssb the pilot carrier is provided a for stabilizing frequency b to reduce noise c for reducing power consumption d as an auxiliary source of power view answer hide answer. Pulse modulation timedivision multiplex tdm continued necessary bandwidth for tdm signal transmission as only the amplitude information is important here, the absolute minimum bandwidth required such that the information in each sampled channel remains independent of that in the. Rc audio generator, oscilloscope, and spectrum analyzer demonstrations with speech and radio. A modulated signal seen on an oscilloscope has a maximum span of 5 v and a minimum. As the amplitude and the width are constant, the power handled is. The following safety and common symbols may be used in this manual and on.
A continuouswave goes on continuously without any intervals and it is the baseband message signal, which contains the information. Basic concept of modulation the information source typically a low frequency signal referred to as the baseband signal carrier a higher frequency sinusoid example. Your browser does not currently recognize any of the video formats available. Pulse amplitude modulation is the basic form of pulse modulation. Among the types of modulation techniques, the main classification is continuouswave modulation and pulse modulation. It is a measure of how fully the carrier has been modulated. Pulse modulation timedivision multiplex tdm timedivision multiplexing is the method of combining several sampled signals in a definite time sequence. Amplitude modulated systemsa conceptual video lecture.
Jun 10, 2015 autoplay when autoplay is enabled, a suggested video will automatically play next. No information is lost, but the energy is redistributed in the frequency domain. Lecture 41 midrise quantizer, quantization error, probability density function pdf. It is an analog pulse modulation scheme in which the amplitudes of a train of carrier pulses are varied according to the sample value of the message signal.
Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. Lecture series on communication engineering by prof. Application note of pampulse amplitude modulation signal. Lecture 38 introduction to pulse amplitude modulation, sample and hold, flat.
Amplitude modulation pam signal, allowing to increase the number of. View notes lecture notes on pulse modulation from ece 4700 at wayne state university. Using a sine waveform there are three parameters which we can use to modulate a message onto the carrier they are the. The modulated peak value of a signal is 10 v and the unmodulated carrier is 8 v. Pulse position modulation is done in accordance with the pulse width modulated signal. Pulse amplitude modulation pam is an analog modulating scheme in which the amplitude of the pulse carrier varies proportional to the instantaneous amplitude of the message signal.
In this modulation, the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the modulating signal. Among them, amplitude modulation am is considered the oldest. Both amplitude and phase of ft carry information of ft. Pulseamplitude modulation pam, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. Pulse amplitude modulation is the simplest form of modulation. A dualoutput video adapter and two monitors are recommended. Pulse modulated signals, such as pam, pwm, ppm, pm and dm are baseband digital signal coding and. View a represents a sine wave of intelligence to be modulated on a transmitted carrier.
Nyquist theory, pulse amplitude modulation pam, quadrature amplitude modulation qam, and frequency translation view the complete course at. Pulse amplitude modulation pam amplitude of periodic pulse train is varied with a sampled message signal m digital pam. Pulse amplitude modulation pam linkedin slideshare. Pradeep kshetrapal, tutorials point india private limited.
Pulse amplitude modulation is one of the kinds of modulation techniques used in signal transmission. Pulsebased modulation for vlc systems tu delft repositories. This refresher video is to facilitate and make the students feel comfortable with the upcoming video lectures related to pulse amplitude modulation. Amplitude modulation early radio ee 442 spring semester. It is the standard form of digital audio in computers, cds, digital telephony and other digital audio applications.
Pulseamplitude modulation, acronym pam, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. The basic theory and equations behind amplitude modulation are relatively straightforward and can be handled using straightforward trigonometric calculations and manipulation. Pulse modulation techniques pam, pwm, ppm, pcm pulse. Sampling theorem and pulse amplitude modulation pam. In pulse code modulation, the message signal is represented by a sequence of coded pulses. Transmitters that transmit amplitude modulated signals require an am modulator circuit to produce the required signal. Each trailing edge of the pulse width modulated signal becomes the starting point for pulses in ppm signal.
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