The mdsr was also tested with wspr and jt65hf with excellent results. This lab introduces students to communications theory with amplitude modulation and demodulation. To study frequency modulation and determine its modulation factor 4. To study sampling and reconstruction of pulse amplitude modulation system 6. Vectors and modulation cse 466 interfacing 3 spose m and n are orthogonal unit vectors. In this process, the amplitude of the carrier signal is varied so that it is proportional to the instantaneous amplitude of the modulating. We can define amplitude modulation by saying that a modulating signal, should produce an am wave of the form well use s instead of v or e to indicate that were talking about a modulated quantity and that it can be either a field or a voltage. First, just consider a simple example of throwing a paper for a much far distancecould u do that with ease. Restoring or recovering the message signal from the received modulated waveform that is generally corrupted by noise types of am detectors. Build simple envelope detector for fm demodulation. In amplitude modulation am, we utilize the amplitude of the audio signal to modulate the amplitude of carrier signal, which means that the amplitude of carrier signal will be varied with the amplitude of the audio signal.
Indian institute of technology kanpur ee 381 electrical. Pdf merge combine pdf files free tool to merge pdf online. Amplitude modulation and demodulation 2017 frank dorenberg n4spp v1. There are many methods of generating am, and this experiment explores only one of them. One approach to reduce this interference, known as frequencydivision multiplexing, allocates different carrier frequencies to different users or for dif. In singlechannel efield sensing, the carrier we transmit is m, the sensed value is a, and the noise is n vectors. Demodulation channel decoding is the corresponding process at the receiver of converting the received waveform into a.
Laboratory manual principles of communication system lab ee226f ivth semester prepared by. Aly elosery october 25, 2010 this lab is divided into two parts. Aug 20, 2012 amplitude modulation demodulation trainer, model tlb017, manufactured by taglab, india. Each channel sharing scheme a set of basis vectors.
Choose from a variety of file types multiple pdf files, microsoft word documents, microsoft excel spreadsheets, microsoft powerpoint. The diode detector is the simplest and most basic form of amplitude modulation, am signal detector and it detects the envelope of the am signal. Group3 umang gupta 2010ee50564 indrabhushan 2010ee50548 vivekmangal 2010ee50566 jitendra kumar meena 2009ee50483 12912 experiment 2. That could be the amplitude, phase, or frequency, which result in amplitude modulation am, phase modulation pm, or frequency modulation fm. But the term demodulation tends to be used more widely when referring to the process of extracting the modulation from the signal. To study amplitude demodulation by linear diode detector 3. Combine multiple pdf files into one pdf, try foxit pdf merge tool online free and easy to use. Demonstrate the modulation and demodulation process of ssb. Yet, am continues to be used today in many communication applications. Our pdf merger allows you to quickly combine multiple pdf files into one single pdf document, in just a few clicks. Build simple envelope detector for am demodulation. The term detection is the older term dating back to the early days of radio. Hapter modulation and demodulation mit opencourseware. The focus of this lab is to familiarize the student with the modulation and demodulation of an.
Request pdf digital phase modulation and demodulation digital phase modulation is a class of power and bandwidthefficient modulations widely used in telecommunications. Demodulation uses either standard am or dsbsc demodulation, depending on whether a carrier tone is transmitted. If the received carrier phase is assumed to be constant, each of the seven reference values will have to be shifted only once at the beginning of the simulation. Vsb modulation with envelope detection is used to modulate image in analog tv signals. Third gure from the top red shows the amplitude modulation of the 20 khz signal with the 1 khz signal. Modulation allows us to transmit multiple signals in the same medium i. Frequency modulation is a form of modulation, which represents information as variations in the instantaneous frequency of a carrier wave. In modulation, one characteristic of a signal generally a sinusoidal wave known as the carrier is changed based on the information signal that we wish to transmit modulating signal. Note that it looks like the double sideband modulated signal shown in figure 2 of the lecture notes. Observe a combine 2khz message with a of 3khz message in the spectrum. The am diode detector can be built from just a diode and a few other components and as a result it is a very low cost circuit block within an overall receiver. The last gure green shows the modulation for modulation index of 0.
Digital phase modulation and demodulation request pdf. But if u use a stone or any other object to wind the paper, then the paper reaches more t. Vsb signals are generated using standard am or dsbsc modulation, then passing modulated signal through a sideband shaping. In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that of the message signal being transmitted. To study and perform pulse position 6 to study and perform pulse code modulation and demodulation.
One common way is to use a simple device called the envelope detector, shown in figure 4. The wave form of am modulation is shown in figure 3. Amplitude modulation and demodulation electrical and computer. Ee3 prelab 1 amplitude modulation and demodulation. Readers are referred to the textbooks for more insight about how the envelope detector works intuitively. On amplitude and frequency demodulation using energy operators. Amplitude modulation demodulation training system youtube. Double sideband amplitude modulation with carrier setup 1a. This way, the antenna size can be made small as well as more. Ee4512 analog and digital communications chapter 6 the dsbsc am coherent receiver has a bandpass filter centered at f c and with a bandwidth of twice the bandwidth of st because of the lsb and usb. Demodulation is defined as extracting the original informationcarrying signal from a modulated carrier wave. To understand the principles of frequency modulation and demodulation. Amplitude modulation this experiment examines the characteristics of the amplitude modulation am process. Modulation is the process of altering the characteristics of the amplitude, frequency, or phase angle of the highfrequency signal in accordance with the instantaneous value of the modulating wave.
Oct 30, 2017 amplitude modulation and demodulation. Overmodulated am signals and its requirement for coherent detection are also considered. Amplitude demodulation matlab amdemod mathworks india. Source called v1 generates the message to be transmitted. Amplitude modulation and demodulation basics ens 203. As we mentioned before, well use dsbc modulation because of its ease in demodulation. Ee4512 analog and digital communications chapter 6 chapter 6 analog modulation and demodulation amplitude modulation pages 306309. Build simple am modulator by using crystal oscillator. Terms like diode detector, synchronous detector and product detector are widely used.
Modulation and demodulation medium, it would be dif. Amplitude modulation and demodulation objective amplitude modulation am is one of the simplest methods for modulating a sinusoidal carrier wave. By the end of this experiment, the student should be able to. The demodulation is performed by an envelope detector. Introduction modulation is used in efficient radiation of signals. In addition to a variable bandpass filter, one auto notch and one manual notch filter can be utilized to eliminate interfering signals. Dutton ee3 winter 2004 1 ee3 prelab 1 amplitude modulation and demodulation 1 introduction this week we will be taking a look at the amplitude modulation am scheme. Then, students will use labview to program an am demodulator and use it to explore and visualize the. There are different types of modulation and so are demodulators. Here is the circuit used for modulation and its simulation. Another method, which introduces more variables into the model, is explored in the experiment entitled. Lab manual ssb modulation and demodulation experiment 7 ssb modulation and demodulation objectives. Then inner products dot products are 1 1 0 can interpret inner product as projection of vector 1 v1 onto vector 2 v2in other words, inner product of v1 and v2 tells us how much of vector 1 is there in the direction of vector 2.
Soda pdf is the solution for users looking to merge multiple files into a single pdf document. Build simple fm demodulator by using frequency discriminator. The gain of entire circuit is determined by the r8 value. Pdf on amplitude and frequency demodulation using energy.
Normally detector can be classified as synchronous detector and asynchronous detector. Remember, neither yt, nor the oscillator signal, appears at the multiplier output. Frequency division multiplexing, fdma amplitude modulation and demodulation. A demodulator is an electronic circuit that is mainly used to recover the information content from the modulated carrier wave. Merge pdf online combine pdf files for free foxit software. The modulated carrier signal is sent to the receiver where demodulation of the carrier occurs to. Both amplitude and phase of ft carry information of ft. The purpose of this lab is for you to gain familiarity with the concepts of amplitude modulation and. The transmission bandwidth required by dsb sc is b t2b. In analog applications, the carrier frequency is varied in direct proportion to changes in the amplitude of an input signal. Students will explore the mathematical theory behind amplitude modulation and use the analog discovery 2 to visualize the effects of amplitude modulation in the time and frequency domains. To study and perform pulse amplitude modulation and demodulation. Set the modulation signal vst to a 500 hz sine wave with amplitude 2.
As in modulation, there are several ways to achieve demodulation. We will discuss these two types of detectors in this experiment. To study and perform pulse width modulation and demodulation. To study sampling and reconstruction of pulse amplitude modulation. We show that the probability density function pdf characterizing the output of tkeo. Single sideband ssb is a common analog modulation scheme for.
Amplitude modulation am is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. The message signal is, for example, a function of the sound to be reproduced by a. Amplitude modulated signal can be represented by the following equation. How to combine files into a pdf adobe acrobat dc tutorials. Generation and demodulation of an amplitude shift keyed ask signal. Amplitude modulation demodulation trainer, model tlb017, manufactured by taglab, india.
In part i you will learn how to design an amplitude modulator am and in part ii you will be able to demodulate an am signal. Connections are made for the am modulator and demodulator as shown in the circuit. Amplitude modulation and demodulation abstracta single tone sinusoidal signal is transmitted using amplitude modulation and is demodulated at the receivers end using an envelope detector and the attenuated signal is amplified using common source bjt amplifer i. The modulated signal y has zero initial phase and zero carrier amplitude, resulting from a.
Experiment 5 frequency modulation 1 objective to understand the principles of frequency modulation and demodulation. It would be advantageous to have completed some of the experiments in volume a1 involving linear modulation and demodulation. Implementing an amplitude demodulator with a product detector. The carrier signal and y have sampling frequency fs.
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