Remember that the am waveform appears like the diagram of view b and the amplitude variations of the peaks represent the original audio signal, but no modulating. Figure 1 shows the block diagram of an am modulation and demodulation system. Es442 lab 4 amplitude modulation and demodulation i. Am modulation at a carrier frequency, kc, specified by the student.
To study and perform amplitude modulation and demodulation. Frequency division multiplexing, fdma amplitude modulation and demodulation. This is based on a dsp, using dsp for demodulation of ssb, variable bandwidth filters, agc, noise reduction etc. 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. In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that. Modulation is inherently a nonlinear process, and always gives rise to frequency components that did not exist in either of the two original signals amplitude modulated wave form if the amplitude modulated signal shown here is passed through a frequency analyzer, the following spectrum is the result. Double sideband amplitude modulation with carrier setup 1a. Note that it looks like the double sideband modulated signal shown in figure 2 of the lecture notes. Pdf an analog method to modulate and demodulate signals is presented in.
If a rolling element bearing has a defect such as a crack in one of the races, there will be an impact created every time a rolling element passes over it. Modulation demodulation maps retrieves the digital information into from an analog waveform appropriate for transmission over the channel. Experiment 10 amplitude modulation and demodulation introduction in this experiment we generate and display. That could be the amplitude, phase, or frequency, which result in amplitude modulation am, phase modulation pm, or frequency modulation fm. Introduction for am signals, the information is carried by the amplitude or envelope of the signal. Download modulation d amplitude demodulation d amplitude book pdf free download link or read online here in pdf. The modulator outputs two files, the first with the modulated signal exactly n real elements long and the. 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. Modulation allows us to transmit multiple signals in the same medium i.
This amplitude modulation is tested in ni usrp rio 2920 as transmitter. Amplitude demodulation applied to bearing analysis. Am modulation simply means the shifting of a signal frequency to another usually higher frequency. Amplitude modulation and demodulation objective amplitude modulation am is one of the simplest methods for modulating a sinusoidal carrier wave. Matlab and labview have great modulationdemodulation toolkits, but we are looking for source code. Amplitude demodulation matlab amdemod mathworks india.
The two common forms of analog modulation are amplitude modulation. Lab manual ssb modulation and demodulation experiment 7 ssb modulation and demodulation objectives. This leaves a signal consisting only of the carrier and this can be used as the local oscillator signal in the mixer as shown in fig. Id bet it could probably be pretty readily adapted i. Amplitude modulation am is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. Repeat the experiment by mixing in a multitone modulating signal generated as in part 1. Synchronous demodulation of amplitude modulation am. There are many ways to detect the envelope of am signals. Yet, am continues to be used today in many communication applications.
Demonstrate the modulation and demodulation process of ssb. Build simple am modulator by using crystal oscillator. Sinusoidal modulation slowly increase the modulation signal voltage am over the range 0 v to 4 v i. A continuouswave goes on continuously without any intervals and it is the baseband message signal, which contains the information. The amplitude of the input signal controls the oscillation frequency of the vco output signal. Normally detector can be classified as synchronous detector and asynchronous detector. Jun 17, 2014 introduction to modulation and demodulation 1. Pdf simulation of analog modulation and demodulation. Restoring or recovering the message signal from the received modulated waveform that is generally corrupted by noise types of am detectors.
Generally involve translating recovering the baseband digital information to from a bandpass analog signal at. To study sampling and reconstruction of pulse amplitude modulation system 6. Among the types of modulation techniques, the main classification is continuouswave modulation and pulse modulation. Then, students will use labview to program an am demodulator and use it to explore and visualize the effects. We will discuss these two types of detectors in this experiment. Simulation of analog modulation and demodulation techniques in virtual instrumentation and remote lab. In singlechannel efield sensing, the carrier we transmit is m, the sensed value is a, and the noise is n vectors. Multimedia tools downloads samplitude by magix ag and many more programs are available for instant and free download. Experiment with various carrier and modulation frequency settings. But for fm demodulation kenwood have chosen to convert to another if frequency 455 khz and add an fm demodulator chip. Build simple envelope detector for am demodulation. Eee2009eee2009 communicationscommunications contents introduction to communication systems analogue modulation am, dsbsc, vsb, ssb, fm, pm, narrow band fm, pll demodulators, and fll loops sampling systems time and frequency division multiplexing systems, nyquist principle, pam, ppm, and pwm.
Oct 30, 2017 amplitude modulation and demodulation. Another method, which introduces more variables into the model, is explored in the experiment entitled. Onoff modulation change the message signal to a square wave 2 khz and with vpp 4v. In this experiment, a carrier signal and an audio modulating signal are applied to the modulator ic mc 1496 and the produced modulated waveform is observed. Connect frequency counter across the fm out sockets and measure free run span by rotating vr. Aly elosery october 25, 2010 this lab is divided into two parts. To study and perform pulse width modulation and demodulation. Eee2009eee2009 communicationscommunications contents introduction to communication systems analogue modulation am, dsbsc, vsb, ssb, fm, pm, narrow band fm, pll demodulators, and fll loops sampling systems time and frequency division multiplexing systems, nyquist principle, pam, ppm. Group3 umang gupta 2010ee50564 indrabhushan 2010ee50548 vivekmangal 2010ee50566 jitendra kumar meena 2009ee50483 12912 experiment 2. This principle is at the heart of amplitude modulation. Demodulation part number and description qty dp73010 windows based dynamic signal an alyz ersoftw dp730101 rotating machinery package includes rpm based analysis, disk throughput, waterfall analysis and order tracking 1 1 1 1 1 amplitude modulation spectrum phase modulation spectrum 0500 hz baseband analysis. Laboratory manual principles of communication system lab ee226f ivth semester prepared by. 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. In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that of the message signal being transmitted.
Read online modulation d amplitude demodulation d amplitude book pdf free download link book now. In the fm demodulation what we need to recover is the variation of the. To study frequency modulation and determine its modulation factor 4. Modulation damplitude demodulation damplitude pdf book. This is most convenient, cheapest and certainly the most elegant method of producing synchronous demodulation. By the end of this experiment, the student should be able to. Connect frequency counter across the fm out sockets and measure free run span by rotating v r control to both.
Phase modulation pm is used primarily in digital communication. The gain of the amplifier is such that it limits, and thereby removing all the modulation. These impulses cause the bearing race to ring at its natural frequency, just as a bell will ring when tapped. To study and perform pulse amplitude modulation and demodulation. Pdf amplitude demodulationbased em analysis of different. The continuous wave modulation techniques are further divided into amplitude modulation and angle modulation. The innovative point of this study is the elaboratio n of the method that enables the. There are many methods of generating am, and this experiment explores only one of them. Vary the modulation signal amplitude calculate the corresponding changes in modulation index. Indian institute of technology kanpur ee 381 electrical. Note that this is on the very low end of the recommended voltage range. Multimedia tools downloads samplitude pro x suite by magix software gmbh and many more programs are available for instant and free download. Vectors and modulation cse 466 interfacing 3 spose m and n are orthogonal unit vectors. For more info please visit our website or join the yahoo user group.
A bit stream is mapped to symbols during baseband modulation, each symbol say for qpsk represents two bits. Each channel sharing scheme a set of basis vectors. This perl program does a similar task, but for a different modulation scheme frequency shift keying. To study amplitude demodulation by linear diode detector 3. To study and perform pulse position 6 to study and perform pulse code modulation and demodulation.
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. The purpose of this lab is for you to gain familiarity with the concepts of amplitude modulation and. In the case of bask, under noisefree conditions, z would be either. All they use the dsp for on fm is for audio processing.
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