The modulating signal contains the intended message or information sometimes consisting of audio data, as in am radio. The depth of modulation at the detector output greater than unity and circuit impedance is. Pam4 indicates pulse amplitude modulation, with the 4 indicating four levels of pulse modulation. However, it is the first step in another very popular conversion method called pulse code modulation. File type pdf lab 6 pam pulse amplitude modulation demodulation on lab 6 pam pulse amplitude modulation demodulation on right here, we have countless books lab 6 pam pulse amplitude modulation demodulation on and collections to check out. User manual for pulse amplitude modulation and demodulation. Learn to observe the output of the agilent 33120a arbitrary waveform generator on the agilent 54645a oscilloscope 3.
To study and perform amplitude modulation and demodulation. If you continue browsing the site, you agree to the use of cookies on this website. Increase the modulated signal until an am waveform appears. Effectively it is formed by having two carriers 90 out of phase. Because, atmospheric propagation is good for amplitude modulated signals. Pdf a pulseamplitudemodulated differentialtimesignaling pamdts architecture for serial. Pam the amplitude of the pulses is varied in step with the message signal. Pulse amplitude modulation pam theory of and its applications. Am modulation, quadrature amplitude modulation qam, and frequency modulation. The message signal xt is modulated by a carrier waveform ac cos2fct. For flattop sampling, a sampleandhold circuit is used in conjunction with the.
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. Experiment 2 amplitude modulation and demodulation. Experiment 3 amplitude modulation and envelope detection. Switching amplitude modulator pulse spectrum generated. Analog communication pulse modulation tutorialspoint. Print means choose the print command in the file menu. Process by which a property or a parameter of a signal is varied in proportion to a second signal.
An application of this is the simulation of a communication system that uses pulse amplitude modulation pam to transmit text messages over a bandlimited channel, such. To provide a familiarization with the use of a multipliercircuit unit to generate an amplitudemodulated am signal, with an adjustable modulation factorm. Theory and applications by angel vladimirov peterchev doctor of philosophy in engineeringelectrical engineering and computer sciences university of california, berkeley professor seth r. Bpsk, qpsk, msk frequency shift keying, fsk quadrature amplitude modulation, qam. Sanders, chair this thesis develops digital pulse width modulation dpwm control of. To study and perform pulse width modulation and demodulation.
Amplitude modulation, modulators, and demodulators fall 2009 double sideband amplitude modulation am t figure 1 sinusoidal signal with a dc component in double sideband modulation the usual am a dc component is added to the signal voltage before the signal is multiplied by a carrier. 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. Amplitude modulation am 9 t15 use speech or music from trunks as the message, and show that this also generates a trapezoid, and that setting the message amplitude so that the depth of modulation reaches unity on peaks a triangle is especially easy to do, using the gain control g of the adder. The modulated signal has the information in the whole band except at the carrier frequency. These form some of the main uses of amplitude modulation. Indian institute of technology kanpur ee 381 electrical. Pulse amplitude modulation an overview sciencedirect topics. For the baseband digital transmission, pulse amplitude modulation pam is the most efficient in terms of power and bandwidth utilization.
Diagram from 1922 showing the circuit of a crystal radio. The amplitude modulation am modulation index can be defined as a measure of the amplitude variation upon a carrier. Application note of pampulse amplitude modulation signal. Amplitude modulation is the simplest of the three to understand. 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. 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. Amplitude modulation and demodulation objective amplitude modulation am is one of the simplest methods for modulating a sinusoidal carrier wave. Hence, pam is continuous in amplitude but discrete in time. Department of ece 11 ec207l analog communications lab ii iv b. Sampling theorem and pulse amplitude modulation pam reference stremler, communication systems, chapter 3. Lab 6 pam pulse amplitude modulation demodulation on. This type of pulse modulation, where pulse amplitude is varied. Yet, am continues to be used today in many communication applications.
Pulse amplitude modulation pam, quadrature amplitude modulation qam 12. Analog communication lab manual, prepared by nakka. With the modulating voltage adjusted to zero amplitude, increase the carrier amplitude until v o has a value of 2 v pp. User manual for pulse amplitude modulation and demodulation trainer. Pulse code modulation pcm is a method used to digitally represent sampled analog signals. Delta modulation and demodulation frequency modulation and demodulation 4. Pulse amplitude modulation is a technique in which the amplitude of each pulse is controlled by the instantaneous amplitude of the modulation signal. The message signal amplitude must be small and must have a. Pulse amplitude modulation pulse amplitude modulation is a technique in which the amplitude of each pulse is controlled by the instantaneous amplitude of the modulation signal.
To study and perform pulse position 6 to study and perform pulse code modulation and demodulation. What is amplitude modulation, am electronics notes. Pulse modulation techniques pam, pwm, ppm, pcm pulse amplitude, pulse width, pulse position, code duration. The output of a sampling circuit with a zeroorder hold zoh is one example of a pam signal. An eye diagram for a pam4 signal is unusual, with three eye openings and four levels stacked vertically as shown in the figure. The particular form of pulse amplitude modulation is referred to as natural pam, because the tops of the pulses follow the.
Aug 18, 20 it is assumed that and that amplitude modulation is formed by the product. 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 transmitter side consists of a dtsmodulation circuit. Pulse amplitude modulation free download as powerpoint presentation.
The output is a series of pulses, the amplitudes of which vary in proportion to the modulating signal. Denoting the modulating signal as mt, pulse amplitude modulation is achieved by multiplying the carrier with the mt. Pdf differentialtime and pulseamplitude modulation signaling. Experiment 2 amplitude modulation and demodulation books pdf.
Pulse amplitude modulation modulation radio technology scribd. Pn code amplitude modulation on a narrow band carrier at a predetermined frequency, performing amplitude demodulation, and conducting matched filter correlation with the reference pn code to obtain the range capability. 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. Pcm pulse code modulation quantized pam signal pcm modifies the pulses created by pam to create a completely digital signal. The following safety and common symbols may be used in this manual and on the equipment. Amplitude modulated signal can be represented by the following equation. National college of science and technology amafel building, aguinaldo highway dasmarinas city, cavite experiment no. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. Set channel b to be a 29khz sine wave, amplitude 1v, phase 90deg, destination out1 set channel c to be a 31khz sine wave, amplitude 1v, phase 270deg, destination out1 at this point, you should have a 100 % amplitude modulated signal. Pulseamplitude modulation pam, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. Design and implementation of amplitude modulator and demodulator introduction communication is the most important needs from the very beginning of civilization. Pulse amplitude modulation pam is the transmission of data by varying the amplitude s voltage or power levels of the individual pulses in a regularly timed sequence of electrical or electromagnetic pulses. To study pulse amplitude modulation and demodulation.
To study sampling and reconstruction of pulse amplitude modulation system 6. Amplitude modulation am is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. Amplitude modulation am is a modulation technique where the. The percent modulation can be varied simply by changing the amplitude of the 30 khz carrier signal. Pulse position modulation ppm is an analog modulation scheme in which, the amplitude and the width of the pulses are kept constant, while the position of each pulse, with reference to the position of a reference pulse varies according to the instantaneous sampled value of the message signal. In each of these systems, a characteristic of the pulse such as amplitude, duration, or position is continuously varied in accordance with the modulating signal.
Modulation is defined as the process by which some characteristics of a carrier signal is varied in accordance with a modulating signal. In this video i tried to explain the experiment amplitude modulation and demodulation. Department of electronics and communication engineering. To study sampling and reconstruction of pulse amplitude modulation. When expressed as a percentage it is the same as the depth of 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.
The transmitter just uses the information signal, v m t to vary the amplitude of the carrier, v co to produce a modulated signal, v am t. Pulse amplitude modulated pam fluorometry is a useful technique for identifying the amount of energy that is not used in photosynthesis but is reemitted as fluorescence or dissipated as heat in. I tried to explain the circuit connections that is needed for the experiment. Some useful tutorials can be found on the ee 370 courselab website. Pulse modulation timedivision multiplex tdm timedivision multiplexing is the method of combining several sampled signals in a definite time sequence. Pulse time modulation is a class of signaling techniques that encodes the sample values of an. A sideband is a band of frequencies, containing power, which are the lower and higher frequencies of the carrier. The purpose of this lab is to explore digital communications with a software radio to understand how each component works together. The pulse amplitude modulated signal, will follow the amplitude of the original signal, as.
A low cost demonstration of this was implemented using hilbert transforms forms for amplitude demodulation. The ideal modulated signal should have a minimum euclidean distance of 2. In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that of the message signal being transmitted. The standard form of an amplitude modulated am wave is defined by st a c 1 k a mt cos2f c t where k a is a constant called the amplitude sensitivity of the modulator. There are many methods of generating am, and this experiment explores only one of them.
Principles of communication systems 20022003 8 chapter 7. The amplitude modulation receiver will be wider when compared to the fm receiver. To perform the amplitude modulation and demodulation using am kit. Dutton ee3 winter 2004 1 ee3 lab 1 amplitude modulation and demodulation 1 lab notes a word about power. In pulse position modulation, both the pulse amplitude and pulse duration are held constant but the position of the pulse is varied in proportional to the sampled values of the message signal. To understand the operation theory of amplitude shift keying ask. Bandwidths limit is also big advantage for amplitude modulation, which doesnt have in frequency modulation. Digital pulsewidth modulation control in power electronic. At the lowest level is 00, followed by 01, 10, and 11, respectively.
Sampling theorem determines the necessary conditions which allow us to change an analog signal to a discrete one. Pulse amplitude modulation pam the actual amplitude of the pulse represents the number being transmitted. 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. The second is to investigate classical analog amplitude modulation and the envelope detector. Illustrate the concept of an amplitude modulated am waveform. Matlab, simulink, and a communications example 1 introduction linear systems are very often used for signal and information processing. We additionally pay for variant types and after that type of the books to browse. Pulse amplitude modulation pam is the simplest pulse modulation scheme. Digital pulsewidth modulation control in power electronic circuits. Amplitude modulation early radio ee 442 spring semester. Note that this is on the very low end of the recommended voltage range. In the process of amplitude modulation or phase modulation, the modulated wave consists of the carrier wave and two sidebands. The wave form of am modulation is shown in figure 3. The lab will cover, analog to digital conversion, modulation, pulse shaping, and noise analysis 1.
In a pcm stream, the amplitude of the analog signal is sampled regularly at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps. As illustrated in figure 5, the amplifier is biased class c and the output rf signal amplitude is modulated by causing the collector supply voltage to vary with the modulation voltage. To understand the theoretical foundations of analog communications as well as of doublesideband amplitude modulation and demodulation dsbam to design the simulink model of the dsbam to analyze each signal in time and frequency domains using time scope and spectrum analyzer. Commutator determines the synchronization and sequence of the channels signals to be sampled. Another method, which introduces more variables into the model, is explored in the experiment entitled.
You can publish your book online for free in a few minutes. Advanced sine wave modulation of continuous wave laser system. Pulseamplitude modulation pam and timedivision multiplexing tdm raymond john reyes 430192944 zeyi yang 460472331 yao zhu 450505001 introduction the aim of this experiment is enabling students to generate a pulse amplitude modulation signal and know the characters of pam signal in time domain and frequency domain respectively. Pulse amplitude modulation pulse code modulation sampling. The transmitter circuit produces the am signal which is. The number of possible pulse amplitudes can be infinite in the case of analog pam, but it is usually some power of two so that the. Why we use modulation to transmit the baseband signals. Am is widely used for the transmission of data in everything from short range wireless links such as wifi to cellular telecommunications and much more. Pulse amplitude modulation has some applications, but it is not used by itself in data communication. Sampling theorem and pulse amplitude modulation pam. In pulse amplitude modulation system the amplitude of a carrier pulse train is varied in accordance with the instantaneous level of the modulating signal. Amplitude modulation is defined as a process in which the amplitude of the carrier wave ct is varied linearly with the instantaneous amplitude of the message signal mt. It is still in use today in a variety of systems, including, of course, am broadcast radio.
Transmitter and receiver are simple in amplitude modulation. 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 demonstration centers around a number of signals displayed in both the time domain and the frequency domain using a signal generator, an oscilloscope to view the signal. In pam the amplitude of the pulses is varied in step with the message signal. It may be necessary to adjust the level and frequency of both v c and v m to achieve a suitable waveform and index of modulation. The concluding part will be spent looking at the more popular form of high level modulation known as collector modulation or heising, named after its inventor. 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.
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