Indian institute of technology kanpur ee 381 electrical. Process by which a property or a parameter of a signal is varied in proportion to a second signal. To study and perform amplitude modulation and demodulation. Read, download and publish amplitude modulation magazines, ebooks for free at. Frequency modulation fm the process of combining the message signal with the carrier signal that causes the message signal to vary the frequency of the carrier signal. The continuous wave modulation techniques are further divided into amplitude modulation and angle modulation. Each part may be of any convenient amplitude at the input to an adder. Amplitude modulation am the process of combining the message signal with the carrier signal and the two sidebands.
The amplitude of the modulation signal determines the amount of the frequency change from the center frequency. 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. To generate amplitude modulation am waveform and to measure modulation index of am wave using waveform method. The purpose of this lab is for you to gain familiarity with the concepts of amplitude modulation and. Amplitude modulation definition, types, solved examples. Pdf effects of amplitude modulation on vibrotactile flow. The pulse train acts as a periodic switching signal to the modulator, which when switched on allows samples of. It is often called as am and is commonly used in transmitting a piece of information through a radio carrier wave.
Sampling theorem and pulse amplitude modulation pam reference stremler, communication systems, chapter 3. Pulse width modulation and in position ppm, pulse position. Pdf pulse amplitude modulation pam and discrete multitone dmt technology are attractive modulation techniques for shortreach. Sampling theorem determines the necessary conditions which allow us to change an analog signal to a discrete one. A continuouswave goes on continuously without any intervals and it is the baseband message signal, which contains the information. To study sampling and reconstruction of pulse amplitude modulation system 6. The frequency of the modulation signal determines the rate of the frequency change from the center frequency. Amplitude modulation and demodulation objective amplitude modulation am is one of the simplest methods for modulating a sinusoidal carrier wave. Pulse amplitude modulated signal and demodulated signals are observed. Pulse amplitude modulation pam the actual amplitude of the pulse represents the number being transmitted.
Connect frequency counter across the fm out sockets and measure free run span by. Connect the carrier signal at carrier ip of the modulator circuit. Experiment 10 amplitude modulation and demodulation introduction in this experiment we generate and display. Trelliscoded pulse amplitude modulation tcpam is the modulation format that is used in hdsl2 and g. The potential of pulse amplitude modulation pam fluorometry was evaluated during a weathering experiment designed to evaluate the algal resistance effectiveness of an admixture of microscopic glass bubbles in silicon paint.
This complete 3volume lab manual offers handson labs for teaching basic analog and digital communication topics such as am, fm, snr concepts, sampling, tdm, and deltasigma modulation. Demonstrate understanding of various amplitude modulation and demodulation techniques. Pulse width modulation pwm is a modulation technique, which converts an analog signal into a digital signal for transmission. The transmitter circuit produces the am signal which is. What is amplitude modulation, am electronics notes. In singlechannel efield sensing, the carrier we transmit is m, the sensed value is a, and the noise is n vectors. Currently there is no open source, free software or alternative commercial. The wave form of am modulation is shown in figure 3. The experiment of rf modulation at the hls hefei light source is introduced. Pulse amplitude modulation is the basic form of pulse modulation. To perform the amplitude modulation and demodulation using am kit.
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. Bpsk, qpsk, msk frequency shift keying, fsk quadrature amplitude modulation, qam. The emona datex addon board combines with the ni elvis platform, providing a foundation to assist the student in visualizing and better understanding the concepts. There are three audio sources, all of which may be used as either the modulator signal, or the carrier signal and in some cases, both simultaneously. Sampling theorem and pulse amplitude modulation pam. Experiment 3 amplitude modulation and envelope detection. Cahn, combined digital phase and amplitude modulation communication systems, ire transactions on communications systems, vol. The am1 uses up to 6 square or sine wave oscillators per voice and amplitude modulation. Amplitude modulation am is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. Pam is a pulse modulation system is which the signal is sampled at regular intervals. 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. To provide a familiarization with the use of a multipliercircuit unit to generate an amplitudemodulated am signal, with an adjustable modulation factorm.
Hence, pam is continuous in amplitude but discrete in time. Pdf differentialtime and pulseamplitude modulation signaling. Pulse amplitude modulation pam is the simplest of all pulse modulation techniques. 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. Compared to the 2b1q scheme used in the older hdsl and sdsl standards, tc.
If this minimum value is zero, the modulation depth is 100%. 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. The purpose of this lab is for you to gain familiarity with the concepts of amplitude. Analog communicationpulse width modulation and demodulation is proposed to user friendly to process the experiments and the trainer had all internal features like message signal, carrier signal, power supply etc. In one method of radio transmission a signal at an audio frequency f s the signal frequency controls the amplitude of a carrier wave of radio frequency f c the carrier frequency, where f c is much greater than f s. Vestigial sideband amplitude modulation vsbam is a modulation that improves the spectral e. Generation of pam signal using the integrated circuit. To study and perform amplitude modulation 2 to study and perform frequency modulation and 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. Frequency modulation software free download frequency. The ideal modulated signal should have a minimum euclidean distance of 2. Pulseamplitude modulation pam, is a form of signal modulation where the message information is encoded in the amplitude of a series of signal pulses. To study frequency modulation and determine its modulation factor 4. There are many methods of generating am, and this experiment explores only one of them.
This form of modulation is essentially derived from two carriers that are 90 out of phase and adding information, either analogue or digital. Adaptation of the information signal to the transmission channel. 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. Modulation is defined as the process by which some characteristics of a carrier signal is varied in accordance with a modulating signal.
Explain generation and demodulation of pam, ppm and pwm. Analog communication lab viva questions and answers pdf analog communication lab viva questions with answers pdf ac interview questions jntu free download. The am1 synthesizer is a realtime, midicontrolled, music synthesizer for the macintosh platform. To study sampling and reconstruction of pulse 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.
You can publish your book online for free in a few minutes. Why modulation is used suitable for signal transmission distanceetc. No information is lost, but the energy is redistributed in the frequency domain. The modulator can permit the modulating signal to amplitude modulate the carrier wave without generating extra unwanted frequencies. Additionally, software packages like national instruments lab view and other graphical. The particular form of pulse amplitude modulation is referred to as natural pam, because the tops of the pulses follow the shape of the modulating signal. The transmitter side consists of a dtsmodulation circuit. 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. 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.
Amplitude modulation demodulation software free download. To study amplitude demodulation by linear diode detector 3. This method is capable of producing nearly 100% modulation with reasonable linearity. Pulse amplitude modulation is the process by which the amplitude of the regularly spaced pulses varies according to the the amplitude of the modulating signal. Frequency modulation software free download frequency modulation top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices.
Experiment 3 amplitude modulation and envelope detection 1. Pulse amplitude modulation pam, quadrature amplitude modulation qam 12. Analog communication pulse modulation tutorialspoint. Pulse modulation techniques pam, pwm, ppm, pcm pulse amplitude, pulse width, pulse position, code duration.
Department of electronics and communication engineering. In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that of the message signal being transmitted. Read, download and publish amplitude modulation magazines. Amplitude modulation of a sinusoidal carrier is widely used in radio and line communications systems. The amplitude of the fm signal is constant at all times and is independent of the modulation signal. That could be the amplitude, phase, or frequency, which result in amplitude modulation am, phase modulation pm, or frequency modulation fm. Pwm converts an audio signal into a sequence of pulses having constant amplitude, but the width is proportional to amplitude of. 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.
Before we study in detail about pam lets know the concepts of modulation. 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. Pulse shaping filter j 1 dn an bn at bt gtt gtt at bt inphase component quadrature component st sin wct cos wct. Quadrature amplitude modulation qam pam signals occupy twice the bandwidth required for the baseband transmit two pam signals using carriers of the. The output of a sampling circuit with a zeroorder hold zoh is one example of a pam signal.
It is a variant of trellis coded modulation tcm which uses a onedimensional pulse amplitude modulation pam symbol space, as opposed to a twodimensional quadrature amplitude modulation qam symbol space. Pulse amplitude modulation pam linkedin slideshare. The possible number of amplitudes can be infinite, but mostly it is some power of two. The original waveform amplitude is quantized with a resulting loss of information. Pdf a pulseamplitudemodulated differentialtimesignaling pamdts architecture for serial communication links is presented in this. In a baseband pam system, we are free to design the transmit and receiver. In this paper we report the hardware implementation of the padm in bandwidth limited visible light link and compare its performance with an existing techniques. 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. Pulse amplitude modulation pam theory of and its applications.
Among the types of modulation techniques, the main classification is continuouswave modulation and pulse modulation. In a new technique called pulse amplitude and delay modulation padm was proposed to enhance the bandwidth efficiency of an optical link. Amplitude modulated signal can be represented by the following equation. Vectors and modulation cse 466 interfacing 3 spose m and n are orthogonal unit vectors. Telecommunications labs for emona datex addon board. Pdf experimental comparison of pulse amplitude modulation.
Yet, am continues to be used today in many communication applications. Quadrature amplitude modulation qam pam signals occupy. Amplitude modulation is a process by which the wave signal is transmitted by modulating the amplitude of the signal. The pulse amplitude modulated signal, will follow the amplitude of the original signal, as the signal traces out the path of the whole wave. Amplitude modulation a1 53 experiment aligning the model the low frequency term at to generate a voltage defined by eqn. Pam 4 introduction and how to set up your pam4 signal on your scope duration. The pulse may take any real voltage value that is proportional to the value of the original waveform. Thus the amplitude of the signal is proportional to the modulating signal through which information is carried. The fact that rapidly modulating the amplitude of one wave results in a waveform identical to playing two notes of different frequencies is quite remarkable and for more information on such wave interference, please see our wave interference and beat frequency demo.
Amplitude modulation is mostly used in the form of electronic communication. In this modulation, the signal is sampled at regular intervals and each sample is made proportional to the amplitude of the modulating signal. The pulse train acts as a periodic switching signal to the modulator, which when switched on allows samples of the modulating signal to pass through to the output. 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.
A comprehensive modulation effect,offering 3 types of modulation of audio signal a comprehensive modulation effect, offering 3 types of modulation of audio signals. Hapter modulation and demodulation free online course. Then as the audio signal amplitude is changed to 150 mvpp, the percentage modulation dropped to around 30%. Amplitude modulation, modulators, and demodulators october 4, 2006 double sideband amplitude modulation am 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. 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.
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. In pam, the amplitude of the message or modulating signal is mapped to a series of pulses, with two possible variant detailed below. This conforms to the expectation as the maximum and minimum peak of the modulated signal waveform varies proportional to the amplitude of the modulating signal. Sound amplitude modulation freeware free download sound. Another method, which introduces more variables into the model, is explored in the experiment entitled. Explore the power of amplitude modulation the magpi magazine. The fig1 shows the generation of pam signal from the sampler which has two inputs i.
To study pulse amplitude modulation and demodulation. The following diagram shows the setup of am modulator in the teaching lab. 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. Quadrature amplitude modulation is widely used for carrying many digital signals, everything from wifi to mobile phone communications and very much more. Ee3 lab 1 amplitude modulation and demodulation broadcast analog television tv signals have a bandwidth of approximately 6mhz and this is achieved with a quadrature modulation. 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.
The pulse amplitude modulation is the simplest form of the pulse modulation. Demonstrate understanding of frequency modulation and demodulation technique. Pulse amplitude modulation is defined as the data transmission by altering the amplitudes power levels or voltage of every pulse in a regular time sequence of electromagnetic pulses. Pulse amplitude modulation is a technique in which the amplitude of each pulse is controlled by the instantaneous amplitude of the modulation signal. The potential of pulse amplitude modulation fluorometry. For flattop sampling, a sampleandhold circuit is used in conjunction with the.
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