Understanding rf circuits with multisim 10 slideshare. Multisim simulation results of the circuit coincide with matlab simulation of. Use multisim software to construct the amplitude modulation circuit as. One of the principal techniques used in electronic communication is the modulation. Detailed explanation of am modulation amplitude modulation, its working principle, and basic need of modulation. Amplitude modulation and demodulation circuit simulation in multisim. Because you are not logged in, you will not be able to save or copy this circuit. This circuit uses two signal generators to simulate an amplitude modulated rf carrier wave. Amplitude modulation definition, types, solved examples. When the modulating information signal a sine wave is. Amplitude modulation simulation lab manual using multisim. The trouble im having is givena circuit with conditions i have to input, i set the spectrum anaylzer to the values that are given and run the simulation and it produces an output of a spectral plot.
That design wasnt meant for passing frequencies high enough to be able to pass an audio file, e. Amplitude modulation am is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. We can also use amplitude modulation to send digital data. Amplitude modulation this experiment examines the characteristics of the amplitude modulation am process. Multisim simulation of amplitude modulation youtube.
Here we use ic8038 as a signal generator to generate modulating and carrier signal. In ppm modulation technique the power required for transmitting individual pulses are constant, but synchronization of transmitter and receiver are required. Amplitude modulation is mostly used in the form of electronic communication. The demodulation is performed by an envelope detector. Pulse amplitude modulation circuit diagram circuit design. If the distance is involved is beyond direct communication, electronic communication comes into the picture.
Pulse width modulation pwm components multisim live. What is am modulation amplitude modulation need of. Get help on how to use our online circuit design and simulation tools as well as. 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. Content introduction what is modulation types of modulation amplitude modulation modulation index amplitude demodulation circuit diagram about project conclusion 3. The fundamentals that are discussed herein include filters, oscillators, amplitude modulation and detection along with principles of frequency. The following algorithm is commonly used to represent amplitude modulation. Amplitude modulation a continuouswave goes on continuously without any intervals and it is the baseband message signal, which contains the information. Two signal generators are used in this circuit, one representing a high frequency 200khz rf carrier, vg2, the other signal generator is used to inject a 1khz audio signal.
Its still used in radio systems to transmit audio signals although it has lesser in popularity compared to fm due to its lower signal to noise ratio. What we do in am, very roughly,is to throw away the frequency content of. How does one select the values of components used in amplitude modulation circuit using a transistor common emitter amplifier circuit. It is often called as am and is commonly used in transmitting a piece of information through a radio carrier wave. Ece 4670 communication systems laboratory experiments.
Modulation is the process of varying one or more properties of a periodic waveform carrier signal with a modulating signal information to be transmitted. Transistors am modulator with bjt 2n3904 electrical engineering. When i measure the values of the spectral plot, they do not match up to the. Amplitude modulation and demodulation national instruments. The original method of electronically encoding sound information on radio waves is called amplitude modulation, or am. Amplitude modulation can be carried out by linearly combining the carrier and intelligence signals then applying the result to a nonlinear component or circuit. This part of the lab will demonstrate the use of an ota op amp to provide low level amplitude modulation. Multisim simulation of amplitude modulation amplitude modulation is defined as a process in which the amplitude of the carrier wave ct is varied linearly with the.
In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that of the message signal being transmitted. Am modulation and demodulation with circuit and output. I got the idea for this circuit from one of my professors. Fm modulation and demodulation circuit multisim live. Then, students will use labview to program an am demodulator and use it to explore and visualize the effects.
Am is a relatively simple way to add audio information to a carrier wave so that sounds can be transmitted. Hi, it is a very nice video tutorial on am implementation in multisim. The circuit was designed to be able to obtain signals via amplitude modulation where the sensitivity and selectivity is fairly good terminology amplitude modulation am a method of emphasizing data on an alternating current waveform or radio wave wherein the carried transmitted signal varies with reference to the amplitude. With no modulation, the am carrier is transmitted by itself. Fm modulation and demodulation circuit this site uses cookies to offer you a better browsing experience. Though it is theoretically possible to transmit baseband signals or information without modulating it, it is far more efficient to send data by modulating it onto a higher frequency carrier wave. Please point me to resources that can help me decide what values of components to use. The output can be used to simulate the response of lc and tank circuits. Quadrature amplitude modulation qam uses four predetermined amplitude levels to determine digital bits. Watch video entitled module 1 am signals in multisim 2. Amplitude modulation is a process by which the wave signal is transmitted by modulating the amplitude of the signal. Spectrum analyzer driverinterface circuit is the modulation level at 50% as calculated from the frequency domain display and is the inband second order product at an acceptable level. The dc offset control is used to vary the amplitude of the dc component added to the message input. To code an analog signal in pulse form one can use the height of the pulse, the width or duration, or the position of the pulse relative to standard position.
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. Advanced students can challenge themselves to build a system to send data between two analog discovery 2s or to build an analog am demodulator. Answer to lab 1 amplitude modulation fundamentals 1. Amplitude modulation am, demodulation and their circuit. Am modulation and demodulation with circuit and output 1. Typical applications include suppressed carrier and amplitude modulation, synchronous detection, fm detection, phase detection, and chopper applications. Amplitude modulation am the process of combining the message signal with the carrier signal and the two sidebands.
This lab introduces students to communications theory with amplitude modulation and demodulation. Frequency shift keying modulation circuit and simulation using multisim. The amplitude modulation and demodulation technique involved in this project comprises of three stages. General electronics chat simple amplitude modulation circuit. It was developed in the first few decades of the twentieth century. As the input signal rises or falls quickly high frequency, the output amplitude increases. Then, students will use labview to program an am demodulator and use it to explore and visualize the. As we mentioned before, well use dsbc modulation because of its ease in demodulation. In amplitude modulation, it is the voltage level of the signal to be transmitted that changes the amplitude of the carrier in proportion, see figure 63. Ni multisim live lets you create, share, collaborate, and discover circuits and electronics online with spice simulation included. Basic concept of modulation the information source typically a low frequency signal referred to as the baseband signal carrier a higher frequency sinusoid example. Pulse amplitude modulation pam is defined as the data transmission by altering the amplitudes of every pulse in a regular time sequence of electromagnetic pulses.
The equivalence of amplitude modulation created by multiplying a carrier by a modulator and by summing sum and difference frequencies with. Amplitude modulation an overview sciencedirect topics. Along with circuit components, introductions, an appendix section which. There is a simple pulse modulation technique called pulse amplitude modulation pam which is proved to be more power efficient than the pwm and consumes constant power for individual pulses. Amplitude modulation or am is a method to transmit signals via electromagnetic transmission. Amplitude modulation modulation is the process of varying a higher frequency carrier wave to transmit information. In this lab, students will create an amplitude modulated signal from a variety of message sources, calculate the modulation index, and confirm the frequency spectrum of this signal type. Like amplitude modulation, an ask is also linear and sensitive to atmospheric noise, distortions,propagation conditions on different routes in pstn, etc the ask technique is also commonly used to transmit digital data over optical fiber. Amplitude modulation is a powerful tool that allows you to create and play new sounds that you cannot obtain using conventional oscillators alone. Source called v1 generates the message to be transmitted. Multisim includes the pwm, pwm complementary, and pwm 3 phase. The message signal is, for example, a function of the sound to be reproduced by a. Communication is a process of conveying information at a distance.
Gathering like terms and simplifying the equation leaves. Amplitude modulation using multisim detector radio modulation. Pulse amplitude modulation is a technique in which the amplitude of each pulse is controlled by the instantaneous amplitude of the modulation signal. Here is the circuit used for modulation and its simulation.
Amplitude modulation using multisim free download as pdf file. When the height is used, it is called pulseamplitude modulation pam. In many applications this control is used to null the carrier spectral component seen at the modulator output. Special circuits can extract information about the carrier from one of the sidebands.
For led transmitters, binary 1 is represented by a short pulse of light and binary 0 by the absence of light. Overmodulated am signals and its requirement for coherent detection are also considered. The demodulator circuit works as a low pass filter, it allows low. Mc1496, mc1496b balanced modulators demodulators these devices were designed for use where the output voltage is a product of an input voltage signal and a switching function carrier. Amplitude modulator and demodulator trainer kit 5 steps with pictures. Amplitude modulation receiver circuit circuit wiring. Amplitude modulation using lab view in this video you will see amplitude modulation using different type of signals and channels. Pdf ask modulation simulation in multisim researchgate. 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. This is true even though everything we have discussed assumes that we have used simple sine waves as our input signals. Amplitude shift keying refer to a type of amplitude modulation in. Amplitude modulation can be accomplished by multiplying the carrier sine wave by a gain or attenuation factor that varies in accordance with the intelligence signal 2. It is lowered to 20% of the amplitude for either 0.
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