How to make a circuit of amplitude modulation using. Amplitude modulation is mostly used in the form of electronic communication. Amplitude shift keying refer to a type of amplitude modulation in. Amplitude modulation is a process by which the wave signal is transmitted by modulating the amplitude of the signal. Mc1496d 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. Multisim simulation of amplitude modulation youtube. Amplitude modulation is defined as a process in which the amplitude of the carrier wave ct is varied linearly with the instantaneous amplitude. The oscillator is built around q1 and associated components. Schematic of mc1496 and circuit diagram of an amplitude modulator prelab tasks. Set the modulating frequency to 1khz and sampling frequency to 12khz 3.
Advanced students can challenge themselves to build a system to send data between two analog discovery 2s or to build an analog am demodulator. The application of these pulses to the tuned tank circuit will give amplitude modulation. It is often called as am and is commonly used in transmitting a piece of information through a radio carrier wave. Set the proper amplitude and frequency of the modulating signal to get a reasonable am waveform. Why is a dc component added to a message signal before multiplying the message signal. At audio signal input port audio ip, input 600 mv amplitude, 3 khz sine wave. Content introduction what is modulation types of modulation amplitude modulation modulation index amplitude demodulation circuit diagram about project conclusion 3. Typical applications include suppressed carrier and amplitude modulation, synchronous detection, fm detection, phase detection, and chopper. Amplitude modulation am is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. Let j1 be short circuit and j2 be open circuit to produce the modulated am signal as the signal source in this experiment. How does one select the values of components used in amplitude modulation circuit using a transistor common emitter amplifier circuit. Hello all, using multisim to simulate a series lc circuit i am seeing amplitude modulation across the capacitor at the resonant freq. 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. Circuit diagram of pulse width modulation pwm the 1m ohm resistor is used to adjust the amplitude of the sine wave signal generated by the wbo.
The block diagram of the completed program should resemble the image below. Amplitude modulation using multisim free download as pdf file. When i measure the values of the spectral plot, they do not match up to the bessel table with a given modulation index of 5. Information and modulated signals are shown in fig. The demodulator circuit works as a low pass filter, it allows low.
Which one statement is right about amplitude modulation, amplitude changes according to modulating voltage or amplitude changes according to m. The amplitude of the sine wave should be adjusted in such a way that it matches with the amplitude of the ramp signal generated. Signal modulation worksheet discrete semiconductor. Circuit theory the basic circuit diagram for amplitude modulation consists of diode, resistors and lc circuit as shown in the simulation. When the data is 1 of modulating digital signal, sine wave is switched to output because sine wave is using as carrier signal, and when the data is 0, the transistor is disabled to produce the sinewave.
Amplitude modulation am the process of combining the message signal with the carrier signal and the two sidebands. The basic circuit diagram for amplitude modulation consists of diode, resistors and lc. Free propagation of signals requires it to posses considerable power. It is lowered to 20% of the amplitude for either 0. Then i explain what modulation and amplitude modulation are, and show you how to build a low powered am radio transmitter out of a tl072 dual op amp ic. Transistors am modulator with bjt 2n3904 electrical engineering. Here is the circuit used for modulation and its simulation. Fpga implementation of an amplitudemodulated continuous. Therefore one performs modulation of signals where a characteristic of a high frequency signal called carrier is modified w. Simulation and analysis of mc1496 amplitude modulation circuit based on. Circuit design of pulse amplitude modulation a pam is generated from a pure sine wave modulating the signal and a square wave generator which produces the carrier pulse and a pam modulator circuit.
The circuit that i designed ends up giving a weird waveform but i am pretty sure my professor gave us the same circuit. In addition, the pulseshaping and amplitudelimiting circuits provide a digitized output devoid of any distortions in the waveform, caused by the preceding amplifier and filtering stages. 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. In the above circuit the transistor is using as switch for performing the operation of on and off. Vary the values for the carrier and modulation amplitude and frequency to see the effect it has on the signal. Amplitude modulation and demodulation national instruments. An accurate ultrasonic range finder employing sliding discrete fourier transform sdft based restructured phaselocked loop rpll, which is an improved version of the recently proposed integrated phaselocking scheme ipll, has been expounded. Public circuits tagged amplitudemodulation circuitlab. Introduction to analog communication modulation the process of combining the message signal with the car.
I have tried using a simple voltage divider network such as the one below, but with a transistor and resister in parallel with the second resistor which would control the amplitude. The resulting plate flows in pulses, the amplitude of each pulse being proportional to the instantaneous bias and therefore to the instantaneous modulating voltage. Amplitude modulation and demodulation circuit simulation in multisim. Amplitude modulator and demodulator trainer kit 5 steps with pictures. Ans amplitude modulation is the type of modulation technique in which the amplitude. That design wasnt meant for passing frequencies high enough to be able to pass an audio file, e.
The circuit is in two halfs, an audio amplifier and an rf oscillator. The possible number of amplitudes can be infinite, but mostly it is some power of two so that the final output signal can be digital. The gain of entire circuit is determined by the r8 value. 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.
Amplitude modulation definition, types, solved examples. The output can be used to simulate the response of lc and tank circuits. Frequency shift keying modulation circuit and simulation using multisim. The simple pulse modulation technique called pulse amplitude modulation pam proved to be more power efficient than the pwm and consumes constant power for individual pulses like ppm. Apply a 5 khz signal to both rf and af inputs of 0. Amplitude modulation using multisim detector radio modulation. Am modulation and demodulation with circuit and output slideshare.
As we mentioned before, well use dsbc modulation because of its ease in demodulation. Pdf ask modulation simulation in multisim researchgate. Basic concept of modulation the information source typically a low frequency signal referred to as the baseband signal carrier a higher frequency sinusoid example. Connect the circuit as per the circuit diagram shown in the fig 3 2. Am modulation and demodulation with circuit and output. We can see that carrier signal and message signal belongs to single ended input. Source called v1 generates the message to be transmitted. Graph image for fm modulation and demodulation circuit. Amplitude modulation circuit implementation electrical.
One of the simplest electronic methods of modulation is amplitude modulation, or am. Explain briefly in your report how amplitude modulation is accomplished by this circuit. The message signal is, for example, a function of the sound to be. Am modulation and demodulation with circuit and output 1. The tank circuit l1 and vc1 is tunable from about 500khz to 1600khz. 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. 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. Connect the circuit as per the given circuit diagram. Here we use ic8038 as a signal generator to generate modulating and carrier signal. Frequency shift keying fsk is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier wave. A sine wave generator is used which is based on wien bridge oscillator circuit.
In amplitude modulation, the amplitude signal strength of the carrier wave is varied in proportion to that of the message signal being transmitted. Fm modulation and demodulation circuit multisim live. This range finder principally utilizes amplitudemodulated ultrasonic waves assisted by an infrared ir pilot signal. An envelope detector is used to demodulate the signal. For a perfect modulation, the value of modulation index should be 1, which implies the percentage of modulation should be 100%. Multisim simulation results of the circuit coincide with matlab simulation of. Study the operation of the gilbert cell multiplier. Measure the output signal frequency and amplitude by connecting the output to cro. Read online modulator using multisim symphonic love foundation. This site uses cookies to offer you a better browsing experience. In pam the amplitude of the individual pulses are varied according to the amplitude of the modulating signals. Remember, for analysis purposes keep the modulation index and frequency the same as part 2, step 3.
The carrier signal and modulating signal are linearly. Use the spectrum analyzer to compare this modulator to the one in part 2. I got the idea for this circuit from one of my professors. A student desires to use this circuit as the basis for a pulsewidth modulation pwm power controller, to vary the amount of power delivered to a dc load. It uses a pair of discrete frequencies to transmit binary 0s and 1s information. Simple amplitude modulation circuit all about circuits. Multisim mc1496 simulation, downloaded from the ni website, welcome to download. The oscillator circuit in this diagram generates a square wave with an adjustable duty cycle. Please point me to resources that can help me decide what values of components to use. This circuit uses two signal generators to simulate an amplitude modulated rf carrier wave. 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. The pam modulator and demodulator circuits simple compared to other kind of modulation and.
1226 746 466 1117 195 1039 664 593 726 412 1157 132 983 1242 81 1499 954 1464 52 61 1029 946 1124 1353 1273 247 1076 385 120 1464 1324 124 1390 842 441 1237