The virtual experiments of this lab are computer simulations that implement the. Altium designer also gives you access to a complete set. Fm spectral modeling and fdmfm simulation programs ntia. A new highperformance digital fm modulator and demodulator for. For nbfm the audio or data bandwidth is small, but this is acceptable for this type of communication. Phase modulation, and frequency modulation are both the modulation techniques. Although digital technologies are taking over, nbfm is still widely used and very. Fm frequency modulation modulation and demodulation circuit simulation using bc107 with multisim software. Sep 06, 2014 amplitude modulation and demodulation circuit simulation in multisim. For instance, the crackling form of radio interference caused by natural lightning or the buzzing noise produced by highvoltage power lines are both easy to hear on an am radio, but absent on an fm radio. As part of the modulation practices we simulated this am modulator circuit to test the effects of the modulation quotient in the signal we plan to transfer.
It does signal encoding and decoding, filtration, modulation and even has awgn noise option incorporated into it. Chowning in the late 1960s and described in the synthesis of complex audio spectra by means of frequency modulation, jaes 21. The individual component of proposed fm modulator and demodulator has been optimized in such a way that the overall design consists of a highspeed, area optimized and lowpower features. The fm modulator baseband block applies frequency modulation to a real input signal and returns a complex output. 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.
At the initial simulation phase, the demodulated output overshoots since the. Frequency modulation frequency modulation is a technique in which the carriers frequency the number of cycles a radio wave completes in a given period of time. Frequency modulation is widely used on frequencies above 30 mhz, and it is particularly well known for its use for vhf fm broadcasting. Software simulator development for orthogonal frequency. Jan 30, 2017 a multichannel fm demodulator a few days ago programmer phil v wrote in and wanted to let us know about his tslsdr multifm software for the rtlsdr. You can access the fm modulator block from menu parts modulation blocks fm modulator block. Pdf simulation of analog modulation and demodulation.
Chowning has said, while performing some not very rigorous experiments with vibrato in 196768, i suddenly realized that with extreme vibrato, i was not hearing changes in pitch. The resulting signal can be spelled out quite nice and stable so that the result will be more perfect. This paper deals with an fpga implementation of a high performance fm modulator and demodulator for software defined radio sdr system. Frequency modulation fm is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. In this second experiment, we will examine the most common modulation scheme in daily life, namely, the frequency modulation, or fm. Spicesimulation using ltspice iv reverse engineering. Selection of components to set the lock field and the capture field. The individual component of proposed fm modulator and demodulator has.
Phase modulation, and frequency modulation are both the modulation techniques analyzed in angle modulation. The results of simulation show that the interface of each system is. Frequency modulation uses the information signal, v m t to vary the carrier frequency within some small range about its original value. Is this the correct way to create fm modulated signal in ads or is. The characteristics of pm are very similar to fm and so the terms are often used interchangeably. Software simulator development for orthogonal frequency division multiplexing ofdm modulation a dissertation submitted by barry dunbar in ful. Chowning has said, while performing some not very rigorous experiments with vibrato in 196768, i suddenly realized that with. Fm frequency is widely used in telecommunication devices to transmit voice without disturbances 23. The fm modulator baseband block applies frequency modulation to a real input signal and returns a complex. Sep 11, 2016 fm modulator circuit is a simple fm modulation circuit using ic 555, where the resulting modulated signal has a tenuous meeting depends on the signal frequency information. A new highperformance digital fm modulator and demodulator for softwaredefined radio and its fpga implementation.
Transportable license may be used on one instrument computer at a time but may be transferred to another using keysights online tools or usb dongle floating networked instruments computers can access a license from a server one at a time. Operation of lc circuit in frequency modulation with. Using proteus eda software advanced simulation features duration. Instrument embedded license to enable custom modulation waveforms offline playback with the supported keysight signal generator. Building frequency modulated radio channels is quite a demanding task. Angle modulation provides the improved noise performance. The satellite communications training system is a versatile telecommunications training platform designed to teach modern telecommunications technologies in the classroom using a fully operational satellite link. To keep the compatibility the new device should be able to perform the analog modulation.
Fm modulator circuit is a simple fm modulation circuit using ic 555, where the resulting modulated signal has a tenuous meeting depends on the signal frequency information. Generating an fm signal using the sffm voltage supply 152 21. Abstract analog modulations are more and more replaced by digital ones. Frequency modulation simulation in altium designer pcb design. A multichannel fm demodulator a few days ago programmer phil v wrote in and wanted to let us know about his tslsdr multifm software for the rtlsdr. The system allows students to observe and study a wide. Frequency modulation equations formulas bessel rf cafe. Signal modulation worksheet discrete semiconductor devices. Complex waveforms iii frequency modulation software synthesis.
While amplitude modulation is achieved by varying e p, frequency modulation is realized by varying. This is because hit and trial experimentation are too costly and problems encountered in such designs looks too complicated to be analyzed. Oct 24, 2012 multisim software fm simulation duration. The fm transmitter accomplishes the most excellent range with the least power. Question asked by terokaija on mar 19, 2006 latest reply on mar 20, 2006 by wrivas. Frequency modulation fm is a process in which the carrier frequency is varied by the amplitude of the modulating signal i.
Both frequency and phase modulation are important not only in electronics but also in science and physics in general. It seems like a trivial chore but when i first tried to model such a signal some time back i hit a hard wall. The modulator and demodulator contain an optimized direct digital. An interactive demo which enables you to both see and hear the result of multiplying a sine wave with a cosine amplitude envelope.
Modulation of a carrier waves frequency by the program signal being transmitted. Modelling and simulation of frequency modulated radio channel. Frequency modulation software free download frequency. Am modulation am modulation, upper side band, lower side band, carrier. Our minds easily understand kinematics concepts such as coordinate, speed, acceleration and the relations between them in real life situations, but phase, frequency and.
Frequency modulationsimulation experiment introduction. It is also possible to change the frequency of a signal to give frequency modulation or fm. The simulation of natural instrument tones using frequency modulation. A modulator, followed by a filter, is sufficient to obtain an amplitude modulated signal, but it should be pointed out that this type of modulation generates numerous distortions. The term and technology is used in both telecommunications and signal processing in analog frequency modulation, such as fm radio broadcasting of an audio signal representing voice or music, the instantaneous frequency deviation, the difference between the. This report is concerned with the spectral representation of analog frequency modulated fm signals, with particular attention to frequency division multiplexing. Here, the maximum frequency f max causes a maximum deviation of 25f max in the carrier. While changing the amplitude of a radio signal is the most obvious method to modulate it, it is by no means the only way. Both amplitude and frequency modulated radio signals nowadays use quadrature modulation and demodulation as a mean to transfer and receive radio signals. A new highperformance digital fm modulator and demodulator. Am and fm radio to illustrate how a signal is sent via am or fm radio. Frequencymodulation synthesis, or fm synthesis for short, works differently than what weve talked about so far. Oct 09, 2014 frequency modulation and its application 1. Amplitude modulation to show the effect of modulating a sine wave with another sine wave.
The use of fm for audio synthesis was discovered and developed by john m. Amplitude modulation amplitude modulation was the original method used for transmitting audio signals over radio frequency waves. The input audio signal from the mic is fed to the base of transistor which modulates the lc tank circuit carrier frequency in fm format. Set the carrier frequency to 10mhz and the maximum frequency deviation to 5mhz. Narrowband fm is widely used for two way radio communications. Amplitude modulation am is the simplest and the oldest of modulation methods, primarily because the stage of demodulation, at the receiver, is simple to carry out.
Fm signals have the same peak frequency deviation, then when mt is a sinusoidal signal set such that the pm and note. Data communication virtual lab this virtual laboratory was built using java. Frequency modulation fm is utilized within radio broadcasts, as well as in police and healing center interchanges, channel emergency, tv sound, and remote systems. In fm modulation when the bandwidth becomes so large that the input noise power is relatively large, the performance of the fm system degrades rapidly and the system exhibits a threshold. How to model a frequency modulated fm signal an insight. A simple car radio would likely use something much simpler. For concurrent usage, multiple licenses may be purchased. Pdf a new highperformance digital fm modulator and. The use of a quadrature transmitter receiver is not needed unless you are using a quadrature signal.
Fm modulation and demodulation electrical and computer. Recall that we can write an equation for a sine wave as follows. Frequency modulation software free download frequency modulation top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices. The variable capacitor is used to change the resonant frequency for fine adjustment to the fm frequency band. Fm gives preferred sound quality and constancy over am. For nbfm, the fm modulation index must be less than 0. In the simulation experiment section2, we used the vco to demodulate the. By analogy to the radio sense of the term, frequency modulation is used in. Most documentation about fm which is actually the almostequivalent phase modulation pm in many common cases including the fm by yamaha concerns sine waves only. What is fm, frequency modulation electronics notes. The individual component of proposed fm modulator and demodulator has been. This software is targeted at third grade universities which might not have the capacity to purchase expensive devices such as spectrum analyzers and the likes. The property dialog of this block is shown in the figure below.
The power is being calculated by simulationbased switching activities of all the signals. Modulation also provides a means for simultaneous transmission of several signals, using the same transmission channel hertzian, cable. The modulation of a signal is essential if one wishes to transmit it over long distances. In this part of the lesson, you will use different waveforms as the input signal to the fm modulator. Ive been looking at making an fm demodulator for a software defined radio. It has a spectrum analyzer, digital filter and modulator in it. Custom modulation waveform creation and offline playback. Implementation of fm demodulator algorithms on a high. Signal studio pro software for custom modulation signal creation and downloading with the licensed signal generator. Fyi in case you dont already know, the most famous fm synth is probably the yamaha dx7 which was revolutionary in its day and also one of the first ever synths with midi. Pm and digital modulation s p where 2 is the pkpk phase change in one symbol duration, t for digital signals the modulation index. It uses one wave to rapidly increase or decrease modulate the frequency of another, which creates entirely new frequencies that arent part of the first two.
Fm modulator and demodulator with pll cd4046 youspice. Complex waveforms iii frequency modulation basicsynth. When input noise power is quite large we would be inclined to use fm and allows a sacrifice of bandwidth for the sake of improved output signaltonoise ratio. The goal of this experiment is to become familiar with fm modulation and demodulation. Fm basic frequency modulation components, testing of fm.
Signal modulation worksheet discrete semiconductor. Amplitude modulation and demodulation circuit simulation in multisim. Simulation result of fm demodulator for triangular wave modulated input. It has a spectrum analyzer, digital filter and modulat. Spice simulation of the cascade of cd4046 in modulator and demodulator configuration.
Frequency modulation synthesis, or fm synthesis for short, works differently than what weve talked about so far. Bpsk, qpsk, msk frequency shift keying, fsk quadrature amplitude modulation, qam. Fm modulation and demodulation circuit multisim live. Fm tends to be a far more noiseresistant means of signal modulation than am. In principle at least this is trivial if you have a complex signal i and q, as you can compute the phase atanqi, then the modulation amplitude is just the derivative of phase with time. The usage of labview software and its vi programs are explained in this paper.1077 1371 1641 822 458 690 1548 573 1607 937 571 924 1218 335 1032 291 1441 699 162 1099 1380 1317 1382 1223 856 871 1463 1056 1020 581 652