Therefore, pulse width modulation is a preferred technique for control circuits of switchmode power supplies. Featuring 10 lab classes to fill one semester, the course deep dives into algorithm design for modulation and demodulation. Labview modulation toolkit provides modulated signal generation and analysis in labview for research, design, prototyping, validation, and test applications. Fm demodulation is a key process in the reception of a frequency modulated signal. Labview software, ni usrp transceivers provide a powerful system to help. Synthesizer created in labview based on frequency modulation synthesis.
If the digital signal is cycled fast enough, then the voltage seen at the output appears to be the average voltage. To maximize the signaltonoise ratio of a lockin measurement, its important to find the transfer function of the system and to use the optimal modulation frequency. The modulation techniques used for discussion are amplitude and frequency modulation followed by demodulation. Hi everyone, i am very new to labview somehow i managed to simulate frequency modulation. Usrp 2901 based fm transceiver with large file capabilities in. Frequency modulation using labview knowledge unlimited.
As a result, the modulated signal will have instantaneous frequencies from 75 khz to 925 khz. Phase modulation, and frequency modulation are both the modulation techniques analyzed in angle modulation. It is somewhat similar to gnu radio in that programming is done by connecting a series of various blocks together, each of which performs some function. If you are using ni hardware, with the drivers you would have got a cd containing which contains examples for.
These individual data flows can now be observed by frequency and amplitude for a specific behavior. 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 frequency. Fsk modulation and demodulation using labview software. Frequency modulation fm is a form of modulation in which changes in the. The radio signal processing capability can be provided by universal software radio. You can change the xaxis label to read frequency instead of time. Mt modulate fm vi labview analog modulation documentation. Modulation is the process of changing the parameters of the carrier signal, in accordance with the instantaneous values of the modulating signal. The sdr software performs all of the demodulation, filtering both radio frequency and audio frequency, and signal enhancement equalization and binaural presentation. Angle modulation provides the improved noise performance. The wide range of frequencies is evident by observing the minimum amplitude of the baseband, when the modulated frequency is very small. Frequency modulation fm is most commonly used for radio and. Musical signal processing with labview, a multimedia educational resource for students and facult,y augments traditional dsp courses and supports dedicated courses in.
This article shows the development of a sdr based on labview and common hwfrontends. Design of the software radar signal generator using labview. The recovered information signal is returned in the fm demodulated waveform parameter. The second is to investigate classical analog amplitude modulation and the envelope detector. Softwaredefined radio using labview and the pc sound card. Labview modulation toolkit is a software addon for labview with functions and tools for generation, analysis, processing, and visualization of analog and digital modulated signals. Frequency modulation software free download frequency modulation top 4 download offers free software downloads for windows, mac, ios and android computers and mobile devices. Set up your compactrio project in scan mode, as described in using ni compactrio scan mode wth ni labview software. Fsk is chosen to be the modulation scheme of the designed software defined. The main objective of our paper is to perform demodulation using labview and also realize both modulation and demodulation using c6748 kit. Implementation of analog modulation techniques using. Principles of communication modulation tutorialspoint. The fm or frequency modulation has been available approximately since am amplitude modulation although it has only some issues. Solution in order to use the specialty digital modes for the ni 94xx digital input module, go through the following steps.
It frees up the programmer to focus on the system from a holistic point of view. Frequency modulation free download frequency modulation. The universal software radio peripheral usrp 2900 board is used to design frequency modulation fm demodulation. I need to implement the demodulation without using modulation tool kit. Based on the labview frequency modulation continuous wave. But now, i am facing difficulty in demodulating it.
Set up your project to match the project window shown in the figure below. Fm itself didnt have a problem apart from we couldnt recognize the fm transmitter potential. Radio peripheral usrp 2900 board is used to design frequency modulation fm demodulation. Ask modulation using labview software amplitude shift. Labview interfacing usrp for fm demodulation zambrut. The baseband signals are incompatible for direct transmission. The spectrum of fm from 70mhz to 7ghz can be inputed to usrp 2900 which acting as software defined radio device. Pdf simulation of analog modulation and demodulation. This lab exercise is a nice illustration of the utility of the software defined radio approach, since the. To create a 3v signal given a digital source that can be either high on at 5v, or low off at 0v, you can use pwm with a duty cycle of 60% which outputs 5v 60% of the time.
Software defined radio replaced majority of hardware modules like mixers, filters, modulators and demodulators etc. Noise and bandwidth are two basic limitations on the performance of a communication system. What is a pulse width modulation pwm signal and what is. Frequency modulation and demodulation with spectrum. Labview, as a graphical programming environment, keeps away from a lot of program syntax. Pdf analog and digital modulation toolkit for software. Labview modulation toolkit download national instruments.
Generated signal is displayed in both time and frequency domain. Labview is a widely used graphical programming environment which allows. Study of modulation using graphical programming and. As mentioned by andy earlier, the amplitude of the carrier is kept constant. The system has been designed using the labview communication design suit. Fm modulation vi ni community national instruments. It is still in use today in a variety of systems, including, of course, am broadcast radio. It provides control of carrier and modulator frequencies by value or by ratio, modulation index, feedback, carrier and modulator waveforms and filters. For such a signal, to travel longer distances, its strength has to be increased by modulating with a high frequency. Pdf a labviewbased analog modulation tool for virtual and. Advanced data acquisition series pulse width modulation. Programming pwm in labview using nidaqmx advanced pwm applications in labview conclusion introduction to pulse width modulation pulse width modulation pwm is a technique in which a series of digital pulses is used to control an analog circuit.
Only ni data acquisition devices can be used for signal output. Delaytimecalculator dtc is a simple software designed to help you calculate frequency modulation values in hertz and delay times in milliseconds for a song tempo in beats per minute or for a frequency value. If the digital low is 0v which is usually the case then the average voltage can be calculated. Introduction to communication systems using national. July 27, 2018 ask modulation using labview software amplitude shift key modulation hai guys in this video i am showing about how to construct amplitude modulation using labview software. A teaching platform for digital communications jose carlos lanzoni university of new hampshire, durham follow this and additional works at. The rtlsdr is compatible with labview via a simple rtlsdr. In this paper, a software defined radio 4qam quadrature amplitude modulation modem system is implemented in labview. Fsk based sdr transceiver in a shorter time with the use of labview. In this second experiment, we will examine the most common modulation scheme in daily life, namely, the frequency modulation, or. Labview is a popular visual programming environment often used in industry and by engineers for test, automation and control applications. In the graph below, the fm deviation has been selected as 425 khz. Frequency modulation fm is the standard technique for highfidelity communications as is evident in the received signals of the fm band 88108 mhz vs.
The design of the software radar signal generator using labview environment and the universal hardware ni pxi 5673 has been presented in the paper. Labview is an industryleading graphical software tool for designing test. Instrumentation suite nielvis and labview software 7. Analog and digital modulation toolkit for software defined. Frequency modulation fm is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. This laboratory exercise introduces frequency modulation. An ofdm transmitter and receiver using ni usrp with labview. Once the signal has been received, filtered and amplified, it is necessary to recover the original modulation from the carrier. A host program can display the data as a spectrum on a screen or make decisions if certain signal patterns are present. The system has been designed using the labview communication design. An introduction to software defined radio with labview and.
It looks like the spectrum of modulated signal is in the frequency domain, but the xaxis is just the number of nonredundant points in fft and not scaled to a normalized frequency check the spectral measurements vi that is attached to spectrum of modulated signal and adjust the settings to get it to a normalized frequency. In this example, we will build a labview vi that scans the frequency of the local oscillator lo and plots the measured amplitude as a function of lo frequency. The simulation of modulation schemes such as amplitude modulation and frequency modulation are designed using vi models are used as reference for designing fire rescue system 14. Ni usrp software defined radio 1 gigabit ethernet to pc plugandplay capability up to 25 mss baseband iq streaming tunable rf front ends frequency range 50 mhz 2. It is this process that is called demodulation or detection. Where can i find an example of fsk demodulation in labview. The aim of this paper was to analyze frequency shift keying fsk transceiver built. The standard fm equation contains the modulation index, carrier frequency. This lab exercise is a nice illustration of the utility of the software defined radio approach, since the algorithms for creating and demodulating fm in software are much simpler than those used in the traditional hardware approach. The use of labview virtual instrumental technology, research and development of the related code, the virtual completion signal acquisition system design, at any time on the echo signal acquisition and processing, the calculation result and the safety distance.
A software defined radio consists of a programmable communication system where functional changes can be made by merely updating software. Frequency modulation software free download frequency. Measuring frequency with ni 94xx digital input module. Design of a hybrid reconfigurable software defined radio. In frequency modulation, the instantaneous frequency of the radiofrequency wave is varied in accordance with the modulating signal. Software defined radio using labview and the pc sound card. Pulse width modulation also resolves the issues which occur in pulse frequency modulation. There are many pwm pulse width modulation controller integrated circuits available in the market just like sg3525. Modulation is a process by which characteristics of a high frequency carrier signal are altered to convey information contained in a lower frequency message. Frequency modulation is a special case of angle modulation where the instantaneous frequency of a carrier is varied by an amount proportional to the modulating signal amplitude. This toolkit enables you to modulate and demodulate signals with a variety of modulation schemes including am, fm, pm, ask, fsk, msk, psk, and qam. Lockin amplifier lia frequency sweep with labview a.
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