To study the series and parallel lcr circuit and plot the resonance curve at the. The use of the software and of the documentation is granted free of charge for private and noncommercial use in. Lissajous patterns of cro or cathode ray oscilloscope. Lissajous figure on an oscilloscope, displaying a 3. If the ratio of the frequencies is rational, the curve will always eventually close.
If you are having trouble viewing the below java applet, you may need to authorize permission to run the applet by right clicking on it or managing your browsers. To use this catalogue, adjust the oscilloscope so that the x and y. The electron beam that strikes the phosphorous face then had position. In the free run mode, the horizontal sweep runs at a set rate. Included in the simplified illustration are a cathode ray gun, which produces the lissajous figures on the oscilloscope screen by means of an electron beam that causes a glow when it hits the. Experiments based on cro the wave shapes analysis, measurement of frequency and voltage values peak to peak and rms at different ac.
Meanwhile, the theory of lissajous figures 827 finds a wide range of applications in engineering 9,28physics10,11and biomedicince12. For few lissajous figures based on their shape, we can directly tell the phase difference between the two sinusoidal signals. Determine the frequency of the sinusoidal voltage from the generator box using lissajous figures. Let us compute the period of this curve, assuming that. Lissajous patterns experiment 3 linkedin slideshare. These lissajous patterns have two applications to analysis the signals. The cathoderay oscilloscope furnishes the most important and practical means for the generation of the figures. Lissajous figures in the application of microvibration. Also a good tool to create lissajous figures and explore them. Enter your email below to receive free informative articles on electrical. Lissajous figure definition of lissajous figure by. We can connect a function generator to both the x and y axis and begin to draw lissajous patterns. Cathode ray oscilloscope cro is very important electronic device.
The plot is usually seen in xy mode of oscilloscope. Lissajous figures are parametric curves where both xt and yt are sine functions. Typically, an oscilloscope will plot the voltage of an primary input on the y axis vs. Using a scope to display lissajous patterns electrical. Lissajous figures are figures that are turned out on the face of an oscilloscope when sinusoidal signals with different amplitudes and different phases are applied to the time base real axis and deflection plate imaginary axis of the scope. Lissajouslike gures with triangular and square waves. This property is exploited to produce a set of points, called padua points, at which a function may be sampled in order to compute either a bivariate interpolation or quadrature of the function over the domain. Liassajou curves are described by the parametric equations below. A cro is an electronic device with a crt as its main component and other associated circuits consisting of a power supply unit, a sawtoothwave generator, horizon and vertical amplifiers. Aug 25, 2016 the simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. Lissajous figure and oscilloscopes problem physics forums. Generating lissajous figures wolfram demonstrations project. In this case the coordinates are damped harmonic oscillators and the curve is a damped lissajous curve. This page can be used as a playground or learning tool to see how changing basic parameters affects the generated images.
The diagram shown is identical to one of the figures you can obtain with the laser lissajous device. Pdf calibrating the frequency of tuning forks by means of. Optically addressed springpatterned membrane mirror mems with megahertz response. At each instant, the scope plots a dot with the input x sample as the horizontal coordinate and the output. When both pairs of the deflection plates horizontal deflection plates and vertical deflection plates of cro cathode ray oscilloscope are connected to two sinusoidal voltages, the patterns appear at cro screen are called the lissajous pattern. Sep 16, 2017 lissajous figures on an oscilloscope a level physics physics online. If the file has been modified from its original state, some details such as the timestamp lisssajous not fully reflect those of the original file. Lissajous figure definition of lissajous figure by the free. On the oscilloscope locate the knob that adjusts the amplitude of the display, and bring the amplitude to within the limits of the screen.
If the frequencies are incommensurable, the figure is not a closed curve and, except for very low frequencies, will appear as a patch of light because of the. Aug 11, 2016 the simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. Faculty of engineering chulalongkorn university cathode. The figures, sometimes called bowditch curves, were first described in the early 1800s by american mathematician nathaniel bowditch, who experimented with a pendulum undulating around perpendicular axes at the same time.
The following chapter is free to read preliminaries. How to draw 2d oscillations and lissajous curves using 3d. For example, if you had two sinusoidal signals of equal amplitude and frequency, you could determine the phase difference by looking at the shape of the trace. To use lissajous figures to take frequency measurements. How to make lissajous figures on an oscilloscope duration.
Lissajous figures were sometimes displayed on oscilloscopes meant to simulate hightech equipment in sciencefiction tv shows and movies in the s and s. Lissajous figure definition of lissajous figure by merriam. Geometrical and graphical representations analysis of. Lissajous figures on an oscilloscope, with 90 degrees phase difference between x and y inputs one of the most frequent uses of scopes is troubleshooting malfunctioning electronic equipment. Lissajous patterns at the dawn of the technological revolution. A lissajous curve, named after jules antoine lissajous is a graph of the following two parametric equations. Given two wheels connected by a belt and a point on the outer rim of each, one can generate a lissajous figure by the motion of the wheels. For example, where a voltmeter may show a totally unexpected voltage, a scope may reveal that the circuit is.
Geometrical and graphical representations analysis of lissajous. Lissajous figures james emery 42008 contents 1curves 1 2 program 4 1curves let xta1 sin. Softscope software is a simulator of a vintage oscilloscope. Lissajous pattern theory lissajous figure or lissajous pattern is the quickest way to calculate frequency and phase difference. Lissajous patterns at the dawn of the technological revolution the lissajous pattern or lissajous figure is named for the french mathematician jules antoine lissajous 1. The coordinates of a point on a wheel can be described by sine functions of a certain frequency and phase shift.
While these signals are primarily voltages, all manner of signals can be converted into voltages for observation. Apparatus used in the measurement of the speed of sound using lissajous figures. Of course, oscilloscopes can be calibrated to read the correct voltage. One of the most frequent uses of scopes is troubleshooting malfunctioning electronic equipment. Cro cathode ray oscilloscope oscilloscope cathodique. Lissajous figures plane curves traced by a point which executes two independent harmonic motions in perpendicular directions, the frequencies of the motion being in the ratio of two integers. Lissajous figures are produced by combining two oscillations at right angles to each other. Sep 29, 2016 from a historical point of view lissajous figures or curves were also used for frequency comparison before practical frequency counters could be built. Lissajous work in the nineteenth century centered around the study of vibrating objects and wave phenomena.
Lissajouslike gures with triangular and square waves 37023 another interesting point to mention is the lack of continuity of the square lissajouslike. The xdeflection plates of the tube are supplied with one alternating voltage, and the ydeflection plates with another. Measurement of the speed of sound in air medium using. For now, a qualitative study of how oscilloscopes operate is the main purpose of this experiment.
The figures, drawn by mechanical devices called harmonographs, have scientific uses, but are also enjoyed for their own beauty. Lissajous pattern generator this is a dual, sine wave oscillator that generates audio signals of 4500hz and 1500hz. We have already discussed cathode ray oscilloscope or cro. Shape of these lissajous pattern changes with changes of phase difference. Lissajous figures where a 1, b n n is a natural number and 2 1 s g n n 3 lissajous curves can also be generated using an oscilloscope as illustrated. The user interface above allows you to modify each of these five parameters and see how the graph is affected. Lissajous figures on an oscilloscope, with 90 degrees phase difference between x and y inputs.
Lissajous figures where a 1, b n n is a natural number and. So the microvibration displacements can be directly obtained by measuring the central angles of lissajous figures. To show how such a figure can be created, consider the. To restore the figure to the original view, click the front view button. Lissajous patterns of cro or cathode ray oscilloscope electrical4u. For large lecture halls the ega output from the oscilloscope is fed into an rgb converter and then to a video projector providing a 12foot diagonal rearprojection display, so several hundred people can easily view the oscilloscope output. The oscilloscope takes in both analog signals and using a complex circuit, it plots the lissajous figures on the screen of oscilloscope. Meanwhile, the theory of lissajous figures827 finds a wide range of applications in engineering 9,28physics10,11and biomedicince12. Use a laser pointer and two small rotating mirrors to create a variety of lissajous figures. For example, in the harmonic case with equal frequencies, one has a continuous change from a straight line seg. This software and all previous versions are no freeware.
Lissajous figures are not observed if the periods differ substantially. Mar 07, 2011 lissajous figures are parametric curves where both xt and yt are sine functions. An octopus circuit can be used to demonstrate the waveform images on an oscilloscope. We show a generalization of the wellknown lissajous figures, changing the two orthogonal simple harmonic oscillations to. Lissajous curves in oscilloscopes wikimedia commons. Pdf calibrating the frequency of tuning forks by means. Calibrating the frequency of tuning forks by means of lissajous figures article pdf available in american journal of physics 795. The experimental results indicate that the microvibration displacements measuring range can reach 5775 nm, with a resolution of about 5 nm. Later on they appeared in many scifi films with x and y driven at different frequencies but harmonically related by an integer ratio ab but with one generator slightly offset in frequency so. When \d\gt0\, the amplitudes of the oscillations of the coordinates decay exponentially through the factor \edt\. The smaller sliding optical rail makes it easier to move the microphone and set it to one of the desired points in the evolving lissajous pattern.
Pdf in this paper, an innovative method based on an algorithm utilizing discrete convolutions of discretetime functions is developed to obtain. The normal signal applied to the horizontal deflection is a sawtooth, this causes the sweep to cross the screen at the uniform rate specified by the time base. Two phaseshifted sinusoid inputs are applied to the oscilloscope in xy mode and the phase relationship. Feb 23, 2005 to create lissajous patterns you must provide a signal to drive the horizontal sweep. Lissajous figures article about lissajous figures by the. The horizontal axis displays the signal input to a loudspeaker while the vertical axis displays the changing signal picked up by a microphone as it is moved to a known distance away from the source. When this condition is met and when the phase shift is 0, the display consists of a straight line sloping. When this condition is met and when the phase shift is 0, the display consists of a straight line sloping upward from the left side of the screen to the right side.
This tutorial is a threedimensional simulation of a cathode ray oscilloscope producing lissajous figures as it compares sinusoidal voltages. Measure at least for five different frequency ratios. The graph gives the relation between the frequencies and the phase difference. Lissajous figures where a 1, b n n is a natural number and 2 1 s g n n 3 lissajous curves can also be generated using an. Articles needing additional references from november all articles needing additional references all articles with unsourced statements articles with unsourced statements from september articles lacking intext citations from november all articles lacking in. The normal signal applied to the horizontal deflection is a sawtooth, this causes the sweep to cross the screen at. Aug 07, 2018 shape of these lissajous pattern changes with changes of phase difference between signal and ration of frequencies applied to the deflection plates traces of cro. Lissajous figure definition is any of an infinite variety of curves formed by combining two mutually perpendicular simple harmonic motions, commonly exhibited by the oscilloscope, and used in studying frequency, amplitude, and phase relations of harmonic variables. Or it can be used to create and save your own lissajous artwork. More commonly today, lissajous figures are generated with an oscilloscope, a type of cathode ray tube that provides a picture of electrical signals in the form of a graph. The heart of an oscilloscope is a cathode ray tube crt, similar to that in a tv set, in which. Lissajouslike figures with triangular and square waves scielo. Here the two channels are displayed against each other.
Such figures are widely used in frequency and phase measurements see illustration. Lissajous figures are patterns generated by the junction of a pair of sinusoidal waves with axes that are perpendicular to one another. To show how such a figure can be created, consider the diagram to represent a dualaxis amusement park ride. Zeitnitz 062011 manual for the sound card oscilloscope v1. This video takes a fairly detailed look at the basics of lissajous patterns on an oscilloscope. However, if the periods are related as integers, the moving point will return to its original position in a period of time equal to the least multiple of the two periods, and a lissajous figure with a more complex shape is produced. Lissajous figures introduction lissajous figures displayed on an oscilloscope can be used to give a quick estimate of the relative phase of two signals at the same frequency. Manual for the sound card oscillograph v1 zeitnitz.
However, most oscilloscope will allow you to supply an external input that will allow you to directly control the x axis. Basics of lissajous patterns on an oscilloscope youtube. Which makes these lissajous patterns very useful to analysis the signals applied to deflection plated of cro. If it is irrational, the curve will never close and eventually fill a region. For this the frequencies can be adjusted in the signal generator. To create lissajous patterns you must provide a signal to drive the horizontal sweep. Just unzip all files in a folder on your pc and run the executable. It is a very important oscilloscope used to analyse the waveform and measure them. This is an article about lissajous curves lissajous curves sometimes also known as lissajous figures or bowditch curves, are pretty shapes first investigated by nathaniel bowditch in 1815, and later and in much more detail by jules antoine lissajou in 1857. Now here we will discuss how the measurement of waveform i. Pdf discrete lissajous figures and applications researchgate.