This tutorial is a threedimensional simulation of a cathode ray oscilloscope producing lissajous figures as it compares sinusoidal voltages. Lissajous patterns are the plane curves traced by a point that executes two independent harmonic motions in perpendicular directions. Lissajous patterns of cro or cathode ray oscilloscope electrical4u. The cathoderay oscilloscope cro is a common laboratory instrument that provides accurate time and amplitude measurements of voltage signals over a wide.
The beam in some versions traces out a lopsided figure8 pattern on its side. The question was how to do lissajous figures, particularly with a triangle wave and a square wave. As the frequency, amplitude and phase difference are altered, different patterns are seen on the screen of the cro. Sand pendulums lissajous patterns homemade science. Faculty of engineering chulalongkorn university cathoderay. In the old days, whenever they showed an engineer working, there was usually an oscilloscope nearby with a pattern on the screen. Some of the many ways you can transform the lissajous patterns with magnetism, friction, turn inside out, change the formula, change to line segments for string figure effect, broad ribbon varying in size, bead effect, etc etc. You can change the curves to line segments to get a string figure type effect like this. We have already discussed cathode ray oscilloscope or cro. Lissajous figures for some simple frequencies ratios and phase differences. Hazy sea creature screen shot movie as animated gif. Lissajous figures or lissajous curves are produced in two dimensions when the x and y coordinates are given by two sine waves, which may have any amplitude, frequency and phase. Lissajous had a figure for it, march 1957 popular electronics.
A lissajous curve, named after jules antoine lissajous is a. The lissajous lab provides you with a virtual oscilloscope which you can use to generate these patterns. Jan 12, 2017 hello id like to create a lissajous figures with triangular and square waves in matlab but i don t know howe some help. Phy2028 practical electronics ii information lissajous figures 1 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. Which makes these lissajous patterns very useful to analysis the signals applied to deflection plated of cro. Solved lissajous pattern obtained on a cro when a and. The applet also allows you to apply a signal to modulate the hue of the trace, so you can create colorful designs. Lissajou figures click on the sketch to change the x and y frequencies or wait a while, and theyll change at random.
Repeat the procedure for 45 unknown frequencies it will give. Lissajous figures with triangular and square waves in m. On the other hand, if the frequencies are commensurable, the figure is closed and strictly periodic. Such figures are widely used in frequency and phase measurements see illustration. These devices are easy to build and can be adjusted to give a variety of patterns. Lissajous curves can also be generated using an oscilloscope as illustrated. Energy, vibrating particles and other invisible forces pervade our physical universe. If the increased perceptual stability of the lissajous figure at higher shifting frequency is brought about by the increased speed of illusory rotation i. Press any key to stop the generation and save the curve as an image in your sketch folder. Geometrical and graphical representations analysis of. 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. Faculty of engineering chulalongkorn university cathode. Hi, i wanted to make a simple hardware device to create lissajous patterns.
If it is irrational, the curve will never close and eventually fill a region. The pattern of crisscross lines is actually a lissajous figure. It is used to check signals at radio and tv receiver. Lissajous curve synonyms, lissajous curve pronunciation, lissajous curve translation, english dictionary definition of lissajous curve. A quick sketch that generates a lissajous curve using two randomly selected numbers from 010. Cro is called lissajous pattern, when two sine waves of the same frequency are applied to the cro. Connect the output of phase shift network to the vertical input as shown in figure.
Measurement of phase difference between two signals using dual beam cro. We can tell that the lissajous pattern are formed by twofrequency that was given. See harmonic motion typical lissajous figures for ratios of vertical frequency. To use lissajous figures to take phase measurements. 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. Electronic instrumentation experiment 1 signals, instrumentation.
Basics of lissajous patterns on an oscilloscope youtube. I made a cube in directx, but now i want the cube to move around. Prior to modern computer graphics, lissajous curves were typically generated using an oscilloscope as illustrated. Permission is granted to copy, distribute andor modify this document under the terms of the gnu free documentation license, version 1. Oscilloscope fundamentals case school of engineering. Pdf oscilloscope and its applications researchgate. Pattern that results from applying periodic signals to the. Shape of these lissajous pattern changes with changes of phase difference between signal and ration of frequencies applied to the deflection plates. This is a support page to the multimedia chapter interference and consonance in the volume waves and sound, which introduces interactions between sine waves. Lissajous figures where a 1, b n n is a natural number and. Calculate the vertical input frequency if horizontal input frequency is 1500 hz.
Aug 25, 2016 the simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. To use lissajous figures to take frequency measurements. Now here we will discuss how the measurement of waveform i. I want this cube to move around in a lissajous pattern. This phase shift can be measured as the fraction of a cycle delayed times 360. The patterns that appear at the cro screen on connecting both pairs of the deflection plates horizontal deflection plates and vertical deflection. Named after jules antoine lissajous, a lissajous curve. Describe in detail the construction and working of analog type storage oscilloscope. A copy of the license is included in the section entitled gnu free documentation license. You can just run its screen saver to enjoy the patterns or generate new ones of your own and export them as images, movies or 3d animations. Lissajous curve definition of lissajous curve by the. A certain frenchman named lissajous, who lived around 1855, was no exception.
Perceptual stability of the lissajous figure is modulated. Trigonometryfor enthusiastslissajous figures wikibooks. Two small dc motors with a round mirror glued to the shaft under an angle are hit by a 5v laserbeam. To study the series and parallel lcr circuit and plot the resonance curve at the. Geometrical and graphical representations analysis of lissajous figures in rotor dynamic system hisham a. Sand pendulums lissajous patterns homemade science with. By howard burgess centuryold light pattern now serves as electronic yardstick men are traditionally attracted by figures with curves. Originally published in twist collective, the two versions are quite different, with different charts and photography. Jun 17, 2019 one of his methods involved creating vibrations in a mirror with sounds of different frequencies, then reflecting light from that mirror to produce various patterns. Lissajous pattern generator for beginners by willemvd. At each instant, the scope plots a dot with the input x sample as the horizontal coordinate and the output. The resulting waveform due to xy arrangement of two periodic signals having different periods is known as lissajous pattern. One of his methods involved creating vibrations in a mirror with sounds of different frequencies, then reflecting light from that mirror to produce various patterns.
Oct 31, 2011 see all articles from popular electronics. Lissajous figures article about lissajous figures by the. Trace the pattern, record the number of horizontal and vertical tangents and frequency of second function generator. Lissajous figures and cro setup to obtain lissajous figures. Frequency measurements using lissajous figures lissajous pattern also helps to measure frequency. Maharashtra state board of technical education autonomous. Lissajous figures are parametric curves where both xt and yt are sine functions if the ratio of the frequencies is rational the curve will always eventually close if it is irrational the curve will never close and eventually fill a region. Aug 11, 2016 the simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. Even light part particle, part wave has a fundamen. Lissajous 3d can make many beautiful relaxing animations. Using a scope to display lissajous patterns electrical.
Lissajous figures are obtained with an oscilloscope when this is. 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. The frequencies of the motion are in the ratio of two integers. Experiments based on cro the wave shapes analysis, measurement of frequency and voltage values peak to peak and rms at different ac. Adjust the vertical and horizontal gains properly for good display.
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. Lissajous curve definition of lissajous curve by the free. By examining the lissajous pattern, certain information about the relationship between the two signals becomes clear. Lissajous figures search and download lissajous figures open source project source codes from. 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. Discussion in this experiment we was exposed to another function of oscilloscope which are tomeasure frequency and to measure phase angle and also to display lissajous pattern. Observe lissajous patterns for different combinations of r and c values. This pattern include directions for knee high version with calf shaping and shortened sock version.
It is used to test af circuit for different distortion. We can tell that oscilloscope can measure the phase and thefrequency reference 1. But for some reason no matter what variables i enter my cube just makes circles instead of the. Sinusoidal voltages are applied to the horizontal and vertical deflection plates, they have the form v a sin. Observing phase shift with lissajous patterns with the fg at khz, set the scope time base to observe 15 cycles. A lissajous curve, named after jules antoine lissajous is a graph of the following two parametric equations. Maharashtra state board of technical education autonomous isoiec 27001 2005 certified. Faculty of engineering chulalongkorn university cathoderay oscilloscope cro objectives you will be able to use an oscilloscope to measure voltage, frequency and phase on a variety of displayed waveforms introduction the oscilloscope is the basic instrument for the study of all types of waveforms.
Lissajous figures james emery 42008 contents 1curves 1 2 program 4 1curves let xta1 sin. To measure unknown frequency from lissajous figures using cro. A purely mechanical application of a lissajous curve with a 1, b 2 is in the driving mechanism of the mars light type of oscillating beam lamps popular with railroads in the mid1900s. Lissajous figures are obtained with an oscilloscope when this is operated in xy mode. This video takes a fairly detailed look at the basics of lissajous patterns on an oscilloscope. Click on the save data icon of the oscilloscope and provide a file name. Note that signal across the capacitor lags the signal across the function generator. Sand pendulums are an easy and beautiful method for students of all ages to learn a bit about the harmonic motion. Lissajous figure can be displayed by applying two a. These lissajous patterns have two applications to analysis the signals. Lissajous patterns of cro or cathode ray oscilloscope. Storage oscilloscopes, capable of high persistence phosphors, have many applications. The simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i.
Lissajous patterns lissajous figures or lissajous curve. Let us compute the period of this curve, assuming that. Originally published in twist collective, the two versions are quite different, with different charts and photography the version includes 4 foot and 8 calf circumference sizes that can be combined for a customized fit. Inspired by sound, the first lissajous patterns were made by reflecting a beam of light in mirrors attached to two tuning forks to make a dot of light that bounced around following a lissajous curve. I have played around with pc software tone generators that will output to leftright channels and you can play with the frequency, phase and amplitude, and choose between sine,square and triangle waves. It is a very important oscilloscope used to analyse the waveform and measure them. Lissajous 3d trace the curves using a ribbon, or a tube, and the dot can oscillate in three or more directions, which takes the patterns. Shape of these lissajous pattern changes with changes of phase difference between signal and ration of frequencies applied to the deflection. From the shape of lissajous pattern displayed on cro screen, one can determine information about relative phases of signals and frequency ratio of signals too.
Rms voltage for sine and square waves, and why your dmm might not work right. Lissajous figures are parametric curves where both xt and yt are sine functions. There is a relation with the tchebyscheff polynomial. Set the frequency of generator one to 1 khz, vary the frequency of second function generator until a stable lissajous pattern is displayed to the screen of cro. If the ratio of the frequencies is rational, the curve will always eventually close. Oscilloscope fundamentals introduction nature moves in the form of a sine wave, be it an ocean wave, earthquake, sonic boom, explosion, sound through air, or the natural frequency of a body in motion. See frequency measurement, oscilloscope, phaseangle measurement.