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