The applet also allows you to apply a signal to modulate the hue of the trace, so you can create colorful designs. Lissajous figures are obtained with an oscilloscope when this is. Shape of these lissajous pattern changes with changes of phase difference between signal and ration of frequencies applied to the deflection plates. You can change the curves to line segments to get a string figure type effect like this. Sep 21, 2014 experiments based on cro the wave shapes analysis, measurement of frequency and voltage values peak to peak and rms at different ac. They modulate a laser beam along two perpendicular directions to. This video takes a fairly detailed look at the basics of lissajous patterns on an oscilloscope. Feb 09, 2017 the aim of this experiment is to show how to trace the lissajous figures on the cathode ray oscilloscope using two function generators connected to x and y plates of cro. To measure unknown frequency from lissajous figures using cro.
Frequency measurement by lissajous method basic circuit. Lissajous figure, also called bowditch curve, pattern produced by the intersection of two sinusoidal curves the axes of which are at right angles to each other. Also we try to replace the dso by a labview software. Lissajous patterns are the plane curves traced by a point that executes two independent harmonic motions in perpendicular directions. Measurement of frequency by lissajous method the oscilloscope is a sensitive indicator for frequency and phase measurements. Lissajous figures james emery 42008 contents 1curves 1 2 program 4 1curves let xta1 sin.
One example 0 12 1 11 10 2 6 7 5 9 3 8 4 the diagram shown is identical to one of the figures you can obtain with the laser lissajous device. Care is taken such that a very high volume is not used. All the values which are obtained by cro or dso can be easily obtained by this effort. They illustrate one of the earliest uses to which the cro was put.
A lissajous pattern is produced on the screen when two sine wave voltages are applied simultaneously to both pairs of deflection plates of a cro. Straight line tilted at 45 degree with respect to xaxis b. Lissajous pattern trainer experiment setup electronics lab. 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. Trigonometryfor enthusiastslissajous figures wikibooks. Lissajous figures article about lissajous figures by the. We have already discussed cathode ray oscilloscope or cro.
Pdf discrete lissajous figures and applications researchgate. Lissajous setup was similar to the apparatus which is used today to project laser lightshows 6, 7. Aug 11, 2016 the same lissajous pattern is displayed when the phase shift is 360, illustrating that these two phase shifts are equivalent. This page can be used as a playground or learning tool to see how changing basic parameters affects the generated images. In order to generate a lissajous pattern a known reference frequency sine wave is applied to one of the deflection plates of the oscilloscope and the unknown sinusoidal signal to the other deflection plates a lissajous pattern is produced on the scren according to the frequency ration between the two signal. Lissajous patterns are derived in the old cathode ray tubes, by feeding one sine wave signal onto the x plates, and another onto the yplates. The simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i.
Which makes these lissajous patterns very useful to analysis the signals applied to deflection plated of cro. When the phase shift is 45, the lissajous pattern is an ellipse whose centerline slopes upward from left to. There are a lot of videos that show lissajous patterns on youtube. As the frequency, amplitude and phase difference are altered, different patterns are seen on the screen of the cro. Some of these patterns are shown in the below figure. A and b represent amplitudes in the x and y directions, a and b are constants, and.
Let us now assume two harmonic waves moving along two perpendicular directions given by 1. This frequency measurement by lissajous method techniques used are simple and dependable, and measurement may be made at any frequency in. A labview based simulation of lissajous pattern using daq. Various fixed geometric shapes and patterns can be produced on the oscilloscope screen by selecting the desired option from the choose a preset pulldown menu. Measurement of the speed of sound in air medium using. Lissajous patterns of cro or cathode ray oscilloscope electrical4u. Electronic measurement or electronic instrumentation.
In the old days, whenever they showed an engineer working, there was usually an oscilloscope nearby with a pattern on the screen. This video uses online simulation software falstad circuit simulator for creating lissajous patterns. If the two frequencies are unrelated, then therewill be only a patch of light observed because of the persistence of the oscilloscope screen. Lissajous figures displayed on an oscilloscope can be used to give a quick estimate of the relative. The relationship between the two signals is shown by the type of display.
Storage oscilloscopes, capable of high persistence phosphors, have many applications. A much wider range of lissajous figures can be created by manually adjusting the amplitude, frequency, andor phase of one or both of the voltages via the designated sliders. Liassajou curves are described by the parametric equations below. We can tell that the lissajous pattern are formed by twofrequency that was given. Lissajous figures are patterns generated by the junction of a pair of sinusoidal waves with axes that are perpendicular to one another.
See more ideas about parametric equation, drawing machine and curves. Prior to modern computer graphics, lissajous curves were typically generated using an oscilloscope as illustrated. On the other hand, if the frequencies are commensurable, the figure is closed and strictly periodic. Make lissajous patterns with diy sand pendulums or light. In this lesson ive discussed lissajous pattern and phase angle measurement using cro. To study the series and parallel lcr circuit and plot the resonance curve at the. The lissajous lab provides you with a virtual oscilloscope which you can use to generate these patterns. The lissajous pattern results,when sine waves are applied simultaneously to both pairs of deflection plates.
Geometrical and graphical representations analysis of lissajous figures in rotor dynamic system hisham a. Each cycle object is independent with controls for frequency, phase and amplitude. Budgetpriced transistor testing and lissajous patterns. This pattern include directions for knee high version with calf shaping and shortened sock version. The pattern of crisscross lines is actually a lissajous figure. Lissajous figures or patterns are named in honor of the french scientist who first obtained them geometrically and optically.
Dec 12, 2012 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 figures and cro setup to obtain lissajous figures. Frequency measurement is very important in many applications of alternating current, especially in ac power systems designed to run efficiently at one frequency and one frequency only. If the two input waveforms f equal amplitude and 90 degree phase difference is applied to the cro then the lissajous patterns obtained will be a. Lissajous art peter elsea 112608 2 figure 1 is a basic lissajous generator. An oscilloscoope in the xy triggered mode displays lissajous patterns which can be used to determine the status of a transistor. Measurement of phase difference between two signals using dual beam cro. Multivariate polynomial interpolation on lissajouschebyshev. Mar 10, 2019 lissajous patterns are derived in the old cathode ray tubes, by feeding one sine wave signal onto the x plates, and another onto the yplates.
If the ratio of the first frequency to the second is a rational number, thena closed curve will be observed on the cro. Geometrical and graphical representations analysis of. The lissajous pattern or lissajous figure is named for the french mathematician jules antoine lissajous 1. Lissajous patterns at the dawn of the technological revolution. When using an oscilloscope, we can plot one sinusoidal signal along the xaxis against another sinusoidal signal along the yaxis, the result is a lissajous figure. 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. The frequencies of the motion are in the ratio of two integers. To show how such a figure can be created, consider the diagram to represent a dualaxis amusement park ride.
A labview based simulation of lissajous pattern using daq card. A known frequency f h is applied to the horizontal input, and an unknown frequency f v is applied to the vertical input. A lissajous curve, named after jules antoine lissajous is a graph of the following two parametric equations. Frequency and phase measurement ac metering circuits. 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. Lissajous pattern may be constructed in the usual way and a 8 shaped pattern with two loops is obtained. Basics of lissajous patterns on an oscilloscope youtube. These tests take place using an octopus, which eliminates problems associated with testing components that are in a circuit board. Frequency measurements using lissajous figures lissajous pattern also helps.
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. Lissajous patterns are formed when two sine waves are applied simultaneously to the vertical and horizontal deflecting plates of a cro. Lissajous figures where a 1, b n n is a natural number and. When the phase shift is 90 or 270, and both signals are the same frequency, a perfect circle displays. If the two waves do not start at the same instant we get different patterns for the same frequency ratio. These lissajous patterns have two applications to analysis the signals. Lissajous patterns of cro or cathode ray oscilloscope. One example 0 12 1 11 10 2 6 7 5 9 3 8 4 the diagram shown is identical to one of the figures you can obtain with the laser. The oscilloscope is a sensitive indicator for frequency and phase measurements. Jules antoine lissajous 18221880 was a french physicist who. It is a very important oscilloscope used to analyse the waveform and measure them. Some lowspeed waveforms are used so that the trace movement that draws the lissajous figures can be seen and understood. This frequency measurement by lissajous method techniques used are simple and dependable, and measurement may be made at any frequency in the response range of the oscilloscope. 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.
Originally published in twist collective, the two versions are quite different, with different charts and photography. Lissajous figures are obtained with an oscilloscope when this is operated in xy mode. Hazy sea creature screen shot movie as animated gif. Sep 29, 2018 lissajous patterns lissajous figures or lissajous curve lissajous pattern on cro simulation this video explains the simulation of lissajous pattern.
The result of these patterns help in analyzing signal parameters. Shape of these lissajous pattern changes with changes of phase difference between signal and ration of frequencies applied to the. See frequency measurement, oscilloscope, phaseangle measurement. We can tell that oscilloscope can measure the phase and thefrequency reference 1. An important electrical quantity with no equivalent in dc circuits is frequency. 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. A pendulum that begins with two point of support can alter the periods of the pendulum as it moves on two perpendicular axis at the same time. Describe in detail the construction and working of analog type storage oscilloscope. The patterns that appear at the cro screen on connecting both pairs of the deflection plates horizontal deflection plates and vertical deflection. The beam in some versions traces out a lopsided figure8 pattern on its side. Using a scope to display lissajous patterns electrical. 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.
Experiments based on cro the wave shapes analysis, measurement of frequency and voltage values peak to peak and rms at different ac. Lissajous figure can be displayed by applying two a. Week 2 v20170314overview welcome to the rst assignment of the physics computation sequence. In order to accurately examine the function of a variable one needs to graph the system of parametric equations below while keeping. Observe lissajous patterns for different combinations of r and c values.
In the system of parametric equations, the variables affect the outcome of the lissajous figure in different ways. Lissajous patterns lissajous figures or lissajous curve. These devices are easy to build and can be adjusted to give a variety of patterns. When two sinusoidal signals of same frequency and magnitude are applied two both pairs of deflecting plates of cro, the lissajous pattern. Now here we will discuss how the measurement of waveform i. Before the days of digital frequency meters and phaselocked loops, lissajous figures were used to. Pdf calibrating the frequency of tuning forks by means. Geometrical and graphical representations analysis of lissajous. 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.
The cathoderay oscilloscope cro is a common laboratory instrument that provides accurate time and amplitude measurements of voltage signals over a wide. 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. Ph 2022 is meant to give you a toolkit for approaching numerical and computational problems like a physicist. Faculty of engineering chulalongkorn university cathode. Or it can be used to create and save your own lissajous artwork. First studied by the american mathematician nathaniel bowditch in 1815, the curves were investigated independently by the french. Aug 25, 2016 the simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. Labview, daq, lissajous pattern, dso, phase difference, function generator. The lissajous patterns for other frequency ratios can be similarly drawn. Lissajous figures by jed margolin in the old days, whenever they showed an engineer working, there was usually an oscilloscope nearby with a pattern on the screen.
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