Lissajous patterns experiment 3 linkedin slideshare. The figures, drawn by mechanical devices called harmonographs, have scientific uses, but are also enjoyed for their own beauty. The actual frequencies input to the oscilloscope are f x 1500 hz and f y 500 hz, i. Lissajous figures in the application of microvibration measurement. Meanwhile, the theory of lissajous figures 827 finds a wide range of applications in engineering 9,28physics10,11and biomedicince12. To use lissajous figures to take phase measurements. Typically, an oscilloscope will plot the voltage of an primary input on the y axis vs. Introduction to lissajous figures caroline teti, 2008 lissajous figures are. The fourvolume set lncs 8925, 8926, 8927 and 8928 comprises the thoroughly refereed postworkshop proceedings of the workshops that took place in conjunction with. Pdf discrete lissajous figures and applications researchgate. Aug 11, 2016 the simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. Direct oscilloscope methods lissajous figures zero.
Which makes these lissajous patterns very useful to analysis the signals applied to deflection plated of cro. The diagram shown is identical to one of the figures you can obtain with the laser lissajous device. How to draw 2d oscillations and lissajous curves using 3d. These lissajous patterns have two applications to analysis the signals.
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 scopes surface, which is coated in phosphor. Lissajouslike gures with triangular and square waves 37023 another interesting point to mention is the lack of continuity of the square lissajouslike. Analysis of lissajous figures on oscilloscope screens was the accepted method of impedance measurement prior to the availability of lockin amplifiers and frequency response analyzers. Basics of lissajous patterns on an oscilloscope duration.
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. 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. The simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. 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. Lissajouslike gures with triangular and square waves. Lissajous figure definition of lissajous figure by the. 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. The australian broadcasting corporation is a mostly. However, most oscilloscope will allow you to supply an external input that will allow you to directly control the x axis. Generating lissajous figures wolfram demonstrations project. The media project is born with the purpose of investigating the relationship. When the periods of motion in the two directions make a simple ratio, then a. The pattern of crisscross lines is actually a lissajous figure.
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. 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. In order to accurately measure the central angles of lissajous figures, a standard and transparent circle, which is divided 72 equal circular arcs and is concentric with the lissajous figures, is pasted on the oscilloscopes display. Swift 16671745 objective to learn to operate a cathode ray oscilloscope. The applet also allows you to apply a signal to modulate the hue of the trace, so you can create colorful designs. The eight lissajous figures ah, simulated by using the software matlab when a 1 and the phase modulation coefficients are. We have already discussed cathode ray oscilloscope or cro. Pdf calibrating the frequency of tuning forks by means of.
It is a very important oscilloscope used to analyse the waveform and measure them. Volume 281, issue 18, 15 september 2008, pages 47444746. Use a laser pointer and two small rotating mirrors to create a variety of lissajous figures. In mathematical29terminology, a lissajous curve is a. Lissajous patterns of cro or cathode ray oscilloscope. 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. In this experiment we will use the function generator, the oscilloscope, and a speaker. Lissajous figures in the application of microvibration. 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. Electronic instrumentation experiment 1 signals, instrumentation. Two phaseshifted sinusoid inputs are applied to the oscilloscope in xy mode and the phase relationship. In the example in curvilinear motion, the lissajous figure is a circle. Usb oscilloscope from digilent mouser electronics, inc. Geometrical and graphical representations analysis of lissajous.
To show how such a figure can be created, consider the diagram to represent a dualaxis amusement park ride. Pdf calibrating the frequency of tuning forks by means. This w3c unspecified plot was created with gnu plot. He would use sounds of different frequencies to vibrate a mirror.
This is a dynamic lissajous emulator in the sense that the waveform is obtained by combining 2 time varying sinusoidal waves with different frequencies. When the periods of motion in the two directions make a simple ratio, then a closed curve results. 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. Lissajous figures are patterns generated by the junction of a pair of. Sep 16, 2017 lissajous figures on an oscilloscope a level physics. Mar 07, 2011 lissajous figures are parametric curves where both xt and yt are sine functions. We can connect a function generator to both the x and y axis and begin to draw lissajous patterns. 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. This property is exploited to produce a set of points, called padua points, at. Lissajous figures lissajous pronounced leesuhzhoo figures were discovered by the french physicist jules antoine lissajous. If one period is twice the other, we get a quartic curve. Lissajous is a complex audiovideo signal generator built in maxmsp and inspired by the work of jules antoine lissajous. If the ratio of the frequencies is rational, the curve will always eventually close.
Lissajous figures on an oscilloscope a level physics. For few lissajous figures based on their shape, we can directly tell the phase difference between the two sinusoidal signals. An oscilloscope is a device that displays a graph of instantaneous voltages as a. Lissajous figures where a 1, b n n is a natural number and. Lissajous figure synonyms, lissajous figure pronunciation, lissajous figure translation, english dictionary definition of lissajous figure. This is a support page to the multimedia chapter interference and consonance in the volume waves and sound, which introduces interactions between sine waves. An octopus circuit can be used to demonstrate the waveform images on an oscilloscope. From a historical point of view lissajous figures or curves were also used for frequency comparison before practical frequency counters could be built.
Soundtrack is beethovens pathetique sonata, 3rd movement. Lissajous figures were first mentioned by nathaniel bowditch in 1815, and rediscovered by jules antoine lissajous in 1857. If the frequencies arent in small whole number ratio. However, most oscilloscope will allow you to supply an external input that will allow you to directly. To create lissajous patterns you must provide a signal to drive the horizontal sweep. Now here we will discuss how the measurement of waveform i.
When this condition is met and when the phase shift. The horizontal axis displays the signal input to a loudspeaker while the. If it is irrational, the curve will never close and eventually fill a region. Sound card oscilloscope pdf download free pdf books. In this case the coordinates are damped harmonic oscillators and the curve is a damped lissajous curve. Frequency measurements using lissajous figures lissajous pattern also helps to measure frequency. Geometrical and graphical representations analysis of. Feb 28, 2012 lissajous patterns shown on an oscilloscope. To restore the figure to the original view, click the front view button. Theory the oscilloscope, or scope for short, is a device for.
Lissajous figure on an oscilloscope, displaying a 3. Measurement of the speed of sound in air medium using. The fourvolume set lncs 8925, 8926, 8927 and 8928 comprises the thoroughly refereed postworkshop proceedings of the workshops that took place in conjunction with the th european conference on computer vision, eccv 2014, held in. Phase comparison with lissajous figures do not use a too high test frequency. Theory the oscilloscope, or scope for short, is a device for drawing calibrated graphs of voltage vs time very quickly and conveniently. Download direct to your kindle device for instant, offline reading lissajous figures are produced by combining two oscillations at right angles to each other. Lissajous pattern generator this is a dual, sine wave oscillator that generates audio signals of 4500hz and 1500hz. The oscilloscope vision is the art of seeing things invisible. Lissajous figure and oscilloscopes problem physics forums. 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.
Other lissajous figures result from frequencies that are exactly or nearly in small whole number ratio, like 2. To use this catalogue, adjust the oscilloscope so that the x and y. The figure below summarizes how the lissajous figure changes over different phase shifts. Optically addressed springpatterned membrane mirror mems with megahertz response. The coordinates of a point on a wheel can be described by sine functions of a certain frequency and phase shift. Lissajous curves can also be generated using an oscilloscope as illustrated. The lissajous lab provides you with a virtual oscilloscope which you can use to generate these patterns. For example, in the harmonic case with equal frequencies, one has a continuous change from a straight line seg. Lissajous figures are parametric curves where both xt and yt are sine functions. Lissajous figures are created by combining a periodic motion in one direction with a periodic motion in a perpendicular direction. 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. Jules antoine lissajous 18221880 was a french physicist who was interested in waves, and around 1855. 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.
Meanwhile, the theory of lissajous figures827 finds a wide range of applications in engineering 9,28physics10,11and biomedicince12. Lissajous figures are obtained with an oscilloscope when this is. At each instant, the scope plots a dot with the input x sample as the horizontal coordinate and the output. Calibrating the frequency of tuning forks by means of lissajous figures article pdf available in american journal of physics 795. Trigonometryfor enthusiastslissajous figures wikibooks. Feb 23, 2005 to create lissajous patterns you must provide a signal to drive the horizontal sweep. To use lissajous figures to take frequency measurements. This means that your horizontal speed controls are disabled. We can tell that oscilloscope can measure the phase and thefrequency reference 1. Such an instrument is obviously useful for the design and. 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. Lissajous figures for some simple frequencies ratios and phase differences. If the periods are equal, the curve is always an ellipse.
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. 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. The timestamp is only as accurate as kissajous clock in the camera, and it may be completely wrong. 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.
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