Nvis 6543 lissajous pattern trainer is a unique product designed to explain the measurement of unknown frequency, phase difference and resonance frequency using lissajous pattern. Lissajous work in the nineteenth century centered around the study of vibrating objects and wave phenomena. Both types of lissajous patterns are shown in figure. 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.
Learn more about homework not originally tagged as homework, triangle wave, square wave, sawtooth, lissajous. Pdf lissajous fiber scanning for forward viewing optical. Measurement of phase difference between two signals using dual beam cro. Geometrical and graphical representations analysis of lissajous. The above lissajous figure is in elliptical shape and its major axis has some. Lissajous figures with triangular and square waves in m. 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. It means that the spot traces out the same pattern for every cycle of a voltage signal. If one of the curves is 180 out of phase with respect to the other, another straight line is produced lying 90 away from the. A straight line inclined to x axis at 5 calculate the phase difference between the inputs. These lissajous patterns have two applications to analysis the signals.
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. 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. I will probably still build the example listed using the oscillator example above with lamp, if i can source the parts easily and cheaply enough around here. Using a scope to display lissajous patterns electrical. If the oscilloscope hasthe xversusy capability, one can apply one signal to the vertical deflection plates whileapplying a second signal to the horizontal. See harmonic motion typical lissajous figures for ratios of vertical frequency. The patterns that appear at the cro screen on connecting both pairs of the deflection plates horizontal deflection plates and vertical deflection plates to two sinusoidal voltages. 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. The cro has the cathode ray tube which acts as a heart of the oscilloscope. You can change the curves to line segments to get a string figure type effect like this. A lissajous pattern fiber scanner was assemble d with a singlemode optical fiber, silicon microstructures, a fiber fragment, and a pz t tu bular actuator 2. A variation is the display of signals in the frequency domain. Measurements using lissajous figures tutorialspoint. 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.
A lissajous pattern is a pattern which is stationary on the screen of a cro. Aside from this common feature, squarewavetype figures show a very different behavior, with discontinuous phase changes and impossibility of using a simple formula to get the frequency ratio between the two component oscillations. If the frequency and phase angle of the two curves are identical, the resultant is a straight line lying at 45 and 225 to the coordinate axes. Lissajous patterns at the dawn of the technological revolution. First one is closed lissajous pattern and has no free end. Lissajous figures are patterns generated by the junction of a pair of sinusoidal waves with axes that are perpendicular to one another. In an oscilloscope, the crt produces the electron beam which is accelerated, decelerated and focus with the help of accelerating and focusing anode at a high velocity and brings to the focal point on a fluorescent screen. Connect the output of phase shift network to the vertical input as shown in figure.
Lissajouslike figures with triangular and square waves. So the condition for having a lissajous pattern on the cro screen is. These patterns are called lissajous figures and are a common means of comparative frequency measurement in electronics. Lissajous figures article about lissajous figures by the. The frequencies of the motion are in the ratio of two integers. Lissajous is a complex audiovideo signal generator built in maxmsp and inspired by the work of jules antoine lissajous. To contribute towards the free videos on youtube, make a. The resulting pattern was a function of theratio of the two frequencies. If the two waves do not start at the same instant we get different patterns for the same frequency ratio. 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. 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.
The number of linecrossings or loops is what counts. When two signals having some frequency are applied to input terminal of cro and get superimposed perpendicularly when ab or ba is pressed, then a pattern of closed figure is obtained which is known as lissajous figure. Also we try to replace the dso by a labview software. Lissajous figures where a 1, b n n is a natural number and. 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. 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. Sep 29, 2018 lissajous patterns are the plane curves traced by a point that executes two independent harmonic motions in perpendicular directions. Lissajous patterns are the plane curves traced by a point that executes two independent harmonic motions in perpendicular directions. The patterns obtained on cro screen and discussed in previous sections are called the lissajous patterns. Faculty of engineering chulalongkorn university cathoderay.
Labview provides the flexibility of integration of data acquisition softwarehardware with the process control application software for automated test and measurement applications. The general shape of the pattern is not important for frequency comparison. Lissajous patterns of cro or cathode ray oscilloscope electrical4u. Describe in detail the construction and working of analog type storage oscilloscope. One of the quickest methods of determining frequency is by using lissajous patterns produced on a screen. 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. All the values which are obtained by cro or dso can be easily obtained by this effort. Shape of these lissajous pattern changes with changes of phase. My youtube channel your support in watching this video has been invaluable. In most oscilloscopes that have this capability, the frequency domain is accessed by pressing a button labeled math. Crochet pattern central free crohook crochet pattern link.
The simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. Lissajous patterns of cro or cathode ray oscilloscope. Lissajous figure on an oscilloscope, displaying a 3. To study the series and parallel lcr circuit and plot t he resonance curve at the consta nt frequency.
He started off standing tuning forks in water and watching the ripple patterns, but his most famous experiments involved tuning forks and mirrors. Hazy sea creature screen shot movie as animated gif. Jules antoine lissajous 18221880 was a french physicist who was interested in waves, and around 1855 developed a method for displaying them optically by reflecting a light beam from a mirror attached to a vibrating object such as a tuning fork. Originally published in twist collective, the two versions are quite different, with different charts and photography. This pattern include directions for knee high version with calf shaping and shortened sock version. Observing phase shift with lissajous patterns with the fg at khz, set the scope time base to observe 15 cycles. Lissajous patterns experiment 3 linkedin slideshare. Labview, daq, lissajous pattern, dso, phase difference, function generator.
Such figures are widely used in frequency and phase measurements see illustration. My lissajous figures would be rotating around as i will unlikely get exact multiples of frequency and the phase relation will keep changing. Replacing the cosine function in the parametrization by a triangle wave transforms every lissajous knot isotopically into a billiard curve inside a cube. This phase shift can be measured as the fraction of a cycle delayed times 360. Lissajous pattern may be constructed in the usual way and a 8 shaped pattern with two loops is obtained. Set frequency to hz, amplitude to 24 vpeak and the output waveform to sinusoidal wave. Basics of lissajous patterns on an oscilloscope youtube. Aug 11, 2016 the simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. Measurement of electrical quantities with a cro circuitstoday. Pdf discrete lissajous figures and applications researchgate. 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.
Aug 25, 2016 the simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. To find this feature in lissajous 3d, go to pattern more shape opts swoop around the curve another thing you can do is to show just one step of the pattern, and let that swoop around, using tubes, you get spinning and moving patterns dancing in a kind of a ballet this example uses a tube with a star shaped cross section. 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. Sand pendulums lissajous patterns homemade science. Oct 31, 2011 in using the lissajous form of oscilloscope display, several things should be remembered. Prior to modern electronic equipment, lissajous curves could be generated mechanically by means of a harmonograph practical application. It includes two sine wave generators for ease of operation. In this paper, an effort is made to obtain a lissjous pattern using daq card and measure the phase difference between two signals acquire by daq. Measurement of the speed of sound in air medium using. Lissajous patterns lissajous figures or lissajous curve. Liassajou curves are described by the parametric equations below. A labview based simulation of lissajous pattern using daq. Pdf jules lissajous and his figures semantic scholar.
Lissajous figures and cro setup to obtain lissajous figures. 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. 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. Solved lissajous pattern obtained on a cro when a and b. A labview based simulation of lissajous pattern using daq card. 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. At each instant, the scope plots a dot with the input x sample as the horizontal coordinate and the output. Lissajous 3d can make many beautiful relaxing animations. 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. Cro gives the visual representation of time varying signals. Sand pendulums are an easy and beautiful method for students of all ages to learn a bit about the harmonic motion. Cro cathode ray oscilloscope working electronics club. 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.
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. Phase measurement using lissajous patterns xy mode. Connect a 1volt peakpeak, 1khz sine wave signal from the function generator to the horizontal input of the cro. Storage oscilloscopes, capable of high persistence phosphors, have many applications. An octopus circuit can be used to demonstrate the waveform images on an oscilloscope. Which makes these lissajous patterns very useful to analysis the signals applied to deflection plated of cro. 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.
The alternative way of using oscilloscope to measure frequency. Combine a small number of segments with wide ribbons and you get this sort of effect. Lissajous figures are not observed if the periods differ substantially. 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. To find this feature in lissajous 3d, go to pattern ribbon steps per cycle, and set that number low. To show how such a figure can be created, consider the diagram to represent a dualaxis amusement park ride. 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. 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. Frequency and phase measurement ac metering circuits. This video takes a fairly detailed look at the basics of lissajous patterns on an oscilloscope. The aim of this experiment is to show how to trace the lissajous figures on the cathode ray oscilloscope using two function generators. The most common use of an oscilloscope is to display one or more signals in the time domain. Second one is open lissajous pattern and has free ends. If the two frequencies are the same, we will obtain a simple figure on the screen of the crt, the shape of that figure being dependent upon the phase shift between the two ac signals.
In a lissajous pattern ratio of frequency of vertical. Measurement of electrical quantities with a cro notes for. Some of these patterns are shown in the below figure. If the oscilloscope hasthe xversusy capability, one can apply one signal to the vertical deflection. 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. Lissajous curves can also be generated using an oscilloscope as illustrated. It explores the field of harmony and disorder and let the user dip into an elegant, dreamlike. Lissajous figures are obtained with an oscilloscope when this is. The projection of a lissajous knot onto any of the three coordinate planes is a lissajous curve, and many of the properties of these knots are closely related to properties of lissajous curves. To study the series and parallel lcr circuit and plot the resonance curve at the constant frequency.
Note that signal across the capacitor lags the signal across the function generator. Lissajous pattern trainer experiment setup electronics lab. Lissajous figures jules antoine lissajous was a french physicist who lived from 1822 to 1880. The patterns that appear at the cro screen on connecting both pairs of the deflection plates horizontal deflection plates and vertical deflection. Dec 12, 2012 the resulting pattern was a function of theratio of the two frequencies. Jul es antoine lissajous 18221880 is not among the giants in the history of science, yet his name is known to physics students through the lissajous figures patterns formed when two vibrations along perpendicular lines are superimposed. Pdf oscilloscope and its applications find, read and cite all the research you need.
Two phaseshifted sinusoid inputs are applied to the oscilloscope in xy mode. Like many physicists of his time, lissajous was interested in being able to see vibrations. If the oscilloscope hasthe xversusy capability, one can apply one signal to the vertical deflection plates whileapplying a second signal to the horizontal deflection plates. To determine the frequency of an unknown signal using lissajous figure. Lissajous figures a lissajous figure is produced by taking two sine waves and displaying them at rightangles to each other. Exp 4 measurement of phase difference lissajous figures vs voltagetime 1 connect the function generator to the phase shift circuit as shown in fig. 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.
The result of these patterns help in analyzing signal parameters. These devices are easy to build and can be adjusted to give a variety of patterns. Experimental investigation of lissajous figure shapes in. Pdf oscilloscope and its applications researchgate.
Sand pendulums lissajous patterns homemade science with. To measure the phase difference of two sine waves their frequencies must be equal. Lissajous figure lissajous figure on an oscilloscope. The lissajous patterns for other frequency ratios can be similarly drawn. Choosing a backup generator plus 3 legal house connection options transfer switch and more duration. Geometrical and graphical representations analysis of. Crohook patterns preceded by an asterisk are in pdf format. The block diagram shows the general purpose of cro internal contraction. Cro setup to obtain lissajous figures figure1 depicts lissajous figure obtained on cro using two sinusoidal voltages having frequency ratio of 2. Lissajous figures on an oscilloscope a level physics youtube. If the two frequencies are the same, we will obtain a simple figure on the screen of the crt, the shape of that figure being dependent upon. Frequency measurement by lissajous method basic circuit. Cro setup to obtain lissajous figures figure1 depicts lissajous figure obtained on cro using.
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