Lissajous figures and cro setup to obtain lissajous figures. 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. In the system of parametric equations, the variables affect the outcome of the lissajous figure in different ways. Lissajous patterns experiment 3 linkedin slideshare. Storage oscilloscopes, capable of high persistence phosphors, have many applications. Lissajous pattern trainer experiment setup electronics lab. This pattern include directions for knee high version with calf shaping and shortened sock version. Labview, daq, lissajous pattern, dso, phase difference, function generator. 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. These socks are worked in the round from the top down and feature cables and twisted stitches.
The lissajous pattern or lissajous figure is named for the french mathematician jules antoine lissajous 1. We will use the graticule on the oscilloscope, a ratio formula, and sine sin table to compute the angle. Sinusoidal voltages are applied to the horizontal and vertical deflection plates, they have the form v a sin. Abstractour present work focuses on the beautiful but simple technique for determination of the speed of sound using analysis of the lissajous patterns. This frequency measurement by lissajous method techniques used are simple and dependable, and measurement may be made at any frequency in. The patterns that appear at the cro screen on connecting both pairs of the deflection plates horizontal deflection plates and vertical deflection. The lissajous patterns for other frequency ratios can be similarly drawn. Download fulltext pdf discrete lissajous figures and applications article pdf available in ieee transactions on instrumentation and measurement 6312. Example of an analog oscilloscope lissajous figure, showing a harmonic. Lissajous patterns lissajous figures or lissajous curve. Geometrical and graphical representations analysis of. Choosing a backup generator plus 3 legal house connection options transfer switch and more duration. As the frequency, amplitude and phase difference are altered, different patterns are seen on the screen of the cro.
We can tell that oscilloscope can measure the phase and. The resulting pattern was a function of theratio of the two frequencies. A labview based simulation of lissajous pattern using daq. Measurement of phase difference between two signals using dual beam cro.
Adjust the vertical and horizontal gains properly for good display. 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. Lissajous figures are obtained with an oscilloscope when this is operated in xy mode. Lissajous patterns, showing the effects of phase relationships.
Experiments based on cro the wave shapes analysis, measurement of frequency and voltage values peak to peak and rms at different ac. Lissajous figure on an oscilloscope, displaying a 3. Pdf oscilloscope and its applications researchgate. 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. 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 frequencies of the motion are in the ratio of two integers. This video takes a fairly detailed look at the basics of lissajous patterns on an oscilloscope. A cro is an electronic device with a crt as its main component and other associated circuits consisting of a power supply unit, a sawtoothwave generator, horizon and vertical amplifiers. Measurement of the speed of sound in air medium using. Also we try to replace the dso by a labview software. Shape of these lissajous pattern changes with changes of phase difference between signal and ration of frequencies applied to the. Laser scanning based on microelectromechanical systems mems scanners has become very attractive for biomedical endoscopic imaging, such as confocal microscopy or optical coherence tomography oct. Lissajous patterns at the dawn of the technological revolution.
Lissajous patterns are the plane curves traced by a point that executes two independent harmonic motions in perpendicular directions. Shape of these lissajous pattern changes with changes of phase difference between signal and ration of frequencies applied to the deflection plates. Cro setup to obtain lissajous figures figure1 depicts lissajous figure obtained on cro using. If the two waves do not start at the same instant we get different patterns for the same frequency ratio. The light source for lissajous mirrorgenerated patterns was a simple candle. Observe lissajous patterns for different combinations of r and c values.
The result of these patterns help in analyzing signal parameters. Connect the output of phase shift network to the vertical input as shown in figure. Cro gives the visual representation of time varying signals. 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. The block diagram shows the general purpose of cro internal contraction. 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 is a complex audiovideo signal generator built in maxmsp and inspired by the work of jules antoine lissajous. These scanners are required to be fast to achieve realtime image reconstruction while working at low actuation voltage to comply with medical standards. 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. 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. Lissajous pattern may be constructed in the usual way and a 8 shaped pattern with two loops is obtained. 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 patterns of cro or cathode ray oscilloscope electrical4u.
Measurement of electrical quantities with a cro notes for. 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. To use this catalogue, adjust the oscilloscope so that the x and y. Osa realtime lissajous imaging with a lowvoltage 2. Lissajous patterns of cro or cathode ray oscilloscope. This gun shoots about 6,000,000,000 electrons per second in a concentrated highvelocity beam toward the face of.
Lissajous figures where a 1, b n n is a natural number and. Lissajous figure can be displayed by applying two 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 lissajous device. Lissajous work in the nineteenth century centered around the study of vibrating objects and wave phenomena. 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. Approximately 550 900 yards of fingering weight yarn, shown in louet gems fingering. The cathoderay oscilloscope cro is a common laboratory instrument that provides accurate time and amplitude measurements of voltage signals over a wide. Lissajous figures a lissajous figure is produced by taking two sine waves and displaying them at rightangles to each other. The oscilloscope is a sensitive indicator for frequency and phase measurements. Using a scope to display lissajous patterns electrical.
Frequency measurement by lissajous method basic circuit. When two sinusoidal signals of same frequency and magnitude are applied two both pairs of deflecting plates of cro, the lissajous pattern. All the values which are obtained by cro or dso can be easily obtained by this effort. Figure 8 will aid you in computing a phase angle if a more precise calculation is needed. To show how such a figure can be created, consider the diagram to represent a dualaxis amusement park ride. Describe in detail the construction and working of analog type storage oscilloscope. The simplest lissajous patterns appear in the oscilloscope display when the frequencies of the signals are the same, i. Lissajous figures are patterns generated by the junction of a pair of.
Lissajous 3d can make many beautiful relaxing animations. The patterns obtained on cro screen and discussed in previous sections are called the lissajous patterns. Pdf oscilloscope and its applications find, read and cite all the. In place of a candle, the modern oscilloscope contains an electron gun in the narrow neck of the tube. 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 cro has the cathode ray tube which acts as a heart of the oscilloscope. The pattern of crisscross lines is actually a lissajous figure. The applet also allows you to apply a signal to modulate the hue of the trace, so you can create colorful designs. Cro cathode ray oscilloscope working electronics club. If the oscilloscope hasthe xversusy capability, one can apply one signal to the vertical deflection. It explores the field of harmony and disorder and let the user dip into an elegant, dreamlike. Frequency measurements using lissajous figures lissajous pattern also helps to measure. Lissajous figures are patterns generated by the junction of a pair of sinusoidal waves with axes that are perpendicular to one another. The relationship between the two signals is shown by the type of display.
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