# Phase Differences Cannot Distinguished Lissajous Figures

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Lissajous (1822–80). Inside each probe there is a parallel circuit of a resistor RP and capacitor Cp that is connected in series with the oscilloscope channel input as shown in circuit below. Use the position knobs to make sure that the center of ellipse is on the center of the screen. For simplicity we have assumed that the two waves have equal amplitude, although this is not necessary.

Figure below shows displays of the above equation for different values of . Observe and record the corresponding displays ( label amplitude and periods). 3- Three Methods for Making Voltage and Time measurements There are three ways you can make measurements of displayed voltage On larger, more sophisticated audio mixing consoles an oscilloscope may be built-in for this purpose. Now count the number of horizontal and vertical tangencies by Lissajous pattern with these horizontal and vertical line. https://en.wikipedia.org/wiki/Lissajous_curve

## What Is Lissajous Pattern

Other ratios produce more complicated curves, which are closed only if a/b is rational. We cannot do this by simply connecting the two leads of the probe to the ends of the resistor as shown in Figure 7. b) Adjusting The Triggering point If for any reason we are not satisfied with the display presented with the AUTSET function, we can choose the vertical and horizontal scale and triggering Set the frequency of the output signal generator at 100 Hz .

Finally, the value of δ determines the apparent "rotation" angle of the figure, viewed as if it were actually a three-dimensional curve. Sign up to view the full content. Your cache administrator is webmaster. Lissajous Figures Phase Difference Formula In the case of sound the varying amplitude gives rise to variations in loudness which are called beats .

EQUIPMENTS: Oscilloscope Signal Generator Resistors (1K x 1) Capacitors(22µF,44µF) Inductors(150µH) Theory : 1.1 Measurement of Voltage Using CRO: A voltage can be measured by noting the Y deflection produced by the Measurement Of Phase Difference And Frequency Using Cro Lissajous Figure Push the **format menu box** button to select XY. Select FREQ, PERIOD, MEAN, and PK-PK for the four measurement types. https://www.coursehero.com/file/12378482/Exp4-A/ Such figures are widely used in frequency and phase measurements (see illustration).

b) Another way of measuring the voltage across the resistor is to measure the voltage difference between the ends of the resistor. Lissajous Pattern Theory Two signal generators 3. Two-channel oscilloscope 2. This gives rise to "Lissajous Figures" .

## Measurement Of Phase Difference And Frequency Using Cro Lissajous Figure

Lissajous Figures In experiment No.5 we considered a special case of the combination of two vibrations at right angles, that is when the two vibrations have the same frequency . directory The beam in some versions traces out a lopsided figure-8 pattern with the "8" lying on its side. What Is Lissajous Pattern The phase shifts are all negative so that delay semantics can be used with a causal LTI system (note that −270 degrees is equivalent to +90 degrees). Phase Measurement Using Lissajous Figures Retrieved 17 September 2015.

Which makes these Lissajous patterns very useful to analysis the signals applied to deflection plated of CRO.

These lissajous patterns have two Applications to analysis the signals. No current flows through the capacitor. Set the frequency of the output signal at 50 Hz . 3. In Figure 1-a we plot the displacement produced at such a point by the two waves separately as a function of time. Frequency Measurement Using Lissajous FiguresNote: When using **CH1-CH2 both channels should have** the same VOLTS/DIV scale.... V (volts) Channel 1: Channel 2: t (ms) T=Period Question 1: In above display find . Obtain the Lissajous figures shown in Figure 2 . 4. Application for the case of a = b[edit] In this figure both input frequencies are identical, but the phase variance between them creates the shape of an ellipse.

At higher frequencies individual beats cannot be distinguished in the sound produced . Lissajous Pattern Experiment The time at Cursor 2. With sound such a condition exists when, for example , two adjacent piano keys are struck simultaneously. 49 Consider some one point in space through which the waves

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Want to thank TFD for its existence? Use the CURSOR 2 knob to place the remaining cursor at the top of the peaks. Another method for fast calculation is to multiply the scale factor by the phase difference ( in cm ) where the scale factor is degrees per box or degrees per cm. Lissajous Pattern Pdf xmax = a yintercept = c **=/2 ymax= b =0** =/3 Note: On oscilloscope ymax is controlled by scale on x-axis and yintercept is controlled by scale on y-axis.

This preview shows document page 1. The x-deflection plates of the tube are supplied with one alternating voltage, and the y-deflection plates with another. Since each of these values occurs once in each cycle, the number of beats per second is twice the frequency of amplitude as given by equation (5) or : fbeat = Experimental Procedure : I.

In contrast, any non-zero δ produces a figure that appears to be rotated, either as a left/right or an up/down rotation (depending on the ratio a/b). Hendy Buttons Probe comp 5V c) Attach the probe’s tip to the PROBE COMP 5V connector and press AUTOSET I Handy Buttons area. View Full Document TERM Winter '08 PROFESSOR Baghda-Sarian Click to edit the document details Share this link with a friend: Copied! By using this site, you agree to the Terms of Use and Privacy Policy.

The input impedance of each channel of the oscilloscope can be approximated by a parallel circuit of 1M resistor and a 20pF capacitor. Consider the simplest case when fy = 2fx . Please try the request again. Practical application[edit] Lissajous curves can also be generated using an oscilloscope (as illustrated).

Delta shows the time difference, which is the length of the period, and the frequency (reciprocal of the period). Electrical Instruments & Measurements(EE-211) Experiment # 4 Frequency and Phase Measurement with Lissajous Patterns PRE-LAB: To perform amplitude, frequency, and phase measurements using a calibrated cathode ray oscilloscope and to make The system returned: (22) Invalid argument The remote host or network may be down. Connect the output of one signal generator to the channel that represent the x-axis.

Then do the following steps: 1. 2. 3. 4. Rubber striking hummer 6. size(px) 750x600 750x500 600x500 600x400 start on 1 Link Report Description Electrical Instruments & Measurements(EE-211)Experiment # 4 Text RACHNA COLLEGE OF ENGINEERING & TECHNOLOGY, GUJRANWALA. For phase angles of 90 180 , the ellipse has a negative slope and the angle calculated by the above method must be subtracted from 180 to obtain the phase shift.

The system returned: (22) Invalid argument The remote host or network may be down. SCHOOL UCLA COURSE TITLE EE 110L TYPE Test Prep UPLOADED BY hjluvcamaro PAGES 18 Click to edit the document details This preview shows page 1. Log in Sign up Home UCLA EE EE 110L Exp4_A Exp4_A - Experiment IV Part A Please read the “pdf”...