ThePrincipleandUseof Digital OscilloscopeOscilloscope is an instrument used to display the waveform of signals, which can beused to measure the temporal evolution of shape,frequency,phase difference ofvoltagesignals and so on. Oscilloscope is frequently used to qualitatively observe the dynamicprocess of electrical signals and non-electrical signals (such as speed, pressure, stress,vibration, concentration, sound, magnetism, light, heat, etc.)with different sensors.Digital oscilloscopes have the functions of screenshots, data display, mathematicaloperations, data and waveform storage, which are not available in traditional analogoscilloscopes. Digital oscilloscopes can be connected to networks, USB flash drives,printers, and computers.Nowadays, digital oscilloscopes become the significantequipment in science research and education.In this experiment, students should understand the principle of oscilloscope, andlearn howtooperate theDS2072Adigital oscilloscope.Motivation(1) Understanding how the oscilloscope works(2)Learningtoobservevarioussignalwaveformswithanoscilloscope(3) Measuring the voltage, frequency and phase difference of the signal with anoscilloscopeExperimentalPrinciple1.The operatingprinciple of digital oscilloscopeA schematic diagram of the digital oscilloscope is shown in Figure 53-1. The detectedsignal is firstly delivered to a voltage amplification (or attenuation) circuit, and thesignal will be amplified (or attenuated) to an appropriate value for the subsequentcomponents. Secondly, the continuously variational signals will be sampled at a certainfrequency.Then, the sampled analog quantity is converted into a digital quantity by theanalog-to-digital (A/D) converter, and these digital quantities are stored in the memory.In this way,the stored digital waveform can be displayed on the screen with the help ofCPU and logic control circuit
The Principle and Use of Digital Oscilloscope Oscilloscope is an instrument used to display the waveform of signals, which can be used to measure the temporal evolution of shape, frequency, phase difference of voltage signals and so on. Oscilloscope is frequently used to qualitatively observe the dynamic process of electrical signals and non-electrical signals (such as speed, pressure, stress, vibration, concentration, sound, magnetism, light, heat, etc.) with different sensors. Digital oscilloscopes have the functions of screenshots, data display, mathematical operations, data and waveform storage, which are not available in traditional analog oscilloscopes. Digital oscilloscopes can be connected to networks, USB flash drives, printers, and computers. Nowadays, digital oscilloscopes become the significant equipment in science research and education. In this experiment, students should understand the principle of oscilloscope, and learn how to operate the DS2072A digital oscilloscope. Motivation (1) Understanding how the oscilloscope works (2) Learning to observe various signal waveforms with an oscilloscope (3) Measuring the voltage, frequency and phase difference of the signal with an oscilloscope Experimental Principle 1. The operating principle of digital oscilloscope A schematic diagram of the digital oscilloscope is shown in Figure 53-1. The detected signal is firstly delivered to a voltage amplification (or attenuation) circuit, and the signal will be amplified (or attenuated) to an appropriate value for the subsequent components. Secondly, the continuously variational signals will be sampled at a certain frequency. Then, the sampled analog quantity is converted into a digital quantity by the analog-to-digital (A/D) converter, and these digital quantities are stored in the memory. In this way, the stored digital waveform can be displayed on the screen with the help of CPU and logic control circuit
InputAmplify orSamplingandmemorydisplayattenuateA/DconrsioruniteExternalTriggelLogiccontroltriggerCPUcircuitcircuitInput and outputinterfaceFigure53-1.Schematic diagram of digital oscilloscopeIn order to stably display the real-time waveform of the input signal, the scansignal of oscilloscope must be synchronized to the input signal, and the starting pointof each displayed scan waveform is fixed at the same position on the oscilloscopescreen. If the signals after amplification (or attenuation) is selected as the trigger source,the trigger circuit of oscilloscope will generate a trigger signal when the trigger circuitdetect delivered signal over the set trigger condition (certain level and polarity).Receiving this trigger signal, subsequent logic control circuit start a set of dataprocessing,including ofacquisition, conversion,and memory write processing.Finally,the digital oscilloscope reads the data from the memory and displays it stably on thescreenwiththeparticipationofCPUandthelogiccontrolcircuit.Since the analog signal has been converted into a digital quantity and stored in thememory, the digital oscilloscope can be used to perform some mathematical operations(such as addition,subtraction,multiplication,fastFourier transform)and automaticmeasurement, etc. It also can be used to communicate with computers or otherperipherals through input/output interfaces.2.LissaiousFigureThe default model of waveform display on our oscilloscope is a “Y-T mode, asshown in Figure 53-2(a). The voltage values of the tested signal are sampled follow thesame time interval and displayed after a series of processes. The horizontal axis of thedisplayed waveform is corresponding to time.However, in many cases, it is necessary to compare the signals of two waveforms.For example, we need to observe the change of waveform and phase ofa specific signalbefore and after passing a certain circuit. The“Y-T mode" is very inconvenient.Weusually use the“X-Y mode", in which the X-axis and Y-axis of the displayed curves arethe detected signals of channel 1 and channel 2, respectively.Lissajous figure is defined as a regular and stable closed curve, which is formed by
Figure 53-1. Schematic diagram of digital oscilloscope In order to stably display the real-time waveform of the input signal, the scan signal of oscilloscope must be synchronized to the input signal, and the starting point of each displayed scan waveform is fixed at the same position on the oscilloscope screen. If the signals after amplification (or attenuation) is selected as the trigger source, the trigger circuit of oscilloscope will generate a trigger signal when the trigger circuit detect delivered signal over the set trigger condition (certain level and polarity). Receiving this trigger signal, subsequent logic control circuit start a set of data processing, including of acquisition, conversion, and memory write processing. Finally, the digital oscilloscope reads the data from the memory and displays it stably on the screen with the participation of CPU and the logic control circuit. Since the analog signal has been converted into a digital quantity and stored in the memory, the digital oscilloscope can be used to perform some mathematical operations (such as addition, subtraction, multiplication, fast Fourier transform) and automatic measurement, etc. It also can be used to communicate with computers or other peripherals through input/output interfaces. 2. Lissajous Figure The default model of waveform display on our oscilloscope is a “Y-T mode”, as shown in Figure 53-2(a). The voltage values of the tested signal are sampled follow the same time interval and displayed after a series of processes. The horizontal axis of the displayed waveform is corresponding to time. However, in many cases, it is necessary to compare the signals of two waveforms. For example, we need to observe the change of waveform and phase of a specific signal before and after passing a certain circuit. The “Y-T mode” is very inconvenient. We usually use the “X-Y mode”, in which the X-axis and Y-axis of the displayed curves are the detected signals of channel 1 and channel 2, respectively. Lissajous figure is defined as a regular and stable closed curve, which is formed by
two simpleharmonicvibrationsperpendiculartoeachother,withanintegerratiobetween their frequencies.Different initial phases and different frequency ratios willproducedifferent shapesof Lissajous curves,as shown inFigure53-22=2n=4UaUxit(b)1UUe4C(a)(c)Figure 53-2.Lissajous figure:(a)Different frequencies and phases of Y-axis and X-axis signals.(b)The synthesized Lissajous curvebetween Uxi and Uy.(c)The synthesized Lissajous curvebetween Ux2and UyFig.53-2(b) show the Lissajous figure obtained by taking Uxi and Uy as X-axis and Y-axis, respectively. Fig. 53-2(c) show the Lissajous figure obtained by taking Ux2 and UyasX-axisand Y-axis,respectively.Since theUxiandUx2 signals havethe samefrequency and different phases, the shape of the Lissajous figure is quite different.However, the ratio of the maximum intersections of any horizontal line intersectingwith the Lissajous curve and those of the vertical line with the Lissajous curve is same
two simple harmonic vibrations perpendicular to each other, with an integer ratio between their frequencies. Different initial phases and different frequency ratios will produce different shapes of Lissajous curves, as shown in Figure 53-2. Figure 53-2. Lissajous figure: (a) Different frequencies and phases of Y-axis and X-axis signals. (b) The synthesized Lissajous curve between Ux1 and Uy. (c) The synthesized Lissajous curve between Ux2 and Uy. Fig. 53-2(b) show the Lissajous figure obtained by taking Ux1 and Uy as X-axis and Yaxis, respectively. Fig. 53-2(c) show the Lissajous figure obtained by taking Ux2 and Uy as X-axis and Y-axis, respectively. Since the Ux1 and Ux2 signals have the same frequency and different phases, the shape of the Lissajous figure is quite different. However, the ratio of the maximum intersections of any horizontal line intersecting with the Lissajous curve and those of the vertical line with the Lissajous curve is same t Ux1 a b c d e f g h i t a b c d e f h i Uy g Uy Ux1 a b c d e f g h i nx= 2 ny= 4 t (b) Ux1 g t a b c d e f h i Uy (a) t Ux2 t (c) Ux2 i a b c d e g f h t t a b c d e f h i Uy g Uy a Ux2 c b d e g f h i nx= 1 ny= 2
(1: 2).So it is follow the relation as:n,:n,=f,:f,(53-1)Figure53-3showstheLissajousfiguresforseveraldifferentfrequencyratiosDt(d) O(e) J.2I.Figure 53-3.Lissajous figures of several frequency ratiosExperimental Instruments1.DS2072AdigitaloscilloscopeFigure53-4 shows the operation panel of the DS2072Adigital oscilloscope.The signalsare input to the oscilloscope through the two input channels (CH1 and CH2).Table 53-1 shows thefunction introductionoftheoscilloscope.If you want toknowthedetailedfunction of one button during operation, you can press the "Help" button firstly, andthen press the button. Then the function introduction of this button will be displayed onthe oscilloscope screen
(1: 2). So it is follow the relation as: x y y x n : n = f : f （53-1） Figure 53-3 shows the Lissajous figures for several different frequency ratios. Experimental Instruments 1. DS2072A digital oscilloscope Figure 53-4 shows the operation panel of the DS2072A digital oscilloscope. The signals are input to the oscilloscope through the two input channels (CH1 and CH2). Table 53- 1 shows the function introduction of the oscilloscope. If you want to know the detailed function of one button during operation, you can press the “Help” button firstly, and then press the button. Then the function introduction of this button will be displayed on the oscilloscope screen. (a) (b) (c) (d) (e) (f) Figure 53-3. Lissajous figures of several frequency ratios
QuickFunctionOperationMulti-functionScreenmenuknobcontrol areacontrol areaselection buttonmeasurementaQAADaHelp/printE一ParametersettingbuttonOHorizontalcontrol area口WaveformrecordingareaTrigger control areaProbe compensation endExternal trigger inputchannel zoneVertical controlSwitchUSB interfaceSignal inputFigure 53-4.Schematic diagram of the operation panel of the DS2072A digital oscilloscopeTable 53-1.Functions of the DS2072ADigital OscilloscopeNameAreaFunctionAutomatically detect the signal input channel, automaticallyAUTObuttonselect the appropriate measurement range, period, trigger, anddisplay the detected signal in Y-T mode.RUN/STOPDisplaythereal-timewaveform/displaythewaveformbeforeOperationbuttoncontrolpressingthestopbutton.(Screenshot)AreaThe singletriggerbutton:theoscilloscopewillbetriggeredbyanSINGLEbuttonappropriate signal satisfiedthe certain requestcondition anddisplays the signal.CLEAR buttonIn the case ofa single trigger mode, it will clear the screen.Press helpbuttonfirstly,andthenpress anotherbuttontodisplayHelp buttonHelpthefunction of that button.printPrint buttonSave screen data to a USB flash drive or print itCHI buttonDisplay / (stop display) CH1 channel signal and operation menu.VerticalCH2 buttonDisplay / (stop display) CH2 channel signal and operation menu.controlAccording to selected function, display the results of adding.AreaMATHbuttonsubtracting, multiplying and FFT (fast Fourier transform)operations of CHI signal and CH2channel signal
Table 53-1. Functions of the DS2072A Digital Oscilloscope Area Name Function Operation control Area AUTO button Automatically detect the signal input channel, automatically select the appropriate measurement range, period, trigger, and display the detected signal in Y-T mode. RUN/STOP button Display the real-time waveform / display the waveform before pressing the stop button. (Screenshot) SINGLE button The single trigger button: the oscilloscope will be triggered by an appropriate signal satisfied the certain request condition and displays the signal. CLEAR button In the case of a single trigger mode, it will clear the screen. Help print Help button Press help button firstly, and then press another button to display the function of that button. Print button Save screen data to a USB flash drive or print it. Vertical control Area CH1 button Display / (stop display) CH1 channel signal and operation menu. CH2 button Display / (stop display) CH2 channel signal and operation menu. MATH button According to selected function, display the results of adding, subtracting, multiplying and FFT (fast Fourier transform) operations of CH1 signal and CH2 channel signal. Help/print Parameter setting button Probe compensation end Screen menu selection button Multi-function knob Function control area Operation control area Switch USB interface Vertical control zone Signal input channel Quick measurement button Figure 53-4. Schematic diagram of the operation panel of the DS2072A digital oscilloscope Horizontal control area Waveform recording area Trigger control area CLEA AUT SINGL Measur Acquire Storage Cursor Display Utility Help Print MENU SCALE C 1 C 2 MATH REF Decode Decode MOD MEN FORC POSITI SCALE CH1 CH2 External trigger input channel zone
Displaythereference signal waveform.Thereferencesignal canREF buttonbe input temporarily or a stored waveform in REF format.Shift thedisplayed waveformup and downvertically.Ifpress thePOSITIONknobknob,themovementof theselectedchannel will becancelledAlter the vertical resolution of display signal on the screen toSCALEknobchange the waveform height. If press this knob, you can switchbetween coarseandfineadjustment.Displaytheoperationmenuofthehorizontal control system.The'delay scan"can expand a certain part of the waveformhorizontally,and the"timebase"can selectthedisplaymodeMENUbuttonbetween "Y-T" and "X-Y" (the signal ofCHl is X, and the signalof CH2isY).Ifthe"X-Y"modeis selected,thedelaytimeiscontrolled by the horizontal area"SCALE"knobHorizontalAdjustthehorizontalpositionofthewaveform.Ifpresstheknob.controlPOSITION knobthewaveformwill returntothecenterofthescreenAreaAdjust the time base of the scanned waveform (the timecorrespondingtoeachlargegridonthescreen,s/div).Ifpressthisknob,youcan switchbetween"Scan"and"Delayed Scan".In theSCALE knob"x-y" mode, the delay time of the track and the number ofsampling points are changed to adjust the integrity of theLissajous figureDisplaythe"Data"menu.You canuse theMulti-functionKnob”with the“Function Menu SettingButton"to measure all theMeasure buttonparameters of the waveform and display the results directly onthescreenDisplay the "Sampling" menu. Different sampling methods andAcquire buttonsamplingtimescanbeselectedtoobtaindifferentresultsFunctionalcontrolDisplay the"Save"menu.The information about waveforms,AreaStorage buttonsettings,bitmaps,CSVfiles andparameters can be stored.Inthismenu, you can restore thefactory default settingsDisplay the "Cursor"menu.Automatic, manual and trackingmodes can be selected.Thedata of the cursor position can beCursorbuttonautomaticallydisplayedonthescreen.Thepositionofthemenuhighlight cursor can be changed by the“multi-function knob
REF button Display the reference signal waveform. The reference signal can be input temporarily or a stored waveform in REF format. POSITION knob Shift the displayed waveform up and down vertically. If press the knob, the movement of the selected channel will be cancelled. SCALE knob Alter the vertical resolution of display signal on the screen to change the waveform height. If press this knob, you can switch between coarse and fine adjustment. Horizontal control Area MENU button Display the operation menu of the horizontal control system. The "delay scan" can expand a certain part of the waveform horizontally, and the "time base" can select the display mode between "Y-T" and "X-Y" (the signal of CH1 is X, and the signal of CH2 is Y). If the "X-Y" mode is selected, the delay time is controlled by the horizontal area "SCALE" knob. POSITION knob Adjust the horizontal position of the waveform. If press the knob, the waveform will return to the center of the screen. SCALE knob Adjust the time base of the scanned waveform (the time corresponding to each large grid on the screen, s/div). If press this knob, you can switch between "Scan" and "Delayed Scan". In the "X-Y" mode, the delay time of the track and the number of sampling points are changed to adjust the integrity of the Lissajous figure. Functional control Area Measure button Display the "Data" menu. You can use the “Multi-function Knob” with the “Function Menu Setting Button” to measure all the parameters of the waveform and display the results directly on the screen. Acquire button Display the "Sampling" menu. Different sampling methods and sampling times can be selected to obtain different results. Storage button Display the "Save" menu. The information about waveforms, settings, bitmaps, CSV files and parameters can be stored. In this menu, you can restore the factory default settings Cursor button Display the "Cursor" menu. Automatic, manual and tracking modes can be selected. The data of the cursor position can be automatically displayed on the screen. The position of the menu highlight cursor can be changed by the “multi-function knob
Display the"display" menu. Set the type of display,menu holdDisplaybuttontime,screengrid, brightness,etc.Display the"Auxiliary"menu. Set parameters about language,Utlity buttoninterface,recording waveform,printing and soonChange the trigger level. If press the knob, the trigger level willLEVELknobbe resetTriggerSet the trigger menu on the screen. Change the trigger signalMENU buttoncontrolsource, trigger mode, trigger mode, etcareaMODEbuttonSwitch the trigger mode among automatic, normal, and singleProduce a trigger signal. Mainly be used in the "normal" andFORCEbutton"single" trigger mode.Assist “Function Menu Setting Button". Set the on-screen menuMulti-function knoband waveform.Ifpresstheknob,thecurrent setting is confirmedUse alone to adjust the screen brightnessIn concertwithotherbuttons,displaytheon-screenmenuandScreenmenuselectionbuttonmeasurerelatedparametersDisplay the relevant parameters of the horizontal and verticalQuickmeasurementbuttonmeasurementmenuofthedetectedwaveformProvide a square wave signal of about 3.0V, 1.0kHz, adjust theattenuationprobe ofthe inputsignal in concert withtheCHi/CH2button on the upper end of the input channel and the probeProbe compensation portcompensation adjustment bar, and select the"probe ratio"in then-screen menu option.If a non-attenuating probe is used,the"Probe Ratio"option of the on-screenmenu must beIX.WaveformrecordingareaRecord and play back waveforms.In concert with the multi-function knob to adjust the parametersParameter settingknobof a wide rangeofchanges2. DG1000Z type function /arbitrary waveform generatorFigure 53-5 shows the operation panel of the DG1000Z function/arbitrary waveformgenerator, which can generate various custom waveforms.The parameters of outputsignal (such as frequency, amplitude, phase, etc.) can be changed by the “screen dataoutput button" or “"screen data adjustment knob" It can also be used to observe theparameters and waveforms ofexternal signals.Next,wewill introduce thefunctions of
Display button Display the "display" menu. Set the type of display, menu hold time, screen grid, brightness, etc. Utlity button Display the "Auxiliary" menu. Set parameters about language, interface, recording waveform, printing and so on. Trigger control area LEVEL knob Change the trigger level. If press the knob, the trigger level will be reset. MENU button Set the trigger menu on the screen. Change the trigger signal source, trigger mode, trigger mode, etc. MODE button Switch the trigger mode among automatic, normal, and single. FORCE button Produce a trigger signal. Mainly be used in the "normal" and "single" trigger mode. Multi-function knob Assist “Function Menu Setting Button”. Set the on-screen menu and waveform. If press the knob, the current setting is confirmed. Use alone to adjust the screen brightness. Screen menu selection button In concert with other buttons, display the on-screen menu and measure related parameters. Quick measurement button Display the relevant parameters of the horizontal and vertical measurement menu of the detected waveform. Probe compensation port Provide a square wave signal of about 3.0V, 1.0kHz, adjust the attenuation probe of the input signal in concert with the CH1/CH2 button on the upper end of the input channel and the probe compensation adjustment bar, and select the "probe ratio" in the on-screen menu option. If a non-attenuating probe is used, the "Probe Ratio" option of the on-screen menu must be 1X. Waveform recording area Record and play back waveforms. Parameter setting knob In concert with the multi-function knob to adjust the parameters of a wide range of changes. 2. DG1000Z type function / arbitrary waveform generator Figure 53-5 shows the operation panel of the DG1000Z function/arbitrary waveform generator, which can generate various custom waveforms. The parameters of output signal (such as frequency, amplitude, phase, etc.) can be changed by the “screen data output button” or “screen data adjustment knob”. It can also be used to observe the parameters and waveforms of external signals. Next, we will introduce the functions of
thebuttonsandknobs,whicharecommonlyusedinthisexperimentThe button area ofThe button area of basicscreen menu selectionwaveformselectionScreen data[Sine]Squa] Ram]Pulse]Noise[Arbadjustment[ModO日1knob andStore000corresponding[Help]JDOa-data digitCH/CH2OutputtCouCHselection50buttonFunctioncontrolareaScreen data input buttonFigure53-5.Schematicdiagramof panelofDG1000Zfunction/arbitrarywaveformgeneratorTable53-2.IntroductionofcommonfunctionsofEE1641B1functionsignalgeneratorArea/buttonFunctionThe switch ofCHl channel signal output, CHI channelwill output signalOutput1buttonwhenpressthisbuttonThe switch ofCH2 channel signal output, CH2 channel will output signalOutput2buttonwhen press this button.CH1/CH2 buttonAlternatelyadjust the CH1/CH2channel signal on the screenAfter press the button, CH2 channel does not output any signal, and theCounter buttonscreen displays the signal input from theCounter channelScreen menuAfterpressthecorrespondingbutton,thecorrespondingdataontheselection buttonscreen will be highlighted, and it is adjustable.Screen data inputEnter the data,and the highlighted data on the screen will be changedbuttonScreen dataadjustmentknobandTurntheknob andthe highlighteddata on the screenwill bechangedcorrespondingdataaccordingly.It can be used with the data bits selection buttondigit selection button
the buttons and knobs, which are commonly used in this experiment. Figure 53-5. Schematic diagram of panel of DG1000Z function/arbitrary waveform generator Table 53-2. Introduction of common functions of EE1641B1 function signal generator Area/button Function Output1 button The switch of CH1 channel signal output, CH1 channel will output signal when press this button． Output2 button The switch of CH2 channel signal output, CH2 channel will output signal when press this button． CH1/CH2 button Alternately adjust the CH1/CH2 channel signal on the screen. Counter button After press the button, CH2 channel does not output any signal, and the screen displays the signal input from the Counter channel. Screen menu selection button After press the corresponding button, the corresponding data on the screen will be highlighted, and it is adjustable. Screen data input button Enter the data, and the highlighted data on the screen will be changed. Screen data adjustment knob and corresponding data digit selection button Turn the knob and the highlighted data on the screen will be changed accordingly. It can be used with the data bits selection button. Sine Squa Ram Pulse Noise Arb Mod Swee Burst Utility Store Help Output1 CH1/CH2 Output2 1 4 7 2 5 8 3 6 9 0 • Count +/- Output1 CH1/CH2 Output2 CH1 CH2 Counter Counter The button area of screen menu selection Function control area Screen data input button Screen data adjustment knob and corresponding data digit selection button The button area of basic waveform selection
Select the type of output waveforms: sine wave,"Sine"; square wave,Basicwaveform"Square";sawtooth wave,"Ramp"pulsewave,"Pulse";noise,"Noise"selection buttonandcustomwaveform"Arb".Perform complex waveform output:modulated wave,"Mod"; sweepingFunctioncontrolareawave,"Sweep"; burst, "Burst".Restore default setting,"Utility".Store,"Store".View the button function,"Help".Experimental content and procedure1. Restore oscilloscope default settingsPress the storagebutton in theoscilloscopefunction control area,as shown inFigure53-4. After the option menu appearing on the screen, press the “Default Settings"option to restore the oscilloscope to the default setting state.2.Measure thevoltageand frequencyof signals using the oscilloscopeInput the unknown signal provided by the laboratory into the oscilloscope channelCH2/CH1throughtheprobe.AdjustSCALEknobintheverticalcontrolareaandthe"SCALEknob in thehorizontal control area to make thewaveform size and lengthsuitable. (If the waveform is unstable, try adjusting the “LEVEL" knob in the triggercontrol area, or pressing the “AUTO" button.)(PINDT(ms/div)/ (div)Figure 53-6. Oscilloscope measures signal voltage and frequencyAsshowninFigure53-6,thevoltagevalueofthepeakdisplayedonthescreenis
Basic waveform selection button Select the type of output waveforms: sine wave, "Sine"; square wave, "Square"; sawtooth wave, "Ramp"; pulse wave, "Pulse"; noise, "Noise"; and custom waveform "Arb". Function control area Perform complex waveform output: modulated wave, "Mod"; sweeping wave, "Sweep"; burst, "Burst". Restore default setting, "Utility". Store, "Store". View the button function, "Help". Experimental content and procedure 1. Restore oscilloscope default settings Press the storage button in the oscilloscope function control area, as shown in Figure 53-4. After the option menu appearing on the screen, press the “Default Settings” option to restore the oscilloscope to the default setting state. 2. Measure the voltage and frequency of signals using the oscilloscope Input the unknown signal provided by the laboratory into the oscilloscope channel CH2/CH1 through the probe. Adjust “SCALE” knob in the vertical control area and the “SCALE” knob in the horizontal control area to make the waveform size and length suitable. (If the waveform is unstable, try adjusting the “LEVEL” knob in the trigger control area, or pressing the “AUTO” button.) Figure 53-6. Oscilloscope measures signal voltage and frequency As shown in Figure 53-6, the voltage value of the peak displayed on the screen is
equal to the waveform height multiplied by the voltage value corresponding to the unitheight of the screen, which can be written asUp-p=hxa(53-2)Up-p is defined as the peak voltage, which is the voltage value difference between thehighest point (peak) and the lowest point (valley) of the waveform in one cycle. h isthe height of the waveform, and its units is div. a is the vertical deflection factorshown on the lower left corner of the screen, and its unit is V/div.Similarly, the period of the waveform can be written asT=lxb(53-3)where the unit of lis div, and the unit of b is s/div shown on the white box in the upperleft corner of the screen.The frequency can be written as(53-4)TTips: The digital oscilloscope provides a direct reading function for some normativesignals. The method is shown in Figure 53-7.Record screenDisplay cdataobservationcursoand datalitudevaluFigure 53-7. Data query for this digital oscilloscope3.Observehalfwaverectifierwaveformbyoscilloscope(1) Connect the unknown signal provided by the laboratory to the AB binding posts asshown in Figure 53-8. Input the signals from CD binding posts by the appropriate probeto the CH2/CH1 channels+AOCAoBFigure 53-8 Half-wave rectifier circuit
equal to the waveform height multiplied by the voltage value corresponding to the unit height of the screen, which can be written as Up− p = h a （53-2） Up-p is defined as the peak voltage, which is the voltage value difference between the highest point (peak) and the lowest point (valley) of the waveform in one cycle. ℎ is the height of the waveform, and its units is div . 𝑎 is the vertical deflection factor shown on the lower left corner of the screen, and its unit is V/div. Similarly, the period of the waveform can be written as T = l b （53-3） where the unit of l is div, and the unit of b is s/div shown on the white box in the upper left corner of the screen. The frequency can be written as T f 1 = (53-4） Tips: The digital oscilloscope provides a direct reading function for some normative signals. The method is shown in Figure 53-7. Figure 53-7. Data query for this digital oscilloscope 3. Observe half wave rectifier waveform by oscilloscope (1) Connect the unknown signal provided by the laboratory to the AB binding posts as shown in Figure 53-8. Input the signals from CD binding posts by the appropriate probe to the CH2/CH1 channels. Figure 53-8 Half-wave rectifier circuit