User manual
Contents
1. SM ALL 11 BLOCK DIAGRAM Coil BIG SM ALL T Diode 4 9 VERTICAL SIGNAL MODE SWITCH OUTPUTAMP 40 50MHz on 12kv CH 1 SIGNAL CHI X ONTPUT INPUT CH 1 ATT CHI PREAMP CHI CH2 Y INPUT a SWITCHING 71 CH2ATT PREAMP LOGIC y CH2 ere gt TRIG TRIG SWITCH PICKUP AMP X AXIS SIGNAL TRIGGER INPUT AMP TRIGGER GENERATOR AUTO CIRCUIT LINE TRIG A SWEEP GENERATOR FREE RUN SIGNAL CRT CIRCUIT lt H V SUPPLY HORIZONTA LI SWITCHING TO EACH BLOCK 2V p p 1 KHz SQUARE WAVE POWER SUPPLY O CALIBRATOR HORIZONTA 2 0 OUTPUT AMP AC LINE I 50 60Hz Specifications are subjectto change without notice 292. direction the triggering threshold shifts to a more negative value When the control is centered the threshold level is set at the approximate average of the signal used as the triggering source The TRIG LEVEL control adjusts the start of the sweep to almost any desired point on a waveform On sine wave signals the phase at which sweep begins is variable Note that if the TRIG LEVEL control is rotated toward its extreme or setting no sweep will be developed in he NORM trig ger mode because triggering threshold exceeds the peak amplitude of the sync signal When the TRIG SLOPE switch is set to the position up the sweep is developed from the trigger source waveform as it Slope Range Level crosses the threshold level in a positive going direction When Slope Range the TRIG SLOPE control is set to the position down a sweep trigger is developed form the trigger source waveform as it crosses the threshold level in anegative going direction This switch selects the slope polarity triggering signal as shown in Figure4 6 Figure 4 6 19 4 Function of TRIG ALT switch The TRIG ALT switchis used to select alternate triggering and alternate display when the DUAL trace VERT MODE is selected the switch has on effectin the CH 1 CH 2 or ADD modes In the alternate triggering mode when dual trace operation is selected the trigger source alternates between channel l and channel 2 with each sweep This is convenient for checking
3. CH2 INV 1 0 25 1M0 25pF ries CAL INTEN FOCUS TRACE DES ROTATION avp A 4 O 300V CAT II I 300V MAX 400V pk 400V pk 1 KHz O OSCILLOSCOPE TRIGGER MODE SOURCE HORIZONTAL AUTO NORM CH2 LINE TV H EXT 4 5 SWPVAR TRIG IN 1 0 25 SS VERTICAL roe L 1M0 25pF 0 725 1M9 25pF De CAL INTEN FOCUS TRACE ie ROTATION 7 2Vp p A 300V CAT Il O 300V CAT IL MAX 400 400Vpk 1 KHz 0 dd GH GOO Figure 4 2 LNE VOLTAGE RANGE SELECTION 50 60H2 FUSE WARNING TO AVOID ELECTRIC SHOCK THE POWER CORD PROTECTIVE GROUNDING POWERMAX 35 WATTS 4
4. Upon receiving the instrument immediately unpack and inspect it for any damages that might have been sustained during transportation Ifany sign of damage is found immediately notify the bearer and or the dealer 3 2 Checking the Line voltage These oscilloscopes will operate on AC 230V or 110V set by manufactory Before connecting the power plug to an AC line outlet make sure the voltage selector is set to the correct position corresponding to the line voltage Note the oscilloscope may be damaged if it is connected to the wrong AC line voltage WARNING To avoid electrical shock the power cord protective grounding conductor must be connected to ground Replace the required fuses shown below Line voltage Range Fuse 0 5 AC 230V 207 253 250V T 1 0A AC 110V 109 121 250V WARNING To avoid personal injury disconnect the power cord before removing the fuse holder 3 3 Environment The normal ambient temperature range of this instrument is 01040 C 32 to 104 F Operation of the instrument above this temperature range may cause damage to the circuits Do not use the instrument ina place where strong magnetic or electric field exists such fields may disturb the measurement 3 4 Equipment Installation and Operation Ensure there is proper ventilation for the hole vents in the oscilloscope case If this equipment is usedin a manner not specified by the manufacturer the protection provided by the eq
5. amplitudes wave shape or waveform period measurements and even permits simultaneous observation of two waveforms which are not related in frequency or period However this setting is not suitable for phase or timing comparison measurements For such measurements both traces must be triggered by the same sync signal When the CHOP and the TRIG ALT switches are both engaged during dual trace operation synchronization of the display is not possible because the chopping signal becomes the trigger Use the ALT mode by itself or select CH 1 or CH 2 as trigger source 4 7 TIME DIV control Set the TIME DIV control to display the desired number of cyclesoft he waveform If there are too many cycles displayed for good resolution switch to a faster sweep speed If only a line is displayed try a slower sweep speed When the sweep speed is faster than the waveform being observed only partof it will be displayed which may appear as a straight line fora square wave or pulse waveform 4 8 Sweep Magnification When acertain partof the displayed waveform is needed to be expanded time wise a faster sweep speed may be used However if the required portion is apart from the starting point of the sweep the required portion may run off the CRT screen In sucha case push i n the x10 MAG button When this has been done the displayed waveform will be expanded 10 times to theright andlef t withthe center of screenas the center of e xpansion Thesweeptime
6. page 26 DC BAL adjustments for the details AV POSITION 11 19 Vertical positioning control of trace or spot VERT 14 Select operation modes of CH and CH 2 amplifiers CH1 Theoscilloscope operates as a single channel instrument with CH 1 alone CH2 Theoscilloscope operates as a single channel instrument with CH 2 alone DUAL The oscilloscope operates as a dual channel instrument both CH1 and CH2 ADD Theoscilloscope displays the algebraic sum CH 1 CH 2 or difference CH 1 CH 2 of the two signals The pushed in state of CH2 INV 16 button is for the difference CH I CH 2 ALT CHOP cre 12 When this switch is released in the dual trace mode the channel 1 and channel 2 inputs are alternately displayed normally used at faster sweep speeds When this switch is engagedin the dual trace mode the channel 1 and channel 2 inputs are chopped and displayed simultaneously normally used at slower sweep speeds CH 2 INV ence 16 Inverts the CH2 input signal when the CH2INV switch mode is pushed in The channel 2 input signal in ADD mode and the channel 2 trigger signal pick off are also inverted 11 Triggering EXT TRIG IN input terminal 25 Input terminal is used for external triggering signal Touse this terminal set SOURCE switch 24 to the EXT position SOURCE 24 Select the internal triggering source signal and the
7. to frequency 1 Set the TIME DIV control to the X Y position fully counterclockwise In this mode channel 1 becomes the X axis Input and channel 2 becomes the Y axis input 2 The X and Y positions are now adjusted using the horizontal lt POSITION and CH2 POSITION controls respectively 3 Adjust the amount of vertical Y axis deflection with the CH 2 VOLTS DIV and VAR controls 4 Adjustthe amount of horizontal X axis deflection with the CH 1 VOLTS DIV and VAR controls 21 4 10 Calibration of Probe As explained previously the probe makes up a wide range attenuator Unless phase compensation is properly done the displayed waveform is distorted causing measurement errors Therefore the probe must be properly compensated before use Connect the 10 1 probe BNC to the INPUT terminal of CH1 or CH2 and set VOLTS DIV switch at 50mV Connect the Probe tip to the calibration voltage output terminal and adjust the compensation trimmer on probe for optimum square wave minimum overshoot rounding off and tilt il __ Il 4 Figure 4 9 a Correct compensation b Over compensation c Insufficient compensation 4 11 DC BAL Adjustments The ATT balance of the vertical axis can be made easily 1 Set the
8. whichis applied across the component under test The sine voltage across the test object is used for the horizontal deflection V and voltage drop current through the test object is used for vertical deflection I of the oscilloscope By this V I characteristic curve the good or fault of component is measured 7 Toset up the oscilloscope Only Type T for componenttest operation proceed as follows 1 Turn TIME DIV switch to the X Y position and set both vertical coupling switches to DC position as well as setting up the both VOLTS DIV knob CH1 X to 5V DIV CH2 Y to 2V DIV then pushthe COMP TEST SW To TEST position 2 Then horizontal bar graph of about 5 6 div is displayed on the screen 3 The position of graph is controlled with CH2 POSITION and H POSITION 4 Componets may be directly hooked to testing code Then waveform chartis displayed on the screen 8 Test condition 1 Resitor capacitor coil diode zener or simple combination of the components can be tested 2 Testing voltage approx 9V ACp p 3 Testing frequency 50 60Hz 4 Testing current approx 0 6mA 9 lt CAUTION gt 1 Using the component test function don t apply the singal to theCH1 and CH2 input because the oscilloscope doesn t operate inthe component test mode 2 Don t push X10 MAG switch because the bar will be fatted 3 Don t test the live circuit operating the power signal component 24 26 10 WAVEFORM CHART Re rsister Capacitor
9. 0VA CONDUCTOR MUST BE CONNECTED TO GROUND FOR CONTINUED FIRE PROTECTION REPLACE ONLY WITH SPECIFIED TYPE AND RATED FUSE NO OPERATOR SERVICEABLE COMPONENTS INSIDE DO NOT REMOVE COVERS REFER SERVICING TO QUALIFIED PERSONNEL 4 0 PERATION METHOD 4 1 Introduction of Front Pa nel FOCUNS ettet teen 3 For focusing the trace to the sharpest image TRACE 4 Filter for ease of waveform viewing Vertic al Axis 8 Vertical input terminal of CH 1 When in operation X axis input terminal CH 2 CY Winput tere 20 Vertical input terminal of CH 2 When in X Y operation Y axis input terminal AC GND DC eene 10 18 Switch for selecting connection mode between input signal and vertical amplifier AC AC coupling GND Vertical amplifier input is grounded and input terminals are disconnected DC DC coupling 8 7 22 Select the vertical axis sensitivity from SmV DIV to SV DIV in 10 ranges 9 21 Fine adjustment of sensitivity with afactor of 1 2 5 of the indicated value When in the CAL position sensitivity is calibrated to indicated value CH1 amp CH2 DC BAL 13 17 These are used for the attenuator balance adjustment See
10. C BAL 8 22 5 1 Fuse replacement ee e e mmm emm ee ee eee 23 5 2 Cleaning mmm ee em ee m m 10 WAVEFORM 25 SAFETY TERMS AND SYMBOLS These terms may appear in this manual or on the product WARNING Warning statements identify condition or practices that could result in injury or loss of life CAUTION Caution statements identify conditions or practices that __ could result in damage to this product or other property The following symbols may appear in this manual or on the product DANGER ATTENTION Protective Earth ground High Voltage referto Manual Conductor Terminal Terminal 1 GENERAL 1 1 Description The 20MHz 25MHz 30MHz 40MHz 50MHz family oscilloscope are dual channel oscilloscope with maximum sensitivity of5mV DIV The time base provides a maximum sweep time of 0 2 uS DIV When magnified by 10 the sweep speed is 20nS DIV Each of these oscilloscope employs a 6 inch rectangular type cathode ray tube with red internal graticule These oscilloscopes are sturdy easy to operate and exhibits high operational reliability 1 2 Features 1 High intensity CRT with high acceleration voltage The CRT is a high beam transmissio
11. CH 1 Set the AC GND DC switchto the AC state Adjust vertical POSITION knobs 11 and 19 so that both channel signals are displayed as shown in Figure4 4 an Figure 4 4 Signal of CHI Signal of CH2 When ALT CHOP switch is released ALT MODE the input signals applied respectively to and CH2 appears on the screen alternatively at each sweep This setting is used when the sweep time is shortin 2 channel observation When ALT CHOP switch is engaged CHOP MODE the input signals applied to CH 1 and CH 2 are switched at about 250KHz independent and at the same time appear on the screen This setting is used when the sweep time is long in 2 channel observation When in the dual channel operation DUAL or ADD mode the CHlorCH2 signal must be selected for the triggering source signal by means of the SOURCE switch If both land CH 2 signals are in asynchronizedrelationship both waveforms canbe displayed stationary if not only the signal selected by the SOURCE switch can bestationary Ifthe TRIG ALT push switch is engaged both waveforms can be displayed stationary 4 5ADD Operation An algebraic sum of the CH 1 and CH 2 signals can be displayed on the screen by setting the VERT MODE switch to the ADD State The displayed signal is the difference between CH 1 and CH 2 signals if the Ch2 INV push switch is enga
12. CHI CHI single channel CH2 CH2 single channel DUAL CHI1 and CH2 are displayed ALT or CHOP selectable at any sweep rate ADD CH1 CH2 algebraic addition Chopping repetition frequency Approx 250KHz Input coupling AC GND DC Maximum input voltage 400V DC AC peak AC frequency IKHz or lower When set probe switch atl 1 the maximum effective readout is 40Vpp 14Vrms at sine wave or set probe switch at 10 1 the maximum effective readout is 400Vpp 140Vrms at sine wave Common mode rejection ratio 50 1 better at 50KHz sinusoidal wave When sensitivities of CH 1 and 2 set equally Isolation between channels At 5mV DIV range gt 1000 1 at SOKHz gt 30 1 at 1ISMHz 23071 at 25MHz gt 30 1 at35 MHz gt 30 1 at 45 MHz CH2 INV BAL Balanced point variation lt 1 DIV Reference at center graticule MODEL SPECIFICATIONS 20 MHz OSCILLOSCOPE 30MHz OSCILLOSCOPE 40MHz OSCILLOSCOPE 50MHz OSCILLOSCOPE Triggering source CH2 LINE EXT CH 1 and CH 2 canbe selected only when the vertical mode is DUAL or ADD In ALT mode if the TRIG ALT switch is pushed in itcan be use for alternate triggering of two different source Coupling AC 20Hz to full bandwidth Slope Sensitivity 20Hz 2MHz 0 5DIV TRIG ALT 2 DIV
13. Dual Trace Oscilloscope USER MANUAL II CONTENTS PAGE INCID 1 1 1 Description Pa 1 2 Features ii 2 TECHNICAL SPECIFICATIONS eene nnns nns enne 2 3 PRECAUTIONS BEFORE OPERATING THE OSCILLOSCOPE 20222222 3 1 Unpacking the Oscilloscope 3 2 Checking the Line voltage 3 3 Environment cone cone nace Seem cane cone cane cene ance cone nmn anne nnm on 3 4 Equipment Installation and Operation e 3 5 CRT Intensity nce mM MM 4 1 Introduction of Front 10 4 2 Introduction of Rear 1 4 3 Basic Operation Single channel Operation 4 4 Dual Channel Operation e e e eee 16 4 5 ADD e 17 4 6 Triggering 4 7 TIME DIV control 4 8 Sweep Magnification 4 9 X Y 3 4 10 Calibration of Probe sl _ 4 11 D
14. EXT 200mV 2 20MHz 1 5 DIV 20 30MHz 2 5 DIV 30 40MHz 3 0 DIV 40 50MHz 3 0 DIV O TRIG ALT 3DIV EXT 800mV TV Sync pulse more than 1 div EXT 1 V Si Triggering modes AUTO Sweeps in the free mode when no triggering input signal is applied O Applicable for repetitive signals of frequency 25Hz or over 7 NORM When triggering signal is applied the trace is in the ready state and not displayed TV V This setting is used when observing the entire vertical picture of television signal TV H This setting is used when observing the entire horizontal picture of television signal Both TV V and TV H synchronize only when the synchronizing signal is negative EXT triggering signalinput Inputimpedance Approx IM ohm approx 25 pF Max Input voltage 400V DC AC peak AC Frequency not higher than IKH z Sweep time 0 2 uSec 0 5 Sec DIV 20steps in 1 2 5 sequence a Sweep time accuracy 4 3 10 C 35 2 Vernier sweep time control lt 1 2 5 of panel indicated value Sweep magnification 10 times N c lt x10MAGsweeptimeaccuracy 5 20nSec 50nSec are uncalibrated 9 Linearity 5 10 0 2s and lus Position shiftcausedby xIOMAG Within 2 DIV at CRT screen center Sensitivity Same as vertical axis X axis CH l input signal Y axis CH 2 input signal XY Frequency bandwidth DC to at least 500 KHz MOD X Y phase difference lt 3 at DC 50 KHz SPECIFICATIONS MODEL 20MHz OSCILLOSCOPE 30MHz OSCI
15. EXT TRIG IN input signal CH l When the VERT MODE switch 14715 setin the DUAL or ADD state select CH 1 for the internal triggering source signal CH2 When the VERT MODE switch 14 is setin the DUAL or ADD state select CH 2 for the internal triggering source Signal LINE To select the AC power line frequency signal as the triggering signal EXT The external signal applied through EXT TRIG IN input terminal 25 is used for the external triggering source signal TRIG Lud 28 When the VERT MODE switch 14 is setin the DUAL or ADD state and the SOURCE switch 24 is selected at or CH2 with the engagement of the TRIG ALT switch 28 it will alternately select CH 1 amp CH 2 for the internal triggering source signal selectthe triggering slope Triggering occurs when the triggering signal crosses the triggering level in positive going direction Triggering occurs when the triggering signal crosses the triggering level in negative going direction 12 LEVEL 29 To display a synchronized stationary waveform and set a start point for the waveform Towards The triggering level moves upward on the display waveform Towards The triggering level moves downward on the display waveform TRIGGER MODE 26 Select the desired trigger mode AUTO When no triggering signal is applied or when triggering signal frequency isless than 25Hz sweep runs in the free run mode NORM
16. LLOSCOPE 40MHz OSCILLOSCOPE 50MHz OSCILLOSCOPE Waveform Positive going square wave Frequency Approx 1 kHz CALIBEATION Duty ratio Within 48 52 VOLTAGE Output voltage 2Vp p 2 Output impedance Approx 1K ohm Type 6 inch rectangular ty pe internal graticule Phosphor P31 CRT Acceleration voltage Approx 2kV Approx 2kV Approx 12 kV Approx 12 kV Effective screen size 8x10 DIV 1 DIV 10mm 0 39in Graticule Internal Trace rotation Provided 25MHz OSCILLOSCOPE Operating Environment Frequency bandwidth DC 25MHz Indoor use 5 Rise time Approx 15 3nS Altitude up to 2000m 3 Isolation betw h 1 21000 50 Ambient temperature solation between channels a 2 To satisfy specifications 10 to 35 C 50 to 95 F gt At SmV DIV range 730 1 at 20MHz Maximum operating ranges 0 to40 C 32 to104 F Relative humidity 75 RH max non Condensing Installation Category II Pollution degree 2 Line Power Requirements Voltage AC 110V 220V 10 Note AC110V needs to prearrange to my factory Frequency 50Hz or 60 Hz Power consumption Approx 40VA 35W max Storage Temperature amp Humidity Accessories Power cord 10 to 70 C 70 RH maximum Mechanical Specifications Dimensions 310 Wx150Hx 455 D mm Weight Approx 8kg 17 61bs 3 PRECAUTIONS BEFORE OPERATING THE OSCILLOSCOPE 3 1 Unpacking the Oscilloscope The oscilloscope is shipped from the factory after being fully inspected and tested
17. TATION control adjustable by screwdriver 4 Connect the probe to the CH 1 INPUT terminal and apply the 2Vp p CALIBRATOR signal to be probe tip 5 Set the AC GND DC switchto the AC state Awaveformasshown in the figure 4 3 Will be displayed on the CRT screen 6 Adjust the FOCUS control so that the trace image appears sharply 7 For signal viewing set the VOLTS DIV switch and TIME DIV switch in appropriate positions so that signal waveform is displayed clearly 8 Adjust the AYPOSITION and 4 POSITION controls in appropriate positions so that the displayed waveform is aligned with the graticule and voltage V p p and period T can be read conveniently Figure 4 3 The above are the basic operating procedures ofthe oscilloscope It is for single channeloperation with Chl Single channel operation with CH2 can also be achieved ina similar manner Further operation methods are explained in the subsequent pages 4 4 Dual channel Operation Change the VERT MODE switch to the DUAL statesso that trace CH 2 isalso displayed The explanation in the proceeding sectionis of CH1 At this state of Procedure the CH ltrace is the square wave of the calibrator signal and the CH 2 trace is a straight line since no signal is applied to this channel yet Now apply the calibrator signal to the vertical input terminal of CH 2 with the probe as isthe case for
18. When no triggering signal is applied sweep is in a ready state and the trace is blanked out Used primarily for observation of signal 25Hz TV V This settingis used when observing the entire vertical picture of television signal TV H This setting is used when observing the entire horizontal picture of television signal Both TV V and TV H synchronize only when the synchronizing signalis negative FAMILY 33 Display a synchroninzde signal frequency models have this function only 13 Time Base TIME DIV 30 Sweep time ranges are available in 20 steps from 0 2 uS DIV to 0 5 S DIV X Y This position is used when using the instrument as an X Y oscilloscope SWP VAR 31 Vernier control of sweep time This control works as CAL sweep time is calibrated to the value indicated by TIME DIV of weep can be varied continuously when Shaft is out of CAL position Then the control is rotated in the direction of arrow to the full the CAL state is produced and the sweep time is calibrated to the value indicated by TIME DIV Counterclockwise rotationto the full delays the sweep by 2 5 time or more 10 22 2 32 Horizontal positioning control of the trace or spot Others GND 15 AC Power input connector 39 AC Power input socket Connect the AC power cord supplied to this connector 14 16 4 3 Basic O per
19. ation Single channel Operation Before connecting the power cord to an AC line outlet make sure that the voltage selector on the rear panel of the instrument is correctly set forthe AC line voltage After ensuring the voltage setting Set the switches and controls of the instrument as shown below Item No Setting POWER 6 Disengage position OFF INTEN 2 Mid position FOCUS 3 Mid position VERTMODE 14 CHI ALT CHOP 12 Released ALT CH 2INV 16 Released POSITION 11 19 Mid position VOLTS DIV 7 22 0 5V DIV VARIABLE 9 21 CAL clockwise position AC GND DC 10 18 GND SOURCE 24 CHI Item No Setting SLOPE 27 TRIG ALT 28 Released TRIGGER MODE 26 AUTO TIME DIV 30 0 5mSec DIV SWP VER 31 CAL position lt gt POSITION 34 Mid position X10 MAG 32 Released LEVEL 29 Locked After setting the switches and controls as mentioned connect the power cord to the AC line outlet and then continue as follows 1 Engage the POWER switch and make sure that the power LED is turned on In about 20 seconds a trace will appear on the CRT screen If no trace appears in about 60 seconds counter check the switch and control setting 2 Adjust the trace to an appropriate brightness and image with the INTEN control and FOCUS control respectively 15 3 Align the trace with the horizontal center line of the graticule by adjusting the POSITION control and TRACE RO
20. during the magnification operation is as follows Value indicated by TIME DIV switch x1 10 Pa _ Thus the unmagnified maximum sweep speed luSec DI V can be increased Any part can be covered by means of POSITION control luSec DIV x 1 10 100 nSec DIV Figure 4 7 wi th the magnification as follows 4 9 X Y Operation Y axi s CH2 Set the TIME DIV switch to X Y position Then the instrument works as an X Y oscilloscope Each input is applied to the instrument as follows X axis CH1 X axis signal horizontal axis signal CH 1 INPUT Y axis signal vertical axis signal CH 2 INPUT Note When high frequency signals are displayed in the X Y operation pay Figure 4 8 attention to the frequency bandwidths and phase difference between X and Y axis X Y operation permits the oscilloscope to perform many measurements not possible with conventional sweep operation The CRT display becomes an electronic graph of two instantaneous voltages The display may be a direct comparison of the two voltages such as a vector scope display of video color bar patterns However the X Y mode can be used to graph almost any dynamic characteristic if a transducer is used to change the characteristic frequency temperature velocity etc into a voltage One common applicationis frequency response measurements where the Y axis corresponds to signal amplitude and the X axis corresponds
21. ged For accurate addition or subtraction it is a prerequisite that the sensitivities of the two channels are adjusted accurately at the same value by means of the VARIABLE knobs Vertical positioning can be made with the AV POSITION knob of either channel In view of the linearity of the vertical amplifiers itis most advantage to set both knobs in their mid positions 4 6 Triggering Proper triggering is essential for efficient operation of an oscilloscope The user must be thoroughly familiar with the triggering functions and procedures 1 Functions of MODE switch AUTO Whenthe AUTO switch is engaged automatic sweep operation is selected in automatic sweep operation the sweep generator free runs to generate a sweep without a trigger signal However it automatically switches to triggered sweep operation if an acceptable trigger source signal is present The AUTO position is handy when first setting up the scope to observe a waveform It provides sweep for waveform observation until other controls can properly set Once the controls are set operation is often switch back to the NORM triggering mode since itis more sensitive Automatic sweep must be used for DC measurements an signals of such low amplitude that they will not trigger the sweep 17 NORM The NORM switch provides normal triggered sweep operation The sweep remains at rest until the selected trigger source signal crosses the threshold level set by the TRIG LEVEL control The tri
22. gger causes one sweep to be generated after which sweep again remains at rest until triggered In the NORM position there will be no trace unless an adequate trigger signal is present Inthe ALT mode of dual trace operation with NORM sweep selected there will be trace unless both channel land 2 signals are adequate for triggering TV V Setting the MODE switch to the TV V position permits selection of vertical sync pulses for sweep triggering when viewing composite video waveforms Vertical sync pulses are selected as trigger to permit viewing of vertical fields and frames of video A sweep time of 2 ms DIV is appropriate for viewing fields of video and 5ms DIV for complete frames two interlaced fields of video TV H Setting the MODE switch to the TV H position permits selection of horizontal sync pulses for sweep triggering when viewing composite video waveforms Horizontal sync pulses are selected as trigger to permit viewing of horizontal fields of video A sweep time of about 10us DIV is appropriate for displaying lines of video The SWP VAR control can be set to display the exactnumber of waveforms desired This oscilloscope synchronizes with only polarity that is the sync pulses are negative and the video is positive as shown in Figure 4 5 2 Functions of SOURCE switch The displayed signal itself or a trigger signal which has a time relationship with the displayed signal is required to be applied to the trigger circuit to display a
23. input coupling switches of CH1 and CH2 to GND and set the TRIG MODE to AUTO Then position the Base line to the center 2 Turn the VLOTS DIV switch to 5m V 10mV and adjust so that the line does not move 22 5 MAINTENANCE WARNING The followinginstructions are for use by qualified personnel only To avoid electrical shock do not perform any servicing other than in the operating instructions unless you are qualified to do so 5 1 Fuse Replacement If the fuse blows thepowerlampindicatorswillnotlightandthe oscilloscope will not operate The fuse should notnormally open unless aproblem has developedinthe unit Try to determine and correct the cause of the blown fuse The replace only witha fuse of the correct ratingandtype see page 5 The fuse is located on the rear panel see fig 4 2 WARNING Forcontinued fire protection Replace fuse only with 250V fuse of the specified type and rating and disconnect power cord before replacing fuse 5 2 Cleaning To clean the oscilloscope use a soft cloth dampened in a solution of mild detergent and water Donot spray cleaner directly on to the oscilloscope because it may leak into the cabinet and cause damage Do not use chemicals containing benzine benzene toluene xylene acetone or similar solvents Do not use abrasive cleaners on any portion of the oscilloscope 23 6 Component Test Operation Only Type The component test board delivers a sine voltage 50Hz or 60Hz
24. n high intensity type with a high acceleration voltage of 2K V for 20MHz 25MHz 30MHz and 12 for 40MHz 50MHz It displays clear readable traces even at high sweep speeds 2 A trigger level lock function which makes the triggering adjustment unnecessary 3 Alternate triggering Even an observation of two waveforms of different frequencies the waveform of the each channel is stably triggered 4 TV sync triggering The oscilloscope has a sync separator circuit for triggering of TV V and TV H signals 5 X Y operation Set the switchto X Y Then the instrument works as an X Y oscilloscope can be applied as horizontal deflection X axis while CH2 provide vertical deflection Y axis 2 TECHNICAL SPECIFICATIONS VERTICAL AXIS SPECIFICATIONS MODEL 20MHz OSCILLOSCOPE 30MHz OSCILLOSCOPE 40MHz OSCILLOSCOPE 50MHz OSCILLOSCOPE Sensitivity SmV 5V DIV 10 steps in 1 2 5 sequence Vernier Vertical sensitivity To 1 2 5 orless of panel indicated value Frequency bandwidth DC 20MHz DC 30MHz DC 40MHz DC 50MHz AC coupling Low limit frequency10Hz With reference to 100KHz 8DIV Frequency response with 3dB Rise time Approx 17 5nS Approx 11 7nS Approx 8 75nS Approx 7nS Input impedance Approx 1M ohm Approx 25 pF DC balance shift Adjustable on panel Linearity lt 0 1 DIV of amplitude change when waveform of 2 DIV atgraticule center is moved vertically Vertical modes
25. stationary signal on the CRT screen The SOURCE switch is used for selecting such a triggering source Figure 4 5 CHI CH2 The internal trigger method which is used most commonly The signal applied to the vertical input terminal is branched off from the preamplifier and is fed to the trigger circuit through the VERT MODE switch Since the triggering signal is the measured signal itself astable wavefrom can be readily displayed on the CRT screen When in the DUAL or ADD operation the signal selected by the SOURCE switch is used as the triggering source signal 20 Line The AC power line frequency signal is used as the triggering signal This method is effective when the measured signal has a relationship with the AC line frequency especially for measurements of low level AC noise of audio equipment thyristor circuits etc EXT The sweep is triggered with an external signal applied to the external trigger input terminal An external signal which has a periodic relationship with respect to the measured signal is used Since the measured signal is not used as the triggering signal the waveforms can be displayed more independent than the measured signal 3 Functions of TRIG LEVEL control and SLOPE switch A sweep trigger is developed when the trigger source signal crosses a preset threshold level Rotation of the TRIG LEVEL control varies the threshold level Inthe direction the triggering threshold shifts to a more positive value and in the
26. uipment may be impaired 3 5 CRT Intensity To prevent permanent damage to the CRT phosphor do not make the CRT trace excessively bright or leave the spot stationary for an unreasonably long time 3 6 Withstanding voltages of Input Terminals The withstanding voltages of the instrument input terminals and probe input terminals are as shown in the following table Do not apply voltages higher than these limits When set probe switch at 1 1 the maximum effective readout is 40Vpp 14Vrms at sine wave When set probe switch at10 1 the maximum effective readout is 400 Vpp 140 Vrms at sine wave Input terminal Maximum input voltage e CAUTION To avoid instrument damage CHI CH2 inputs 400V DC AC peak EXT TRLGIN input 400 V DC AC peak i a A Probe inputs 600 V DC AC peak 9 frequencies less than 1 KHz If an AC voltage which is superimposed ona DC voltage is applied the maximum peak value of CH land CH2 input voltages must not exceed or 300V So for AC voltages with a mean value of zero volt the maximum peakto peak value is 600V Figure 4 1 OSCILLOSCOPE TRIGGER fe MODE SOURCE Li CH1 cH2 LINE EXT NS X10 MAG TRIG IN 4 POSITION gt 1M0 25pF VOLTS DIV
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