Kenwood CS-5140 Instruction Manual

5 . Adjust the S W E E P T I M E / D I V control (§) to obtain anappropriate display. Now a normal sweep display is ob-tained.[B] EQUIVALENT SAMPLINGT h e equivalent sampling mode is activated automaticallywhen the S W E E P T I M E / D I V control ' f | is set to the rangebetween 0 . 1 /xs/div and 1 0 /*s/div. When the mode isswtiched from the real-time mode to equivalent samplingmode, the bandwidth is also switched from 4 0 MHz( - 3 dB) to 1 0 0 MHz ( - 3 dB) so that the displayamplitude may vary with higher input signal frequencies.When it is required to observe amplitude variations, fix themode either to the real-time or equivalent sampling mode.With a sampling oscilloscope, different parts of the inputsignal are sampled with certain time differences, and thesignals obtrained are amplified and applied to the verticalamplifier. A t the same time, the time signals correspondingto the sampling time difference are applied to the horizontalamplifier, so that the same image a s the input signal is re-constructed on the display using the t w o types of signals.This s y s t e m therefore necessitates that the input signal is arepetitive waveform, and the repetitions shall continue fora certain period and shall be stable.[2] SWEEP magnification operationMerely shortening the s w e e p time to magnify a portion ofobserved waveform can result in the desired portion disap-pearing off the screen, the desired portion can be displayedwithout such trouble if the sweep magnification feature isused (also refer to " S w e e p Magnification" on page 5 ) .Using the < • POSITION control, adjust the desired por-tion of waveform to the C R T . Pull out the P U L L x 10 MAGcontrol to magnify the display 1 0 times. For this type ofdisplay the sweep time is the S W E E P T I M E / D I V settingdivided by 1 0 .[3] X-Y operationX - Y operation permits the oscilloscope to perform manymeasurements not possible with conventional sweepoperation.Set the T R I G G E R MODE s w i t c h (g) to the X - Y position. Inthis mode, channel 1 becomes the Y axis input and channel2 becomes the X axis input.The X and Y positions are now adjusted using the •POSITION @ and C H 1 • POSITION controls respectively.X and Y sensitivity are set by using the channel 2 and chan-nel 1 V A R I A B L E V O L T S / D I V controls respectively.[41 VIDEO signal observationSetting the C O U P L I N G (§) s w i t c h , to the T V F R A M E or T VLINE position permits selection of vertical or horizontalsync pulses for s w e e p triggering when viewing compositevideo waveforms.T h i s makes stable triggering in video signal observationspossible regardless of the T R I G L E V E L control (£j) .A t most points of measurement, a composite video signalis of the polarity, that is, the s y n c pulses are negative andthe video is positive. In this case, use " — " S L O P E .If the waveform is taken at a circuit point where the videowaveform is inverted, the s y n c pulses are positive and thevideo is negative. In this c a s e , use " + " S L O P E .Fig. 10Fig. 10 s h o w s a case in which a sampling pulse that isdelayed by a specified period from the input signal isgenerated, and the signal held by the sampling pulsebecomes the output signal.In the example s h o w n in this figure, the output signal S Y N Cis 1/12 of the input signal.NOTE: When the input signal frequency is low, the dotsof the waveform observed by equivalent samplingbecome coarse.If triggering is applied incorrectly, the equivalentsampling operation will be abnormal, so that thedisplayed waveform will be totally different fromthe real input signal.16C R T displayHold-off time0 Insufficient hold-off time (2) Insufficient hold-off time( 3 ) Optimum hold-off timeInputSamplingpulseOutput