Oscilloscope Bandwidth!

Myauk · 2007-01-04T07:10:00+00:00

Can anybody tell me the highest frequency that can be measure with theoscilloscopes these days.As far as I have known, it is about 1GHz I think.How will they capture of the waveforms of the clock signals formicroprocessor?How can we measure the characteristics of the waveforms in High SpeedCircuits.There are many application notes but still I need some initiatives.I think the highest clock speed is about 4GHz.Regards

Jan 04, 2007 24 Replies

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Myauk 19 years ago

One question, again!

I measured the composite video signal by setting the display to PM5644 test card. The problem is that although setting to time/div = 5,10,20 micro second, volt/div = 200, 500 milli volts, and trigger values around 40,

344,420 and -100 milli volts, I just could not get the stable captured waveform. (colour burst was clearly seen in each wave from, but there are several different patterns displayed every time I pressed the RUN/STOP button.). Isn't it normal? I am using TDS 744A 500 MHzz Tektronix oscilloscpe. More over I would like to have the best possible settings for measuring Y Pb Pr and S Video Y, C signals. Can anybody share me the links for example measurement of those video signals? Or some example waveforms. I have some measured waveform but still I would like to have more just for knowledge.

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Peter Bennett 19 years ago

It is normal to see a "mess" during the "active picture" portion of the scan line, as you are looking at all scan lines at once. If, instead of the PM5644 test signal, you look at a colour bar or gray scale test signal, the active portion of the video signal will make more sense.

To see these signals independently, you would have to look somewhere within the equipment where they exist as independent signals. It sounds like you are looking at a composite video signal at present - a normal oscilloscope can't isolate the individual colour components in that signal.

Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca new newsgroup users info : http://vancouver-webpages.com/nnq GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca

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Myauk 19 years ago

Actually I am measuring different outputs, not isolating them from CVBS. The outputs I am going to measure are YPbPr, S Video, and Composite Video Outputs from a DVD Player. Is there any test discs available in the market for colour bar output?

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joseph2k 19 years ago

In your position i would just record one. But i may be wealthier than you.

JosephKK Gegen dummheit kampfen die Gotter Selbst, vergebens. --Schiller

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Myauk 19 years ago

Thank you very much for all your answers and encouragements. Now I am working well with my measurements. I have almost finished reading XYZ of oscilloscope to understand more about digital oscilloscopes. And I found the required PAL and NTSC Test Discs for my wave form measurement. I also found the complete list of test patterns for NTSC and PAL at

formatting link

Without the discussion this group, I would not be able to do this that fast for my first measurements. I am now quite motivated to buy an oscilloscope very soon. :) Best Regards

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