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Oscilloscope for verifying pixel clock rate?

Discussion in 'Handy Tools & Equipment' started by BradsXmasLights, Apr 17, 2013.

  1. BradsXmasLights

    BradsXmasLights WiFi Interactive

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    After the hassles I've had in the past with finding the correct clock rates for my pixels, I've been thinking maybe an getting an Oscilloscope would come in handy for verifying signal actual integrity.

    At the moment I know flickering at low brightness means the clock is too slow; and high brightness flicking means it's too fast. But getting the sweet spot has been a bit of guess work + trial & error. This has me thinking that maybe with the assistance of a scope I'll be able to get a faster idea of the correct clock by visually seeing how the data waveform is.

    Am I correct in assuming this?

    If so, what scope should I get? I am deciding between these two...EEVblog #451 - Rigol DS1052E vs DS2072 Oscilloscope
     
  2. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    Im wondering why your finding it so hard to get a stable signal to warrant buying a scope.

    What pixels are you using and what is the distance of the run, and how are you injecting your power


    Flickering of lights can mean ground loop issues so i would be looking at that first.

    But if its 2811 you are using they should happily run with +/- 250 variation in most cases.
     
  3. OP
    OP
    BradsXmasLights

    BradsXmasLights WiFi Interactive

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    Mostly 2811, but some legacy 6803 too. Distances vary, and I also use the J1SYS extenders.

    I guess, I'm hoping a scope will tell me that the signal is OK at pixel 1 before any possible other issues like string voltage drop are introduced down the track.
     
  4. fasteddy

    fasteddy I have C.L.A.P Global Moderator Generous Elf

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    I think your looking for an excuse to buy yourself a new toy :D

    All i can say is the higher the frequency/sampling rate the better
     
  5. anon

    anon Apprentice Elf

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    Sounds like you need a Fluke ;)


    I think smartalec has this:


    http://www.ebay.com.au/itm/Mini-Storage-Digital-Oscilloscope-Handheld-Scope-ARM-DSO203-Nano-Portable-Kit-/130885392451?pt=AU_B_I_Electrical_Test_Equipment&hash=item1e79609843&_uhb=1


    Nice and portable too so you can trouble shoot when everything is setup. It won't set records with 72MHz sampling, but should do.


    Check your multimeter to see if it has a frequency function too, while it's not as confidence inspiring with only giving a number, it should work at a pinch.
     
  6. OP
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    BradsXmasLights

    BradsXmasLights WiFi Interactive

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    haha how did you guess Eddy that I'm going to buy a scope either way :D

    That pocket scope looks alight on paper but this guy doesn't sound too crash hot according to this review...
    Scope review. DSO 201 nano & DSO203 Quad
     
  7. anon

    anon Apprentice Elf

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    It's not going to be great for the price, but at the price point it's pretty good. It's 72MHz sampling so not surprising it will only be good up to 2MHz for a detailed waveform. But it depends on an the application, if you want to see detailed wave forms and noise that it needs to be a lot better, but if you just need to see frequency then it you just need to see a bump :)
     
  8. smartalec

    smartalec Im a SmartAlec what can i say! Community Project Designer

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    I wish i had that.. thats a sweet toy

     
  9. anon

    anon Apprentice Elf

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    Oh, though I remember you talking about this in the chat once, perhaps it was someone else :)
     
  10. mangoat

    mangoat Full Time Elf

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    i have a tpi440 scope i use for tuning audio systems :) its a scope, digital multimeter, all the good stuff :)
     

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