Need help with DSO project

Discussion in 'The Projects Forum' started by Slef25, Apr 21, 2012.

  1. Slef25

    Thread Starter New Member

    Apr 21, 2012
    Hi everyone. I'm trying to build a 1Mhz digital storage oscilloscope but having troubles with the clock. I use the arduio uno microcontroller to collect the data and store it but it seems to be too slow for creating the clocks that I need. I am using a 3MSPS serial A/D which requires at least 18Mhz clock and 2Mhz CS clock to satisfy the Nyquist sampling theory, but I had problem to synchronize two external clocks to satisfy this rates. Can anyone recommend how to clock the A/D correctly or and what input circuits I should consider to avoid noise. Or, maybe there is another way of doing this?
  2. panic mode

    AAC Fanatic!

    Oct 10, 2011
    one look at schematic revealed that arduinouno uses 16MHz clock.

    anything serial requires bunch of clock cycles. so you can forget anything above 8MHz (ad that is when your arduino does not do anything else but toggle output).

    you have three options:
    - pick platform with some muscle (MHz)
    - use parallel ADC (so you can transfer byte or word in single clock - downside it uses more pins)
    - use built in ADC instead of external (not sure how fast it is but it may just do the job)

    next thing is storage. where do you plan to store all the data before you can read it from computer?
  3. Markd77

    Senior Member

    Sep 7, 2009
    You could use an SRAM chip connected to the ADC then read back from that. It's complicated but it's a way of getting good speeds without a powerful processor.
    Have a look at the link to the article at the bottom of this page.