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  1. C

    USB noise in ADC readings?

    Paul: I am already re-wired for the external ADC but I will whip up some battery packs and try that out, thanks for the advice. In the final deployed configuration there is only one battery pack though. I will talk to the EE about it, see what he thinks. I am just curious at this point, and it...
  2. C

    USB noise in ADC readings?

    I figured it would be unlikely to drop packets over USB, so maybe the buffer is losing samples? in the single buffer setup some samples could be overwritten during a write if it is going really fast. Theoretically if I am getting evenly spaced samples at 96ksps (as I can see on my scope) and all...
  3. C

    USB noise in ADC readings?

    UPDATE: USB noise still present, in fact with the new code it seems to present itself as a constant hum at 3kHz, 6kHz, 9kHz, 12kHz... etc when I look at spectogram in audacity. Probably due to a ton of small writes versus a bunch all at once a few times a second. Still not sure why the USB would...
  4. C

    USB noise in ADC readings?

    Holy cow, your code is great. The IDC_ISR runs in 540ns (mine ran in 1.2us) so between that and the interrupt priority I am now sampling at 400ksps! My pie in the sky goal was 300ksps so that is great (the current animal vocalizes at around 150kHz), and gives me hope for my attempts at a tiny...
  5. C

    USB noise in ADC readings?

    AGND is wired to GND (redundant i think), Vin is 4.5V, 3.3V goes to the mic, and AGND to the mic as well. there is a .1uf cap between AGND and 3.3V since there was a small ripple in the teensy voltage when I was troubleshooting this bigger problem. Just tried hooking the mic right into pin 16...
  6. C

    USB noise in ADC readings?

    I will put the code inline next time, just thought it was kind of long :) The USB writes seem to take 2.5us no matter how big a buffer i send it. I don't think I ever tried just sending it exactly 64bytes before, I will experiment with that.
  7. C

    USB noise in ADC readings?

    Everything up to the ADC pins is being designed by another student and it is very nice and shielded. The sensor we are working with now is a hydrophone to record echolocation clicks, but they want it designed very generically so it can be used for other bio-acoustic projects. The other student...
  8. C

    USB noise in ADC readings?

    I am working on a project to collect scientific data from sensors via the ADC, at high sample rates (right now at about 150-160ksps). The data is not being stored on the Teensy, but is being piped into a linux computer for a variety of processing and machine learning tasks. The Teensy is...
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