Beaglebone ADC and other options

Discussion in 'General Electronics Chat' started by BastiaanMDC, Feb 18, 2016.

  1. BastiaanMDC

    Thread Starter New Member

    Oct 27, 2015
    23
    0
    Hello Tinkerers,

    I am having questions and maybe you can shine a light on it/thought on it.

    1 is it possible to attain a 16 bit through oversampling? my signal should be sampled at 1KHz with a beaglebone Black(12Bit)
    2 how noisy is the beaglebone? the arduino Uno is quite noisy over its internal bus, if there are many processes running (RTC, SPI, I2c and 1 Wire)
    3 if I connect the ILI9341 TFT to the beaglebone how much do I deminish my processing time for other processes? (I would like to display in 10ms) delay
    4 if 16 bits is achievable, why not 24 bits or are the requirements (board layout, traces etc pose a problem?)
    5 is the SPI of the beaglebone faster then the ADC with its 200KHz sample rate?
    6 which ADC is the best suited for 1ms signals with 1.8V Vpp, less noise.
    7 I would like to record also 2 Thermocouple with an AD595A over an ADC
     
  2. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    JohnInTX likes this.
  3. Sensacell

    Well-Known Member

    Jun 19, 2012
    1,130
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    The noise performance is going to be horrible.

    The beaglebone is designed as a "do-everything" board, as such, the analog layout of the inputs, grounding etc are not optimized for low noise performance. 16 bits at 1.8 volts = 27 Microvolts!! / Count.

    It takes real effort and significant design chops to get performance at this level.
    You probably need to use an external DAC to have a prayer of getting even close.
     
  4. BastiaanMDC

    Thread Starter New Member

    Oct 27, 2015
    23
    0
    Thanks for the App note:) Ill read it. oversampling can be done but at the cost of processing speed,

    27 uV did you count + the errors from resistors, Opamps and diodes?
    also the ADC has also a certain error factor that reduces the 16bit.
    as a other reason I would like to attain a accurate signal, without loosing that much at high througput.

    I think I am going to hook up a Max1132 single channel, Bipolar input or a LTC2400.
    I think this version is a 18bit one. downgraded to a 16bit.
     
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