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
    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
    JohnInTX likes this.
  3. Sensacell


    Jun 19, 2012
    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
    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.