need help on oversampling converters

Discussion in 'General Electronics Chat' started by xljin2014, Apr 5, 2015.

  1. xljin2014

    Thread Starter New Member

    Nov 11, 2014
    15
    0
    hi, friend,

    i am totally lost on oversampling coverters, i don't understand how the convertion works, even the goodness is totally unknown to me, so can anyone tell me in brief how it works out? and about the goodness of it is even better,

    thx
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,055
    3,245
    Are you referring to Delta-Sigma type converters?
     
  3. xljin2014

    Thread Starter New Member

    Nov 11, 2014
    15
    0
    yes, i guess so,
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,055
    3,245
    Delta-sigma Analog-Digital converters take many coarse samples of the analog signal (often only with 1-bit resolution) for each desired digital sample word.
    The average value of these digital samples equals the analog value.
    These 1-bit digital samples are averaged with a digital filtered to generate a high resolution digital word.
    The more samples that are averaged, the higher the resolution of the digital sample word. For example, a Delta-sigma converter may take more than 100 samples (a factor of 100 oversample rate) to get a digital word of 20 bit accuracy.

    Some advantages of a Delta-Sigma converter are:
    Digital averaging allows accuracy higher than can be obtained with other types of A/D converters.
    High oversample rate eliminates the need for high order anti-alias analog filters at the A/D input to prevent out of band noise from appearing in the sample. This noise can now be filtered by an internal digital filter.

    A disadvantage is, due to the high oversample rate, the the Delta-Sigma is only practical for lower frequency analog signals (generally no higher than mid audio frequencies).
     
  5. Gibson486

    Member

    Jul 20, 2012
    199
    12
    What crutschow said!

    I have used them in the past. The best thing about them is is the digital averaging. It usually eliminates the need for lots of external filters. Instead, you are good with a simple RC filter and you can call it a day.
     
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