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  1. #1
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    Limitations of analog signal processing

    The book says

    In analog signal processing as compared to digital signal processing, dynamic range for voltage and currents are limited"

    plz explain

    •   Alt13th February 2011, 11:40

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    Re: Limitations of analog signal processing

    In DSP you can just add bit-width (trading speed, power, area) and get any
    precision you like, with accuracy limited only by the input SNR.

    In analog every stage has a noise contribution, as well as built-in errors of
    some size (designed against but never zero). Against a fixed voltage headroom
    and a likely lesser common-mode range, this presents a fundamental dynamic
    range (differential voltage range being 2*VDD, max, against an equivalent
    noise and error voltage sum) limit.

    Of course similarly to DSP, you can improve the noise and error terms at the
    cost of area, speed, power, complexity. But there is more of a "wall" (or a
    hill of ever-increasing slope) that simply throwing gates at the problem,
    will not get you over.

    On the other hand I see people trying to read a thermocouple with 24-bit
    ADCs and wonder if they really understand what matters.



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