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Shay wrote:
> I study Sigma-delta data converters. Sigma-delta is a specific type of
> architecture that works well for 16 to 24-bit applications like audio. A
> data converter is a specific type of integrated circuit (IC) that
> converts analog signals to or from digital signals.
IIRC, this involves generating a pulse train from an analogue signal.
This train consists of negative and positive pulses in such a way that
if you average them together, you get the original signal. But actually
to make the converter, you send the pulses to a counter, which then
converts them into normal binary numbers.
(The pulse train itself has the desirable property that all the pulses
are "equal". In other words, unlike a binary signal that has a most
significant bit and a least significant bit, and you need to know which
bits those are, the pulse train doesn't require any such synchronisation.)
The DSP book I read had a whole chapter on A/D and D/A conversion.
Apparently A/D conversion actually works better if you deliberately add
a tiny amount of noise. (For the same reason that POV-Ray purposely adds
sampling jitter to the antialias pass.)
> The big areas of research in this field are (1) lower power and (2)
> migrating technologies.
Makes sense...
> In my opinon, data converter design is one the most difficult aspects of
> IC design. A good designer has to know analog circuits, digital
> circuits, signal-processing, and sensors/transducers. And as long as
> innovative designs are required, there will be good jobs for high
> quality engineers.
Heh. It's well beyond my field... ;-)
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