On Oct 13, 6:11=A0am, Randy Yates <ya...@[EMAIL PROTECTED]
> wrote:
....
>
> Note also that a 1-bit quantizer ALWAYS saturates!
an im****tant point to repeat.
because of that and that the quantizer is only one step of what would
be a staircase function if it was more than 1-bit, since there is no
other steps in the staircase, you cannot infer a gain from the slope
of the staircase if you were trying to model the quantizer as an
additive noise source. then it's a little harder to infer the
effective gain of the quantizer (which is something like the mean
absolute value of the input times delta/2, half the step size, divided
by the mean square of the input).
the other im****tant fact to remember is that if you were to put a
linear gain stage (with a positive gain coef) before the 1-bit
quantizer (a.k.a. a comparator), the inherent gain of the comparator
would absorb whatever positive gain you insert. we know this because
we know that the comparator output would be unchanged (still +/- delta/
2). if the inherent gain of the comparator did not absorb any
preceding gain, then the linear model of the delta-sigma modulator
would change (and get better) with increased loop gain. but we know
that increasing the gain there at that part of the loop cannot change
anything.
r b-j
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