A/D converters for Mac's

[LOLL at BIOVAX.UCHICAGO.EDU]

Hi folks,
	We're looking for A/D converters so we can use
an oxygen electrode for kinetic measurements with our
Mac.  The demands are not terribly stringent:  We're
looking at measuring input voltages in the 0-1 volt
range with millivolt precision (so 16-bit, I guess)
at sampling rates of 100 Hz or greater over roughly
30 s intervals.  Ideally, we'd like something where
we can then (in a user-friendly manner) subject the
raw voltage vs. time data to simple manipulations:
background subtractions, smoothing, derivative 
calculation, etc.
	We've found a few systems that will indeed
do this, but they all represent serious overkill, 
and cost in the ballpark of $3K.  Does anyone have
any suggestions for something that'll get the 
job done for less?
	Thanks.

Pat Loll
Univ. of Chicago
loll at biovax.uchicago.edu