One good reason: On the Aspect 3000, SIM does not work with
16 bit digitizer resolution (DR=16) --- this is related to the fact
that
the A3000 uses a 24-bit word in memory, and you need two 16 bit spots
in
memory simultaneously to run SIM mode (if my non-digital memory serves
me right, and my math that 2*16 > 24 :) ). From local word of mouth
and rough testing done on an AM500, this problem can be seen
manifesting
itself in some intriguing baseline artifacts. According to some Bruker
tech support folks, SIM apparently works fine with DR=12 although this
puts a fair number of interesting experiments needing high DR out of
reach (e.g. nat'l abundance 13C/15N expts, looking at 1H spectra in
H2O, etc). I wholeheartedly sympathize with your concerns, on both
practical and theoretical grounds --- does anyone know if this has been
cured in the more recent generations of machines/computers from
Bruker?
Kevin
-- ************************************************************************* Kevin Gardner Yale University Dept. of Molecular Biophysics and Biochemistry Internet: gardner@zinc.csb.yale.edu Bitnet: gardner@yalemed