acquiring >>64K transients on a FID with an AMX
Gerald Pearson (gpearson@umaxc.weeg.uiowa.edu)
Tue, 28 Sep 93 14:49:48 -0500
UXNMR seems to forbid us from adding more than 64K transients to a FID, which
is an inconvenience when fishing for weak signals from compounds with short
T1's. Running N-15 of a paramagnetic sample with a rep time of 150 msec over
a weekend, we wound up acquiring 24 FID's of 65528 scans each, efp'd them, and
added the spectra. (We also haven't been able to coax uxnmr into adding
together more than 2 fid's, but we _can_ add all of the spectra.)
Is there a more graceful way of doing this? On our MSL-300, WM-360, and AC-
300, for example, we would simply set NS=-1 and manually stop the data
acquisition a day or two later with a Ctrl/H. Our AMX-600 has CPU1 (!!!), and
we're running uxnmr 911101.2.
Also, where does the signal averaging take place during data acquisition? Is
it in the 24-bit Aspect 3000 slave processor, or in the 32-bit X-32? In other
words, does the FID overflow at 24 bits or 32?
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Gerald A. Pearson INTERNET: gpearson@umaxc.weeg.uiowa.edu
Chem. Dept., Univ. of Iowa VOICE: 319-335-1336
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