NuAmps drops samples

[Peter Quain]

Anyone out there using E-Prime with NuAmps?

We've discovered that our NuAmps seems to be randomly dropping 
samples in what looks predominantly to be 11-12ms chunks, with 
another distribution around 36ms. The diagnostic paradigm (in 
E-Prime) runs trials and sends TTL pulse every 3600ms. Over 20 runs, 
of varying length (40, 130, or 310 trials) totalling 3000+ trials, 
4.1% exhibited sample drop > 9ms between successive pulses. This also 
happens, same basic pattern, using different computers to control the 
acquisition so unlikely to be PC related on the NuAmps side. The 
stimulus presentation computer appears to behave perfectly.

Has anyone else identified a similar issue, or might it just be our 
unit / system?? No word back yet from Neuroscan on what the problem might be.

Peter


Peter Quain
School of Psychology
University of New England
Armidale, Australia, 2351
Phone:  02 6773 5193
Fax:      02 6773 3820