This whine can come from devices that use capacitance to sense touch or
pressure. You apply a high-frequency signal to part of the touch-sensitive
gizmo and then you can easily determine when another part of it makes
physical contact. It wouldn't surprise me if the Newton display worked like
this.
Fore more info, do a web search on FAQs for the HP 48G/GX calculators,
as they use this technology for their keypads, as do the "loud" IBM keyboards.
The cool thing about this method is that there doesn't have to be any physical
contact between the parts--you can sense merely the motion. That's why the
HP keypads and the IBM keyboards can last ages and ages, since there are
no switch contacts.
-- David Evans (NeXTMail/MIME OK) dfevans_at_bbcr.uwaterloo.ca PhD Student, Computer/Synth Junkie http://bbcr.uwaterloo.ca/~dfevans/ University of Waterloo "Default is the value selected by the composer Ontario, Canada overridden by your command." - Roland TR-707 Manual-- This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries List FAQ/Etiquette/Terms: http://www.newtontalk.net/faq.html Official Newton FAQ: http://www.chuma.org/newton/faq/
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