Tim Wescott skrev:
> > Why would EKG recorders be especially problematic? If they are, then
> > maybe EEG and polygraph recorders too?
>
> AFAIK they aren't especially problematic, it's just one that I'm
> familiar with being an issue -- goodness knows why,

I once attended a conference on DSP where somebody presented
some scheme for processing EKG (that's the heart monitor, right?)
signals.

According to that presentation, ringing and transients are severe
issues since physicians inspect the transient characteristic of the
heartbeat in order to come up with a diagnostics. Any transient
that is not "natural" (i.e. does not conform with text-book
descriptions of normal heartbeat behaviour) is, by necessity,
interpreted as an indicator of some non-healthy condition.
It would be very, very dangerous to meddle with these
systems such that the sensor system somehow alters
the transient shape of the signal.

Rune