Rune Allnor wrote:

> 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
>
That is my understanding, too. Come to think of it, I'm not sure if it
would be as much of a case with EEG and polygraph machines, because they
don't have the same sort of sharp transient embedded in bumps the way
EKGs do.

--

Tim Wescott
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