how do you detect spikes?
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From: Luna Moon on 11 Jun 2010 14:12 Hi all, I have very spiky signals. Visually it's very easy to detect spikes, but how do I detect spikes in a computerized appraoch? thanks a lot!
From: Jerry Avins on 11 Jun 2010 14:23 On 6/11/2010 2:12 PM, Luna Moon wrote: > Hi all, > > I have very spiky signals. Visually it's very easy to detect spikes, > > but how do I detect spikes in a computerized appraoch? Peak detect? Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
From: Walter Roberson on 11 Jun 2010 14:23 Luna Moon wrote: > I have very spiky signals. Visually it's very easy to detect spikes, > > but how do I detect spikes in a computerized appraoch? Visually it isn't easy to detect spikes, because there is no fixed definition for when a "spike" becomes a "peak" or when multiple local maxima close together are multiple spikes, vs regular noise on the system response to a spike, vs regular noise on a spike that is out of phase, vs regular noise on a peak, vs regular noise on a peak that is out of phase, vs regular noise on a peak that is broadened because the sampling rate is not high enough, vs ... If you have an out-of-phase peak and a spike close to it that goes higher, or noise on the peak measurement that takes the reading higher, then many humans would place the peak maximum at the higher point instead of recognizing that the energy absolute magnitude would be higher if you were to do phase correction for the smaller peak. These difficulties for humans (which are inherent in the vague meaning of "spike") make it difficult to write a robust spike detection algorithm. Did the reading reach 255 because the signal reached 255, or did the reading reach 255 because from time to time a spike caused by system response to a floating line forced the data lines low and "low" in the signal encoding happens to correspond to binary 1?
From: Luna Moon on 11 Jun 2010 15:08 On Jun 11, 2:23 pm, Walter Roberson <rober...(a)hushmail.com> wrote: > Luna Moon wrote: > > I have very spiky signals. Visually it's very easy to detect spikes, > > > but how do I detect spikes in a computerized appraoch? > > Visually it isn't easy to detect spikes, because there is no fixed definition > for when a "spike" becomes a "peak" or when multiple local maxima close > together are multiple spikes, vs regular noise on the system response to a > spike, vs regular noise on a spike that is out of phase, vs regular noise on a > peak, vs regular noise on a peak that is out of phase, vs regular noise on a > peak that is broadened because the sampling rate is not high enough, vs .... > > If you have an out-of-phase peak and a spike close to it that goes higher, or > noise on the peak measurement that takes the reading higher, then many humans > would place the peak maximum at the higher point instead of recognizing that > the energy absolute magnitude would be higher if you were to do phase > correction for the smaller peak. > > These difficulties for humans (which are inherent in the vague meaning of > "spike") make it difficult to write a robust spike detection algorithm. Did > the reading reach 255 because the signal reached 255, or did the reading reach > 255 because from time to time a spike caused by system response to a floating > line forced the data lines low and "low" in the signal encoding happens to > correspond to binary 1? Let's say you are monitoring the measurement online and continuously the measurements come in, how do you say hey here is a spike occurred, we need to raise an alert... What's the best way to do this? Thank you!
From: Vladimir Vassilevsky on 11 Jun 2010 15:10 Luna Moon wrote: > Hi all, > > I have very spiky signals. Visually it's very easy to detect spikes, > > but how do I detect spikes in a computerized appraoch? > > thanks a lot! Cretin!
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