# Determine fundamental period from zero crossing signal

I have got a signal which consists of zero crossings over discrete time and I would like to estimate the fundamental frequency (period) from this signal in order to remove noisy samples.

The signal is about 500 to 1500 samples long and has about 10-50 zero crossings, e.g. x[93] = 0; x[183] = 0; x[244]; x[282]; x[310]; x[439]; x[502]; x[515]; x[570]; x[590]; x[640]; x[635]; x[650]; x[710]; x[740]; x[835]; x[850]; x[905]; x[915]; x[980]; x[1050]; x[1110];

The output should be zero crossings again or their fundamental period, but without the "noise". I'm only interested in the position of the "new" zero crossings.

I'm also not quite sure, how to model a zero-crossing signal for further processing.

Thanks for any ideas.

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What kind of signal is it? A sine wave? –  Deve Nov 2 '12 at 10:06
I don't have a signal form, only the zero crossings define my signal –  the_max Nov 2 '12 at 10:07
This question seems to ask the same thing: dsp.stackexchange.com/questions/4886/… –  Deve Nov 2 '12 at 12:23
@the_max: If you don't know the shape of the signal, then it's not possible to determine the fundamental frequency from the zero crossings. You could guess by trying to find repetitive patterns in the periods, but it still wouldn't necessarily be correct. –  endolith Nov 2 '12 at 13:26