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Let's say I have a data stream of bits in which I'm attempting to detect a sixteen bit sync pattern (The pattern is FB28 or 1111 1011 0010 1000 in binary, if that matters)

If I allow a one bit error in the pattern to still be considered a match (e.g. EB28), what are the odds of a false positive?

I know that, if I confine the error to a single bit (say the high bit), the odds are 1 in 2^15 (or one in 32768), but if any bit can be in error, is it simply 32768 / 16? Or is it a combination/permutation problem?

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up vote 2 down vote accepted

The number of pattern of 16 bits which differ by a single bit to the given pattern are 16 (one for every bit you can modify). So you have a false positive in $16/2^{16}$ cases.

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Oy, that ugly. Once every 4096 bits. – Robert Harvey Feb 19 '13 at 17:30

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