78 includes a sequence of a minimum number of segments corresponding to a minimum length of a repetition in the example shown the segments correspond to five seconds of transmission time or transmission interval therefore the diagonal 78 indicates a 15 second transmission other transmission intervals corresponding to an expected duplicate transmission time could be employed such as 20 or 30 seconds described further below the low distance value tier threshold and the minimum number of repeated segments for a match define the granularity of the system as described above the product of the segment size transmission interval and the minimum number of segments gives the minimum duration of a repeated segment found by the system if the segment size is too large the beginning of a repeated segment may not be detected until the following segment and may be missed altogether if there is insufficient overlap similarly if the minimum number of segments is too large a shorter sequence of actual repetition may not be detected possibly from only a portion of an advertisement having been sampled conversely if the minimum number of segments or the segment size are too small repetitions may be indicated from trivial commonalities in each case the low distance tier threshold affects the degree of similarity and therefore the likelihood of a near miss or trivial match and may be employed to tune the sensitivity of.