Patent ID: 6246322
Filing Date: 2001-06-12
Classification: G01H,G01V,G08B

Abstract:
A missing object locator responsive to an expected humanly-produced actuation sequence of triggering sounds to provide a missing object locator signal in a manner that is free from false alarms in noisy environments, comprising:analog means including a transducer for providing analog signals in response to acoustic energy received by said transducer;discriminator means coupled to said analog means for providing a digital pulse train in response to said analog signals; anda detector providing first and second patterns respectively representative of genuine, actuation and false, noisy sequences coupled to said discriminator means and operative in response to said digital pulse train to compare said first and second patterns to said digital pulse train and to generate said missing object locator signal if said first pattern is detected in said digital pulse train, but, if said second pattern is detected in said digital pulse train at any time prior to detection of said first pattern, said detector is operative to suspend first pattern comparison for an indefinite time, that lasts so long as any pulse train pulses following detection of said second pattern are detected in a predetermined time which is reset each time any pulse train pulses are detected in said predetermined time, and, at the expiration of said indefinite time that expires only when no pulse train pulses are detected in said predetermined time, indicating a period of quiescence for that predetermined time, said detector is operative to resume said first and second pattern and digital pulse train comparison.