| 摘要 |
An ultrasonic locationing system using a dual phase pulse includes an emitter emitting two consecutive frequency bursts, each having a different phase, within one ultrasonic pulse. A receiver microphone receives the ultrasonic pulse, and a processor runs an amplitude-based detection algorithm on the pulse for a band of frequencies of interest and detects a first burst of the pulse within the proper frequency band and having an amplitude exceeding a threshold. Whereupon, the processor determines a relative phase difference between the first burst and a second burst of the pulse and determines whether the relative phase difference is within a predetermined acceptance window, indicating that the pulse is valid for use in locationing the emitter and associated mobile device. |
