Binaural Ultrasound Detector and Imager.
Patent, Filed 15 Feb 90, Patented 26 Nov 91,
DEPARTMENT OF THE NAVY WASHINGTON DC
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This patent discloses a frequency translator which converts inaudible sounds into audible sounds while preserving the phase relationship of the sounds. The translator mixes a local reference frequency with an inaudible receive signal to translate the receive signal to an audible frequency. If the receive signal exceeds a predetermined value, the reference frequency gets shifted in phase to correspond to the phase of the receive signal at that moment. The resulting translated signal is thus in phase with the receive signal at the moment of shift, so that the time-of-arrival of the receive signal is not lost. When used individually in conjunction with left and right listening channels, the translator enables a listener to hear as well as sense the time-of-arrival of otherwise inaudible signals.
- Electrical and Electronic Equipment