Abstract: The present invention provides a new technique for solving the problem of detecting and locating soft faults, such as frays, in electrical conductor wires. This new technique utilizes the nonlinear ferroelectric capacitive properties of piezoelectric ceramic elements, such as PZT, in conjunction with an antenna coil, to realize a tuned antenna receiver circuit with significantly increased reception sensitivity. The present invention consists of a battery powered, hand-held transmitter, with an output terminal for physical connectors, and a battery powered, hand-held receiver. Soft faults are detected and accurately located, to within a half inch distance of the actual soft fault, as the receiver is passed along the path of the electrical conductor wire, by the operator, who determines a reduction or cessation of the visible and audible indicators.

Abstract: Apparatus and method for shifting the frequency range of an audio frequency range signal using digital frequency shifting and single sideband amplitude modulation techniques. In one embodiment, a frequency shifted single sideband, amplitude modulated signal is formed for application to the human hearing sensory system to provide enhanced hearing for hearing impaired persons. In another embodiment, the audio signal is shifted to an ultrasonic frequency range utilizing digital signal processing techniques in which an audio frequency signal is frequency shifted by modulation to a carrier frequency and in which a single sideband modulated signal is formed. The digital single sideband amplitude modulation techniques of this embodiment are also applicable to digital modulation systems for uses other than in hearing aids. In another embodiment, analog single sideband modulation is utilized for frequency shifting in a hearing aid application.

Abstract: A hearing aid apparatus and method of the type in which audio frequency signals are frequency upshifted to ultrasonic frequency bands and are applied as vibrations to the human body to generate a hearing response. Frequency upshifting of the audio frequency signals to the ultrasonic frequency band is attained in one embodiment by amplitude modulation of an ultrasonic frequency carrier signal with an audio frequency modulating signal to form a modulated signal in which one of the two sidebands is either completely or substantially suppressed and a modulated signal having only one predominant sideband is thus derived for application to the human sensory system to generate a hearing response.