87 results about "Amplitude demodulation" patented technology

Methods and systems for neurostimulation and / or neurotelemetry of electrically-excitable biological tissue. Embodiments include implanting single or multiple semiconductor diodes and applying a high frequency electrical volume current. Neurostimulation embodiments include local rectification of the volume current by the diode, which can provide a pulsating electrical waveform capable of locally stimulating neural tissue, hi neurotelemetry embodiments, semiconductor diodes can be placed in contact with excitable tissue and a low level electrical carrier wave can be passed through the tissue and implanted diode whereby low level tissue bioelectric events intermodulate with the carrier wave and encode bioelectrical effects. Remote detection and amplitude demodulation of the volume-conducted carrier wave can allow recovery of the bioelectrical waveform and provide a neurotelemetry function, hi other embodiments, implanted diodes are placed in series with a pressure switch or piezoelectric material which enables their function only with the focal application of an acoustic pressure wave. This enables a selectivity amongst multiple diode channels by acoustic wave focusing or alternately by a process of range-gating of a surface applied electrical current to the arrival time of an acoustic wave at a particular device.

A parameter-free method to analyze sensor signals incorporates two or more of frequency demodulation, amplitude demodulation and phase demodulation of the raw signal data. The resulting signal is transformed to a frequency domain, and target fault characteristics from the demodulated signal are identified. The method is used to detect faults in bearings, gears and other mechanical components.

The present invention is directed an ultrasonic frequencies fault detecting apparatus. The present invention uses high frequency ultrasonic energy signals to analyze bearings and determine the presence of faults therein. The ultrasonic return signals are heterodyned (by amplitude demodulation) into the audio spectrum for purposes of audio detection. In addition, a FFT spectrum of the signal is displayed on a monitor for more accurate results. According to the present invention software is used to automatically analyze the FFT spectrum by comparing the current spectrum with stored spectrums of known bearing conditions as modified based on the rotary speed of the bearing and the number of balls. Once a defect in a bearing has been located in this manner using automated FFT analysis, an operator can then use a device, such as a calibrated lubricant dispenser, to effectuate maintenance and / or repair.

An amplitude demodulator comprising a capacitive element for filtering a first D.C. component of a received signal, an element for detecting edges in the signal provided by the capacitive element, and at least one switching element for forcing, at least after detection of an edge, the returning of the signal provided by the capacitive element to a second D.C. component.