40 results about "Microphone preamplifier" patented technology

A microphone circuit assembly for an external application processor, such as a programmable Digital Signal Processor, may include a microphone preamplifier and analog-to-digital converter to generate microphone signal samples at a first predetermined sample rate. A speech feature extractor is configured for receipt and processing of predetermined blocks of the microphone signal samples to extract speech feature vectors representing speech features of the microphone signal samples. The microphone circuit assembly may include a speech vocabulary comprising a target word or target phrase of human speech encoded as a set of target feature vectors and a decision circuit is configured to compare the speech feature vectors generated by the speech feature extractor with the target feature vectors to detect the target speech word or phrase.

The present invention relates in one aspect to a microphone circuit assembly for an external application processor such as a programmable Digital Signal Processor. The microphone circuit assembly comprises a microphone preamplifier and analog-to-digital converter generate microphone signal samples at a first predetermined rate. A speech feature extractor is configured for receipt and processing of predetermined blocks of the microphone signal samples to extract speech feature vectors representing speech features of the microphone signal samples. The microphone circuit assembly additionally comprises a speech vocabulary comprising a target word or target phrase of human speech encoded as a set of target feature vectors and a decision circuit is configured to compare the speech feature vectors generated by the speech feature extractor with target feature vectors to detect the target speech word or phrase. A controller is configured to generate a recognition signal on an externally accessible output terminal of the microphone circuit assembly in response to a recognized target word or phrase in the microphone signal samples. Additional aspects of the invention relates to Digital Signal Processing Systems comprising the microphone circuit assembly.

The present invention relates to an electret condenser microphone which comprises an exterior sidewall structure attached to a carrier. The exterior sidewall structure comprises a non-conductive base material carrying first and second electrical wiring patterns electrically connected to first and second electrical traces, respectively, of the carrier. A diaphragm holder, carrying a conductive microphone diaphragm is attached to the sidewall structure to establish electrical connection between a conductive microphone diaphragm and one of the first and second electrical wiring patterns of the sidewall structure. A conductive perforated backplate is arranged in spaced relationship to the conductive microphone diaphragm. The conductive perforated backplate is electrically connected to another one of the first and second wiring patterns of the sidewall structure. The sidewall structure may therefore be utilized to provide electrical connectivity from the conductive microphone diaphragm and from the backplate to a microphone preamplifier arranged on the carrier.

A graphene microphone preamplifier is a minimalist design working in class A with large quiescent current in a push-pull configuration, with automatic balancing of voltage imbalance.

With a microphone amplifier using an operational amplifier, there has been a problem that a sensitivity of the condenser microphone is reduced by an influence of a parasitic capacitance generated at an input terminal of the operational amplifier. This invention offers a microphone amplifier having a condenser microphone that converts a sound into a voltage signal, an operational amplifier having an inverting input terminal to which the voltage signal from the condenser microphone is applied and a non-inverting input terminal to which a direct current bias voltage is applied, a capacitor connected between the inverting input terminal and an output terminal of the operational amplifier, and a resistor connected between the inverting input terminal and the output terminal of the operational amplifier.

The invention relates to a high-power digital power amplifier integrated machine system of a digital movie player. Amplification and microphone pre-amplification are connected to the addition circuit; each addition circuit, input balance circuit, buffer circuit, controllable pulse width modulation circuit, drive, control circuit, final power amplifier circuit, and filter are connected in series in sequence, and the final power The amplifying circuit is connected to the drive and control circuits through the controllable pulse width modulation circuit, and the delay start of the short circuit and overload protection circuit is connected to each drive and control circuit. The invention can well meet the actual application requirements of mobile projection in the rural digital movie market, greatly reduces the volume and weight of the whole set of digital movie system, and lowers the cost. At the same time, it greatly facilitates the effective management of government departments, and can realize the requirement of showing one movie per month in every village in the country.

A device with recording and microphone testing functions used with an intelligent terminal, including a recording or measuring microphone, a preamplifier, a connector, a TRRS plug and a TRS socket, the back end of the recording and measuring microphone is connected to the front end of the preamplifier, The rear end of the preamplifier is connected with the TRRS plug and the TRS socket through the connecting body. The advantage of the present invention is: through the TRRS interface of the audio input and output interface of the intelligent terminal platform (such as a smart phone, a smart tablet computer, etc.), an external high-grade condenser microphone system is connected. Compared with the terminal's own pickup, the external high-grade condenser microphone system has the characteristics of strong directivity, high sensitivity, convenience and flexibility. The external microphone system can also be used to measure the microphone. With the acoustic measurement software of the terminal, it can conduct on-site sound field measurement, which is convenient and flexible. Small and easy to carry, except for the smart terminal platform, no other peripheral equipment is needed, simple and practical.

The invention discloses a method and system for automatically calibrating the microphone sensitivity of a noise collection device for power equipment. The method of the invention includes collecting an AC voltage signal at the outlet of a microphone preamplifier; performing Fourier transform on the AC voltage signal to obtain a signal spectrum; judging the signal spectrum Whether the main frequency is the first preset frequency, and the ratio of the frequency component energy of the first preset frequency in the spectrum to the energy sum of each frequency component in the range of the second preset frequency is greater than the preset threshold, and if it is true, it is judged When is the microphone sensitivity calibration working state, the effective value of the AC voltage signal at the outlet of the microphone preamplifier is the latest sensitivity of the microphone. The invention does not need to artificially set the sensitivity of the microphone, is suitable for the automatic calibration of the microphone of the noise collection device of the electric equipment, can reduce the workload of the noise detection personnel, and improves the noise collection efficiency.

The invention discloses a bearing acoustic diagnosis system and method used in combination with a wheel set bearing running-in machine. The system comprises a bearing acoustic diagnosis work station, a microphone, a microphone sound collecting cover and a front microphone amplifier, wherein the microphone is located in the microphone sound collecting cover, the microphone sound collecting cover is fixed to the outer side of a bearing through a supporting frame, the microphone collects a bearing sound signal and forms a microphone signal, and the microphone signal is output to the bearing acoustic diagnosis work station through the front microphone amplifier; the bearing acoustic diagnosis work station comprises an audio signal collecting card, four digital filters, a resonance envelope demodulation discriminator, a characteristic parameter discriminator and a specialist system, the specialist system performs calculation to obtain the envelope frequency spectrum, the crest factor, the clearance factor, the impact factor, the kurtosis factor and the shape factor of the bearing to be detected through the resonance envelope demodulation discriminator and the characteristic parameter discriminator, whether faults happen to the bearing to be detected or not is judged, and the fault types are obtained. Various faults of the bearing are discriminated by collecting the sound of the rotating bearing.