40 results about "Microphone preamplifier" patented technology

A preamplifier having extremely high input impedance amplifies the electrical signal output from an electret condenser microphone (ECM) without suffering from the effects of a DC leakage current at the input. The preamplifier circuit includes a pair of cross-coupled PN junction diodes setting the input impedance, a PMOS device, and a load resistor configured similarly to a conventional preamplifier. A capacitor is placed between the input and the cross-coupled diodes such that a DC path no longer exists to bias the cross-coupled diodes. Therefore, leakage currents are prevented from upsetting the DC operating point of the preamplifier and biasing the cross-coupled diodes. Consequently, small signal gain distortion, excessive demodulation products and increased noise can be avoided.

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 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.

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.

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.

A microphone amplifier arrangement comprises at least one microphone input connected to a dual output microphone pre-amplifier having an input resistance comprising a first resistance and a second resistance in a first voltage-to-voltage mode of operation, and only the second resistance in a second current-to-voltage mode of operation. A first output is operably coupled to a first feedback path comprising a V2V feedback resistor; and a second output is operably coupled to a second feedback path comprising an I2V feedback resistor. In this manner, the microphone amplifier arrangement is arranged to support both a V2V microphone amplifier and a low-noise I2V microphone amplifier.

A portable binaural recording and playback accessory for a multimedia device includes headphones with embedded outside facing microphones, a protective mobile electronic device case with embedded stereo microphone preamplifier or audio video codec containing a microphone preamplifier, analog to digital converter / digital to analog converter (or digital signal processor), and a battery, allowing for the recording and playback of high quality binaural audio, while at the same time acting as a protective case and as an additional power supply.

A microphone preamplifier circuit is provided in a system on chip. An amplifier comprises a first input end, a second input end, and an output end. A bias voltage is provided by a bias voltage source. A first sensor is coupled to the first input end and the bias voltage source for sensing a first physical parameter and a second physical parameter. A second sensor is coupled to the second input end and the bias voltage source for sensing the first physical parameter, wherein the second sensor is insensitive to the second physical parameter. The output end of the amplifier outputs a difference of the first and second input ends whereby noises and interferences are reduced.

A microphone preamplifier circuit is provided. An amplifier comprises a first input end, a second input end, and an output end. A bias voltage is provided by a bias voltage source. A first sensor is coupled to the first input end and the bias voltage source for sensing a first physical parameter and a second physical parameter. A second sensor is coupled to the second input end and the bias voltage source for sensing the first physical parameter, wherein the second sensor is insensitive to the second physical parameter. The output end of the amplifier outputs a difference of the first and second input ends whereby noises and interferences are reduced.

A microphone preamplifier. An electrical signal from a microphone is received via a shielded cable by an input stage cascaded with an output stage. The input stage contains an impedance converter and a phase inverter and receives feedback that reduces input capacitance, actively shields the coaxial cable, and stabilizes the input stage. The output stage contains a buffer and output driver and provides amplified versions of the input stage output. The preamplifier contains means for transformerless phantom powering the microphone and the microphone preamplifier, for sharing current between the input and the output stages, and for limiting the frequency at the output of the microphone.

A portable binaural recording and playback accessory for a multimedia device includes headphones with embedded outside facing microphones, a protective mobile electronic device case with embedded stereo microphone preamplifier or audio video codec containing a microphone preamplifier, analog to digital converter / digital to analog converter (or digital signal processor), and a battery, allowing for the recording and playback of high quality binaural audio, while at the same time acting as a protective case and as an additional power supply.

The invention discloses an in-vehicle engine multi-sound-effect active control system, and relates to an active control technology of vehicle interior sound. The system comprises an engine speed sensor, an accelerator pedal position sensor, a microphone, a microphone preamplifier, a speaker, a power amplifier, an engine multi-sound-effect controller and a human-computer interaction module; the engine multi-sound-effect controller includes an A / D conversion module, a multi-sound-effect processing module, a D / A conversion module and a communication interface; a software architecture of the multi-sound-effect processing module includes an order signal generator, an ignition self-adaptive control module, a dynamic gain adjuster and a control signal selection module; the system obtains three in-vehicle sound effects of "comfortable", "powered" and "sporty" by actively weakening or actively adding engine sound of appropriate order components, the sound preferences and needs of different groups of people can be met, driving interaction and experience are enhanced, and the brand competitiveness and attractiveness of vehicle products are enhanced.

Current microphone designs are still using concepts developed in the early 20th century. A transducer followed by a simple buffer with high impedance, low power, and low gain. Even when tubes were replaced by solid state devices the same practice continued, with the low gain triode being replaced by an even smaller power, lower current FET buffer. The invention offers a microphone system intended for professional audio applications that dispenses with these, low power concepts and incorporates elements of a microphone, microphone pre amplifier, and high power mixing console / pre amp line drivers into a single housing. By combining transducer, high fidelity pre amp circuit, and high power line driving stage with a high voltage, high current external power supply, the capabilities of microphones can be greatly increased in many ways. Our approach can be implemented in a variety of circuit topologies including discrete transistors, tubes and integrated circuits, our concept allows microphones to connect directly to analog or digital recording devices without the need for external mixers or pre amplifiers. The design not only allows for unprecedented simplicity in the work flow of the modern recording studio, which combines the use of stand-alone analog records, standalone digital recorder, and computer workstation based recording options, but also eliminates redundant circuits that are present in microphones, microphone pre amps, and mixing consoles, while offering the customer increased value.

The protection circuit comprises a Zener diode which is connected via a diode to a coupling capacitor of an input stage, wherein a capacitor is arranged in parallel to the Zener diode. The capacitor is, for example, a tantalum electrolytic capacitor with a capacitance value which is in the range of the value of the coupling capacitor. The protection circuit can be used, in particular, for the protection of sensitive microphone preamplifiers which are connected, via the coupling capacitor, to a capacitor microphone.

The invention relates to the technical field of amplifiers. The invention discloses a microphone pre-amplifier circuit with a gain trimming function. The circuit comprises a pre-amplifier, a trimmableresistor array, a digital trimming control unit and a register unit circuit. A group of adjustable resistor arrays are connected in series between the negative end and the output end of the pre-amplifier; the trimming resistor array is connected with the digital trimming control unit; an interference signal source is input from the positive end of the pre-amplifier; wherein the output end of thepre-amplifier is connected with the input end of an audio amplifier of a driving unit, and the digital trimming control unit adjusts the resistance value of the trimmable resistor array according to atrimming target of the pre-amplifier to realize the adjustment and correction of the gain of the pre-amplifier so as to adapt to different types of microphones. According to the technical scheme, thegain of the pre-amplifier can be adjusted and corrected to adapt to different types of microphone tolerances, and the compatibility is high.

An impedance circuit for microphone head amplifier which set between a microphone and an amplifier to provide higher input impedance and improve the performance of the head amplifier.

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.

A headset driver circuit is described which comprises a connector interface. The connector interface comprises a first terminal, a second terminal and a third terminal for establishing respective electrical connections to a first speaker, a microphone and a common ground node of a headphone, earphone or headset, respectively. A first power amplifier is coupled to the first terminal to supply a first audio output signal to the first speaker of the headset. A first switch arrangement comprises a first ground switch is configured for selectively connecting and disconnecting the second terminal and a ground node of the headset driver circuit. The headset driver circuit further comprises a second ground switch configured for selectively connecting and disconnecting the third terminal and the ground node. The headset driver circuit also comprises a differential preamplifier, e.g. a microphone preamplifier, configured to generate a microphone output voltage where the differential preamplifier comprises a first signal input coupled to the second terminal and a second signal input coupled to the third terminal of the connector interface. An error suppression circuit is configured to sense or sample a noise or error voltage at the second terminal when ground connected or the third terminal when ground connected. The error suppression circuit is further configured to add the sensed or sampled noise or error voltage to a predetermined DC bias voltage and generate an error compensated DC bias voltage for the ungrounded one of the second and third terminals of the connector interface.

A microphone positioning system includes a microphone coupler configured to hold a microphone and a microphone positioning mechanism having a low noise motor drive that moves the microphone coupler to different positions. A microphone cable connector is carried by the microphone positioning mechanism. A microphone preamp is also carried by the microphone positioning mechanism and is in signal communication with the microphone cable connector. A cable connector is carried by the microphone positioning mechanism and receives remote control signals that operate the low noise motor drive and move the microphone coupler.

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.

The invention discloses a regional personalized automobile active noise control system, and relates to an automobile active noise control technology. The system comprises an engine rotating speed sensor, a master control unit, a mobile interaction module, a plurality of regional sub-control units, and a microphone preamplifier, a microphone, a seat left loudspeaker, a seat right loudspeaker, a left power amplifier and a right power amplifier which are matched with each regional sub-control unit. The mobile interaction module is used for selecting required control effect modes for different seat passengers in a vehicle, the master control unit determines the control order and the target amplitude of the head area of each seat according to the effect mode requirements of each passenger, andthe regional sub-control units execute the order control scheme of the master control unit to generate control signals of the loudspeakers of each seat. The regional personalized automobile active noise control system can realize various optional control effects in the head area of each seat and meet the personalized sound requirements of different passengers in the vehicle.

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.

A portable binaural recording and playback device includes headphones with embedded outside facing microphones attached to a dongle with embedded stereo microphone preamplifier or audio codec containing a microphone preamplifier, analog to digital converter / digital to analog converter (or digital signal processor), allowing for the recording and playback of high quality binaural audio by connecting the dongle digitally to a mobile phone or electronics device, or via an analog cable to a camera or device with an analog microphone input.

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.

A computer sound card includes a power supply noise isolation circuit for reducing ground plane noise generated during application of heavy electrical loads to the power supply, such as loads presented by computer GPUs. The power supply isolation circuit isolates the output ground from the ground presented from the power supply to the isolation circuit input. The isolation circuit in one embodiment includes switching circuitry and a transformer to reduce the power supply ripple noise that might otherwise be introduced by the power supply into an amplifier such as a microphone preamp. In some embodiments a differential amplifier stage is added to the output of the microphone preamp stage to further reduce noise, such as common mode noise.