Knowles Electronics, Inc.

Dibyendu Nandy

Henrik Thomsen

Claus Erdmann Fürst

Robert A Popper

Oddy Nopporn Khamharn

Yang Li

Sarmad Qutub

Michael Deruginsky

Ramanujapuram Raghuvir

David P Rossum

Kim Spetzler Berthelsen

Niel David Warren

Andrzej Pawlowski

Anders Svava Mortensen

Jacob Midtgaard

John Nielsen

Aziz Yurttas

Rene Rye Larsen

Svetoslav Radoslavov Gueorguiev

Thibault Kassir

Henrick Thomsen

Martin Volk

Oddy N Khamharn

The present disclosure relates generally to a microphone assembly. The microphone assembly has an acoustic activity detection mode of operation when the electrical circuit is clocked using an internal clock signal generator in the absence of an external clock signal at a host interface, and an electrical circuit of the microphone assembly is configured to provide an interrupt signal to the host interface upon detection of acoustic activity by the electrical circuit. The electrical circuit is configured to control the operating mode of the microphone assembly based on a frequency of the external clock signal in response to providing the interrupt signal and is configured to provide data representing the electrical signal to the host interface using the external clock signal received at the host interface.

Acoustic activity detecting microphone

A microphone assembly includes an acoustic sensor configured to produce an electrical signal and an electrical circuit including a voice activity detector coupled to an output of the acoustic sensor. The microphone assembly further includes an internal clock signal generator and a host interface coupled to the electrical circuit. The host interface has external connections including an external clock signal and a data connection. The microphone assembly includes an acoustic activity detection mode of operation when the electrical circuit is clocked by the internal clock signal generator in the absence of an external clock signal at the host interface. The microphone assembly has a plurality of operating modes controlled by an external clock signal received in response to an interrupt signal provided by the electrical circuit. The electrical circuit is configured to provide data representing the electrical signal at the host interface when the external clock signal is received.

VAD detection microphone and method of operating the same

A microphone system includes a first transducer deployed at a first microphone; a second transducer deployed at a second microphone, the first microphone being physically distinct from the second microphone; a decimator deployed at the second microphone that receives first pulse density modulation (PDM) data from the first transducer and second PDM data from the second transducer and decimates and combines the first PDM data and the second PDM data into combined pulse code modulation (PCM) data; and an interpolator deployed at the second microphone for converting the combined PCM data to combined PDM data, and transmits the combined PDM data to an external processing device.

Interface for microphone-to-microphone communications

A microphone assembly includes an acoustic sensor and a voice activity detector on an integrated circuit coupled to an external-device interface. The acoustic sensor produces an electrical signal representative of acoustic energy detected by the sensor. A filter bank separates data representative of the acoustic energy into a plurality of frequency bands. A power tracker obtains a power estimate for at least one band, including a first estimate based on relatively fast changes in a power metric of the data and a second estimate based on relatively slow changes in a power metric of the data. The presence of voice activity in the electrical signal is based upon the power estimate.

VAD detection apparatus and method of operation the same

A method of operating an acoustic system includes detecting an ultrasonic sound signal and pattern matching the received ultrasonic sound signal to determine when the received ultrasonic sound signal is a desired ultrasonic sound signal. The method includes sending a signal to at least one electronic component when the received ultrasonic sound signal is the desired ultrasonic sound signal. The method includes operating the microphone in a lower power state when the received ultrasonic sound signal is not the desired ultrasonic sound signal.

Low power acoustic apparatus and method of operation

An external clock signal having a first frequency is received. A division ratio is automatically determined based at least in part upon a second frequency of an internal clock. The second frequency is greater than the first frequency. A decimation factor is automatically determined based at least in part upon the first frequency of the external clock signal, the second frequency of the internal clock signal, and a predetermined desired sampling frequency. The division ratio is applied to the internal clock signal to reduce the first frequency to a reduced third frequency. The decimation factor is applied to the reduced third frequency to provide the predetermined desired sampling frequency. Data is clocked to a buffer using the predetermined desired sampling frequency.

Decimation synchronization in a microphone

At a microphone, voice activity is detected in a data stream while simultaneously buffering audio data from the data stream to create buffered data. A signal is sent to a host indicating the positive detection of voice activity in the data stream. When an external clock signal is received from the host, the internal operation of the microphone is synchronized with the external clock signal. Buffered data stream is selectively sent through a first path, the first path including a buffer having a buffer delay time representing the time the first data stream takes to move through the buffer. The data stream is continuously sent through a second path as a real-time data stream, the second path not including the buffer, the real-time data stream beginning with the extended buffer data at a given instant in time. The buffered data stream and the real-time data stream are multiplexed onto a single data line and transmitting the multiplexed data stream to the host.

Microphone apparatus and method with catch-up buffer

A far end signal from a far end user and broadcasting the far end signal at a loudspeaker is received. A signal for use in an echo transfer function is determined, and the signal selected from between: the far end signal or an echo reference signal received from a near field microphone disposed in close proximity to the speaker. The near field microphone sensing the far end signal that is broadcast from the speaker while sensing the near-end speech and ambient noise at insignificant energy levels compared to the speaker signal. An echo transfer function is determined based at least in part upon the selected signal, and the echo transfer function represents characteristics of an acoustic path between the loudspeaker and a far field microphone that is disposed at a greater distance from the speaker than the near field microphone. An estimated echo is determined based at least in part upon the echo transfer function. The estimated echo is subtracted from a signal received from the far field microphone, the subtracting effective to cancel an echo present in the signal received from the far end microphone.

Reference microphone for non-linear and time variant echo cancellation

A microphone includes a microelectromechanical system (MEMS) circuit and an integrated circuit. The MEMS circuit is configured to convert a voice signal into an electrical signal, and the integrated circuit is coupled to the MEMS circuit and is configured to receive the electrical signal. The integrated circuit and the MEMS circuit receive a clock signal from an external host. The clock signal is effective to cause the MEMS circuit and integrated circuit to operate in full system operation mode during a first time period and in a voice activity mode of operation during a second time period. The voice activity mode has a first power consumption and the full system operation mode has a second power consumption. The first power consumption is less than the second power consumption. The integrated circuit is configured to generate an interrupt upon the detection of voice activity, and send the interrupt to the host.

A microphone includes a base, a micro electro mechanical system (MEMS) device disposed on the base, and a front end processing apparatus disposed on the base and coupled to the MEMS device, the front end processing apparatus being configured to convert analog signals received from the MEMS device into digital signals. The microphone also includes a DSP apparatus, the DSP apparatus being a digital programmed device with a computer memory, the DSP apparatus configured to process the digital signals received from the front end processing apparatus. The MEMS device, the front end processing apparatus, and DSP apparatus are enclosed within a single microphone enclosure or assembly. During operation the DSP apparatus generates DSP noise. The DSP apparatus includes a noise reduction structure that substantially prevents the DSP noise from reaching or interfering with the operation of the MEMS device or the front end processing apparatus.

Signal processing platform in an acoustic capture device

Streaming audio is received. The streaming audio includes a frame having plurality of samples. An energy estimate is obtained for the plurality of samples. The energy estimate is compared to at least one threshold. In addition, a band pass estimate of the signal is determined. An energy estimate is obtained for the band-passed plurality of samples. The two energy estimates are compared to at least one threshold each. Based upon the comparison operation, a determination is made as to whether speech is detected.

Acoustic activity detection apparatus and method

At a processing device, a first signal from a first microphone and a second signal from a second microphone are received. The first signal indicates whether a voice signal has been determined at the first microphone, and the second signal indicates whether a voice signal has been determined at the second microphone. When the first signal indicates potential voice activity or the second signal indicates potential voice activity, the processing device is activated to receive data and the data is examined for a trigger word. When the trigger word is found, a signal is sent to an application processor to further process information from one or more of the first microphone and the second microphone. When no trigger word is found, the processing device is reset to deactivate data input and allowing the first microphone and the second microphone to enter or maintain an event detection mode of operation.

VAD detection apparatus and method of operating the same

First analog signals are received from a first microphone, converted into first digital data and stored in a first buffer. A determination is made as to whether voice activity has occurred when voice activity is determined, a voice activity detect signal is sent to an external processor. The external processor responsively provides an exterior clock signal upon receiving the voice activity detect signal. Second analog signals are received from a second microphone, converted into second digital data and stored in a second buffer. The first digital data in the first buffer is not necessarily synchronized in real time with the second digital data in the second buffer. The first digital data from the first buffer and the second digital data from the second buffer is decimated using the external clock to provide decimated output data, the decimated output data having the first digital data and the second digital data aligned in real time.

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Naperville, IL, United States of America

Dibyendu Nandy