Abstract: Disclosed is a signal processor for headphone off-ear detection. The signal processor includes an audio output to transmit an audio signal toward a headphone speaker in a headphone cup. The signal processor also includes a feedback (FB) microphone input to receive a FB signal from a FB microphone in the headphone cup. The signal processor also includes an off-ear detection (OED) signal processor to determine an audio frequency response of the FB signal over an OED frame as a received frequency response. The OED processor also determines an audio frequency response of the audio signal times an off-ear transfer function between the headphone speaker and the FB microphone as an ideal off-ear response. A difference metric is generated comparing the received frequency response to the ideal off-ear frequency response. The difference metric is employed to detect when the headphone cup is disengaged from an ear.

Abstract: A system includes at least one processor and at least one memory storing program instructions that, when executed by the at least one processor, cause the system to send an acoustic ranging transmitter signal between a plurality of calibration reference positions and at least one anchor point, receive an acoustic ranging receiver signal associated with the acoustic ranging transmitter signal and with distances between the plurality of calibration reference positions and the at least one anchor point, and estimate a speed of sound based on the acoustic ranging receiver signal.

Abstract: A system can include an analog input port; a digital output port; and a successive approximation register (SAR) analog-to-digital converter (ADC). The SAR ADC can include a voltage comparator Vd having a first input, a second input, and an output; a first plurality of capacitors Cp[0:n] that are coupled with the analog input port and each have a top plate and a bottom plate; a second plurality of capacitors Cn[0:n] that are coupled with the analog input port and each have a top plate and a bottom plate; and a SAR controller coupled between the output of the voltage comparator Vd and the digital output port.

Abstract: A new compensation system for an audio input reduces noise by matching feedback ratios in the positive and negative paths. A variable resistance network allows for fine control of resistance trimming in one of the signal paths, which allows for compensation between tolerance of resistors that are external to an integrated circuit and those that are internal to the integrated circuit.

Abstract: The disclosure includes a mechanism for mitigating electrical current leakage in a Successive Approximation Register (SAR) Analog to Digital Converter (ADC) by using a Flash ADC in conjunction with the SAR ADC. A sequence controller in the SAR ADC uses the output of the Flash ADC to control a switch array. Depending on the output of the Flash ADC, the sequence controller can control the switch array to couple at least one capacitor in the capacitor network of the SAR ADC to a voltage that reduces charge leakage in the SAR ADC. The voltage may be a pre-defined positive or negative reference voltage.

Abstract: Embodiments of the invention include an oversampling Analog to Digital Converter that uses uneven non-overlapping clock phases to reduce switched capacitor circuit power consumption. A return-to-zero sub phase of one of the clock phases may also be used for feedback reference capacitors. A delay lock loop may be combined with the non-overlapping clock phase generator to control accurate timing.

Abstract: A method for re-forming a complete ring network of a plurality of Bluetooth® speakers, after a speaker has left an original ring of speakers, the method including detecting that the speaker has left the ring, and reestablishing the ring without the departed speaker. The detection may include a timeout detection if the speaker left without notice, or include receiving notice that the speaker intends to leave.

Abstract: A fixture for calibrating an active noise canceling (ANC) earphone, the calibration fixture including an ear model and an acoustic path. The ear model is configured to support an ANC earphone and includes an ear canal extending from an outer end of the ear canal to an inner end of the ear canal. The acoustic path is external to the ear canal and extends from, at a first end of the acoustic path, the inner end of the ear canal of the ear model to an opposite, second end of the acoustic path. The acoustic path is configured to transmit a mechanical sound wave received from the inner end of the ear canal to a region external to the ear model and adjacent the outer end of the ear canal.

Abstract: A speaker system includes a case, an audio input, speakers, an accelerometer, and a computer processor. The audio input is structured to receive a program audio signal from an audio device. The speakers are configured to play an audio output based on the program audio signal, the audio output causing a vibration of the case. The accelerometer is configured to detect the vibration of the case as well as a user tap on the case. The computer processor is configured to identify a user gesture that includes the tap on the case, to identify the tap apart from the case vibration by processing the detected vibration of the case and the detected user tap on the case based on information from the program audio signal to separate the detected user tap from the detected vibration, and to commence a particular function associated with the user gesture.

Abstract: Disclosed is a signal processor for headphone off-ear detection. The signal processor includes an audio output to transmit an audio signal toward a headphone speaker in a headphone cup. The signal processor also includes a feedback (FB) microphone input to receive a FB signal from a FB microphone in the headphone cup. The signal processor also includes an off-ear detection (OED) signal processor to determine an audio frequency response of the FB signal over an OED frame as a received frequency response. The OED processor also determines an audio frequency response of the audio signal times an off-ear transfer function between the headphone speaker and the FB microphone as an ideal off-ear response. A difference metric si generated comparing the received frequency response to the ideal off-ear frequency response. The difference metric is employed to detect when the headphone cup is disengaged from an ear.

Abstract: A system for detecting and capturing voice commands, the system comprising a voice-activity detector (VAD) configured to receive a VAD-received digital-audio signal; determine the amplitude of the VAD-received digital-audio signal; compare the amplitude of the VAD-received digital-audio signal to a first threshold and to a second threshold; withhold a VAD interrupt signal when the amplitude of the VAD-received digital-audio signal does not exceed the first threshold or the second threshold; generate the VAD interrupt signal when the amplitude of the VAD-received digital-audio signal exceeds the first threshold and the second threshold; and perform spectral analysis of the VAD-received digital-audio signal when the amplitude of the VAD-received digital-audio signal is between the first threshold and the second threshold.

Abstract: A headphone detector including a headphone and a processor. The headphone has a microphone and a speaker, and the microphone is configured to generate an audio signal based on an output of the speaker. The processor is configured to receive the audio signal, determine a characteristic of the audio signal, and assess whether the headphone is on ear or off ear based on a comparison of the characteristic to a threshold. The threshold corresponds to one or more of an audio response of the audio signal at a corresponding frequency and an audio response of a feedback microphone signal at a corresponding frequency, under one or more known conditions.

Abstract: A speaker system includes a case, an audio input, speakers, an accelerometer, and a computer processor. The audio input is structured to receive a program audio signal from an audio device. The speakers are configured to play an audio output based on the program audio signal, the audio output causing a vibration of the case. The accelerometer is configured to detect the vibration of the case as well as a user tap on the case. The computer processor is configured to identify a user gesture that includes the tap on the case, to identify the tap apart from the case vibration by processing the detected vibration of the case and the detected user tap on the case based on information from the program audio signal to separate the detected user tap from the detected vibration, and to commence a particular function associated with the user gesture.

Abstract: A portable speakerphone having a housing, a receiving transducer, an electrical cable, a transmitting transducer, and a processor. The receiving transducer is affixed to the housing and is configured to receive a first electrical signal from a mobile device. The electrical cable is coupled to and extends from the housing. The transmitting transducer is affixed to the electrical cable, remote from the housing. Also, the transmitting transducer is configured to transmit a second electrical signal, and the second electrical signal is based in part on the first electrical signal. The processor is configured to suppress acoustic echo by modifying the second electrical signal. The processor is also configured to output the modified second electrical signal to the mobile device. A related method is also disclosed.

Abstract: The disclosure includes a mechanism for mitigating electrical current leakage in a Successive Approximation Register (SAR) Analog to Digital Converter (ADC) by using a Flash ADC in conjunction with the SAR ADC. A sequence controller in the SAR ADC uses the output of the Flash ADC to control a switch array. Depending on the output of the Flash ADC, the sequence controller can control the switch array to couple at least one capacitor in the capacitor network of the SAR ADC to a voltage that reduces charge leakage in the SAR ADC. The voltage may be a pre-defined positive or negative reference voltage.

Abstract: A new compensation system for an audio input reduces noise by matching feedback ratios in the positive and negative paths. A variable resistance network allows for fine control of resistance trimming in one of the signal paths, which allows for compensation between tolerance of resistors that are external to an integrated circuit and those that are internal to the integrated circuit.

Abstract: A circuit can have a low mirror input voltage and fast settling while providing a large current mirror gain. The circuit can include a current source, a first current mirror device having a first transistor and a second transistor and electrically coupled with the current source, a third transistor electrically coupled with the first transistor, a second current mirror device having a fourth transistor and a fifth transistor and electrically coupled between the third transistor and the second transistor, and an output device electrically coupled with the first and second current mirror devices.

Abstract: A system can include an analog input port; a digital output port; and a successive approximation register (SAR) analog-to-digital converter (ADC). The SAR ADC can include a voltage comparator Vd having a first input, a second input, and an output; a first plurality of capacitors Cp[0:n] that are coupled with the analog input port and each have a top plate and a bottom plate; a second plurality of capacitors Cn[0:n] that are coupled with the analog input port and each have a top plate and a bottom plate; and a SAR controller coupled between the output of the voltage comparator Vd and the digital output port.

Abstract: A headphone detector including a headphone and a processor. The headphone has a microphone and a speaker, and the microphone is configured to generate an audio signal based on an output of the speaker. The processor is configured to receive the audio signal, determine a characteristic of the audio signal, and assess whether the headphone is on ear or off ear based on a comparison of the characteristic to a threshold. The threshold corresponds to one or more of an audio response of the audio signal at a corresponding frequency and an audio response of a feedback microphone signal at a corresponding frequency, under one or more known conditions.

Abstract: A case having a recessed holding, an acoustic waveguide, and at least one audio transducer device. The recessed holding well is configured to receive and captively hold a stand-alone keyboard within the recessed holding well. The acoustic waveguide is integrated with a bottom cover of the case and between a bottom surface of the case and the recessed holding well. The at least one audio transducer device is coupled to a signal processing device and the acoustic waveguide. The at least one audio transducer device is configured to generate an audible audio output in response to an audio signal output from the signal processing device. The acoustic waveguide is configured to receive the audible audio output and generate an enhanced bass audio output.