Abstract:
A housing having a port for reducing wind-induced noise in a communication device. The housing includes a first channel, a second channel, and a ridge between the first and second channels. The housing further includes a tunnel extending through the ridge, which tunnel connects the first and second channels. The housing further includes a microphone port beneath the ridge, which microphone port is connected to the tunnel and connects the tunnel to a microphone cavity in the housing.
Abstract:
Preprocessing speech signals from an indirect conduction microphone. One exemplary method preprocesses the speech signal in two stages. In stage one, an external speech sample is characterized using an auto regression model, and coefficients from the model are convolved with the internal speech signal from the indirect conduction microphone to produce a pre-conditioned internal speech signal. In stage two, a training sound is received by the indirect conduction microphone and filtered through a low-pass filter. The result is then modeled using auto regression, and inverted to produce an inverted filter model. The pre-conditioned internal speech signal is convolved with the inverted filter model to remove negative or undesirable acoustic characteristics and loss from the speech signal from the indirect conduction microphone.
Abstract:
Preprocessing speech signals from an indirect conduction microphone. One exemplary method preprocesses the speech signal in two stages. In stage one, an external speech sample is characterized using an auto regression model, and coefficients from the model are convolved with the internal speech signal from the indirect conduction microphone to produce a pre-conditioned internal speech signal. In stage two, a training sound is received by the indirect conduction microphone and filtered through a low-pass filter. The result is then modeled using auto regression, and inverted to produce an inverted filter model. The pre-conditioned internal speech signal is convolved with the inverted filter model to remove negative or undesirable acoustic characteristics and loss from the speech signal from the indirect conduction microphone.
Abstract:
A voice activity detection system (100) filters audio input frames (102), on a frame=by-frame basis through a gammatone filterbank (104) to generate filtered gammatone output signals (106). A signal energy calculator (108) takes the filtered gammatone output signals and generates a plurality of energy envelopes. Weighting factors are constructed (112) are applied to each of the energy envelopes thereby producing normalized weighted signal (116), in which voice regions are emphasized and noise regions are minimized. An entropy measurement (118) is taken to extract information from the normalized weighted signals (116) and generate an entropy signal (120). The entropy signal (120) is averaged and compared to an adaptive entropy threshold (122), indicative of a noise floor. Decision logic (124) is used to identifying speech and noise from the comparison of the averaged entropy signal to the adaptive entropy threshold.
Abstract:
An intrinsically safe audio circuit and intrinsically safe portable two-way radio device meet conventional audio output requirements and intrinsically safe design limitations by separating the speaker coil of the device's speaker into separate coils to limit the energy storage possible in any one of the coils. Each separate coil is driven by one of several different audio power amplifiers that each output a substantially identical signal, and each of which are current limited.
Abstract:
A method and apparatus for detecting the connection of an external audio accessory to an audio device via a two-wire audio jack includes providing a DC bias on the output of the audio circuit connected to the audio jack. The audio jack is such that, when a plug is inserted into the audio jack, the DC bias is removed from an internal routing pin of the audio jack. The change in DC voltage at the internal routing pin indicates connection of the external audio accessory. Furthermore, upon detection, the AC response of the external audio accessory can be determined, and used to select a set of audio settings to be applied to the audio components of the audio device to optimize the performance of the external audio accessory.
Abstract:
A communication device is configured to receive signals using at least one acoustic microphone and at least one structural microphone. The communication device calculates one of first a signal-to-noise (SNR) ratio and a speech-to-noise ratio for the at least one acoustic microphone from received signals and calculates a SNR for the at least one structural microphone from received signals. The communication device compares one of the first SNR and the speech-to-noise ratio for the at least one acoustic microphone with the SNR for the at least one structural microphone. The communication device selects one of the at least one acoustic microphone and at least one structural microphone to receive speech responsive to the comparing and places a selected one of the at least one acoustic microphone and at least one structural microphone in a standby mode.
Abstract:
A method and apparatus for visually indicating battery pack information related to wirelessly charging a battery pack via a wireless charging mat. The method includes uniquely associating, with a controller of the wireless charging mat, each visual indicator of a first plurality of visual indicators on the wireless charging mat with one of a first plurality of sensors on the wireless charging mat. The method further includes receiving the battery pack information from the battery pack with one or more of the first plurality of sensors. The method further includes wirelessly charging the battery pack using the wireless charging mat, and illuminating the first plurality of visual indicators based on the battery pack information.
Abstract:
A battery module for a portable communication device having a controller. In one embodiment, the battery module includes a battery accessory interface having a positive terminal, an identifying terminal, and a negative terminal. A voltage regulator is connected to the positive terminal of the battery accessory interface and configured to output a voltage on the positive terminal in response to a control signal. An addressable switch is connected to the identifying terminal of the battery accessory interface. The addressable switch is configured to communicate with the controller and generate the control signal based on input from the controller and the identifying terminal.
Abstract:
A method and apparatus for distinguishing voice signals that are played together over the same speaker employs spectral reshaping of one or more of the audio signals. The spectral reshaping shifts modifies the timber of the voice signal while not modifying the pitch of the voice signal. Additional techniques can be used to further distinguish voice signals, such as dynamic gain offset and frequency shifting. After processing one or more signals to spectrally reshape them, they can be played over the same speaker. A user hearing the resulting acoustic signal will be more able to distinguish between the multiple voice signals being played.