Patent Application
20050100182
The technology described in this patent document relates generally to the field of wireless communications. More particularly, the patent document describes a hearing instrument having a wireless base unit.
Typical hearing instruments that incorporate wireless transceivers may include many disadvantages that are overcome by the hearing instrument system described herein.
In accordance with the teachings described herein, systems and methods are provided for a hearing instrument having a wireless base unit. The base unit may include one or more microphones for generating an audio signal and communications circuitry for wirelessly transmitting the audio signal to the hearing instrument. The hearing instrument may include communications circuitry for receiving the audio signal from the base unit, and may further include a processing device operable to process the audio signal to compensate for a hearing impairment of a hearing instrument user and a speaker for transmitting the processed audio signal into an ear canal of the hearing instrument user. The base unit may be positioned to receive audio signals at a distance from the hearing instrument user.
The base unit 12 may be a hand held device having one or more microphones to receive audio signals, for example from nearby talkers. The base unit 12 may then convert the received audio signals into the digital domain, process the digital signals, modulate the processed signals to an RF carrier and transmit the signals to the hearing instrument 10. The base unit 12 may include an integral processing device, such as a digital signal processor (DSP), for processing received signals. For example, the base unit 12 may perform directional processing functions, audio compression functions, clear channel searching functions, or other signal processing functions.
In addition to transmitting audio signals to the hearing instrument, the base unit 12 may also transmit and receive other data, such as control data. For example, the base unit 12 may receive control data from a user interface to configure parameters, such as frequency channel and operational modes. In addition, control data may be transmitted from the base unit 12 to the hearing instrument 10, for example to program the hearing instrument. In another example, the communication link between the hearing instrument 10 and the base unit 12 may be bi-directional. Bi-directional communication between the hearing instrument 10 and the base unit 12 may be used to transmit data between the devices 10, 12, such as programming data, data uploads/downloads, binaural communication, or other applications. In one example, the base unit 12 may function as a wireless links to an external device or network, such as a computer network, a, CD player, a television, a cellular telephone, or others. For instance, the base unit 12 may receive an input (wired or wireless) from the external device or network and function as a wireless gateway between the device or network and the hearing instrument 10.
As illustrated in
In the case of a hearing instrument user having two hearing instruments 30, 32, the communications circuitry in the hearing instrument may also be used to transmit audio signals and/or other data between the two hearing instruments 30, 32, as illustrated in
The wireless communications circuitry in the hearing instrument and/or base unit may also be used to communicate with a user interface device 40, 50, as illustrated in
In operation, the base unit receives audio signals with the one or more microphones 64 and converts the audio signals into the digital domain for processing by the baseband processor 72. The baseband processor 72 processes the audio signals for efficient wireless transmission, and the processed audio signals are transmitted to the hearing instrument by the communications circuitry 70. In this manner, the received audio signals from the microphone(s) 64 may be digitized near the source of the sound, with further processing and transmission performed in the digital domain and the final digital to analog conversion occurring in the hearing instrument. In addition, the base unit 72, using the built-in communications circuitry and RF signal strength detection, may automatically select a clear frequency channel for low-noise communication with the hearing instrument.
The communications circuitry 70 may include both transmitter and receiver circuitry for bi-directional communication with a hearing instrument or other wireless device. In one example, the frequency channel and/or the frequency band (e.g., UHF, ISM, etc.) used by the communications circuitry may be programmable. In other examples, the communications circuitry 70 may include multiple occurrences of transmitter and receiver circuitry. This these cases the single antenna may be preceded by an RF combiner and impedance matching network. In addition, the communications circuitry 70 may be operable to communicate on multiple channels to support functions such as stereo transmission, multi-language transmission, or others. For example, the communications circuitry 70 may transmit stereo audio to a set or binaural hearing instruments on two channels, one channel for each hearing instrument. The stereo signal may, for example, be synchronized at the base unit 60, or in another example may be synchronized using binaural communications between the two hearing instruments. A more detailed diagram of communications circuitry that may be used in the base unit 60 is described below with reference to
The baseband processor 72 is a digital signal processor (DSP) or other processing device(s), and is operable to perform baseband processing functions on audio signals received from the microphones 64 or other audio inputs 68 (e.g., CD player, television, etc.), such as audio compression, encoding, data formatting, framing, and/or other functions. Also, in the case of a bi-directional system, the baseband processor 72 may perform baseband processing functions on received data, such as audio decompression and decoding, error detection, synchronization, and/or other functions. In addition to baseband processing functions, the baseband processor 72 may perform processing functions traditionally performed at the hearing instrument, such as directional processing, noise reduction and/or other functions. An example baseband processor is described in more detail below with reference to
The baseband processor 72 may also execute a program for automatically selecting a clear frequency channel for low-noise communication with the hearing instrument. For example, a clear channel selection program executed by the baseband processor 72 may cause the communications circuitry 70 to sweep through the operating frequency band to identify a quiet frequency channel, and then set the communication circuitry 70 to operate using the identified quiet channel. A clear channel may be selected, for example, by measuring a noise level at each frequency in the band, and then selecting the frequency channel with the lowest noise level. In another example, the clear channel selection program may only sweep through frequencies in the operating band until a frequency channel is identified having a noise level below a pre-determined threshold, and then set the communications circuitry 70 to operate using the identified channel. A frequency band sweep may be initiated, for example, by a user input (e.g., depressing a button 68), by detecting that the noise level of a currently selected channel has exceeded a pre-defined threshold level, or by some other initiating event. The noise level of a channel may, for example, be measured by the an RSSI process in the baseband processor 72 (see, e.g.,
In another example, the baseband processor 72 may also be used to set the operating frequency band used by the communications circuitry 70. For example, the operating frequency band may be set to unused UHF bands, regulated bands for wireless microphones, or other frequency bands available for wireless communication. The operating frequency band may, for example, be set by a user input 68 or by the clear channel selection program. For example, if a clear frequency channel is not identified by the clear channel selection program in an initial band, then a new operating frequency band may be selected either automatically or by user input.
The RF communication module 92 includes communications circuitry 96, a baseband processor 98 and externals components 100 (e.g., resistive and reactive circuit components, oscillators, etc.) As illustrated, the communications circuitry 96 and the baseband processor 98 may each be implemented on an integrated circuit, but in other examples may include multiple integrated circuits and/or external circuit elements. The communications circuitry 96 may be the same as the communications circuitry 70 in the base unit 60 in order to better ensure compatibility.
The communications circuitry 96 may include both transmitter and receiver circuitry for bi-directional communication with the base unit 60. In addition, bi-directional communications circuitry 96 may be used to communicate with another hearing instrument (e.g., in a binaural fitting) and/or with other wireless devices. The communications circuitry 96 may also be programmable to select an operating frequency channel and/or frequency band. For example, in the case of a clear channel selection program executing on the base unit 60, as described above, the communications circuitry 96 may receive a control signal from the base unit 60 to change operating frequencies or bands. In another example, the clear channel selection program may instead execute on a processor in the hearing instrument, such as the baseband processor 98.
The baseband processor 98 may be a DSP or other processing device, and performs baseband processing functions on the received audio signal, such as audio decompression and decoding, error detection, synchronization, and/or other functions. The baseband processor 98 may also perform baseband processing functions on outgoing transmissions, such as audio compression and encoding, data formatting and framing, and/or other functions. In addition, the baseband processor 98 may perform other processing functions to interface the RF module 82 with the hearing instrument module 84.
The hearing instrument module 94 includes a memory device 102, a CODEC 104, and a hearing instrument processor 106. The memory device 102 may be a EEPROM or other type of persistent memory device. The memory device 102 may be used to store hearing instrument settings, record hearing instrument parameters, or for other data storage. The CODEC 104 may be used to interface the hearing instrument module 94 with the baseband processor 98 and with external devices (e.g., an audiologist's PC or other computing device) via an external serial port 108. The hearing instrument processor 106 is operable to process audio signals received from the base unit or from the hearing instrument microphone(s) 90 to compensate for the hearing impairments of a hearing instrument user and transmit the processed audio signal into the ear canal of the hearing instrument user via the speaker 88. The hearing instrument processor 106 may also perform other signal processing functions, such as directional processing, occlusion cancellation and/or other digital hearing instrument functions. An example hearing instrument processor 106 that may be used in the system described herein is set forth in the commonly-owned U.S. patent application Ser. No. 10/121,221, entitled “Digital Hearing Aid System.”
The RF communication module 112 includes a baseband processor 140 and communications circuitry. The communications circuitry includes a transmit path and a receive path. The receive path includes a low noise amplifier (LNA) 124, a down conversion quadrature mixer 126, 128, buffering amplifiers 126, 128, an I-Q image reject filter 134 and a slicer 136, 138. The transmit path includes a modulator 141, an up conversion quadrature mixer 142, 144 and a power amplifier 146. The receive and transmit paths are supported and controlled by the baseband processor 140 and clock synthesis circuitry 148, 150, 152. The clock synthesis circuitry includes an oscillator 148, a phase locked loop circuit 150 and a controller 152. The oscillator 148 may, for example, use an off chip high Q resonator (e.g., crystal or equivalent) 122. The frequency of the phase locked loop circuit 150 is set by the controller 152, and controls the operating frequency channel and frequency band. The controller 152 may, for example, be accessed by a clear channel selection program, as described above, to select the operating frequency channel and/or frequency band of the system. Also included in the RF communication module 112 are support blocks 154, which may include voltage and current references, trimming components, bias generators and/or other circuit components for supporting the operation of the transceiver circuitry.
In operation, an RF signal received by the antenna 116 is amplified by the LNA 124, which feeds the down conversion mixer 126, 128 to translate the desired RF band to a complex signal. The output of the down conversion mixer 126, 128 is then buffered 130, 132, filtered by the image reject filter 134 and slicer 136, 138 and input to the baseband processor 140. The baseband processor 140 performs baseband processing functions, such as synchronizing the incoming data stream, extracting the main payload and any auxiliary data channels (RSSI and AFC information), and performing necessary error detection and correction on the data blocks. In addition, the baseband processor 140 decompresses/decodes the received data blocks to extract the audio signal, for example as a standard 12S output.
Outgoing audio and/or control signals may be encoded and formatted for RF transmission by the baseband processor 140. In the case of outgoing audio signals, the baseband processor 140 may also perform audio compression functions. The processed signal is modulated to an RF carrier by the modulator 141 and up conversion mixer 142, 144. The RF signal is then amplified by the power amplifier 146 and transmitted over the air medium by the antenna 116.
The receiver baseband processing functions 162 include signal level baseband functions 168, 170, such as a synchronization function 170 to synchronize with the incoming data stream, and a data extraction function 168 for extracting the payload data. Also included in the receiver functions 162 are an error detection function 172 for detecting and correcting errors in the received data blocks, and an audio decompression decoding function 174 for extracting an audio signal from the received data blocks.
The transmitter baseband processing functions 166 include data formatting 180 and framing 184 functions for converting outgoing data into an RF communication protocol and an encoding function 182 for error correction and data protection. The RF communication protocol may be selected to support the transmission of high quality audio data as well as general control data, and may support a variable data rate with automatic recognition by the receiver. The encoding function 182 may be configurable to adjust the amount of protection based on the content of the data. For example, portions of the data payload that are more critical to the audio band from 100 Hz to 8 kHz may be protected more than data representing audio from 8 kHz to 16 kHz. In this manner, high quality audio, although in a narrower band, may still be recovered in a noisy environment. In addition, the transmitter baseband processing functions 166 may include an audio compression function for compressing outgoing audio data for bandwidth efficient transmission.
The interface functions 164 include a configuration function 176 and a data/audio transfer function 178. The data/audio transfer function 178 may be used to transfer data between the baseband processor 160 and other circuit components (e.g., a hearing instrument processor) or external devices (e.g., computer, CD player, etc.) The configuration function 176 may be used to control the operation of the communications circuitry. For example, the configuration function 176 may communication with a controller 152 in the communications circuitry to select the operating frequency channel and/or frequency band. In one example, the configuration function 176 may be performed by a clear channel selection program, as described above, that identifies a low noise channel and/or frequency band and sets the operating parameters of the communication circuitry accordingly.
This written description uses examples to disclose the invention, including the best mode, and also to enable a person skilled in the art to make and use the invention. The patentable scope of the invention may include other examples that occur to those skilled in the art. For example, the RF communication module described herein may instead be incorporated in devices other than a hearing instrument or base unit, such as a wireless headset, a communication ear-bud, a body worn control device, or other communication devices.
This application claims priority from and is related to the following prior application: “Miniature Ultra-Low Power Wireless Transceiver With Digital Audio Receive And Data Transceiver Capability,” U.S. Provisional Application No. 60/519,149, filed Nov. 12, 2003. This prior application, including the entirety of the written descriptions and drawing figures, is hereby incorporated into the present application by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60519149 | Nov 2003 | US |
