WIRELESS HEADPHONES FOR USE WITH A PORTABLE AUDITORY AND

VOICE SYSTEM

FIELD OF THE INVENTION This invention relates to a portable auditory and voice system and in particular a wireless headphone and a wireless microphone for use in with a portable auditory and voice system.

BACKGROUND OF THE INVENTION In general, diagnostic tests for assessing the capabilities of the auditory system of a human subject include:

• measurement of the sensitivity of the subject's hearing at different frequencies. This is a fundamental measurement of auditory function and generates the so-called "audiogram". • measurement of the ability of the subject to resolve or distinguish between two sounds that are close in frequency. This test provides the frequency resolution of the subject's auditory system.

• measurement of the ability of the subject to resolve or detect gaps or silence periods between two sounds. This test provides the temporal resolution of the subject's auditory system.

• measurement of the ability of the subject to understand speech in noisy and/or reverberant backgrounds.

• measurement of the ability of the subject to identify individual words/sentences when two different sentences/words are presented simultaneously to the two ears. This test provides the binaural processing capabilities of the subject.

The first of these tests (the "audiogram" measurement) is routinely administered by the hearing health care professionals using an Audiometer. Conventional Audiometers are bulky, are not readily portable, and are constrained to in-clinic use. While portable Audiometers exist, they are not capable of conducting more advanced measurements such as those mentioned above. In addition the bulkier and the portable audiometers are capable of testing one subject

at a time.

Diagnostic tests for measuring the capabilities of the vocal system in a human subject include:

• measurement of the fundamental frequency and the range of fundamental frequencies that the subject can elicit.

• measurement of the vocal intensity and the range of vocal intensities that the subject can produce.

• measurement of the "vocal noise" in the subject's voice which contributes to the roughness, breathiness, and harshness voice qualities. Speech Language Pathologists typically use PC-based equipment or other dedicated materials to conduct the speech and language tests. The PC- based equipment is cumbersome and is not readily portable.

To summarize, traditional audiometric and vocal function testing systems employ wired headphones and microphones for obtaining data. This often restricts the place and setting where the measurement can take place.

Accordingly it would be advantageous to provide a wireless headset interface which would provide freedom from the testing equipment and would therefore increase the measurement flexibility. This flexibility has the potential to allow assessments to occur in acoustically diverse real world environments, in addition to standard clinical settings. Real-world testing has the potential to dramatically improve the relevance and success of rehabilitation treatments. As well it would be advantageous to provide a portable yet powerful audiometric test platform that can be configured to deliver the advanced audiometric tests, and can be configured to test multiple subjects at the same time. These tests enable the hearing health care professional to accurately and efficiently determine the hearing deficiencies and allow him/her to prescribe remedial actions and therapy accordingly. Further, it would be advantageous to provide a handheld system with adequate functionality which would be of immense use to Speech Language Pathologists, especially to those who travel to schools (to test children) and senior homes regularly for conducting voice and language tests.

SUMMARY OF THE INVENTION

The present invention relates to a portable hearing test system including a handheld device and wireless headphones. The handheld device includes a system controller capable of generating a sound signal and a control signal. The wireless headphones are capable of receiving the sound signal and generating an output sound signal having a sound level of between 0 to 100 dB sound pressure level (SPL) and a frequency range of between 20 Hz to 20 kHz and capable of adjusting the output sound signal responsive to the control signal.

In another aspect of the device there is provided a portable sound test system including a handheld device and a wireless microphone. The handheld device includes a display and a system controller capable of receiving a microphone sound signal and a microphone control signal, wherein the display is capable of displaying characteristics of the microphone sound signal. The wireless microphone is adapted to receive a voice signal and capable of generating the microphone sound signal and generating the microphone control signal. In a further aspect of the invention there is provided a wireless headphone interface for use in association with a headphones having a predetermined dynamic range and a fixed impedance and a device for generating sound signals comprising: a digital reception port for receiving digital sound signals from the device for generating sound signals; a digital to analog converter operably connected to the digital reception port for converting the digital sound signals to analog sound signals; an attenuator operably connected to the digital to analog converter for scaling the analog sound signals to within the predetermined dynamic range of the headphones to produce attenuated sound signals; a headphone amplifier operably connected to the attenuator for amplifying the attenuated sound signals within the predetermined dynamic range and to match the fixed impedance of the headphones to produce amplified sound signals and the headphone amplifier being operably connectable to the headphones; and a microprocessor operably connected to the digital reception port, the digital to analog converter and the attenuator. Another aspect of the invention relates to a wireless microphone interface for use in association with a microphone for receiving sound signals from a subject and a device for receiving sound signals comprising: a microphone pre-

amplifier for receiving the sound signals from the microphone and for generating a pre-amplified sound signal; an amplifier operably connected to the microphone preamplifier for receiving the pre-amplified sound signal and for generating an amplified sound signal having a user adjustable gain; an analog to digital converter operably connected to the amplifier, the analog to digital converter having a predetermined dynamic range and wherein the gain of the pre-amplifier is determined so that the amplified sound signal falls within the predetermined dynamic range of the analog to digital converter; a digital transmitter operably connected to the analog to digital converter for transmitting the digital signal; and a microprocessor operably connected to the digital transmitter port, the analog to digital converter and the amplifier.

Another aspect of the invention is related to a method of testing hearing including the steps of: providing a test subject with a device including a system controller capable of generating a sound signal and a control signal and wireless headphones capable of receiving the sound signal and generating an output sound signal having a sound level of between 0 to 100 dB SPL and a frequency range of between 20 Hz to 20 kHz and capable of adjusting the sound signal responsive to the control signal; sending a first sound signal from the device to the wireless headphones; enabling the test subject to provide a response to the first sound signal and modifying the first sound signal responsive to the response to produce a second sound signal; and sending the second sound signal from the device to the wireless headphones.

In another aspect of the invention there is provided a method for controlling headphones having a headphone interface wherein the headphone interface includes a digital reception port, a digital to analog converter having a predetermined dynamic range, an attenuator, and a headphone amplifier comprising the steps of: receiving a digital sound signal; scaling the digital sound signal to maximize the use of the predetermined dynamic range of the digital to analog converter in the headphone interface to produce a scaled digital sound signal and determining a scaling factor; sending the scaled digital sound signal to the headphone interface; converting the digital sound signal to an analog sound signal; attenuating the analog sound signal based on a user defined scaling factor to

produce and attenuated analog sound signal; amplifying the attenuated analog sound signal to produce an amplified attenuated sound signal; and sending the amplified attenuated sound signal to the headphones.

In another aspect of the invention there is provided a method of testing voice including the steps of: providing a test subject with a device including a display and a system controller capable of receiving a microphone sound signal and a microphone control signal, wherein the display is capable of displaying characteristics of the microphone sound signal and a wireless microphone adapted to receive a voice signal and capable of generating the microphone sound signal and generating the microphone control signal; generating a first microphone sound signal responsive to the voice of a test subject; sending a first microphone sound signal from the wireless microphone to the device; displaying the characteristics of the first microphone sound signal on the device.

A still further aspect of the invention relates to a method for controlling a microphone having a microphone interface wherein the microphone interface includes a digital transmission port, an analog to digital converter having a predetermined dynamic range, an amplifier, and a pre-amplifier comprising the steps of: receiving an analog sound signal; scaling the analog sound signal to maximize the use of the predetermined dynamic range of the analog to digital converter in the microphone interface to produce a scaled analog sound signal and determining a scaling factor; converting the scaled analog sound signal to a scaled digital sound signal; and sending the scaled digital sound signal to a central processor.

Further features of the invention will be described or will become apparent in the course of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a block diagram of the handheld wireless device for auditory function assessment built according to the present invention;

Figure 2 is a block diagram of the invention in multi-subject testing

mode;

Figure 3 is a preferred embodiment of the handheld wireless device for vocal function measurement;

Figure 4 is a block diagram of the software residing in the handheld device;

Figure 5 is a block diagram of the sound and control signal generation portion of the software in the handheld device; and

Figure 6 is a block diagram of the handheld voice analyzer.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 depicts the block diagram of the present invention for testing the auditory functioning of a human subject. The invention supports diagnostic testing of the subject's left and right ear independently or together for binaural measurements. Accordingly completely different sentences could be sent to the right headphone versus the left headphone.

The invention consists of two main parts: a handheld computing device 2 that hosts the software and the method for conducting the auditory tests; and a wireless headphone interface 26 that communicates with the handheld computing device and delivers the sound to the headphones. The wireless headphone interface 16 comprises of a microprocessor

28, digital RF transmission port 18 and reception port 20, a stereo Digital-to-Analog (D/A) converter 22, a stereo programmable attenuator 24, a stereo headphone amplifier 26, and a response button 31. On powering up, the microprocessor initializes the transmission port 18 and reception port 20, establishes a connection with the handheld computing device 2 using the transmission port 18 and reception port 20, and initializes the D/A converter 22, and the programmable attenuator 24.

In its most basic configuration, the handheld computing device 2 is comprised of the digital RF transmission port 12 and reception port 10, a plurality of storage media 4 (compact flash, microdrive, secure digital etc.), and a central processing unit 8, which may include a general purpose processor and a digital signal processing coprocessor. In this embodiment the software 6 residing on the handheld computing device is responsible for conducting the entire auditory test

procedure. On start up, the software 6 initializes the transmission port 12 and reception port 10, establishes a connection with the wireless headphone interface 16, and presents a graphical user interface to the tester.

The graphical user interface allows the tester to either select a previously recorded sound stimulus stored as a file on the storage media, or to dynamically generate a sound stimulus. The tester also selects the presentation level of the sound signal for the left and right channels in dB SPL. When the tester instructs the software to play the sound signal, the software scales the digital sound stimulus such that it spans the dynamic range of the D/A converter 22 in the headphone interface 16. The scaling instructions are sent via the control signal. This step ensures that the signal-to-quantization noise ratio is as high as possible when the digital sound stimulus is converted into an analog form. The software then calculates the appropriate attenuation value for the programmable attenuator on the wireless headphone interface 16 and instructs the microprocessor 28 in the wireless headphone interface 16 to set the programmable attenuator 24 and to prepare the D/A converter 22. The digital data associated with the scaled sound stimulus are then streamed over the wireless channel 14.

The digital data stream is captured by the reception port 20 on the wireless headphone interface 16 and is converted into the analog form by the D/A converter 22. The attenuator 24 reduces the overall level of the analog signal to the desired value and delivers it to the stereo headphone amplifier 26. This amplifier provides the necessary amplification and impedance match to the headphones 30. The sound stimulus of precise level and low quantization noise is then delivered as an output of the headphones 30. The invention may be used with a plurality of different headphone devices through a calibration procedure. Typical headphones used in auditory tests include TDH phones, insert ear-phones, and circumaural audiometric headphones. Each headphone has its own unique sensitivity characteristics which can be accounted for as part of the calibration procedure, which is part of the software residing on the handheld computing device.

During the calibration procedure, a 1000 Hz sinusoidal signal that occupies the entire dynamic range (termed 0 dB full-scale) of the D/A converter is

streamed to the wireless headphone interface, with the programmable attenuator set to 0 dB. The resulting headphone output for any of the plurality of the headphones is measured using standardized sound calibration equipment such as a sound level meter. The corresponding sound level in dB SPL is measured and stored as part of the calibration curve for that headphone. This measurement is performed at several frequencies to obtain a complete calibration curve for any headphone. The calibration curve is stored on the storage media and is retrieved by the software at the beginning of the testing at the behest of the tester. The response button 31 connects to the serial port of the microprocessor 28 in the wireless headphone interface 16. When the subject hears a particular sound, or when he/she understands a particular word or sentence, the response button 31 is pressed. The microprocessor 28 then relays this information to the handheld computing device 2 over the wireless channel 14. The software then responds by either adjusting the level on the left or right channel, or by delivering a different sound stimulus at appropriate level. Note that a set of multiple buttons, instead of single button, can also be used for obtaining subjects' feedback to the delivered sound stimuli.

One of the features of the present invention is its ability to perform multiple auditory tests simultaneously, as shown in Figure 2. Such a feature will be extremely useful and efficient when auditory tests are conducted at a manufacturing facility where a number of workers need to be tested, or at a senior care facility where a number of seniors can be tested in a shorter time. The sound signal may be a variety of sound signals may be speech, music, noise and pure tone. When determining the dynamic range of the sound signal an average is taken of the speech, music, noise or pure tone signal.

Each wireless headphone interface is assigned a unique identification number #1 102, #2 104, to #N 106, similar to the IP address used in internet communications. The software residing on the handheld computing device 100 maintains a table of these unique identification numbers which are obtained during the initialization phase. During testing, the software multiplexes the sound level adjustments and the delivery of the sound stimulus between each of the active wireless headphone interfaces 102, 104, and 106.

Figure 3 depicts the preferred embodiment of the present invention for measuring the vocal function characteristics of a human subject. The system consists a handheld computing device 40 with the vocal function testing software 44, a wireless microphone interface 54 and a microphone 70. The wireless microphone interface 54 is comprised of a microprocessor 66, digital RF transmission port 58 and reception port 60 port, a stereo Analog-to-Digital (A/D) converter 56, a programmable amplifier 62, and a microphone pre-amplifier 64. On powering up, the microprocessor 66 initializes the transmission port 58 and reception port 60, establishes a connection with the handheld computing device 40 using the transmit 58 and receive 60 ports, and initializes the A/D converter 56, and the programmable amplifier 62.

In its most basic configuration, the handheld computing device 40 comprises the digital RF transmission port 50 and reception port 48, a plurality of storage media 42 (compact flash, microdrive, secure digital etc.), and a central processing unit 46. The software 44 residing on the handheld computing device is responsible for conducting the entire vocal function testing procedure. On start up, the software 44 initializes the transmission port 48 and reception port 50, establishes a connection 52 with the wireless microphone interface 54, and presents a graphical user interface to the tester. At the behest of the tester, the software instructs the microprocessor

66 on the wireless microphone interface 54 to start the data acquisition procedure. The programmable amplifier 62 on the wireless microphone interface 54 then adjusts its gain such that its output spans the dynamic range of the A/D converter 56. The programmable amplifier 62 interrupts the microprocessor when its gain changes. The microprocessor 66, in turn, reads the gain value of the programmable amplifier 62 and relays this value to the handheld computing device 40.

The A/D converter 56 transforms the analog microphone signal into a digital stream which is transported to the handheld computing device over the wireless channel 52. The vocal function testing software then displays the microphone signal as : (a) a waveform which depicts the level variations in the subject's voice, (b) a spectrum which displays the level variations at different frequencies and also the range of frequencies in the subject's voice, (c) a

fundamental frequency track which shows how the fundamental frequency or pitch of the subject's voice changes over the course of a sentence or a word, (d) an intensity track which displays how the intensity of subject's voice changes over the course of a sentence or a word, or (e) a vocal noise plot which estimates and displays the amount of background noise in the subject's voice.

The software 44 also facilitates the setting of targets for fundamental frequency, intensity, spectral parameters, and vocal noise for the subject to practice and match. For example, if a subject has poor control over their vocal pitch, a target range can be setup in the fundamental frequency screen of the software. When the client phonates into the microphone, the software acquires the microphone data over the wireless channel, computes the fundamental frequency and displays this information on the screen of the handheld computing device along with the pitch targets. By viewing this information on the screen, the subject will be able to modify their vocal function behaviour and achieve better control over their voice production. Referring to figure 4 the block diagram shows a more detailed description of the software 120 used in the handheld computing device 2. The main software program 122 has the graphical user interface 124 that allows the Audiologist to select the number of psychoacoustic tests to be run, and the parameters associated with the psychoacoustic tests. The software 120 includes the main software program 122 the sound and control signal generation 126, the animation and administering of the test 128 and the data collection and reporting 130.

Referring to figure 5 the sound and control signal generation 126 is described in more detail. The signal generation block 132 can create tonal and noise signals with varying spectral content, levels, and durations. In addition, this block can load digital audio data (speech, music, environmental sounds etc.) from a CD player, or from a storage medium (.wav files, MP3 files etc.). The signal manipulation block 134 can alter the temporal and spectral characteristics of the generated signal. Examples include filtering, adding noise and distortion at a prescribed level, mixing of two different sound sources, and insertion of silence periods ("gaps"). The control generation block 136 creates the necessary control commands for setting up the D-to-A converter and the programmable attenuator in

the wireless headphone interface. The audio data and the control data are then mixed together into a single stream and delivered wirelessly to the wireless headphone interface. All three blocks 132, 134 and 136 mentioned above are controlled by the user feedback 138 during the test. The parameters of the signal generation, signal manipulation, and control generation are varied adaptively based on the response of the listener. This is done automatically without the need for intervention from the tester.

Referring to figure 6 wherein, the voice analysis system 140 is described in more detail. The signal analysis block 142 gathers the raw data from the microphone and performs the signal processing operations to extract meaningful operations. Typical signal processing operations include: (a) Fourier analysis to extract the frequency content in the microphone signal, (b) fundamental frequency estimation to determine the pitch and intensity of the talker, (c) filtering analysis to extract the resonant frequencies of the talker. The signal display block 144 presents the extracted information to the user so that he/she obtains a realtime visual feedback of their voice characteristics and may alter their voice production based on this display. Displays included in this block include:

• spectrogram - the spectrogram display allows clients to see variations in fricative energy and other spectral cues resulting from different articulatory postures. This component is therefore useful for treating articulatory disorders. In addition, the spectrogram can be used in quantifying the severity of a voice disorder. For example, the spectrogram can be used in classifying a voice sample into Type 1, Type 2, or Type 3 signal which signifies the severity of the voice disorder. • pitch - the realtime pitch display will allow clients to monitor and control the vocal fold vibratory characteristics. Pitch timing and intonational patterns are extremely useful for accurate pronunciation and for foreign accent reduction.

• formants - the realtime formant display allows the client to monitor and modify their vowel production. A two-dimensional vowel space display using the first two formant frequencies can be used to specify normative target areas for the client to practice and match.

• phonetogram - a phonetogram is a two dimensional display of the pitch and intensity parameters. This display is therefore useful to quantify the dynamic range of the pitch and intensity values, and in monitoring the effect of speech therapy in increasing the client's dynamic range. The voice analysis software 140 also allows for the clinician to set a range of targets for the user to match. For example, in the pitch display, the clinician may set a minimum and maximum values for the pitch. Using the visual feedback from the realtime pitch display, the client can adjust his/her voice production to keep their pitch within this range. Over time, this type of exercise will allow the user to gain more control and accuracy over their voice.

In one embodiment of the present invention the device possesses full- duplex capability, i.e. it can present the sound signals through the headphones while recording from the microphone. Once again, the sound data for the headphones, the control data for the attenuator and the digital-to-analog converter, the microphone control signal, and the microphone sound signal are all mixed together into a single stream.

There are at least two applications where this feature is useful: delayed auditory feedback and auditory alarms. In delayed auditory feedback, the microphone signal is delayed by a predetermined time and the same signal is played back through the headphones. The effect of delayed auditory feedback is the slow-down of talker's speech rate. Most normal speaking talkers slow down their speech under delayed auditory feedback. For stutterers, this actually improves their fluency. Due to the slowed down speech rate, they can prolong the vowels and consonants and "get around" stuttering. With the provision of a wireless interface and a handheld device, facilitating delayed auditory feedback in a controlled manner becomes quite easy.

Patients suffering from Parkinson's disease are unable to monitor their voice loudness properly. Their voice is often too low and soft and it becomes harder to understand them in noisy situations. With one embodiment of the device here, the microphone signal can be recorded and estimate the voice level with respect to the background noise, and if the voice level is too low, an audible alarm or message is played back through the headphones to elevate their voice loudness.

As used herein, the terms "comprises" and "comprising" are to construed as being inclusive and opened rather than exclusive. Specifically, when used in this specification including the claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or components are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

It will be appreciated that the above description related to the invention by way of example only. Many variations on the invention will be obvious to those skilled in the art and such obvious variations are within the scope of the invention as described herein whether or not expressly described.