Telephone with integrated hearing aid

The present invention relates to telecommunications equipment in general, and, in particular, to a telephone with an integrated hearing aid.

Telephones have become ubiquitous, and hands-free headsets that rest in a user's ear are gaining in popularity. Furthermore, with the advent of electronic miniaturization and wireless standards such as "Bluetooth", entire telephones that rest in and/or on a user's ear are becoming available and will surely be popular.

Since such hands-free headsets typically employ an in-ear-speaker - one that fits in the external auditory meatus and/or outer ear - some individuals with hearing loss might be prohibited from having both a hearing aid and a hands-free headset in an ear at the same time. Therefore, the need exists for a single apparatus that physically enables a user to have both a hearing aid and a hands-free headset in an ear at the same time.

<patcit id="pcit0001" dnum="DE19645259A1"><text>DE19645259 A1</text></patcit> relates to a mobile phone with hands-free set, where the speaker unit is a normal hearing aid equipped with an FM receiver. When a call is received the microphone in the hearing aid is either switched off, or its signal is attenuated.

The present invention enables the integration of a telephone and a hearing aid into a single apparatus having a single in-ear speaker, and, therefore, ameliorates the problem of wearing a hearing aid and an in-ear telephone simultaneously.

In accordance with the invention there is provided an apparatus according to claim 1.

The illustrative embodiments automatically adapt the operation of the hearing aid based on whether or not the user is engaged in a telephone call. For example, when the user is <u>not</u> engaged in a telephone call, the illustrative embodiments function as a normal hearing aid. But when the user does become engaged in a telephone call, the illustrative embodiments alter the hearing aid function to enhance the use's ability to hear the telephone call.

Furthermore, the inventors of the present invention recognize that completely turning off the hearing aid while a call is in progress might be dangerous or disadvantageous because it diminishes the user's awareness of his or her environment. Therefore, the illustrative embodiments attenuate the hearing aid function while a call is in progress so that the user can hear both the telephone call and retain some, albeit diminished, auditory input from the environment. This enables, for example, the user to still hear loud sounds (<i>e.g</i>., a car horn, a fire alarm, a person screaming, <i>etc</i>.).

In some examples which are useful for understanding the invention, the hearing aid function is attenuated by reducing the gain of the hearing aid uniformly across all frequencies of the amplified acoustic signal. In contrast, some embodiments of the present invention attenuate some frequencies more than others. For example, the incoming sound of a telephone call is bandwidth limited to a range of between <i>f</i>₁ and <i>f</i>₂ Hz. In a typical telephony system <i>f</i>₁ = 300 Hz and <i>f</i>₂ = 3000 Hz. Therefore, some embodiments of the present invention reduce the gain of the hearing aid more for frequencies between <i>f</i>₁ and <i>f</i>₂ Hz than for frequencies below <i>f</i>₁ or above <i>f</i>₂. This also helps the user to hear both the ongoing telephone call and to be aware of his or her environment.

A described arrangement, for which no protection is sought, comprises: a microphone for converting a first acoustic signal into a first electromagnetic signal <i>s₁(t);</i> a receiver for receiving a second electromagnetic signal <i>s₁(t);</i> a processor for generating a third electromagnetic signal <i>s₃(t)</i> based on <i>a</i>₁<i>(t) · s</i>₁<i>(t)</i> and <i>a</i>₂<i>(t) · s</i>₂<i>(t),</i> wherein |<i>a</i>₁<i>(t</i>₁<i>)</i>/<i>a</i>₂<i>(t</i>₁<i>)</i>| changes based whether the apparatus is engaged in a telephone call or not; and a speaker for converting the third electromagnetic signal <i>s₃(t)</i> into a second acoustic signal. <ul id="ul0001" list-style="none"><li><figref idref="f0001">FIG. 1</figref> depicts a rendering of telephone/hearing aid 100 in accordance with the described arrangement.</li><li><figref idref="f0002">FIG. 2</figref> depicts a block diagram of the salient components of telephone/hearing aid 100 in accordance with the described arrangement.</li><li><figref idref="f0003">FIG. 3</figref> depicts a rendering of telephone/hearing aid 200 in accordance with an example which is useful for understanding the invention.</li><li><figref idref="f0004">FIG. 4</figref> depicts a block diagram of the salient components of telephone/hearing aid 200 in accordance with the example which is useful understanding the invention.</li></ul>

<figref idref="f0001">FIG. 1</figref> depicts a rendering of telephone/hearing aid 100 in accordance with the described arrangement. As depicted in <figref idref="f0001">FIG. 1</figref>, telephone/hearing aid 100 comprises: housing 101, microphone 102, speaker 103, and volume control 104. Telephone/hearing aid 100 is a wireless telephone (<i>e.g.</i>, a cordless telephone, a cellular telephone, <i>etc.</i>) that operates with the telephone system via radio rather than via a wire. It will be clear to those skilled in the art, however, how to make and use arrangements in which telephone/hearing aid 100 is a wireline telephone.

Housing 101 is designed like a hearing aid so that it can be worn within the external auditory meatus and outer ear. It will be clear to those skilled in the art how to make and use housing 101. Microphone 102, speaker 103, and volume control 104 are all described in detail below.

<figref idref="f0002">FIG. 2</figref> depicts a block diagram of the salient components of telephone/hearing aid 100. As depicted in <figref idref="f0002">FIG. 2</figref>, telephone/hearing aid 100 comprises: microphone 102, speaker 103, volume control 104, antenna 105, wireless transmitter 106, receiver 107, processor 108, and amplifier 109, interconnected as shown.

Microphone 102 picks up an acoustic signal within the vicinity of housing 101, converts it to an electromagnetic signal, <i>s₁(t),</i> and feeds signal <i>s₁(t)</i> to processor 108, in well-known fashion. Signal <i>s₁(t)</i> is a wideband signal with a frequency band in excess of [<i>f</i>₁,<i>f</i>₂].

Receiver 107 receives an incoming electromagnetic signal (<i>e.g.</i>, a telephone call, <i>etc.</i>) via antenna 105 from a remote transmitter (not shown), demodulates the incoming signal, and passes the demodulated signal, <i>s₂(t),</i> to processor 108, in well-known fashion. Signal <i>s₂(t)</i> represents a band-limited acoustic signal with a frequency range of [<i>f</i>₁,<i>f</i>₂].

Speaker 103 receives a third electromagnetic signal, <i>s₃(t),</i> from processor 108 via amplifier 109 and converts it into an acoustic signal, in well-known fashion. How processor 108 generates signal <i>s₃(t)</i> is described in detail below. Amplifier 109 receives signal <i>s₃(t)</i> from processor 108 and amplifies it in well-known fashion. The gain of amplifier 109 is controlled by volume control 104, which enables a user of telephone/hearing aid 100 to affect the volume (<i>i.e.</i>, the amount of acoustical energy) of the sound output of speaker 103. Furthermore, the gain of amplifier 109 is not affected by whether a telephone call is in progress or not.

Transmitter 106 receives an outgoing electromagnetic signal from processor 108, modulates the outgoing signal, and transmits the modulated signal via antenna 105, in well-known fashion.

Processor 108 receives: <ol id="ol0001" compact="compact" ol-style=""><li>(1) signal <i>s₁(t)</i> from microphone 102, and</li><li>(2) signal <i>s₂(t)</i> from receiver 107,</li></ol> and generates based on those signals: <ol id="ol0002" compact="compact" ol-style=""><li>(1) the output to transmitter 106, and</li><li>(2) signal <i>s₃(t).</i></li></ol>

When there is no call in progress (<i>i.e.</i>, <i>s₂(t)</i> = <i>0</i>), telephone/hearing aid 100 functions solely as a hearing aid and, therefore, processor 108 generates signal <i>s₃(t)</i> based solely on signal <i>s₁(t)</i>. For example,<maths id="math0001" num="(eq. 1)"><math display="block"><msub><mi>s</mi><mn>3</mn></msub><mfenced><mi>t</mi></mfenced><mo>=</mo><msub><mi>a</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced></math><img file="EP1379103B2_D0001.tif" /></maths> wherein <i>a₁(t)</i> is a coefficient that affects the gain or contribution of signal <i>s₁(t)</i> to signal <i>s₃(t).</i>

In contrast, when there is a call in progress (<i>i.e., s₂(t)</i> ≠0), telephone/hearing aid 100 functions both as a hearing aid and as a telecommunications device. In this case, processor 108 combines, as described below, signal <i>s₂(t)</i> and signal <i>s₁(t)</i> to produce signal <i>s₃(t).</i> For example,<maths id="math0002" num="(eq. 2)"><math display="block"><msub><mi>s</mi><mn>3</mn></msub><mfenced><mi>t</mi></mfenced><mo>=</mo><msub><mi>a</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced><mo>+</mo><msub><mi>a</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced></math><img file="EP1379103B2_D0002.tif" /></maths> wherein <i>a₂(t)</i> is a coefficient that affects the relative contribution of signal <i>s₂(t)</i> to signal <i>s₃(t).</i>

To ensure that the total sound energy entering the user's ear is a constant regardless of whether a telephone call is in progress or not, the total energy of signal <i>s₃(t)</i> is maintained at a constant level both when a telephone call is in progress and when it is not. This is accomplished by having processor 108 automatically vary the coefficients <i>a₁(t)</i> and <i>a₂(t)</i>, or the ratio of <i>a₁(t)</i>/<i>a₂(t)</i>, based on whether a telephone call is in progress or not. In other words, the absolute value of the ratio of <i>a₁(t)</i>/<i>a₂(t)</i> is less when a call is in progress than when a call is not in progress (<i>i.e.</i>, when signal <i>s₂(t)</i> is less than a threshold).

Furthermore, processor 108 filters - in the frequency domain - signal <i>s₁(t)</i> from microphone 102 so that the frequency components in signal <i>s₁(t)</i> in the frequency range [<i>f</i>₁, <i>f₂</i>] are more attenuated than the frequency components below <i>f</i>₁ or above <i>f</i>₂. In particular, processor 108 generates signal <i>s₃(t)</i> based on: <maths id="math0003" num="(eq. 3)"><math display="block"><msub><mi>s</mi><mn>3</mn></msub><mfenced><mi>t</mi></mfenced><mo>=</mo><mi>f</mi><mo>⁢</mo><mfenced separators=""><msub><mi>a</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><mfenced open="[" close="]" separators=""><mi>h</mi><mfenced><mi>t</mi></mfenced><mo>*</mo><msub><mi>s</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced></mfenced><mo>+</mo><msub><mi>a</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced></mfenced></math><img file="EP1379103B2_D0003.tif" /></maths> wherein <i>h(t)</i> is the impulse response of a frequency-domain notch filter with a notch band of [<i>f</i>₁,<i>f</i>₂]. It will be clear to those skilled in the art how to filter signal <i>s₁(t)</i> in this way.

Furthermore, while a call is in progress, processor 108 feeds the input from microphone 102 - which includes the user's voice - into transmitter 106 for transmission via antenna 105 and - for the purposes of sidetone- into signal <i>s₃(t).</i>

<figref idref="f0003">FIG. 3</figref> depicts a rendering of telephone/hearing aid 200 in accordance with an example which is useful for understanding the invention. As depicted in <figref idref="f0002">FIG. 2</figref>, telephone/hearing aid 200 comprises: housing 201, microphone 202-1, stalk 210, microphone 202-2, speaker 103, and volume control 104. In accordance with the illustrative embodiment, telephone/hearing aid 200 is a wireless telephone (<i>e.g.</i>, a cordless telephone, a cellular telephone, <i>etc.</i>) that operates with the telephone system via radio rather than via a wire.

Housing 201 is designed like a hearing aid so that it can be worn within the external auditory meatus and outer ear. It will be clear to those skilled in the art how to make and use housing 101.

Stalk 210 is a structural member that positions microphone 202-1 closer to a user's mouth than microphone 202-2, which enables microphone 202-1 to pick up more of the user's voice during a telephone call than does microphone 202-2. Although both microphones will typically pick up many common sounds, microphone 202-1 is designed to pick up the user's own voice, whereas, in contrast, microphone 202-2 is designed to pick up all sounds in the vicinity of housing 201. The purpose for having two different microphones that are designed to pick up different sounds is described in detail below. Microphone 202-1, microphone 202-2, speaker 203, and volume control 204 are also all described in detail below.

<figref idref="f0004">FIG. 4</figref> depicts a block diagram of the salient components of telephone/hearing aid 200. As depicted in <figref idref="f0004">FIG. 4</figref>, telephone/hearing aid 200 comprises: microphone 202-1, microphone 202-2, speaker 203, volume control 204, antenna 205, wireless transmitter 206, receiver 207, processor 208, and amplifier 209, interconnected as shown.

Microphone 202-1 picks up an acoustical signal at the end of stalk 210, converts it to an electromagnetic signal, <i>s₁(t),</i> and feeds signal <i>s₁(t)</i> to processor 208, in well-known fashion. In accordance with the example which is useful for understanding the invention, signal <i>s₁(t)</i> is a signal with a frequency band of [<i>f</i>₁,<i>f</i>₂].

Microphone 202-2 picks up an acoustic signal within the vicinity of housing 201, converts it to an electromagnetic signal, <i>s₂(t),</i> and feeds signal <i>s₂(t)</i> to processor 208, in well-known fashion. In accordance with the example which is useful for understanding the invention, signal <i>s₂(t)</i> is a wideband signal with a frequency band in excess of [<i>f</i>₁,<i>f</i>₂].

Receiver 207 receives an incoming electromagnetic signal (<i>e.g.</i>, a telephone call, <i>etc.</i>) via antenna 205 from a remote transmitter (not shown), demodulates the incoming signal, and passes the demodulated signal, <i>s₃(t),</i> to processor 208, in well-known fashion. In accordance with the example which is useful for understanding the invention, signal <i>s₃(t)</i> represents a band-limited acoustic signal with a frequency range of [<i>f</i>₁,<i>f</i>₂].

Speaker 203 receives signal <i>s₄(t)</i> from processor 208 via amplifier 209 and converts it into an acoustic signal, in well-known fashion. How processor 208 generates signal <i>s₄(t)</i> is described in detail below.

Amplifier 209 receives signal <i>s₄(t)</i> from processor 208 and amplifies it in well-known fashion. The gain of amplifier 209 is controlled by volume control 204, which enables a user of telephone/hearing aid 200 to affect the volume (<i>i.e.</i>, the amount of acoustical energy) of the sound output of speaker 203. Furthermore, the gain of amplifier 209 is not affected by whether a telephone call is in progress or not.

Transmitter 206 receives an outgoing electromagnetic signal from processor 208, modulates the outgoing signal, and transmits the modulated signal via antenna 205, in well-known fashion.

Processor 208 receives: <ol id="ol0003" compact="compact" ol-style=""><li>(1) signal, <i>s₁(t),</i> from microphone 202-1,</li><li>(2) signal, s₂(t), from microphone 202-2,and</li><li>(3) signal, <i>s₃(t),</i> from receiver 207,</li></ol> and generates based on those signals: <ol id="ol0004" compact="compact" ol-style=""><li>(1) the output to transmitter 206, and</li><li>(2) signal <i>s₄(t).</i></li></ol>

When there is no call in progress (<i>i.e., s₃(t)</i> = <i>0</i>), telephone/hearing aid 200 functions solely as a hearing aid and, therefore, processor 208 generates signal <i>s₄(t)</i> based solely on signal <i>s₂(t).</i> For example, <maths id="math0004" num="(eq. 4)"><math display="block"><msub><mi>s</mi><mn>4</mn></msub><mfenced><mi>t</mi></mfenced><mo>=</mo><msub><mi>a</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced></math><img file="EP1379103B2_D0004.tif" /></maths> wherein <i>a₂(t)</i> is a coefficient that affects the gain or contribution of signal <i>s₂(t)</i> to signal <i>s₃(t).</i>

In contrast, when there is a call in progress (<i>i.e., s₃(t)</i> ≠0), telephone/hearing aid 200 functions both as a hearing aid and as a telecommunications device. In this case, processor 208 combines, as described below, signal <i>s₁(t)</i>, signal <i>s₂(t),</i> and signal <i>s₃(t)</i> to produce signal <i>s₄(t).</i> For example,<maths id="math0005" num="(eq. 5)"><math display="block"><msub><mi>s</mi><mn>4</mn></msub><mfenced><mi>t</mi></mfenced><mo>=</mo><msub><mi>a</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced><mo>+</mo><msub><mi>a</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced><mo>+</mo><msub><mi>a</mi><mn>3</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>3</mn></msub><mfenced><mi>t</mi></mfenced></math><img file="EP1379103B2_D0005.tif" /></maths> wherein <i>a</i>₁(<i>t</i>) is a coefficient that affects the gain or contribution of signal <i>s</i>₁(<i>t</i>) to signal <i>s₄(t)</i> and wherein <i>a₃(t)</i> is a coefficient that affects the gain or contribution of signal <i>s₃(t)</i> to signal <i>s₄(t).</i>

To ensure that the total sound energy entering the user's ear is a constant regardless of whether a telephone call is in progress or not, the total energy of signal <i>s₄(t)</i> is maintained at a constant level both when a telephone call is in progress and when it is not. This is accomplished by having processor 208 automatically vary coefficients <i>a₁(t)</i>, <i>a₂(t)</i>, and <i>a₃(t)</i> or the ratio of <i>a</i>₁(<i>t</i>)/<i>a</i>₂(<i>t</i>) and <i>a</i>₂(<i>t</i>)/<i>a</i>₃(<i>t</i>) based on whether a telephone call is in progress or not.

Furthermore, processor 208 filters - in the frequency domain - signal, <i>s₂(t),</i> from microphone 202-2 so that the frequency components in signal <i>s</i>₂(<i>t</i>) in the frequency range [<i>f₁</i>,<i>f₂</i>] are more attenuated than the frequency components below <i>f</i>₁ or above <i>f</i>₂. In particular, processor 208 generates signal <i>s₄(t)</i> based on:<maths id="math0006" num="(eq. 6)"><math display="block"><msub><mi>s</mi><mn>4</mn></msub><mfenced><mi>t</mi></mfenced><mo>=</mo><msub><mi>a</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>1</mn></msub><mfenced><mi>t</mi></mfenced><mo>+</mo><msub><mi>a</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><mfenced open="[" close="]" separators=""><mi>h</mi><mfenced><mi>t</mi></mfenced><mo>*</mo><msub><mi>s</mi><mn>2</mn></msub><mfenced><mi>t</mi></mfenced></mfenced><mo>+</mo><msub><mi>a</mi><mn>3</mn></msub><mfenced><mi>t</mi></mfenced><mo>⋅</mo><msub><mi>s</mi><mn>3</mn></msub><mfenced><mi>t</mi></mfenced></math><img file="EP1379103B2_D0006.tif" /></maths> wherein <i>h(t)</i> is the impulse response of a frequency-domain notch filter with a notch band of [<i>f</i>₁,<i>f</i>₂]. It will be clear to those skilled in the art how to filter signal <i>s₂(t)</i> in this way. Furthermore, while a call is in progress, processor 208 feeds the input from microphone 202-1 (<i>i.e.,</i> the user's voice) into transmitter 206 for transmission via antenna 205 and - for the purposes of sidetone - into signal <i>s₄(t).</i>