# Patent

## Title
Telephone with integrated hearing aid

## Abstract

An integrated telephone and hearing aid that has a single in-ear speaker is disclosed. The illustrative embodiments automatically adapt the operation of the hearing aid based on whether a telephone call is in progress or not. For example, when the user is not 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 so that the user can hear the telephone call. For example, 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 (e.g., a car horn, a fire alarm, a person screaming, etc.).

## Background
STATEMENT OF RELATED CASES
This case is a division of co-pending U.S. patent application Ser. No. 10/186,818, filed on Jul. 1, 2002.


FIELD OF THE INVENTION
The present invention relates to telecommunications equipment in general, and, in particular, to a telephone with an integrated hearing aid.
BACKGROUND OF THE INVENTION
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.
SUMMARY OF THE INVENTION
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.
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 not 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 (e.g., a car horn, a fire alarm, a person screaming, etc.).
In some embodiments of the present 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 f1 and f2 Hz. In a typical telephony system f1=300 Hz and f2=3000 Hz. Therefore, some embodiments of the present invention reduce the gain of the hearing aid more for frequencies between f1 and f2 Hz than for frequencies below f1 or above f2. This also helps the user to hear both the ongoing telephone call and to be aware of his or her environment.
The first illustrative embodiment comprises: a microphone for converting a first acoustic signal into a first electromagnetic signal s1(t); a receiver for receiving a second electromagnetic signal s2(t); a processor for generating a third electromagnetic signal s3(t) based on a1(t)·s1(t) and a2(t)·s2(t), wherein |a1(t1)/a2(t1)| changes based whether the apparatus is engaged in a telephone call or not; and a speaker for converting the third electromagnetic signal s3(t) into a second acoustic signal.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a rendering of telephone/hearing aid 100 in accordance with the first illustrative embodiment of the present invention.
FIG. 2 depicts a block diagram of the salient components of telephone/hearing aid 100 in accordance with the first illustrative embodiment of the present invention.
FIG. 3 depicts a rendering of telephone/hearing aid 200 in accordance with the second illustrative embodiment of the present invention.
FIG. 4 depicts a block diagram of the salient components of telephone/hearing aid 200 in accordance with the second illustrative embodiment of the present invention.



DETAILED DESCRIPTION
FIG. 1 depicts a rendering of telephone/hearing aid 100 in accordance with the first illustrative embodiment of the present invention. As depicted in FIG. 1, telephone/hearing aid 100 comprises: housing 101, microphone 102, speaker 103, and volume control 104. In accordance with the first illustrative embodiment, telephone/hearing aid 100 is a wireless telephone (e.g., a cordless telephone, a cellular telephone, etc.) 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 embodiments of the present invention 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.
FIG. 2 depicts a block diagram of the salient components of telephone/hearing aid 100 in accordance with the first illustrative embodiment of the present invention. As depicted in FIG. 2, 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, s1(t), and feeds signal s1(t) to processor 108, in well-known fashion. In accordance with the first illustrative embodiment, signal s1(t) is a wideband signal with a frequency band in excess of [f1, f2].
Receiver 107 receives an incoming electromagnetic signal (e.g., a telephone call, etc.) via antenna 105 from a remote transmitter (not shown), demodulates the incoming signal, and passes the demodulated signal, s2(t), to processor 108, in well-known fashion. In accordance with the first illustrative embodiment, signal s2(t) represents a band-limited acoustic signal with a frequency range of [f1, f2].
Speaker 103 receives a third electromagnetic signal, s3(t), from processor 108 via amplifier 109 and converts it into an acoustic signal, in well-known fashion. How processor 108 generates signal s3(t) is described in detail below.
Amplifier 109 receives signal s3(t) 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.e., 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:

    
    
        (1) signal s1(t) from microphone 102, and
        (2) signal s2(t) from receiver 107,

and generates based on those signals:

        (1) the output to transmitter 106, and
        (2) signal s3(t).
    
    


When there is no call in progress (i.e., s2(t)=0), telephone/hearing aid 100 functions solely as a hearing aid and, therefore, processor 108 generates signal s3(t) based solely on signal s1(t). For example,

s3(t)=a1(t)·s1(t)  (Eq. 1)

wherein a1(t) is a coefficient that affects the gain or contribution of signal s1(t) to signal s3(t).

In contrast, when there is a call in progress (i.e., s2(t)≠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 s2(t) and signal s1(t) to produce signal s3(t). For example,

s3(t)=a1(t)·s1(t)+a2(t)·s2(t)  (Eq. 2)

wherein a2(t) is a coefficient that affects the relative contribution of signal s2(t) to signal s3(t).

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 s3(t) 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 a1(t) and a2(t), or the ratio of a1(t)/a2(t), based on whether a telephone call is in progress or not. In other words, the absolute value of the ratio of a1(t)/a2(t) is less when a call is in progress than when a call is not in progress (i.e., when signal s2(t) is less than a threshold).
Furthermore, processor 108 filters—in the frequency domain—signal s1(t) from microphone 102 so that the frequency components in signal s1(t) in the frequency range [f1, f2] are more attenuated than the frequency components below f1 or above f2. In particular, processor 108 generates signal s3(t) based on:

s3(t)=ƒ(a1(t)·[h(t)*s1(t)]+a2(t)·s2(t))  (Eq. 3)

wherein h(t) is the impulse response of a frequency-domain notch filter with a notch band of [f1, f2]. It will be clear to those skilled in the art how to filter signal s1(t) 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 s3(t).
FIG. 3 depicts a rendering of telephone/hearing aid 200 in accordance with the second illustrative embodiment of the present invention. As depicted in FIG. 2, 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 second illustrative embodiment, telephone/hearing aid 200 is a wireless telephone (e.g., a cordless telephone, a cellular telephone, etc.) 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 embodiments of the present invention in which telephone/hearing aid 200 is a wireline telephone.
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.
FIG. 4 depicts a block diagram of the salient components of telephone/hearing aid 200. As depicted in FIG. 4, 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, s1(t), and feeds signal s1(t) to processor 208, in well-known fashion. In accordance with the second illustrative embodiment, signal s1(t) is a signal with a frequency band of [f1, f2].
Microphone 202-2 picks up an acoustic signal within the vicinity of housing 201, converts it to an electromagnetic signal, s2(t), and feeds signal s2(t) to processor 208, in well-known fashion. In accordance with the illustrative embodiment, signal s2(t) is a wideband signal with a frequency band in excess of [f1, f2].
Receiver 207 receives an incoming electromagnetic signal (e.g., a telephone call, etc.) via antenna 205 from a remote transmitter (not shown), demodulates the incoming signal, and passes the demodulated signal, s3(t), to processor 208, in well-known fashion. In accordance with the illustrative embodiment, signal s3(t) represents a band-limited acoustic signal with a frequency range of [f1, f2].
Speaker 203 receives signal s4(t) from processor 208 via amplifier 209 and converts it into an acoustic signal, in well-known fashion. How processor 208 generates signal s4(t) is described in detail below.
Amplifier 209 receives signal s4(t) 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.e., 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:

    
    
        (1) signal, s1(t), from microphone 202-1,
        (2) signal, s2(t), from microphone 202-2, and
        (3) signal, s3(t), from receiver 207,

and generates based on those signals:

        (1) the output to transmitter 206, and
        (2) signal s4(t).
    
    


When there is no call in progress (i.e., s3(t)=0), telephone/hearing aid 200 functions solely as a hearing aid and, therefore, processor 208 generates signal s4(t) based solely on signal s2(t). For example,

s4(t)=a2(t)·s2(t)  (Eq. 4)

wherein a2(t) is a coefficient that affects the gain or contribution of signal s2(t) to signal s3(t).

In contrast, when there is a call in progress (i.e., s3(t)≠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 s1(t), signal s2(t), and signal s3(t) to produce signal s4(t). For example,

s4(t)=a1(t)·s1(t)+a2(t)·s2(t)+a3(t)·s3(t)  (Eq. 5)

wherein a1(t) is a coefficient that affects the gain or contribution of signal s1(t) to signal s4(t) and wherein a3(t) is a coefficient that affects the gain or contribution of signal s3(t) to signal s4(t).

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 s4(t) 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 a1(t), a2(t), and a3(t) or the ratio of a1(t)/a2(t) and a2(t)/a3(t) based on whether a telephone call is in progress or not.
Furthermore, processor 208 filters—in the frequency domain—signal, s2(t), from microphone 202-2 so that the frequency components in signal s2(t) in the frequency range [f1, f2] are more attenuated than the frequency components below f1 or above f2. In particular, processor 208 generates signal s4(t) based on:

s4(t)=a1(t)·s1(t)+a2(t)·[h(t)*s2(t)]+a3(t)·s3(t)  (Eq. 6)

wherein h(t) is the impulse response of a frequency-domain notch filter with a notch band of [f1, f2]. It will be clear to those skilled in the art how to filter signal s2(t) in this way. Furthermore, while a call is in progress, processor 208 feeds the input from microphone 202-1 (i.e., the user's voice) into transmitter 206 for transmission via antenna 205 and—for the purposes of sidetone—into signal s4(t).

It is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. It is therefore intended that such variations be included within the scope of the following claims and their equivalents.

## Claims

1. An apparatus comprising:
a microphone for converting a first acoustic signal into a first electromagnetic signal s1(t);
a receiver for receiving a second electromagnetic signal s2(t);
a processor for generating a third electromagnetic signal s3(t) based on a1(t)·s1(t) and a2(t)·s2(t), wherein |a1(t)/a2(t)| changes based on whether or not said apparatus is engaged in a telephone call; and
a speaker for converting said third electromagnetic signal s3(t) into a second acoustic signal.

2. The apparatus of claim 1 wherein at least one of a1(t) and a2(t) changes based on s1(t).

3. The apparatus of claim 1 wherein |a1(t)/a2(t1) |<|a1(t2)/a2(t2)| when:
(i) said apparatus is not engaged in at telephone call at time t1,
(ii) said apparatus is engaged in a telephone call at time t2, and
(iii) a1(t1), a1(t2), a2(t1, and a2(t2) are non-zero.

4. An apparatus comprising:
a first microphone for converting a first acoustic signal into a first electromagnetic signal s1(t);
a second microphone for converting a second acoustic signal into a second electromagnetic signal s2(t);
a receiver for receiving a third electromagnetic signal s3(t);
a processor for generating a fourth electromagnetic signal s4(t) based on a1(t)·s1(t), a2(t)·s2(t), and a3(t)·s3(t), wherein |a2(t)/a3(t)| changes based whether or not said apparatus is engaged in a telephone call; and
a speaker for converting s4(t) into a third acoustic signal.

5. The apparatus of claim 4 wherein at least one of a1(t), a2(t), and a3(t) changes based on at least one of s1(t) and s2(t).

6. The apparatus of claim 4 wherein |a2(t)/a3(t1)|<|a2(t2)/a3(t2)| when:
(i) said apparatus is not engaged in at telephone call at time t1,
(ii) said apparatus is engaged in a telephone call at time t2, and
(iii) a1(t1), a1(t2), a3(t1), and a3(t2) are non-zero.