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.).

Description:
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&#39;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&#39;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&#39;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&#39;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 f 1  and f 2  Hz. In a typical telephony system f 1 =300 Hz and f 2 =3000 Hz. Therefore, some embodiments of the present invention reduce the gain of the hearing aid more for frequencies between f 1  and f 2  Hz than for frequencies below f 1  or above f 2 . 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 s 1 (t); a receiver for receiving a second electromagnetic signal s 2 (t); a processor for generating a third electromagnetic signal s 3 (t) based on a 1 (t)·s 1 (t) and a 2 (t)·s 2 (t), wherein |a 1 (t 1 )/a 2 (t 1 )| changes based whether the apparatus is engaged in a telephone call or not; and a speaker for converting the third electromagnetic signal s 3 (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, s 1 (t), and feeds signal s 1 (t) to processor  108 , in well-known fashion. In accordance with the first illustrative embodiment, signal s 1 (t) is a wideband signal with a frequency band in excess of [f 1 ,f 2 ]. 
     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, s 2 (t), to processor  108 , in well-known fashion. In accordance with the first illustrative embodiment, signal s 2 (t) represents a band-limited acoustic signal with a frequency range of [f 1 ,f 2 ]. 
     Speaker  103  receives a third electromagnetic signal, s 3 (t), from processor  108  via amplifier  109  and converts it into an acoustic signal, in well-known fashion. How processor  108  generates signal s 3 (t) is described in detail below. 
     Amplifier  109  receives signal s 3 (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 s 1 (t) from microphone  102 , and   (2) signal s 2 (t) from receiver  107 ,   and generates based on those signals:   (1) the output to transmitter  106 , and   (2) signal s 3 (t).       

     When there is no call in progress (i.e., s 2 (t)=0), telephone/hearing aid  100  functions solely as a hearing aid and, therefore, processor  108  generates signal s 3 (t) based solely on signal s 1 (t). For example,
 
 s   3 ( t )= a   1 ( t )· s   1 ( t )  (Eq. 1)
 
     wherein a 1 (t) is a coefficient that affects the gain or contribution of signal s 1 (t) to signal s 3 (t). 
     In contrast, when there is a call in progress (i.e., s 2 (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 s 2 (t) and signal s 1 (t) to produce signal s 3 (t). For example,
 
 s   3 ( t )= a   1 ( t )· s   1 ( t )+ a   2 ( t )· s   2 ( t )  (Eq. 2)
 
     wherein a 2 (t) is a coefficient that affects the relative contribution of signal s 2 (t) to signal s 3 (t). 
     To ensure that the total sound energy entering the user&#39;s ear is a constant regardless of whether a telephone call is in progress or not, the total energy of signal s 3 (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 a 1 (t) and a 2 (t), or the ratio of a 1 (t)/a 2 (t), based on whether a telephone call is in progress or not. In other words, the absolute value of the ratio of a 1 (t)/a 2 (t) is less when a call is in progress than when a call is not in progress (i.e., when signal s 2 (t) is less than a threshold). 
     Furthermore, processor  108  filters—in the frequency domain—signal s 1 (t) from microphone  102  so that the frequency components in signal s 1 (t) in the frequency range [f 1 ,f 2 ] are more attenuated than the frequency components below f 1  or above f 2 . In particular, processor  108  generates signal s 3 (t) based on:
 
 s   3 ( t )= f ( a   1 ( t )·[ h ( t )* s   1 ( t )]+ a   2 ( t )· s   2 ( t ))  (Eq. 3)
 
     wherein h(t) is the impulse response of a frequency-domain notch filter with a notch band of [f 1 ,f 2 ]. It will be clear to those skilled in the art how to filter signal s 1 (t) in this way. 
     Furthermore, while a call is in progress, processor  108  feeds the input from microphone  102 —which includes the user&#39;s voice—into transmitter  106  for transmission via antenna  105  and—for the purposes of sidetone—into signal s 3 (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&#39;s mouth than microphone  202 - 2 , which enables microphone  202 - 1  to pick up more of the user&#39;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&#39;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, s 1 (t), and feeds signal s 1 (t) to processor  208 , in well-known fashion. In accordance with the second illustrative embodiment, signal s 1 (t) is a signal with a frequency band of [f 1 ,f 2 ]. 
     Microphone  202 - 2  picks up an acoustic signal within the vicinity of housing  201 , converts it to an electromagnetic signal, s 2 (t), and feeds signal s 2 (t) to processor  208 , in well-known fashion. In accordance with the illustrative embodiment, signal s 2 (t) is a wideband signal with a frequency band in excess of [f 1 ,f 2 ]. 
     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, s 3 (t), to processor  208 , in well-known fashion. In accordance with the illustrative embodiment, signal s 3 (t) represents a band-limited acoustic signal with a frequency range of [f 1 ,f 2 ]. 
     Speaker  203  receives signal s 4 (t) from processor  208  via amplifier  209  and converts it into an acoustic signal, in well-known fashion. How processor  208  generates signal s 4 (t) is described in detail below. 
     Amplifier  209  receives signal s 4 (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, s 1 (t), from microphone  202 - 1 ,   (2) signal, s 2 (t), from microphone  202 - 2 , and   (3) signal, s 3 (t), from receiver  207 ,   and generates based on those signals:   (1) the output to transmitter  206 , and   (2) signal s 4 (t).       

     When there is no call in progress (i.e., s 3 (t)=0), telephone/hearing aid  200  functions solely as a hearing aid and, therefore, processor  208  generates signal s 4 (t) based solely on signal s 2 (t). For example,
 
 s   4 ( t )= a   2 ( t )· s   2 ( t )  (Eq. 4)
 
     wherein a 2 (t) is a coefficient that affects the gain or contribution of signal s 2 (t) to signal s 3 (t). 
     In contrast, when there is a call in progress (i.e., s 3 (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 s 1 (t), signal s 2 (t), and signal s 3 (t) to produce signal s 4 (t). For example,
 
 s   4 ( t )= a   1 ( t )· s   1 ( t )+ a   2 ( t )· s   2 ( t )+ a   3 ( t )· s   3 ( t )  (Eq. 5)
 
     wherein a 1 (t) is a coefficient that affects the gain or contribution of signal s 1 (t) to signal s 4 (t) and wherein a 3 (t) is a coefficient that affects the gain or contribution of signal s 3 (t) to signal s 4 (t). 
     To ensure that the total sound energy entering the user&#39;s ear is a constant regardless of whether a telephone call is in progress or not, the total energy of signal s 4 (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 a 1 (t), a 2 (t), and a 3 (t) or the ratio of a 1 (t)/a 2 (t) and a 2 (t)/a 3 (t) based on whether a telephone call is in progress or not. 
     Furthermore, processor  208  filters—in the frequency domain—signal, s 2 (t), from microphone  202 - 2  so that the frequency components in signal s 2 (t) in the frequency range [f 1 ,f 2 ] are more attenuated than the frequency components below f 1  or above f 2 . In particular, processor  208  generates signal s 4 (t) based on:
 
 s   4 ( t )= a   1 ( t )· s   1 ( t )+ a   2 ( t )·[ h ( t )* s   2 ( t )]+ a   3 ( t )· s   3 ( t )  (Eq. 6)
 
     wherein h(t) is the impulse response of a frequency-domain notch filter with a notch band of [f 1 ,f 2 ]. It will be clear to those skilled in the art how to filter signal s 2 (t) in this way. Furthermore, while a call is in progress, processor  208  feeds the input from microphone  202 - 1  (i.e., the user&#39;s voice) into transmitter  206  for transmission via antenna  205  and—for the purposes of sidetone—into signal s 4 (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.