Ear inserting type transmitter-receiver

Abstract

 An ear inserting type transmitter-receiver of full duplex system comprises an ear piece, a sound converting element, an impedance element, an electric signal applying means for applying an electric signal based on a first voice signal to a series circuit of the sound converting element and the impedance element, a detecting means for detecting the voltage across the sound converting element, an analog/digital converting means for converting the electric signal based on the first voice signal into a digital signal, an analog/digital converting means for converting a sound converting element terminal signal to a digital signal, a digital signal operational processing means for extracting a second voice signal from the sound converting element terminal signal based on output signals from the two analog/digital converting means and a digital/analog converting means for converting a digital signal of the second voice signal thus operated into an analog electric signal so as to function in common as a microphone and an earphone by means of the single sound converting element.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] The present invention relates to an ear inserting type transmitter-receiver having functions acting as speaker and microphone so as to be used for transmission and reception of all voice communications and constructed such that both transmitted and received information can be converted into audible voices by means of one energy converting element.

Related Background Art

[0002] Highly directional gun microphones or the like are used in noisy environment such as in a site of construction or in a jet plane, intending that the surrounding background noises hardly enter the microphone. However, since the background noises are reflected from the surrounding walls or vessels, it is difficult to perfectly remove them. In addition, in the gun microphone, an elongated cylindrical sound guiding hole is employed in order to improve directivity, so that collected voices become unaudible and hence audible voice electric signals can not be obtained.

[0003] Therefore, in order to collect voices without picking up the background noises, there has been conventionally used a bone conduction type microphone. The bone conduction type microphone is constructed such that a sound converting element consisting of a vibration energy/electric energy converting element is provided on the cheek bone, the jaw bone or the skull of the human body, the vibration conducted to the bone when a voice is uttered is converted into an electric energy, and the electric energy thus obtained is picked up and amplified into a collected voice electric signal.

[0004] Although the above mentioned bone conduction type microphone is capable of collecting the voices to obtain the electric signal in a state that the background noises present in the air in the form of sound waves are removed, it has such a drawback that the transmission characteristic is significantly different for different position of the above mentioned sound converting element relative to the cheek bone, the jaw bone or the skull, different contact pressure thereof with the bone and different contacting manner thereof with the bone.

[0005] Accordingly, it is required to always maintain constant the position and the contact pressure of the sound converting element by means of a specific supporting tool each time. However, it is difficult to meet this requirement stably every time. In addition, the bone conduction type microphone also has such a draw back that the reproducibility of the transmission characteristic of the sound collecting portion is represented as a change in reproducing characteristic (F characteristic) of frequency band.

[0006] Further, in another conventional bone conduction type microphone, talking speakers and sound collecting microphones are respectively housed within earpieces of a listener and a sender so as to realize voice communication therebetween without being influenced by the background noises. However, it sometimes occurs that the talking portion interferes with the sound collecting portion and hence it has been conventionally said difficult to make the ear piece act in common as the speaker and the microphone.

SUMMARY OF THE INVENTION

[0007] The present invention has been contemplated in view of the above mentioned drawbacks associated with the prior arts.

[0008] Accordingly, an object of the present invention is to provide an ear inserting type transmitter-receiver which is constructed such that a voice to be transmitted to a user and a voice uttered by a speaker or the user which are sent as electric signals can be converted into voice vibrations with the use of one sound converter which is disposed in opposition to the eardrum within the external ear path in common for transmission and reception and the voice uttered by the user is converted into an electric signal.

[0009] In order to achieve the object, according to the present invention, there is provided an ear inserting type transmitter-receiver, comprising:

an ear piece provided with an ear piecing insertion portion to be inserted into the external ear path; a sound converting element which is provided on a base portion of a sound passing hole perforated through the ear inserting insert portion so as to bidirectionally convert a sound vibration into an electric signal and vice versa;

an impedance element which is serially connected to an electric circuit of the sound converting element;

an electric signal applying means for applying an electric signal based on a first voice signal to be transmitted to a person who wears an ear piece series circuit of the sound converting element and the impedance element;

a sound converting element terminal signal detecting means for detecting the voltage across the sound converting element including a second voice signal obtained by electrically converting the voice uttered by the ear piece wearer;

a first analog/digital converting means for converting the electric signal based on the first voice signal to be transmitted to the ear piece wearer into a digital signal;

a second analog/digital converting means for converting the sound converting element terminal signal including the second voice signal obtained by electrically converting the voice uttered by the ear piece wearer into a digital signal;

a digital signal operational processing means for inputting therein the both digital signals output from the first and second analog/digital converting means to extract the second voice signal contained in the sound converting element terminal signal by digital signal operational processing based on the impedance of the sound converting element, the impedance of the impedance element which is serially connected with the sound converting element, the first voice signal applied to the series circuit of the impedance element and the sound converting element terminal signal generated across the sound converting element; and

a digital/analog converting means for converting a digital signal indicative of the second voice signal which is operationally processed by the digital signal operational processing means and is output therefrom into an analog electric signal.

[0010] According to the present invention, the following advantages are attained. The voice communication device of the full duplex system can be provided by one sound converting element built in the ear piece. When the ear piece is inserted into the external ear path, the voice uttered by the user is transmitted to the sound converting element through bone-conduction. However, since the external ear path is tightly shielded against the acoustic noises of the high sound pressure level surrounding the environment in which the ear piece is used, the noises are hardly converted into electric signals as the received sound and the voice which is sent from the outside in the form of the electric signal can be sufficiently picked up at the low sound pressure level, so that it can be effectively utilized in bidirectional voice communication devices in various and wide fields for emergency communication, outdoor communication and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 

Fig. 1 is a schematic block diagram of an ear inserting type transmitter-receiver according to one embodiment of the present invention;

Fig. 2 is a central and longitudinal sectional diagram of an ear piece according to one embodiment of he present invention;

Fig. 3 is an electric circuit diagram of the ear inserting type transmitter-receiver according to one embodiment of the present invention;

Fig. 4 is an electrically equivalent circuit diagram of the ear piece according to the present invention;

Fig. 5 is a block diagram expressing a formula for extracting a second voice signal from a terminal voltage of a sound converting element in which first and second voice signals are superposed on each other according to the present invention;

Fig. 6 is a central and longitudinal sectional diagram of another embodiment of the ear piece according to the present invention;

Fig. 7 is an electric circuit diagram of another embodiment of the ear insertingtype transmitter-receiver for use with the ear piece in Fig. 6.

Fig. 8 is a central and longitudinal sectional diagram of a further embodiment of the ear piece according to the present invention; and

Fig. 9 is an electric circuit diagram of another embodiment of the ear insertingtype transmitter-receiver for use with the ear piece in Fig. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, preferred embodiments of the ear inserting type transmitter-receiver according to the present invention will be described in more detail with reference to the accompanying drawings.

[0013] Fig. 1 is a block diagram of a bidirectional communication system illustrating the gist of embodying the present invention.

[0014] In the drawing, 1 is an ear piece in which a sound converting element 2 is built, and 3 is a bidirectional transmission unit which is connected with the sound converting element 2 via a wiring code 4.

[0015] Also in the drawing, 5 is a bidirectional communication unit for outputting a first voice signal G1 which is fed out toward the bidirectional transmission unit 3 and for inputting a second voice signal G2 which is fed from the bidirectional transmission unit 3.

[0016] The bidirectional communication unit 5 is adapted to perform voice communication of a full duplex communication system (hereinafter referred to as a full duplex) with the other bidirectional communication unit 5' which is connected therewith via a wire or wireless communication means. The first voice signal G1 is a voice signal to be received by a person who wears the ear piece 1 and the second voice signal G2 is a voice signal which is uttered by the person who puts on the ear piece to be transmitted to a person in charge of the other bidirectional communication unit 5'.

[0017] An ear inserting type transmitter-receiver A according to the present invention comprises the ear piece 1 in which one sound converting element 2 is built and the bidirectional transmission unit 3. Two voice signals, that is, the first voice signal G1 for transmitting voice information from the outside to the user of the ear piece 1 and the second voice signal G2 for transmitting voice information uttered by the user to the other person work on the sound converting element 2 in real time.

[0018] Fig. 2 is a longitudinal sectional diagram of the ear piece 1 showing one embodiment of the present invention.

[0019] The ear piece 1 comprises an external ear fitting tube 6 which is fitted into the external ear path, a connecting tube 7 which is detachably fitted into the rear end of the external ear fitting tube 6 and a case frame 8 for housing the sound converting element 2 which is provided at the rear end of the connecting tube 7.

[0020] The external ear fitting tube 6 is provided at the front end with a flange-shaped elastic stopper member 9 protruding forward in a semi- spherical form and having an elastic fin portion 9a provided on the outer peripheral edge thereof so as to protrude rearward and a sound guiding hole 10 is perforated in its axial center so as to pass from its front end to its rear end. A large-diametered annular groove 12 for engaging with a large-diametered flange 11a at the front end of a fitting portion 11 of the connecting tube 7 is provided in the rear end of the sound guiding hole 10. The external ear fitting tube 6 is made of a flexible material such as a soft synthetic resin, rubber or the like such that no pain is caused to the user even when the ear piece 1 is used for a long period of time.

[0021] In particular, the elastic stopper member 9 for elastically fitting into the external ear path is closely fitted into the external ear path with no space by means of the elastic fin portion 9a so as to increase the transmission characteristic of acoustic vibration induced by bone conducted vibration and the reproducibility of the transmission characteristic.

[0022] The external ear fitting tube 6 is made of a flexible material as mentioned above and the connecting tube 7 is made of a hard synthetic resin material. A rear end inner cavity 13 in the sound guiding hole 10 in the external ear fitting tube 6 and an external diameter 116 of the fitting portion 11 of the connecting tube 7 are shaped and sized so as to be closely fitted with each other. The large-diametered groove 12 of the external ear fitting tube 6 and the large-diametered flange 11 of the connecting tube 7 act as a slip-off stopper when these are fitted with each other.

[0023] Once the external ear fitting tube 6 and the connecting tube 7 thus constructed are fitted with each other, these can not be readily separated from each other simply by pulling the both in their axial direction. However, if the flexible outer ear fitting tube 6 is obliquely bent at the fitting portion, the fitting tube 6 will be removed from the connecting tube7 relatively readily.

[0024] Various outer ear fitting tubes 6 in which the diameters of the elastic stopper members 9 are different from one another are prepared so as to replace with one another in accordance with the size of the external ear path of the user.

[0025] A sound guiding hole 14 is perforated in the axial center of the fitting portion 11 of the connecting tube 7 so as to communicate with the sound guiding hole 10 in the external ear fitting tube 6.

[0026] The connecting tube 7 is provided with a drum portion 7a of the diameter which is the same as that of the outer peripheral portion of the elastic stopper member 9 on its center and the fitting portion 11 which is made smaller than the drum portion in diameter by the amount corresponding to the thickness of the outer ear fitting tube 6 is protruded forward (leftward in Fig. 2) in the axial direction of the drum portion 7a.

[0027] A large-diametered flange 15 which is integrally fixed to the case frame 8 is provided at the rear end of the drum portion 7a.

[0028] Within the drum portion 7a, there is defined a hollow chamber 16 which is larger in diameter than the sound guiding hole 14 formed in the axial center of the fitting portion 11.

[0029] The large-diametered flange 15 provided at the rear end of the connecting tube 7 is fixed to a peripheral circular portion 17 of the case frame 8 by integral moulding.

[0030] The sound converting element 2 is sandwiched between the connecting tube 7 and the case frame 8. The sound converting element 2 comprises a vibration unit 18 and a vibration plate 19. The vibration plate 19 constitutes a portion corresponding to a cone of an ordinary disk-shaped (not shown) speaker and the vibration unit 18 constitutes a portion corresponding to an electromagnet of a speaker of the type in which a moving coil and a permanent magnet are built (not shown).

[0031] The vibration plate 19 is tightly sandwiched between a rear end face 22 of the connecting tube 7 and the inner surface of a bottom wall 23 of the case frame 2 in a state that the central portion of the vibration plate 19 is separated from the wall or the like via doughnut-shaped spacers 21 provided on the both surfaces of its peripheral portion 20.

[0032] The vibration unit 18 is fixed to the case frame 7 in a state that the rear end thereof is being embedded in a bottom wall 23 of the case frame 8. The front of the vibration plate 19 is oriented toward the sound guiding holes 10, 14 and the hollow chamber 16. The vibration plate 19 is constructed so as to emit the output vibration which is converted by the vibration unit 18 into the acoustic vibration with the first voice signal G1 (electric energy) into the hollow chamber 16.

[0033] The vibration unit 18 is capable of converting the vibration externally exerted onto the vibration plate 19 into an electric signal by means of a bidirectional energy converting element for electric energy and vibration energy coupled to the vibration plate 19 such as a combination of a moving coil and a permanent magnet or the like.

[0034] The voice uttered by the speaker who puts on the ear piece 1 is conducted to the external ear path through the skull or the like, the voice thus conducted to the external ear path is transmitted to the vibration plate 19 through the external ear fitting tube 6 and the connecting tube 7 which are fitted in the external ear path; and the vibration of the voice is transmitted to the vibration unit 18 via the vibration plate 19 to be converted into an electric signal.

[0035] According to the present invention, the voice uttered by the speaker is transmitted to the external ear path of the listener by cartilage conduction which has not yet been realized by the conventional bone transmission technique. This cartilage conduction exhibits a favorable frequency characteristic.

[0036] The electric signal exited in the vibration unit 18 by the vibration through this cartilage conduction is superposed on the electric signal of the first voice signal G1 applied from the outside and appears at an output terminal of the vibration unit 18.

[0037] As shown in Fig. 31 the vibration unit 18 is connected to the bidirectional transmission unit 3. The bidirectional transmission unit 3 applies the first voice signal G1 to the vibration unit 18 and extracts the second voice signal G2 from the vibration unit 18 based on the voice vibration transmitted by the bone conduction.

[0038] In Fig. 3, the first voice signal G1 which is sent from the bidirectional communication unit 5 is amplified by an amplifier 24 having a low output impedance and an output therefrom is applied to a series circuit of the vibration unit 8 and an impedance element 25 as a sound converting element driving signal e1.

[0039] In this embodiment, the amplifier 24 of a voltage follower type in which the amplification factor is defined as 1 is used such that the voice signal G1 and the sound converting element driving signal e1 are equal to each other in voltage. The impedance element 25 is preferably constituted by a resistor consisting of pure resistance components.

[0040] Voltage Vi across the vibration unit 18 is detected by an amplifier 26 having a high input impedance, by which a sound converting element terminal signal e2 is obtained at an output of the amplifier 26.

[0041] As in the case of the amplifier 24, there is employed the amplifier 26 of the voltage follower type in which the amplification factor is defined as 1 such that the voltage Vi across the vibration unit 18 and the voltage of the sound converting element terminal signal e2 are equal to each other.

[0042] In this connection, it is to be noted that it is not always necessary to define the amplification factor of the amplifiers 24 and 26 as 1, but the factor may be defined so as to obtain a desired gain.

[0043] The first voice signal G1 which is input into the amplifier 24 for driving the vibration unit 18 and is equal to the sound converting element driving signal e1 is converted into a sound converting element driving signal E1 in a digital form by a first analog/digital converter 27 and then is input into a first input terminal 29 of a digital signal Processing means28.

[0044] The sound converting element terminal signal e2 having a voltage equal to the terminal voltage Vi of the vibration unit 18 and output from the amplifier 26 is converted into a sound converting element terminal signal E2in a digital form by a second analog/digital converter 30 and is then input into a second input terminal 31 of the digital signal processing means 28.

[0045] The digital signal processing means 28 is constituted by a high density integrated circuit which is commonly called DPS (Digital Signal Processor) and includes CPU, memory and peripheral controller.

[0046] As IC circuit elements currently manufactured in the form of DPS which can be concretely embodied as the digital signal processing means 28, TMS320LC5 Family, TMS320F2 Family and the like manufactured by Texas Instruments Co., Ltd. are commercially available.

[0047] A program for processing an input signal is loaded in a portion of ROM built in DPS in a state that it is converted into an optimized assembler in the digital signal processing means 28 which is constituted by the above mentioned DPS. Two analog voice signals which are generated in real time with the first digital signal (the sound converting element driving signal E1 in the digital form) which is input into the first input terminal 29 and the digital signal (the sound converting element terminal signal E2 in the digital form) which is input into the second input terminal 30 are digitally processed in accordance with this signal processing program.

[0048] In the signal processing program, there are included processing of suppressing such obstruction (for example, howling, echo and the like) that the voice uttered by the user of the ear piece 1, that is, the speaker returns to the speaker himself, processing of removing noise for improving the anti-noise robustness, processing of correcting distortion in the voice signal to be detected of the speaker, sound signal processing such as automatic gain control (AGC) and calculating processing which will be described later.

[0049] The voice uttered by the speaker is extracted in an audible voice as a digital signal through these signal processings. A digital voice signal E3 thus extracted is converted into an audible analog voice signal e3 by a digital/analog converter 32 to be fed out of the transmission unit 3 as a second voice signal G2.

[0050] The bidirectional transmission unit 3 operates in cooperation with the bidirectional communication unit 5 constituted by talk communication appliances such as ordinary telephone set, interphone and the like, a wireless transceiver, a personal computer, a telephone operation system and the like so as to perfectly maintain compatibility with a general purpose voice input/output device in which a combination of microphone and earphone is used in a hand set or head set of these communication appliances.

[0051] The hand set or head set in which the conventional microphone and ear-phone are set in pairs outputs an output signal from the microphone as an output signal which is conformable with a microphone input terminal of an ordinary acoustic appliance in an analog form and receives an analog electric signal which is conformable with the earphone as an input signal from the outside.

[0052] The ear piece 1 according to the present invention works by itself equally to the hand set and head set.

[0053] The ear piece 1 which is inserted into the external ear path of the user operates as follows.

[0054] When the first voice signal G1 output from the bidirectional communication unit 5 is input into the transmission unit 3, the first voice G1 is amplified by the amplifier 24 and sent through the impedance element 25 which is serially connected to the vibration unit 18 to the vibration unit 18 of the sound converting element 2 on the wiring code 4 to be converted into the voice to be transmitted to the user.

[0055] In this case, the elastic fin portion 9a of the elastic stopper member 9 of the external ear fitting tube 9 of the ear piece 1 comes into elastic contact with the external ear path and hence the inside of the external ear path is sound-insulated from the outside of the ear, which results in a state that the noise hardly enters the ear from the outside.

[0056] On the other hand, when the sound converting element 2 of the ear piece 1 acts as a microphone, the element operates as follows.

[0057] When the user utters the voice, the voice (vibration) is conducted to the bones and cartilages to cause the outside of the inner portion of the external ear to vibrate. As has been described above, this vibration is detected by the vibration unit 18 of the sound converting element 2 in the form of the terminal voltage Vi of the vibration unit 18 as a pseudo-voice electric signal on which the first voice signal G1 is superposed. The terminal voltage Vi indicative of the pseudo-voice electric signal is amplified by the amplifier 26 to turn to the sound converting element terminal signal e2.

[0058] This sound converting element terminal signal e2 is converted into the second digital signal E2 by the above mentioned analog/digital converter 30.

[0059] The first voice signal G1, before being amplified by the amplifier 24, is applied to the analog/digital converter 27 to be converted into the first digital signal E1. These first and second digital signals E1 and E2 are input into the digital signal processing means 28.

[0060] In the digital signal processing means 28, the following signal processings are performed based on the first and second digital signals E1 and E2.

[0061] That is, there are processing of suppressing such obstruction (for example, howling, echo and the like) that the voice uttered by the sender returns to the sender himself, processing of improving the anti-noise robustness, processing of correcting the frequency characteristic of the pseudo-voice electric signal, automatic gain control (AGC) processing and the like.

[0062] Therefore, the voice uttered by the sender is supplied to the digital/analog converter 32 as the electric voice signal to be converted into an audible voice to be output as the electric voice output signal conforming to a microphone input terminal of the ordinary analog type audio appliance-communication appliance.

[0063] In the present invention, the operation of generating the voice vibration to be transmitted to the user and the operation of converting the voice vibration generated from the user into the electric signal are performed by the single vibration unit 18 so as to make the transmission unit 3 cope with the full duplex communication system (hereinafter, referred to as the full duplex), which will be logically described hereinbelow.

[0064] Fig. 4 is an equivalent circuit diagram of the vibration unit 18 of the ear piece 1 and the driving circuit therefor.

[0065] In the equivalent circuit, e1 denotes the sound converting element driving signal e1 output from the amplifier 24. The amplifier 24 is constituted by the voltage follower circuit in which the magnification factor is defined as 1, so that the voltage waveform component thereof is the same as that of the first voice signal G1 sent from the outside and is substantially the same as that of the first digital signal E1 obtained by digitally converting the voice signal G1.

[0066] The amplifier 24 is an electric signal applying means for applying an electric signal obtained by amplifying the first voice signal G1 to the series circuit of the sound converting element 2 and the impedance element 25.

[0067] Also, in Fig. 4, R is an impedance of the impedance element 25 which is serially provided in the vibration unit 18; Z, an impedance of the vibration unit 18; Vi, a terminal voltage (equal to that of the sound converting element terminal signal e2) of the vibration unit 18 corresponding to the pseudo-voice electric signal which is generated in association with user's utterance detected by the vibration unit 18; e3, an electric signal of the voice uttered by the user corresponding to the second voice signal G2; and i, a current flowing through the equivalent circuit.

[0068] Further, in Fig. 4, the pseudo-voice signal in which the sound converting element driving voltage e1 equal to that of the first voice signal G1 is superposed on the second voice signal e3 can be detected as the terminal voltage Vi of the vibration unit 18.

[0069] Next, how only the electric signal e3 corresponding to the second voice signal G2 is extracted from the terminal voltage Vi, that is, how the present invention can cope with the full duplex will be described.

[0070] In the equivalent circuit shown in Fig. 4, the following formula (1) is obtained based on the Kirchhoff' S voltage law.

[0071] The first voice signal G1 is the same as the sound converting element driving signal e1, so that e1 is supposed to denote the first voice signal for the convenience of description of the equivalent circuit.

[0072] The terminal voltage Vi of the vibration unit 18 and the pseudo-voice signal e2 which is output via the amplifier 26 having the amplification factor of 1 by using the terminal voltage Vi as a pseudo-voice signal in which the first and second voice signals are superposed on each other have the same signal components. For the convenience of description of the equivalent circuit, e2 is supposed to denote the terminal voltage.

[0073] The formula 1 is worked out with respect to the current i, by which the following formula (2) is obtained.

[0074] In this case, the terminal voltage e2 is obtained by subtracting the terminal voltage (R · i) of the impedance element 25 from the first voice signal e1. Thus, the following formula (3) is obtained.

[0075] By substituting the current i in the formula (2) into the formula (3), the following formula (4) is obtained.

[0076] By working out the formula (4) with respect to the voice signal (e3), the following formula (5) is obtained.

[0077] Arranged impedance components in the formula (5) can be shown as the block diagram in Fig. 5.

[0078] In Fig. 5, when the respective impedance components (X1) and (X2) are expressed as

   the following formula (6) is obtained.

[0079] By arithmetically operating the formula (6) based on the block diagram shown in Fig. 5, the second voice signal e2 can be taken out of the pseudo- voice signal (the terminal voltage) e2 in which the first voice signal e1 and the second voice signal e3 are mixed with each other.

[0080] In the operational processing of the formula (6) based on the block diagram shown in Fig. 5, the sound converting element driving signal E1 in the digital form which is obtained by converting the sound converting element driving signal e1 which is the same as the first voice signal e1 into the digital signal and the sound converting element terminal voltage E2in the digital form obtained by converting the terminal voltage (the pseudo-voice signal) Vi or e2 of the vibration unit 18 into the digital signal are input into the digital signal processing means 28 to be processed.

[0081] Now, the terminal voltage Vi, the sound converting element driving voltage (the first voice signal) e1 and the impedance R of the impedance element 25 can be measured and hence, if the impedance Z of the sound converting element 2 of the vibration unit 18 is settled, the second voice signal e3 can be calculated.

[0082] As for the impedance z of the sound converting element 2, actually, it is necessary to obtain the impedance Z which changes every second in accordance with the action of the person who utters the voice. However, the operation thereof is complicated more than would be necessary, so that the impedance is calculated by using, for example, the value obtained under the following condition as an approximate value Ze by the digital signal processing means 28.

[0083] Here, the formula 4 is worked out by using the approximate value Ze of the impedance Z of the sound converting element 2, that is, by substituting a provisional value (e2=0) for the terminal voltage e2 in the formula 4, by which the following formula 7 is obtained.

[0084] In the formula 7, the inverse numbers in the both sides are the same as each other, so that the following formula (8) is obtained.

[0085] Thus, the impedance Z of the sound element 2 will be as follows.

[0086] The formula (9) is substituted into the formulas (5) and (6) to correct the obtained values, by which the second voice signal e2 can be obtained.

[0087] Thus, it is understood that the ear inserting type transmitter-receiver according to the present invention can cope with the full duplex with the use of one ear piece 1.

[0088] Figs. 6 and 7 shows another embodiment of the present invention.

[0089] The embodiment shown in Fig. 6 is of the type in which the amplifier 24 for driving the sound converting element 2 and the amplifier 26 for amplifying the terminal voltage Vi of the sound converting element 2 which are provided in the bidirectional transmission unit 3 in the above mentioned embodiment are built in a case frame 8A of an ear piece 1A.

[0090] Fig. 7 shows a diagram of a circuit in which the ear piece 1A shown in Fig. 6 is connected to a bidirectional transmission unit 3A.

[0091] In this connection, it is to be noted that the power circuit connected to respective amplifiers and semiconductor elements is not shown in the drawing, and the same reference numerals are assigned to the same parts as those in the embodiment shown in Figs. 1 to 3 and hence the detailed description thereof will be omitted.

[0092] In Fig. 6, analog operational amplifying IC circuit elements 33 and 34 constituting the amplifiers 24 and 26 are embedded in the case frame 8A of the ear piece 1A at the rear of the vibration unit 18 in a state that these elements are mounted on a wiring substrate 35.

[0093] The impedance element 25 is mounted also on the wiring substrate 35 and an output circuit for driving the vibration unit 18 is connected to the vibration unit 18 via a very short wiring 36.

[0094] An input wiring of the amplifier 26 for amplifying the terminal voltage Vi of the vibration unit 18 is wired also very short within the wiring substrate 35.

[0095] Owing to the above mentioned arrangement, as will be apparent from the equivalent circuit in Fig. 4, the wiring code 4 shown in Figs. 1 and 3 is not included in the series connecting circuit for the impedance element 22 and the vibration unit 18, so that intrusion of disturbance into the inner impedance Z of the vibration unit 18 is significantly reduced and hence faithful extraction of the second voice signal e3 and stable signal processing control can be realized.

[0096] In addition, since the amplifiers 24 and 26 receive input signals in positions which are the closest to the vibration unit 18 to perform voltage follower control, the rate at which the input signal coincides with the output signal is high and hence the first voice signal E1 in the digital form sent to the digital signal processing means 28 and the terminal voltage E2 in the digital form become sufficiently approximate to the first voice signal e1 and the terminal voltage e2 which are recognized as the same ones as those in the equivalent circuit in Fig. 4.

[0097] In Fig. 7, an impedance of a wiring code 37 for connecting the ear piece 1A to the bidirectional transmission unit 3A is not included in any parameter of the equivalent circuit shown in Fig. 4, so that the length and diameter of the wiring code 37 do not directly influence the control of the full duplex.

[0098] Accordingly, no matter which part of the human body the bidirectional transmission unit 3A according to this embodiment is put on without limiting a storage location thereof to a part around the ear when carried, a phenomenon which is acoustically adverse will not induce.

[0099] Figs. 8 and 9 show a further embodiment of the present invention, in which the portion corresponding to the wiring code 37 in the embodiment shown in Fig. 6 and 7 is replaced by a pair of wireless communication means 38 and 39 to connect an ear piece 1B with a bidirectional transmission unit 3B.

[0100] A wireless reception unit 40 for one wireless communication means 38 and a wireless transmission unit 41 for the other wireless communication means 39 are mounted on a wiring substrate 35A of the ear piece 1B in Fig. 8.

[0101] As shown in a circuit diagram in Fig. 9, the wireless reception unit 40 of the ear piece 1B comprises a reception circuit 42 and a demodulation circuit 43 and an output signal from the demodulation circuit 43 is sent to an input of the amplifier 24.

[0102] Likewise, the wireless transmission unit 41 comprises a modulation circuit 44 and a transmission circuit 45 and an output signal from the amplifier 26 is received by an input of the modulation circuit 44.

[0103] The bidirectional transmission unit 3B similarly comprises a wireless transmission unit 46 and a wireless reception unit 47 for the pair of wireless communication means 38 and 39.

[0104] The wireless transmission unit 46 for one wireless communication means 38comprises a modulation circuit 48 and a transmission circuit 49 and the modulation circuit 48 inputs the first voice signal e1 into the ear piece.

[0105] The wireless reception unit 47 for the other wireless communication means39 comprises a reception circuit 50 and a demodulation circuit 51 and an output from the demodulation circuit 51 is sent to an input of the second analog/digital converter 30.

[0106] Thus, the wireless communication means 38 constitutes a wireless voice communication channel for transmitting the first voice signal G1 from the bidirectional transmission unit 3B to the ear piece 1B. While, the wireless communication means 39 constitutes a wireless voice communication channel for transmitting the second voice signal G2 from the ear piece 1B to the bidirectional communication unit 3B.

[0107] The communication system of the wireless communication means 38 and 39 is a frequency modulation system (FM communication system) preferably having a frequency band from several MHz to several hundreds MHz and an electric field intensity of output for communication within a range from 1 to 3 meters in communication area at an output within a range specified for weak electric waves.

[0108] Conductor portion 52 constituting a receiving antenna for the reception circuit 42 and a conductor portion constituting a transmitting antenna for the transmission circuit 45 are provided on the rear end face of a case frame 8B of the ear piece 1B.

[0109] Although the case frame 8B is moulded by an insulating synthetic resin, it is not always necessary to expose the surfaces of the conductor portions 52 and 53 constituting the antennas but theses portions may be embedded in the synthetic resin.

[0110] For the conductor portions 52 and 53, any one of helical pattern, stick pattern and comb pattern is selectively adopted as a two-dimensional pattern depending on the frequency of a communication carrier used.

[0111] The wireless communication means 38 and 39 may be of a type using infrared rays.

[0112] The wireless communication means 38 and 39 of the infrared rays using type have such an advantage that, in particular, in a working site in which electromagnetic wave noises are generated over a wide area from electric welder, large-scale electric motor, electric furnace and the like which generate spark noises and hence the wireless communication of the FM communication system can not be used, the communication system of the infrared rays using type can sufficiently fulfill its function even in the working site as mentioned above.

[0113] In addition, in the working site, when the bidirectional transmission unit 3B is provided on an inner portion of a safety helmet of which putting-on is obliged, a lower edge of a side portion of the safety helmet is positioned directly above the ear into which the ear piece 1B is to be inserted, so that the communication distance can be significantly shortened by providing the bidirectional transmission unit 3B on the inner portion of the side of the helmet directly above the ear.

[0114] In addition, external incidence of infrared rays can be readily prevented by providing an ear flap on one side of the helmet directly above the ear.

[0115] Also, in the embodiments shown in Figs. 1 to 3 and Figs. 6 and 7, it can be readily realized that the bidirectional transmission unit 3 or 3A is provided in an inner portion of the helmet and the transmission unit is wire-connected to the ear piece via a wiring code.

[0116] Further, as shown in Fig. 1, it is also possible to make the bidirectional communication unit 5 wireless. In this case, the bidirectional communication unit 5 can be designed so as to have such large output power that it can sufficiently withstand the electromagnetic noises in the working site. Further, for a modulation system, a digital modulation system or a spectrum modulation system which is highly resistant against the electromagnetic noises may be adopted.

[0117] As has been described above, the ear inserting type transmitter-receiver according to the respective embodiments of the present invention is capable of transmitting and receiving clear voices by means of the full duplex, so that it can be used in the following situations.

[0118] In a case that the ear inserting type transmitter-receiver according to the present invention is used in a hand set consisting of microphone and speaker of a portable telephone, the transmission and reception can be surely performed even in an environment filled with background noises of high sound pressure level such as on a train, in a factory, in a high way construction site or the like.

[0119] In a case that the bidirectional transmission unit 3 and the bidirectional communication unit 5 are integrally formed so as to use as a wireless secondary telephone of an ordinary one, talking can be realized in a state that the secondary one is put in one's pocket and the ear piece 2 is inserted into the ear, that is, in an empty-handed state, a homemaker can make a phone call while managing the house without touching the secondary telephone which is put in the house and it can be also utilized as a sound monitor for a baby or a family care or nursing needed person, an interphone, a household sound monitor or the like.

[0120] Further, a great deal of effects can be obtained by utilizing the transmitter-receiver according to the present invention as a transmitting communication system generally using a head set to generate emergency instructions and command in which the originality of the talking and the freedom of the limbs of an operator are needed, and, in particular, the clearness of the talking is required for use in telephone guidance, emergency communication response stands in police stations and fire departments, control towers and the like.

[0121] Still further, erroneous inputting of voice recognition can be reduced by using the ear inserting type transmitter-receiver according to the present invention for inputting a voice into a computer appliance.

Claims

1. An ear inserting type transmitter-receiver comprising:

an ear piece provided with an ear inserting insert portion inserted into the external ear path;

a sound converting element provided on a base portion of a sound passing hole perforated in the ear inserting insert portion so as to bidirectionally convert acoustic vibration to an electric signal and vice versa;

an impedance element serially connected to an electric circuit of the sound converting element;

an electric signal applying means for applying an electric signal based on a first voice signal to be transmitted to an ear piece wearer to a series circuit of the sound converting element and the impedance element;

a sound converting element terminal signal detecting means for detecting voltage across the sound converting element including a second voice signal obtained by electrically converting a voice uttered by the ear piece wearer;

a first analog/digital converting means for converting the electric signal based on the first voice signal to be transmitted to the ear piece wearer into a digital signal;

a second analog/digital converting means for converting the sound converting element terminal signal including the second voice signal obtained by electrically converting the voice uttered by the ear piece wearer into a digital signal;

a digital signal operational processing means for inputting the both digital signals output from the first and second analog/digital converting means and extracting the second voice signal included in the sound converting element terminal signal based on the impedance of the sound converting element, the impedance of the impedance element which is serially connected with the sound converting element, the first voice signal applied to the series circuit thereof and the sound converting element terminal signal generated across the sound converting element by digital operational processing; and

a digital/analog converting means for converting the digital signal of the second voice signal which is arithmetically operated by and output from the digital signal operational processing means into an analog electric signal.

2. The ear inserting type transmitter-receiver according to Claim 1, wherein the ear piece comprises an impedance element, an electric signal applying means for applying an electric signal based on a first voice signal and a sound converting element terminal signal detecting means for detecting the voltage across the sound converting element.

3. The ear inserting type transmitter-receiver according to Claim 1, wherein the electric signal applying means for applying the electric signal based on the first voice signal is constituted by a voltage follower type amplifier.

4. The ear inserting type transmitter-receiver according to Claim 1, wherein the sound converting element terminal signal detecting means for detecting the voltage across the sound converting element is constituted by a voltage follower type amplifier.

5. The ear inserting type transmitter-receiver according to Claim 1, wherein a bidirectional transmission unit constructed such that the first voice signal is sent to the ear piece, the sound converting element terminal signal including the second voice signal is received from the ear piece and comprising first and second analog/digital converting means, a digital signal processing means and a digital/analog converting means is provided separately from the ear piece such that electric signals relating to the first and second voice signals are transmitted and received between the ear piece and the bidirectional transmission unit via a wiring code.

6. The ear inserting type transmitter-receiver according to Claim 1, wherein a bidirectional transmission unit constructed such that the first voice signal is set to the ear piece, the sound converting element terminal signal including the second voice signal is received from the ear piece and comprising first and second analog/digital converting means, a digital signal processing means and a digital/analog converting means is provided separately from the ear piece such that electric signals relating to the first and second voice signals are transmitted and received between the ear piece and the bidirectional transmission unit via a wireless communication means.

7. The ear inserting type transmitter-receiver according to Claim 6, wherein the ear piece is provided with an impedance element, an electric signal applying means for applying an electric signal based on a first voice signal and a sound converting element terminal signal detecting means for detecting the voltage across the sound converting element within a case frame thereof and a transmitting portion and a receiving portion of the wireless communication means are built in the case frame.

8. The ear inserting type transmitter-receiver according to Claim 6, wherein the wireless communication means is constituted by a frequency modulation type bidirectional wireless communication means having two channels for transmission and reception over weak electric waves.

9. The ear inserting type transmitter-receiver according to Claim 6, wherein the wireless communication means is constituted by a bidirectional optical communication means having two channels for transmission and reception with infrared rays.

Drawing