JP3031663B2 - Two-way audio terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hands-free type two-way voice terminal device capable of performing a telephone call without using hands.

[0002]

2. Description of the Related Art In recent years, a two-way voice terminal device capable of making a telephone call without using hands, that is, a hands-free telephone, has been developed and used. This hands-free phone emits sound as a speaker,
Since sound leaks into the microphone that is the transmitter and causes howling, howling during two-way communication can be achieved by incorporating a one-way circuit that lowers the sensitivity of the transmitting circuit during reception and lowers the volume of the receiving circuit during transmission. And the occurrence of echo.

[0003]

By the way, in the conventional two-way audio terminal device, when the ambient noise of a radio or the like becomes almost the same as the speech voice level or becomes higher than the speech voice level, the one-way traffic described above is performed. If the sex circuit determines that a call is in progress, the volume of the receiving circuit is automatically lowered, and if both parties speak at the same time, the volume of the transmitting circuit or receiving circuit is automatically lowered, so the transmitting or receiving is interrupted. There was an inconvenience that the call was interrupted significantly. In general, the switching between the transmission sound volume and the reception sound volume is adjusted by detecting the average value of the transmission sound level or the reception sound level. There was also an inconvenience that calls were interrupted during the call.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned inconvenience, and it is possible to prevent the occurrence of howling and echo without using the above-mentioned one-way circuit. It is an object of the present invention to provide a two-way audio terminal device that can prevent the communication from becoming uninterrupted and that does not interrupt communication.

[0005]

SUMMARY OF THE INVENTION The present invention provides an earphone-type handset to be worn on the outer ear, an earset-type handset having a transmitter integrated with the earphone-type handset to be located outside the outer ear, A storage unit for storing the earphone type handset not attached to the storage unit, at least one receiver provided in the storage unit, and a handset switching mechanism for selecting one of the earphone type handset and the handset; Wherein the microphone has one bidirectional microphone arranged at a substantially central portion in one pipe and both ends of the pipe are filled with a sound absorbing material, or two unidirectional microphones are provided. Microphones are arranged at both ends in the pipe, and the transmitter and the receiver constitute a storage unit transmitter and receiver.

[0006]

Here, the handset switching mechanism can also switch the input sensitivity and / or frequency characteristics of the handset, and the housing is provided in a handset installation portion of a handset used for a desk phone. It may be provided, or provided in a transmitter installation portion of a portable telephone terminal, or provided in a part of a portable computer. Also, is the housing unit receiver a speakerphone type, or is a handset type in which the transmitter approaches the mouth of the talker when the storage unit handset is placed on the ear of the talker. Alternatively, it may be a dual-purpose type having the functions of the speakerphone type and the handset type.

Further, the handset switching mechanism may be controlled by storage detection means for detecting whether or not the earphone type handset is stored in the storage section. Also,
It is desirable to provide a cord winding mechanism for accommodating the connection cord of the earphone type handset in the accommodation section, and it is desirable that the pipe has a length of 4 cm or more.

[0009] Further, a gain controller having the transmitter as an input of an AC output from the transmitter, a band amplifier for passing only a specific frequency band frequency of the AC signal from the transmitter, A periphery constituted by a peak detector for extracting an output corresponding to the peak value of the AC output passing through the band amplifier, and a peak hold circuit including a hold circuit for suppressing the attenuation of the output level of the peak detector for a predetermined holding time. It is desirable to connect a noise suppression circuit.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 (a) and 1 (b) are side views showing a first embodiment of the present invention, and FIG. 2 is a sectional view of the transmitter shown in FIG. In these figures, reference numeral 1 denotes a transmitter / receiver, and the transmitter 2 and the speaker 3 serving as the receiver have a distance of 7 cm from the sound opening of the transmitter 2 to the center C of the speaker 3.
The antenna 4 is provided so as to have a range of 30 cm.

The transmitter 2 has a central portion rotatably supported at its center so that the direction of the sound pickup opening can be adjusted. The above-mentioned transmitter 2 includes a pipe 2a having a diameter of 6 mm and a length of 4 cm or more, an electret-type bidirectional microphone 2b built in the center of the pipe 2a, and a pipe 2a.
a sound-absorbing material 2c filled on both sides of the bidirectional microphone 2b in FIG. 2a, and a net 2d attached to both ends of the pipe 2a.
It is composed of Reference numeral 2e denotes a connection cord connected to the bidirectional microphone 2b.

Although the transmitter 2 is shown as being composed of one bidirectional microphone 2b, unidirectional microphones are arranged at both ends in the pipe 2a, and each microphone is provided with an external voice. And the difference between the outputs of the two microphones is extracted by an electronic circuit, the same effect as in the case of the bidirectional microphone 2b can be obtained.

Next, a call using the handset of the first embodiment will be described. First, if you want to talk,
The transmitter 2 set in the state shown in FIG. 1A is rotated to turn one sound pickup opening of the transmitter 2 toward the mouth of the caller as shown in FIG. 1B. At this time, it is desirable to make the distance from both sound holes to the center C of the speaker 3 equal. In this state, the transmitter 2 is attached so that both sound holes of the transmitter 2 are within a range of 7 cm to 30 cm from the center C of the speaker 3.

If the sound pickup openings of the transmitter 2 are at least 7 cm from the center of the speaker 3, the output of the speaker 3 is less likely to return to the transmitter 2, thus preventing the occurrence of howling and echo. it can. Then, the voice from the caller is input from both sound holes of the transmitter 2, and an output proportional to the difference between the two input voice levels is output from the transmitter / receiver 1.

In order to secure a sufficient speech sound level as the output of the transmitter 2, the input sound level is almost inversely proportional to the distance between the sound pickup opening and the sound source. It is necessary that the difference between the distances is sufficiently large. Therefore, if the distance between the mouth of the talker, which is the sound source, and the center of the pipe is 1 m, the length of the pipe 2a should be 1/10 or more, at least / 20 or more, and it is necessary to improve the output level from the mouth against ambient noise by shortening the distance 1 m. However, normally, when talking in a hands-free state, the distance from the transmitter 2 to the mouth is 80.
cm or less, it is desirable that the length of the pipe 2a be 4 cm or more.

On the other hand, since the sound source of the ambient noise is almost 2 m or more away from the transmitter 2, the input levels of the ambient noise to both the sound pickup openings of the transmitter 2 become substantially equal. The output is canceled out and transmitted as a sufficiently low output from the handset 1, which is approximately 1/3 or less of the conventional one. Therefore, the voice of the caller is transmitted from the handset 1 as an output sufficiently larger than the ambient noise, so that the voice is clearly transmitted to the other party.

The transmitter / receiver 1 converts its own voice and ambient noise into electric signals and outputs the electric signals. Further, the speaker 3 adds a part of the electric signal of the self-transmitter 2 to the electric signal transmitted from the other party and converts the signal into a voice signal. That is, by confirming the voice uttered by the caller through the speaker 3, the call can be made with confidence, and a part of the transmission signal is added to the reception signal.

For this reason, when making a call under high ambient noise or when listening to the voice of the other party, it becomes very difficult to hear the other party because the ambient noise from the own handset is added to the other party. On the other hand, the other party is very uncomfortable because the surrounding noise is reproduced on the handset during a call, and the other party has difficulty in confirming the voice of the other party and hinders the call. become.

Therefore, as shown in FIG.
A bidirectional microphone 2b accommodated in a pipe 2a of at least cm, and an ambient noise suppression circuit integrated into the transmitter 2 connected to an IC to increase the ratio of the ambient noise level to the sound level from the mouth. In practice, the transmission SN ratio is greatly improved.

The important issues for achieving the above-mentioned improvement are (1) easy and faithful detection of the distinction between a vocal section and a non-vocal section, and (2) a vocal section and a non-vocal section (surroundings). The ratio of the transmission gain in the noise-only section) is large,
There are two points. It is desirable to employ an ambient noise suppression circuit that satisfies this problem.

FIG. 3 is a block diagram of a transmission circuit, FIG. 4 is a frequency characteristic diagram of a band amplifier, and FIG. 5 is a Japanese vowel (generation).
FIG. 6 is a schematic diagram of a gain controller using an analog multiplier, and FIG. 7 is a gain characteristic diagram of the gain controller with respect to an amplitude value of a transmitter output. In FIG. 3, the same parts as those in FIG. 1 or FIG.

Reference numeral 5 denotes an ambient noise suppression circuit, which has a frequency of 0.2 kHz.
To 1 kHz or 0.2 kHz to 2 kHz, a band amplifier 51, a peak detector 52a for detecting a peak value of the sound passing through the band amplifier 51, and a peak value detected by the peak detector 52a. And a gain controller 53 for controlling the gain from the transmitter 2 based on the output from the hold circuit 52b. Note that the peak hold circuit 52 is constituted by the peak detector 52a and the hold circuit 52b.

As a detector for discriminating between the occurrence section and the non-occurrence section of the above-mentioned important problem (1), a band amplifier 51 having a characteristic shown in FIG. 4 for extracting a characteristic frequency region of conversation is used. The reason is that most of human conversations are speech sounds, and most of time and energy of speech sounds are vowels, and vowels (Japanese) are the first, second, and third formants as shown in FIG. The first and second formants account for most of the energy.

The first formant is approximately 0.2 kHz
~ 1kHz, the second formant is about 0.75kHz
２2 kHz. Therefore, the band amplifier 51
By setting the pass band of 0.2 kHz to 2 kHz, the first and second formants of vowels can be selectively extracted. When the pass band is set to 0.2 kHz to 1 kHz, the first formant having the largest energy can be selectively extracted. Can be extracted. The ambient noise contains many low-frequency components (50 Hz to 150 Hz) such as rotating sounds of cars and trains and high frequency components (2 kHz) such as fricative sounds. .2kHz to 2kHz or 0.2kHz to 1k
Setting to Hz is very effective for discriminating and extracting speech of conversation.

Next, a peak hold of the output of the band-pass amplifier 51 is used as a variable transmission gain means for expanding the transmission level between the occurrence section and the non-occurrence section of the above-mentioned important problem (2) to a sense of discomfort in hearing. By using the gain controller 53 that performs gain control according to the magnitude of the value, continuous and smooth control can be realized. As the gain controller 53, for example, an analog multiplier circuit shown in FIG. 6 which outputs a gain control signal and an AC output from the transmitter 2 as a multiplication result is suitable, and the output is V ₀ = K (X ₁₋ X ₂ ) (Y ₁ −Y ₂ ) = K · V ₁ · V _C

Where V ₀ is a control output, K is a proportional constant,
V ₁ is a transmitter AC output, V _C is a gain control signal, and the gain G = K · V _C. Since V _C is the magnitude (amplitude value) of the peak hold value, the relationship between the amplitude value and the output of the gain controller is proportional as shown in FIG.
Then, instead of the analog multiplier, a FET multiplier (FET
Which utilizes the change in channel resistance).

Next, the holding time of the vowel section may be determined by taking into account the holding time of the vowel that occupies most of the linguistic speech. Considering that the lower limit of the spectrum of the first formant of the vowel is about 200 Hz, the longest period of the vowel Since T _m is considered to be about 5 msec, the peak hold circuit 52
The peak value of the periodic waveform may be set hold time T _h to maintain a constant time.

As described above, when the gain controller 53 is controlled by the output of the peak hold circuit 52 in which the holding time _Th is set (see FIG. 7), the gain during a call is proportional to the volume of the caller's voice. Since it is almost constant, the sound is not interrupted on the way. Since the peak hold circuit 52 rises very quickly, a high gain operation, that is, a sufficient volume can be transmitted from the beginning of the call.

The peak hold circuit 52 of this embodiment
Practical attenuation when examined at time T _f until the the thinking may 99% attenuation deviates from substantially hold range, the T _f = 13T _h. According to the above-mentioned relational expression, the time _Tf is 1 second or less, and the decay is sufficiently short in conversation. Therefore, when the speech communication is completed, the peak hold circuit 52 attenuates within a sufficiently short time following the peak value of the silent period operation, so that the ambient noise can be suppressed quickly.

[0030] Then, the holding time T _h in the peak hold circuit 52, the holding time T _h when the attenuation rate of the peak value was defined as stop time within 30% peak detector 52a is unidirectional detection type 5ms to 65ms
ec, by the 2.5msec~32.5msec when bidirectional detection type, the retention time T _h prevents transmission that breaks unnaturally by too short, yet sending it ends by too long Nevertheless, it is possible to prevent the ambient noise suppressing effect from weakening while the transmission output is kept large.

[0031] i.e. in the time holding time T _h corresponds to the lowest frequency 200Hz of the first formant of the vowel, the largest component of the transmission energy, i.e. the period 5 msec 1
If the setting is double to 13 times, the gain after the end of the transmission can be quickly reduced without impairing the smoothness of the transmission,
Practically optimal control can be performed, and ambient noise can be suppressed to 1/10 or less of the conventional level. In addition, in the two-way detection type, peak detection is performed in a half cycle as compared with the one-way detection type.
The optimal holding time is 1 to 13 times 2.5 msec.

FIG. 8 is a side view showing a second embodiment of the present invention, in which an earset type handset is placed in a storage section to realize a speakerphone type handset. FIG. 9 is an enlarged sectional view of the earset type handset shown in FIG.
In these figures, the same or corresponding parts as those in FIGS. In FIG. 8, 1A
Denotes a handset, and includes an earset type handset 11, a speaker 3, and the speaker 3 attached thereto.
The storage base 21 functions as a storage unit for detachably storing the earset type handset 11. In addition,
When the earset type handset 11 is attached to a predetermined position of the storage table 21, the distance from the center C of the speaker 3 to both sound pickup ports is in the range of 7 cm to 30 cm as in the first embodiment. The sound pickup opening faces the mouth of the caller.

The above-mentioned earset type handset 11 is shown in FIG.
As shown in FIG. 2, the transmitter 2A and an earphone type receiver 3A integrated with the transmitter 2A. The transmitter 2A includes a pipe portion of a substantially L-shaped case 2f formed of synthetic resin and a bidirectional microphone 2b.
, A sound absorbing material 2c, a net 2d, and a connection cord 2e. Note that the connection cord 2e is obtained by combining the connection cord 3c of the earphone type receiver 3A into one.
It is stored in the neck of the storage table 21.

Further, the earphone type receiver 3A is a case 2
f, a loudspeaker 3b serving as a receiver provided in the vacant space 3a, a connection cord 3c connected to the loudspeaker 3b, and a swelling detachably attached to the case 2f. 3d. In addition,
The swelling body 3d is formed with a sound emission hole 3e communicating with the empty space 3a.

[0035] Switching between the speaker 3 is disposed a handset earphone receiver and storage unit is performed by the switch SW ₁ shown in FIG. 14, the output of the receiving circuit such as a telephone's earphone receiver or housing part It is switched and connected to one of the receiver speakers 3. Then, although not shown, housed earset type handset 11 to a predetermined position of the storage base 21, when mounted, for example, actuates the switch SW ₁ is the handset speaker 3 via a operating rod, earset type When disengaging the handset 11 from a predetermined position of the storage base 21, the switch SW ₁ operates the earphone loudspeaker.

Next, a description will be given of a part of the telephone call using the handset according to the second embodiment, which is different from the first embodiment. First, the earset-type handset 11 is inserted into the storage table 2.
When a call is made while the mobile phone 1 is mounted on the speaker 1, a speakerphone type two-way call is performed using the transmitter 2A and the speaker 3. At this time, the speaker 3 of the earphone type receiver 3A
No received voice is output from b.

Then, when the earset type handset 11 is detached from the storage table 21 and a call is made in a state of being attached to the ear, the earset type two-way call is performed using the transmitter 2A and the speaker 3b. Will be. In this case, as described above, the switch SW ₁ is switched to the earphone speaker, since the received voice is not output from the speaker 3, does not hinder the call. Therefore, in the second embodiment, the same effect as in the first embodiment can be obtained.

FIG. 10 is a side view showing a third embodiment of the present invention, in which the same or corresponding parts as in FIGS. In FIG. 10, 1B
Denotes a handset type handset, which is provided with an earset type handset 11 and a speaker 3. And
When the earset type handset 11 is attached to a predetermined position of the handset 1B, as in the first embodiment, the distance from the center C of the loudspeaker 3 to both sound pickup ports is in a range of 7 cm to 30 cm. The sound pickup opening faces the mouth of the caller.

Further, when the earset type handset 11 is attached to a predetermined position of the handset 1B, for example, by pulling the connection cord 2e, the holding of the connection cord 2e is released and the pulling of the connection cord 2e is stopped. The connection cord 2e can be clamped, and a cord winding mechanism that winds the connection cord 2e by a winding force when the clamping of the connection cord 2e is released by pressing an operation button is provided.

Next, a description will be given of a handset of the third embodiment which is different from the previous embodiment. First, when a call is made while the earset type handset 11 is mounted, the call is made using the transmitter 2A and the speaker 3. At this time, no received voice is output from the speaker 3b of the earphone type receiver 3A.

Then, the earset type handset 11 is detached and the connection cord 2e can be pulled out by pulling the earset type handset 11, so that the earset type handset 11 can be pulled out similarly to the second embodiment. In a state in which is put on the ear, a call is made using the transmitter 2A and the speaker 3b. Therefore, also in the third embodiment, the same effects as those of the previous embodiment can be obtained, and the connection cord 2e can be wound out of the way by the cord winding mechanism.

When the transmitter 2A is used at the mouth as a handset type, the input sensitivity of the transmitter 2A is approximately five times higher than when the transmitter 2A is used as an earset type.
The input sensitivity is reduced as described later as compared with the case of using as an earset type, and the output saturation of the transmitter 2A is prevented.
It is desirable to improve the SN ratio.

FIG. 11 is a front view showing a fourth embodiment of the present invention, in which the same or corresponding parts as in FIGS. In FIG. 11, 1C
Denotes a handset as a portable telephone terminal, and is provided with an earset type handset 11, a speaker 3, and an antenna 4. When the earset-type handset 11 is attached to a predetermined position of the handset 1C, the distance from the center C of the speaker 3 to both sound pickup openings is 7 as in the first embodiment.
cm to 30 cm, and one of the sound pickup openings faces the mouth of the caller.

FIG. 12 is a side view showing a fifth embodiment of the present invention, in which the same or corresponding parts as in FIGS. In FIG. 12, 1D
Denotes a handset of a cordless telephone terminal used indoors, and is provided with an earset type handset 11, a speaker 3, and an antenna 4. Then, when the earset-type handset 11 is attached to a predetermined position of the handset 1D, the distance from the center C of the speaker 3 to both sound pickup ports is in a range of 7 cm to 30 cm as in the first embodiment, One of the sound holes faces the mouth of the caller.

FIG. 13 is a side view showing a sixth embodiment of the present invention, in which a handset type and a speakerphone type two receivers are provided in a storage section. 1 to 12
The same or corresponding parts are denoted by the same reference characters and description thereof is omitted. In FIG. 13, reference numeral 1E denotes a handset type handset, in which an earset type handset 11 and speakers 3 and 6 are shown.
Is provided. Here, the speaker 3 is a handset-type speaker that is used by pressing the microphone against the mouth and the speaker against the ear, and the microphone 6 is a speakerphone-type speaker that emits sound to the outside. Then, when the earset type handset 11 is attached to a predetermined position of the handset 1E, as in the first embodiment, the distance from the center C of the speakers 3 and 6 to both sound pickup ports is in the range of 7 cm to 30 cm. That is, one of the sound pickup openings faces the mouth of the caller.

Also in the fourth to sixth embodiments, the same effects as in the previous embodiment can be obtained. In addition,
In the fourth to sixth embodiments, the input sensitivity of the transmitter 2A is switched as in the third embodiment, and the transmitter 2A is switched.
It is desirable to prevent output saturation and improve the S / N ratio.
In the fifth embodiment, as described later, 1
It is necessary to provide a handset switching mechanism for selecting one handset.

FIG. 14 is a block circuit diagram showing an example of the handset switching mechanism. The same or corresponding parts as in FIGS. In FIG.
Reference numeral 7 denotes a receiving circuit of a telephone terminal or the like, and SW ₁ denotes a switch. The switch SW ₁ supplies a receiving output from the receiving circuit 7 to the earphone type receiver 11 when the intercept p ₁ is switched to the contact a _1. When the intercept p ₁ is switched to the contact b ₁ , the receiver output from the receiver circuit 7 is supplied to the receiver 3.

When this receiver switching mechanism is used in the third to fifth embodiments, the earphone type receiver 11 is connected to the receiver 1
B, 1C, and 1D, when they are attached to and detached from predetermined positions,
And supplies the reception output from the receiving circuit 7 to the earphone-type handset 11 or handset 3 ₁ cut instead, supplying the reception output from the receiving circuit 7 to the earphone-type handset 11 or handset 3 is switched arbitrarily switch SW ₁ it can.

FIG. 15 is a block circuit diagram showing another example of the handset switching mechanism when two handsets are arranged in the storage section as in the sixth embodiment, and is the same as or equivalent to FIGS. The same reference numerals are given to the parts and the description is omitted. FIG.
In FIG. 5, SW ₂ indicates a switch, and when the intercept p ₂ is switched to the contact a ₂ , the reception output from the receiving circuit 7 is supplied to the earphone type receiver 11, and when the intercept p ₂ is switched to the contact b ₂ , When the reception output from the reception circuit 7 is supplied to the receiver 3 and the intercept p ₂ is switched to the contact c ₂ ,
The receiving output from the receiving circuit 7 is supplied to the receiver 6.

When this receiver switching mechanism is used in the sixth embodiment, the switch SW ₂ can be arbitrarily switched to supply the reception output from the reception circuit 7 to the earphone receiver 11 or the receiver 3. The switches SW ₁ and SW ₂ are
A mechanical switch or an electronic switch (such as an analog switch using a CMOS transistor) can be used.

FIG. 16 shows that the input sensitivity of the transmitter is also turned off at the same time.
FIG. 4 is a block circuit diagram showing an example of a handset switching mechanism for switching.
And the same or corresponding parts as those in FIGS.
And the description is omitted. In FIG. 16, 8 is a transmission circuit,
SW_ThreeIs a switch SW₁Or switch SW _TwoLink with
Switch SW, this switch SW_ThreeIs the switch S
W₁Or switch SW_TwoCuts off the earphone type handset 11
In other words, the section p_ThreeIs the contact a_ThreeSwitch to
Switch₁Or switch SW_TwoIs handset 3 or handset
When switching to 6, the intercept p_ThreeIs the contact b_ThreeSwitch to
It is.

V _CM is a transmitter power supply voltage, R _M and R _Mb are resistors for adjusting output, C _C is a capacitor for cutting DC, V _M
Indicates the transmitter output voltage, and the transmitter power supply voltage V _CM is + 2V
Up to + 7V, the resistance R _M is 1 kΩ to 10 kΩ, and the resistance R _Mb
Is 1/4 of the resistance R _M , and the capacitor C _C is 0.
1 μF to 1 μF.

By using this receiver switching mechanism, the input sensitivity of the transmitter 2A is five times higher when the transmitter 2A is used in the mouth as a handset type than when it is used as an earset type. The input sensitivity is switched to 1/5 as compared with the case where the earset type is used, thereby preventing output saturation of the transmitter 2A and improving the SN ratio.

FIG. 17 is a block circuit diagram showing an example of a receiver switching mechanism for simultaneously switching the frequency characteristics of the transmitter. The same or corresponding parts as those in FIGS. . In FIG. 17, C _Mb indicates a capacitor for lowering the pass frequency band. Thus providing the capacitor C _Mb, when the intercept p ₃ switched to the contact b _3, the high band cut-off frequency f _HC becomes _{f HC = 1 / 2πC Mb ·} R M.

When the transmitter 2A is used as an earset type by using this receiver switching mechanism, the high-frequency sound absorption effect of the skin of the face lowers the frequency characteristics on the high frequency side. When used as a handset type that moves away from the transmitter, howling can be prevented and sound quality can be equalized by lowering the frequency characteristics of the transmitter on the high frequency side and correcting the high frequency characteristics.

FIG. 18 is a block circuit diagram showing an example of a receiver switching mechanism for simultaneously switching the input sensitivity and frequency characteristics of the transmitter. The same or corresponding parts as those in FIGS. Is omitted. In Figure 18, SW ₄ shows a switch interlocked with the switch SW ₁ or the switch SW ₂ with switch SW _3, when the switch SW ₁ or the switch SW ₂ is switched to the earphone handset 11, the intercept p ₄ is cut to the contact a ₄ instead, when the switch SW ₁ or the switch SW ₂ is switched to the handset 3 or handset 6, in which the intercept p ₄ is switched to the contact b _4.

By using this handset switching mechanism, it is possible to prevent output saturation of the transmitter 2A and to improve the SN ratio, to prevent howling and to achieve the same sound quality.

In each of the above-described embodiments, the one which is not provided with the receiver switching mechanism, the storage detecting means for detecting whether or not the earphone type handset 3A is stored in the storage part, and the cord winding mechanism, The desired purpose can be achieved by providing it appropriately. Further, by providing the storage part in a part of the portable computer, the same effect can be obtained and the convenience is improved.

[0059]

As described above, according to the present invention, the distance between the sound pickup opening of the transmitter and the center of the speaker of the receiver is set to 7 cm or more so that the pipe has high sensitivity and bidirectionality. Since the microphone is arranged to configure the transmitter, the sound does not wrap around from the receiver to the transmitter, so that howling can be prevented and clear calls can be made. Also,
An earset-type handset in which an earphone-type receiver and a transmitter are integrated is stored in a storage unit when the earphone-type handset is not attached to the ear to be a storage-unit handset, and an earphone-type receiver or storage of the earphone-type receiver is set by a receiver switching mechanism. Since the receiver of the unit is selected, it can be used as a hands-free type or a handset type.

Further, since the input sensitivity and / or frequency characteristics of the transmitter can be switched by the receiver switching mechanism, the output saturation of the transmitter can be prevented, the S / N ratio can be improved, howling can be prevented, and the sound quality can be kept the same. At least one of the following. Since the housing is provided in a transmitter installation portion of a handset used for a desk-top telephone, a transmitter installation portion of a portable telephone terminal, or a part of a portable computer, a housing receiver is also provided. If the handset is a speakerphone type, or if the handset is placed on the ear of the caller, the handset is close to the talker's mouth, or the speakerphone type and the handset type The dual use type with functions makes it easy to use.

Next, since the receiver switching mechanism is controlled by the storage detecting means for detecting whether or not the earphone type handset is stored in the storage section, the labor for switching the receiver switching mechanism can be saved, and the operability can be reduced. Will be good.
Further, since the cord winding mechanism for accommodating the connection cord of the earphone type handset is provided in the storage section, the connection cord can be wound by the cord winding mechanism so as not to be in the way.

Further, by setting the length of the pipe to 4 cm or more, the input sensitivity of the voice of the caller can be sufficiently secured, and a clear call can be made. Since the ambient noise suppression circuit is connected to the transmitter to suppress the ambient noise, a clear call can be performed even when the ambient noise is at a high level, and the clarity of the call can be enhanced.

[Brief description of the drawings]

FIGS. 1A and 1B are side views showing a first embodiment of the present invention.

FIG. 2 is a sectional view of the transmitter shown in FIG. 1;

FIG. 3 is a block circuit diagram of a transmission circuit.

FIG. 4 is a frequency characteristic diagram of the band amplifier.

FIG. 5 is a frequency characteristic diagram showing a formant of a Japanese vowel (generation).

FIG. 6 is a schematic diagram of a gain controller using an analog multiplier.

FIG. 7 is a diagram illustrating a gain characteristic of a gain controller with respect to an amplitude value of a transmitter output;

FIG. 8 is a side view showing a second embodiment of the present invention.

FIG. 9 is an enlarged sectional view of the earset type handset shown in FIG. 8;

FIG. 10 is a side view showing a third embodiment of the present invention.

FIG. 11 is a front view showing a fourth embodiment of the present invention.

FIG. 12 is a side view showing a fifth embodiment of the present invention.

FIG. 13 is a side view showing a sixth embodiment of the present invention.

FIG. 14 is a block circuit diagram showing an example of a handset switching mechanism.

FIG. 15 is a block circuit diagram showing another example of the handset switching mechanism.

FIG. 16 is a block circuit diagram showing an example of a receiver switching mechanism for simultaneously switching the input sensitivity of the transmitter.

FIG. 17 is a block circuit diagram showing an example of a receiver switching mechanism for simultaneously switching the frequency characteristics of the transmitter.

FIG. 18 is a block circuit diagram showing an example of a receiver switching mechanism for simultaneously switching the input sensitivity and the frequency characteristic of the transmitter.

[Explanation of symbols]

1, 1A-1E handset 11 Earset type handset 2, 2A transmitter 2a pipe 2b bidirectional microphone 2c sound absorbing material 2d network 2e connection cord 2f case 3,6 speaker 3A earphone type receiver 3a vacant space 3b speaker 3c connecting cord 3d swollen portion 3e sound emission hole 4 antenna 5 ambient noise suppressing circuit 51 band amplifier 52 peak hold circuit 52a peak detector 52b hold circuit 53 gain controller 7 receiving circuit 8 transmitting circuit 21 receiving shelf R _M, R _Mb resistance C _Mb , C _C capacitor SW _{1 to} SW ₄ switch

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-57-48852 (JP, A) JP-A-62-281596 (JP, A) JP-A-7-212455 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04M 1/60 H04M 1/62 H04M 1/03 H04R 1/34

Claims (10)

(57) [Claims] 1. An earphone-type handset to be mounted on the outer ear, an earset-type handset having a transmitter integrated with the earphone-type receiver so as to be arranged outside the outer ear, and the earset not mounted on the ear A storage unit for storing a type handset, at least one handset disposed in the storage unit, and a handset switching mechanism for selecting one of the earphone type handset and the handset, Is one in which one bidirectional microphone is disposed at a substantially central portion in one pipe and both ends of the pipe are filled with a sound absorbing material, or two unidirectional microphones are arranged at both ends in the pipe. The two-way voice terminal device, wherein the transmitter and the receiver constitute a storage unit transmitter and receiver. 2. The two-way audio terminal device according to claim 1, wherein the handset switching mechanism has an input sensitivity of the handset and / or
Alternatively, a frequency characteristic can be switched, and a two-way audio terminal device. 3. The two-way audio terminal device according to claim 1, wherein the housing is provided in a transmitter installation portion of a handset used for a desk phone. Interactive audio terminal device. 4. The two-way audio terminal device according to claim 1, wherein the housing is provided at a transmitter installation portion of a portable telephone terminal. Audio terminal device. 5. The two-way audio terminal device according to claim 1, wherein the housing is provided in a part of a portable computer. 6. The two-way audio terminal device according to claim 1, wherein the accommodation unit receiver is configured such that the reception unit is a speakerphone type, or the accommodation unit handset is placed in the ear of a talker. The two-way audio terminal, wherein the transmitter is a handset type that comes close to the mouth of the caller, or is a dual-purpose type having functions of the speakerphone type and the handset type. apparatus. 7. The two-way audio terminal device according to claim 1, wherein the handset switching mechanism determines whether the earset type handset is housed in the housing. The two-way audio terminal device is controlled by a storage detecting unit that detects the state. 8. The two-way audio terminal device according to claim 1, wherein a code winding mechanism for storing a connection cord of the earset type handset is provided in the storage section. A two-way voice terminal device. 9. The two-way audio terminal device according to claim 1, wherein the length of the pipe is 4 cm or more. 10. The two-way audio terminal device according to claim 1, wherein a gain controller that receives an AC output from the transmitter as an input to the transmitter; A band amplifier that passes only the frequency of a specific frequency band of the AC signal from the transmitter, a peak detector that extracts an output corresponding to a peak value of the AC output that has passed through the band amplifier, an output level of the peak detector A bidirectional audio terminal device connected to an ambient noise suppression circuit constituted by a peak hold circuit comprising a hold circuit for suppressing the attenuation of the signal for a predetermined holding time.