JPH10107892A - Loud-speaker telephone set, microphone case and mounting structure for microphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide appropriate communication characteristics corresponding to acoustic coupling between a speaker for public address and a microphone for the public address by extracting the frequency components of signals outputted from the microphone for noise elimination and adding the signals to the signals outputted from the microphone for the public address in an opposite phase. SOLUTION: A public address input system comprising a microphone amplifier 5 for the public address and the microphone 6 for the public address is provided with the microphone 25 for the noise elimination and a band-pass filter amplifier 26 and is also provided with a differential amplifier 27 for taking a difference between the output of the microphone amplifier 5 and the output of the band-pass filter amplifier 26. Then, the microphone 25 for the noise elimination obtains input for detecting and eliminating acoustic coupling components sneaking to the microphone 6 for the public address, the band-pass filter amplifier 26 extracts the frequency components of a part of the signals outputted from the microphone 25 for the noise elimination and the differential amplifier 27 adds the extracted signals to the signals outputted from the microphone 6 for the public address in the opposite phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker capable of communicating with a destination without a handset, a microphone case and a microphone mounting structure used for the loudspeaker.

[0002]

2. Description of the Related Art Conventionally, there has been known a loudspeaker having a built-in speaker and a microphone for loudspeakers and capable of talking with the other party without using a handset. Generally, in a loudspeaker, the speaker and the microphone are installed at a relatively short distance in the same housing, so that acoustic coupling between them is prevented, that is, the voice of the other party output from the speaker is not transmitted. In order to prevent the phenomenon of sneaking into a microphone, there is a type in which an audio switch circuit is built. FIG. 13 is a block diagram showing the configuration of a loudspeaker incorporating a voice switch circuit. As shown in FIG. 1, the loudspeaker includes a hybrid circuit 1, a voice switch circuit 2, a loudspeaker amplifier (hereinafter referred to as a speaker amplifier) 3, a loudspeaker (hereinafter referred to as a speaker) 4, and a loudspeaker microphone amplifier (hereinafter referred to as a microphone amplifier) 5. And a loudspeaker microphone (hereinafter, microphone) 6.

[0003] A hybrid circuit 1 is for making a connection to a telephone network 10, and converts a received signal into a voice switch circuit 2.
And the transmission signal is output to the telephone network 10 so that the transmission signal does not enter the voice switch circuit 2. The voice switch circuit 2 adjusts the transmission level to be low in the reception state and to reduce the reception level in the transmission state.
1. It has a transmission suppression circuit 12 and a control circuit 13. Here, the control circuit 13 compares the transmission signal with the reception signal, and controls the reception suppression circuit 11 to attenuate the reception signal during transmission (transmission signal> reception signal) during transmission (reception signal). (Signal> transmission signal), the transmission control circuit 12 is controlled so as to attenuate the transmission signal.

[0004] Even when the sound from the speaker 4 goes around the microphone 6 by the sound switch circuit 2, the sound output of the microphone 6 is suppressed to a low level, so that the acoustic coupling between the speaker 4 and the microphone 6 can be suppressed. Here, FIG. 14 is a block diagram showing acoustic wraparound from the speaker 4 to the microphone 6. As shown in this figure, after a reception signal Sr from the other party is output as a voice signal from the speaker 4 on the own side, the signal goes around to the microphone 6 on the own side and is output as a transmission signal St to the other side. In this case, if the voice switch circuit 2 is not provided, the level of the transmission signal St wrapping around the microphone 6 becomes large, which may cause howling and acoustic echo. However, since the voice switch circuit 2 is provided, the microphone is provided. The level of the transmission signal St wrapping around 6 is reduced, and the occurrence of howling and acoustic echo is suppressed.

As shown in FIG. 13, a speaker amplifier 3 amplifies a reception signal from the voice switch circuit 2 to a predetermined level, while a microphone amplifier 5 converts a transmission signal from the microphone 6 to a predetermined level. Amplify.
In this case, assuming that the appropriate speech sound level is 94 dBSPL, the received voice from the speaker 4 is output to 94 dBSPPL.
The gain of the speaker amplifier 3 is set so as to output an acoustic output greater than 94 dB from the speaker 4 for listening at L. Also, when the user speaks, a sound level of about 94 dB is added to the microphone 6, so that the gain of the microphone amplifier 5 is set so that the sound level becomes the rated sound level of the telephone line. The reception signal amplified by the speaker amplifier 3 is supplied to the speaker 4 to generate a sound, while the transmission signal amplified by the microphone amplifier 5 is supplied to the voice switch circuit 2.

FIG. 15 is a perspective view showing the appearance of a loudspeaker. As shown in this figure, a sound emitting hole 16 for a speaker is formed in a central portion on the front left side of the housing 15, and a sound collecting hole 17 for a microphone is formed in a right side portion on a front side surface of the housing 15. Have been. The speaker 4 is disposed inside the housing 15 in which the sound emission hole 16 for the speaker is formed, and the housing 15 in which the sound collection hole 17 for the microphone is formed.
The microphone 6 is arranged inside the.

FIG. 16 is a cross sectional view of FIG.
15 is a sectional view of a main part of FIG. 15, and FIG. 18 is an enlarged sectional view of a portion where the microphone 6 is attached. In these figures, the microphone 6 is housed in the rubber case 20 and its sound introduction surface 6A (see FIG. 17) is arranged facing the sound collection hole 17. Microphone 6
The wiring 6B is connected to the circuit board 22. The rubber case 20 blocks sound emitted from the speaker 4 into the housing 15, and the sound introduction surface 6 </ b> A of the microphone 6.
It has a shape that covers all parts other than. Normally, a loudspeaker is provided with a handset 18 in addition to the loudspeaker 4 and the microphone 6, so that a telephone call with the handset 18 is possible.

[0008]

However, the above-mentioned conventional loudspeakers have the following problems. When a call is made at an appropriate call level, the sound from the loudspeaker 4 may largely reach the microphone 6 side, and the other party's voice may sound like an acoustic echo. Also, depending on the variation of the AC impedance on the telephone line side, in the hybrid circuit 1, the transmission signal may leak to the reception signal side and become a hybrid echo. Therefore, conventionally, the amount of audio suppression in the audio switch circuit 2 is set to be large. However, by setting the voice suppression amount large, a slight delay occurs when switching from the priority state of the speaker 4 to the priority state of the microphone 6, and the first part of the word input from the microphone 6 is interrupted and unnatural. There was a call.

Further, when a large volume is output from the speaker 4, the sound emitted from the back of the speaker 4 stays inside the housing 15 of the loudspeaker and forms an effective acoustic coupling path with the microphone 6. Sometimes. However, it is very difficult to cancel this. Even if the rear side of the microphone 6 is shielded by the rubber case 20, the sound from the speaker 4 will not be covered by the cover and the base constituting the housing 15, but also by the circuit board. , Etc., to the microphone 6 via each mechanical component. When the mechanical vibrations of the cover, the base, the printed wiring board, and the like are transmitted to the microphone 6 as described above, the voice switch circuit 2 operates as a transmission state, and in the worst case, the electric switch is constantly switched to the speaker side. In some cases, normal calls could not be made.

To solve this problem, a speaker 4
The distance between the speaker 6 and the microphone 6 is further increased, the back surface of the speaker 4 is completely covered with another component, or the microphone 6 is completely removed from the inside of the housing 15 and the acoustic coupling inside the housing 15 is performed. Or using special directional microphones, etc., have been considered. However, in any case, the housing 15 becomes large and the degree of freedom of design is lost, or expensive parts are used. As a result, the number of components has become unnecessarily large, and the mounting space inside the housing 15 has been lost.

A loudspeaker using an acoustic echo canceller to reduce the amount of audio suppression of the audio switch circuit 2 has also been considered. However, the acoustic echo canceller also has sufficient performance when the acoustic coupling amount is large (from the speaker 4). (The ability to cancel the wraparound to the microphone 6) cannot be obtained.
When an acoustic echo canceller is used, the speaker 4 and the microphone 6 need to be separated, and it is difficult to incorporate the speaker 4 and the microphone 6 in a telephone.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the loudspeaker telephone, and an object of the present invention is to provide an appropriate telephone call characteristic corresponding to the acoustic coupling between the loudspeaker and the loudspeaker microphone. Is to provide a loudspeaker capable of obtaining the following. Another object of the present invention is to provide a microphone case and a microphone mounting structure that are effective for improving the communication characteristics.

[0013]

A loudspeaker according to the first aspect of the present invention includes a loudspeaker for emitting a sound based on a received sound signal, a loudspeaker microphone for inputting a user's voice, A noise canceling microphone for obtaining an input for detecting and canceling an acoustic component circulating around the loudspeaker microphone, extracting means for extracting a partial frequency component of a signal output from the noise canceling microphone, Adding means for adding the signal extracted by the means in opposite phase to the signal output from the loudspeaker microphone.

According to this configuration, the sound signal emitted from the loudspeaker is detected by the noise canceling microphone, and some frequency components of the detected signal are extracted, and the signal from the loudspeaker is detected. The audio input signal output from the loudspeaker is an audio input signal output from the loudspeaker from which the acoustic coupling component circulating from the loudspeaker to the loudspeaker microphone is removed. Then, by using an extracting means for extracting a part of the frequency component of the signal output from the noise canceling microphone, the speech characteristics related to the acoustic coupling which cannot be improved only by the addition of the signals having the opposite phases are improved. In addition, by providing a loudspeaker near the noise canceling microphone, the signal close to the acoustic coupling component that wraps around the loudspeaker is captured by the noise canceling microphone, and signals with opposite phases are added to improve the communication characteristics. Plan. The loudspeaker microphone and the noise canceling microphone are provided inside the housing, and the loudspeaker microphone is configured such that sound comes through a sound collection hole opened in the housing. Sealed inside. As a result, the noise canceling microphone does not change its wraparound irrespective of the acoustic environment where the loudspeaker is installed, so that the component relating to the acoustic coupling can always be detected stably, and the speech can be appropriately used using this. Improve characteristics. In addition, the output from the loudspeaker shows a situation in which the amount of acoustic coupling between the loudspeaker and the loudspeaker microphone is reduced,
The acoustic echo cassette can be used even when the loudspeaker and the loudspeaker microphone are incorporated in the same housing.

The output from the loudspeaker is
Acting as if the amount of acoustic coupling between the loudspeaker and the loudspeaker microphone was reduced, the distance between the loudspeaker and the loudspeaker microphone was increased, or the back of the loudspeaker was completely separate. It is possible to obtain appropriate communication characteristics without covering with a microphone, or putting the microphone for sound out of the housing completely, and without using a special directional microphone. It is possible to prevent problems such as a lack of flexibility, use of expensive components, an increase in the number of components more than necessary, and a lack of mounting space inside the housing.

The output level of the sound from the loudspeaker varies with the frequency due to differences in the size and shape of the speaker. Therefore, as the extracting means, a means having a characteristic of extracting a signal corresponding to a signal in a frequency band having a large output level among all frequency bands of the signal output from the loudspeaker is employed. As a result, the sound coupling characteristics which are not improved by the addition of the signals having the opposite phases are improved. The loudspeaker microphone and the noise canceling microphone may be covered together by an elastic material case.
Accordingly, it is possible to suppress the rate at which the sound transmitted from the cover, the base, and the like that constitute the housing goes around to the microphone for sound amplification. In this case, it is necessary for the loudspeaker microphone to capture sound outside the housing, so that the surface on which the sound is sensed is directed to the sound collection hole opened in the housing. The microphone for noise cancellation needs to detect the sound related to the wraparound,
In order to take in sound mainly from the inside of the housing, it is arranged not only in the sound collection hole of the housing but also in a place where no gap is formed.

Further, a mounting structure may be adopted in which the microphone for sound amplification is covered with an elastic material case, and the microphone for noise cancellation is mounted on the circuit board in the housing at a position closest to the microphone for sound amplification. The microphone case includes a loudspeaker for emitting sound based on a received sound signal, a loudspeaker for inputting a user's voice, and noise elimination for detecting and eliminating an acoustic component circulating around the loudspeaker. Microphone, extracting means for extracting a partial frequency component of the signal output from the noise canceling microphone, and adding the signal extracted by the extracting means to the signal output from the loudspeaker in opposite phases. Used in a loudspeaker telephone comprising
A hole is formed in a portion that covers the microphone for noise reduction and the microphone for noise cancellation and that faces a surface on the side where the sound of the microphone for voices is sensed and a surface on the side where the sound of the microphone for noise cancellation is sensed. It is characterized by being composed of a given elastic material. A band-pass filter amplifier is suitable for the extracting means, and a differential amplifier is suitable for the adding means.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a loudspeaker, a microphone case, and a microphone mounting structure according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of a loudspeaker according to the present invention, FIG. 2 is a block diagram showing a configuration of a loudspeaker processing system of the embodiment, and FIG. 1 shows a cross-sectional view of such a loudspeaker. In these figures, the same reference numerals are given to the same parts as those in FIGS. 13 to 18 described above. In this embodiment, as shown in FIG. 1, a noise canceling microphone (hereinafter referred to as a sub microphone) is provided in a loudspeaker input system including a loudspeaker microphone amplifier (hereinafter referred to as a microphone amplifier) 5 and a loudspeaker microphone (hereinafter referred to as a main microphone) 6. A microphone) 25 and a band-pass filter amplifier (extraction means) 26, and a differential amplifier (addition means) for taking the difference between the output of the microphone amplifier 5 and the output of the band-pass filter amplifier 26
27 are provided. In this case, the sub microphone 25 has the same performance as the main microphone 6.

The main microphone 6 and the sub-microphone 25 are housed in a state of being linearly arranged inside a rubber case 30 constituting a microphone case, as shown in FIG. It is arranged on the right side of the front side surface 15A. As shown in FIG. 4, which is a cross-sectional view of a mounting portion of the main microphone 6 and the sub microphone 25,
Holes 30A and 30B are formed on both the front side and the rear side of the main microphone 6, one of the holes 30A faces the sound introduction surface (the surface on the sound sensing side) 6A of the main microphone 6, and the other hole 30B. Is the sound introduction surface 25A of the sub microphone 25
And is facing. That is, the microphone case has a first room facing the sound collection hole 17 of the housing 15 and a second room provided on the back surface of the first room via a partition,
In the first room, the main microphone 25 whose sound introduction surface 6A is directed to the sound collection hole 17 is accommodated, and in the second room, the sound introduction surface 25A is directed inside the housing 15 through the hole 30B. Sub microphone 25 is accommodated. With this configuration, the user's transmission sound enters through the sound collection hole 17 of the housing 15 and reaches the sound introduction surface 6A of the main microphone 6 through the hole 30A of the rubber case 30. On the other hand, the sound emitted from the back of the speaker 4 into the housing 15 is
The sound reaches the sound introduction surface 25A of the sub-microphone 25 through the hole 30B of zero. In addition, the sound transmitted through the mechanical components such as the circuit board 31 and the like other than the cover and the base constituting the housing 15 reaches the main microphone 6 and the sub microphone 25 via the rubber case 30. The rubber case 30 may be made of an elastic material other than rubber, for example, synthetic resin, sponge, or the like.

The sound introduction surface 25A of the sub-microphone 25 is disposed facing the inside of the housing 15, and the surrounding portion of the sub-microphone 25 except for the sound introduction surface 25A is covered with the rubber case 30. The degree to which the user's transmission sound is directly taken into the sub-microphone 25 is small. Further, since the sub microphone 25 is arranged near the main microphone 6, the time of the acoustic coupling between the speaker 4 and the main microphone 6 and the time of the acoustic coupling between the speaker 4 and the sub microphone 25 are shifted. It is reduced so that the same degree of acoustic coupling can be obtained, so that the acoustic coupling component can be suitably removed at the time of addition by the differential amplifier 27. The wiring 6B of the main microphone 6 and the wiring 25B of the sub microphone 25 are connected to the circuit board 31, and the input audio signal is transmitted to the microphone amplifier 5 and the bandpass filter amplifier 25 on the circuit board 31.

FIG. 5 shows the output characteristics of the microphone amplifier 5 with respect to the frequency in the loudspeaker having the above configuration. As is apparent from FIG.
It can be seen that the output level is highest around 00 Hz. The acoustic coupling amount becomes maximum in the frequency band where the output level becomes the maximum, and the acoustic coupling amount of the loudspeaker is determined. In this case, the frequency band at which the output level becomes maximum varies depending on the size and shape of the speaker 4, etc. Generally, a small-diameter loudspeaker is used, so that the frequency band of the order shown in FIG. become.

Returning to FIG. 1, the description will be continued. The band-pass filter amplifier 26 extracts only a frequency component of approximately 300 to 600 Hz from the output of the sub microphone 25 (that is, a signal in a low band of the audio band). The signal extracted by the band-pass filter amplifier 26 is added by the differential amplifier 27 to the signal output from the microphone amplifier 5 in opposite phase. As a result, an audio signal having a reduced component related to acoustic coupling in the frequency band of 300 to 600 Hz appears at the output of the differential amplifier 27.

FIG. 6 shows the output value of the differential amplifier 27 with respect to the frequency. The output value of the differential amplifier 27 is 3 compared with the output of the microphone amplifier 5 shown in FIG.
It can be seen that the output level in the frequency band of 00 to 600 Hz has decreased. When the output level in the frequency band of 300 to 600 Hz decreases, the speaker 4
The component corresponding to the amount of acoustic coupling between the microphone and the main microphone 6 also decreases. As a result, the speaker 4 can be controlled without increasing the audio suppression amount of the audio switch circuit 2.
It is possible to reduce the component corresponding to the acoustic coupling between the sound signal and the main microphone 6.

The reason why the bandpass filter amplifier 26 is necessary will be described. Even if the sub microphone 25 is arranged in the vicinity of the main microphone 6, the presence or absence of the sound collection hole 17 and the surrounding environment of the microphone are slightly different.
It is extremely difficult to completely match the phases at audio frequencies (200 Hz to 3.3 KHz). Therefore,
Even if the differential amplifier 27 is designed to cancel the component corresponding to the acoustic coupling between the speaker 4 and the main microphone 6 in a low frequency band, the above-mentioned cancellation effect cannot be sufficiently obtained in a high frequency band. Since the output of the microphone 6 and the output of the sub-microphone 25 are not completely the same, there is a possibility that a large value may be returned by adding the signals as opposite phases.

Therefore, the band-pass filter amplifier 26 has a high frequency band (frequency band higher than 600 Hz) in the audio frequency (200 Hz to 3.3 KHz).
In the above, components related to acoustic coupling are suppressed. In FIG.
The frequency characteristic of the output value related to acoustic coupling when only the main microphone 6 is used (in the case of the configuration shown in FIG. 12) is indicated by a broken line and when the main microphone 6 and the sub microphone 25 are used (band-pass filter amplifier). 26 is not used, the frequency characteristic of the output value related to the acoustic coupling is indicated by a dashed-dotted line, and the output value related to the acoustic coupling when the main microphone 6 and the sub microphone 25 and the bandpass filter amplifier 26 are used. The frequency characteristics are shown by solid lines and.

FIG. 7 shows that the case where the sub microphone 25 is used (indicated by a dashed line) is 200 Hz to 1 K in comparison with the case where only the main microphone 6 is used (indicated by broken lines).
In the range of about Hz, the effect of suppressing the component related to acoustic coupling is recognized. However, in the range of 1 KHz to 5 KHz, the output of the main microphone 6 and the output of the sub microphone 25 are not completely coincident signals. It is recognized that a large value is returned by adding as a phase. In contrast, the bandpass filter amplifier 26
By using (solid line and)
In the range of KHz, not only the effect of suppressing the component related to acoustic coupling is recognized, but also in the range of 1 KHz to 5 KHz, the output value decreases, and the effect of suppressing the component related to acoustic coupling is recognized. As described above, the present invention uses the bandpass filter amplifier 26 to suppress components related to acoustic coupling over the entire range of audio frequencies.

On the other hand, this loudspeaker is provided with a handset 35 as shown in FIG.
6 is connected to a telephone circuit 28. This handset 35 can be used by turning on (closed) the switch 36. Handset 35 and switch 3
6, a speaker amplifier 37 and a microphone amplifier 38 are provided. The telephone circuit 28 includes the hybrid circuit 1, the voice switch circuit 2, and the like.

Further, in the embodiment, the sound introduction surface 25A is arranged near the main microphone 6 so as to face the inside of the housing 15, and the sound is emitted from the back of the speaker 4 and transmitted through the inside of the housing 15. The sub microphone 25 can detect the sound and the sound circulating through the mechanical components such as the circuit board 31 in addition to the cover and the base constituting the housing 15. For this reason, a signal that is not related to the acoustic coupling between the speaker 4 and the main microphone 6, such as a sound generated by the user being reflected indoors, is not input, and a signal from which a component corresponding to the acoustic coupling is removed. To the differential amplifier 27
, And the amount of audio suppression of the audio switch circuit 2 can be reduced accordingly. Thus,
The delay at the time of switching from the priority state of the speaker 4 to the priority state of the main microphone 6 is reduced, and the first word after switching to the main microphone 6 is not interrupted, so that a natural telephone call becomes possible.

The speaker 4 and the main microphone 6
Between the main microphone 6 and the main microphone 6
It is not necessary to completely move the housing 15 out of the housing 15 or use a special directional microphone. Therefore, the housing 15 becomes large and the degree of freedom in design is lost, or expensive parts are used. Therefore, problems such as an unnecessarily large number of components and a lack of mounting space inside the housing 15 do not occur.

Also, since the amount of acoustic coupling can be substantially reduced in the output of the loudspeaker, the acoustic echo canceller can be used while securing a sufficient speaker volume, and the simultaneous call performance is improved. Loudspeaker can be realized. That is, in the present embodiment,
As a means for attenuating the transmission signal from the loudspeaker microphone during reception and attenuating the reception signal supplied to the loudspeaker during transmission, a configuration in which the voice switch circuit 2 is provided in the telephone circuit 28 is employed. However, instead of the voice switch circuit 2, the acoustic echo canceller is used to attenuate a transmission signal from a loudspeaker microphone during reception,
There is an embodiment in which a received signal supplied to a loudspeaker is attenuated during transmission. In addition,
In the speaker 4 of this embodiment, 350 to 500 Hz
Since the amount of acoustic coupling is highest in the vicinity of the frequency band, the band-pass filter amplifier 26 having a pass band of about 300 to 600 Hz was used. However, the output level of the microphone amplifier 5 is the highest due to the size and shape of the speaker. Therefore, the pass band of the band-pass filter amplifier is selected according to the speaker to be used.

FIG. 8 is a cross-sectional view of a modified example of the embodiment of the loudspeaker according to the present invention. This loudspeaker has a main microphone 6 and a sub microphone 2 as shown in the figure.
5 are arranged side by side in the width direction of the housing 15, and the circuit configuration thereof is as shown in FIGS. In the configuration of this modified example, the sound introduction surface 6A of the main microphone 6 is disposed so as to face the sound collection hole 17 of the housing 15, while the sound introduction surface 25A of the sub microphone 25 is located inside the housing 15. It is arranged facing. In addition, the main microphone 6 and the sub microphone 2
Rubber case 40, which is a microphone case for housing
Is provided with first and second rooms in which the main microphone 6 and the sub microphone 25 are arranged side by side, and the main microphone 6 and the sub microphone 25 are accommodated in each room. Each room has holes 40A, 40B opened in opposite directions on the surface facing the sound introduction surfaces 6A, 25A.
Are formed. The wirings 6B and 25B of the main microphone 6 and the sub microphone 25 are connected to the microphone amplifier 5 and the band-pass filter 26 on the circuit board 41, respectively. Even in the modification in which the main microphone 6 and the sub microphone 25 are arranged in the width direction of the housing 15, the same effect as in the above embodiment can be obtained.

FIG. 9 is a cross sectional view of a second modification of the embodiment of the loudspeaker according to the present invention. The loudspeaker according to this modification has a main microphone 6 alone housed in a rubber case 44 and a sub-microphone 25 mounted on a circuit board 45 near the main microphone 6 as shown in the figure. 1, as shown in FIG. FIG. 10 is an enlarged view of a portion where the main microphone 6 and the sub microphone 25 are attached. As shown in this figure, the sub microphone 25 has its sound introduction surface 25
A is mounted on the circuit board 45 so as to face upward (the front side of the loudspeaker). By mounting the sub microphone 25 directly on the circuit board 45, the wiring 25
B becomes unnecessary, and the manufacturing process can be simplified and the manufacturing cost can be reduced. In addition, the sub microphone 25
Has a structure that does not directly contact the housing 15, so that sound sneaking from a cover or a base constituting the housing 15 is reduced, and the sub microphone 25 does not necessarily need to be covered with the rubber case. In order to prevent the coupling, the sub microphone 25 is covered with a microphone case made of an elastic material like the main microphone 6, that is, the sub microphone 25 is
In addition to the microphone mounting structure arranged on the circuit board 45 closest to the main microphone 6 inside the housing 15, the sound introduction surface 2 of the sub microphone 25 in such a mounting structure
There is also an embodiment in which a material other than 5A is coated with an elastic material.

FIG. 11 is a cross sectional view of a third modification of the embodiment of the loudspeaker according to the present invention. The loudspeaker according to this modification has the sub-microphone 25 in the second modification described above oriented in the lateral direction (that is, on the side wall of the housing 15). FIG. 12 is an enlarged view of a portion where the main microphone 6 and the sub-microphone 25 of this modified example are attached. As shown in this figure, the sub-microphone 25 has its sound introduction surface 25A directed inward in the housing 15. And is attached to the circuit board 45. Also in the third modified example, since the sub microphone 25 is directly mounted on the circuit board 45, the wiring 25B is not required, so that the manufacturing process can be simplified and the manufacturing cost can be reduced. Further, the sub microphone 25 is mounted on the housing 1.
Since the sub microphone 25 is not directly in contact with the sub microphone 25, the sound sneaking from the cover or the base constituting the housing 15 is reduced, and the sub microphone 25 does not necessarily need to be covered with the rubber case. The circuit board 4 closest to the main microphone 6 inside the housing 15
In addition to the structure disposed on the sub-microphone 5, there is also an embodiment in which the mounting structure other than the sound introduction surface 25A of the sub microphone 25 is covered with an elastic material.

[0034]

According to the first aspect of the present invention, the acoustic coupling component between the loudspeaker and the loudspeaker is detected by the noise canceling microphone, and a part of the frequency component is extracted to extract the acoustic coupling component. Since the signals from the microphones are added in opposite phases, it is possible to obtain an audio signal from which the above-mentioned acoustic coupling amount has been removed, attenuate the received signal during transmission, and convert the transmitted signal during reception. It is possible to reduce the amount of voice suppression in the voice switch circuit that performs the function of attenuating, so that the switching delay from receiving to transmitting is reduced and the first word is not interrupted,
Good call characteristics can be secured.

According to the second aspect of the present invention, since the loudspeaker microphone and the noise canceling microphone are arranged close to each other, a signal close to the acoustic coupling component wrapping around the loudspeaker is captured, and a signal of the opposite phase is captured. By performing the addition, it is possible to obtain a voice signal from which the acoustic coupling component has been further removed, which has an effect of improving the speech characteristics.

According to the third aspect of the present invention, the extracting means extracts a signal in a frequency band having a large output level from all frequency bands of the signal output from the loudspeaker.
In the signal part of the frequency band with a large output level, it is possible to capture a signal close to the acoustic coupling component that wraps around the loudspeaker microphone and add signals of opposite phases, and otherwise, signals that are not completely out of phase Can be suppressed to obtain an audio signal from which the acoustic coupling component has been further removed over the entire band, which has the effect of improving the communication characteristics.

According to the fourth aspect of the present invention, in the signal portion of the frequency band having a large output level, a signal close to an acoustic coupling component wrapping around the loudspeaker microphone is captured by the band-pass filter amplifier, and signals having opposite phases are added. In addition, otherwise, it is possible to obtain an audio signal in which the acoustic coupling component is further removed over the entire band by suppressing the addition result of signals that are not completely out of phase,
This has the effect of improving the call characteristics.

According to the fifth aspect of the present invention, the loudspeaker microphone and the noise canceling microphone are provided inside the housing, and sound comes to the loudspeaker microphone through a sound collection hole opened in the housing. The noise canceling microphone does not directly take in the voice or the like from the environment in which the loudspeaker is installed, but has the effect of appropriately detecting the acoustic coupling component and improving the call characteristics. Have.

According to the sixth aspect of the present invention, the received signal is amplified by the speaker amplifier and supplied to the loudspeaker.
The output of the loudspeaker microphone can be amplified by the microphone amplifier, and an appropriate input / output level can be obtained.

According to the seventh aspect of the present invention, the surface of the microphone for covering the loudspeaker and the noise canceling microphone and the side for sensing the sound of the microphone for loudspeaker and the side for sensing the sound of the microphone for noise elimination are provided. Equipped with an elastic material case with a hole in the part facing each side, sound enters from the necessary direction, reduces the entry of sound from unnecessary directions, detects sound coupling components appropriately and talks This has the effect of improving the characteristics.

According to the eighth aspect of the present invention, since the noise canceling microphone is provided on the circuit board inside the housing closest to the loudspeaker microphone, the wiring and the wiring from the noise canceling microphone to the circuit board. This eliminates the need for separate installation work, thereby simplifying the manufacturing process and reducing manufacturing costs.

According to the ninth aspect of the present invention, there is an effect that it is possible to easily perform the addition with the phase inverted by the differential amplifier.

According to the tenth aspect of the present invention, there is provided means for attenuating the transmission signal from the loudspeaker microphone during reception and attenuating the reception signal supplied to the loudspeaker during transmission. Along with the removal of the acoustic coupling component, it is possible to obtain more appropriate speech characteristics due to appropriate attenuation of the transmission and reception signals.

According to the eleventh aspect of the present invention, the sound enters from a necessary direction, the entry of sound from an unnecessary direction is reduced, and an effect of improving the speech characteristics by appropriately detecting an acoustic coupling component. The microphone case contributing to the loudspeaker can be provided by the elastic material case.

According to the twelfth aspect of the present invention, the portion of the microphone for loudspeaker except for the sound sensing surface is covered, and the sound sensing surface is directed to the sound collection hole formed in the housing.
The noise canceling microphone can be disposed so as to be disposed on the back surface of the microphone for loudness through a partition wall, and the noise canceling microphone and the microphone for loud sound can be integrally held close to each other.

According to the thirteenth aspect of the present invention, the portion excluding the sound sensing surface of the loudspeaker microphone is covered, and the sound sensing surface is directed to the sound collection hole formed in the housing.
A noise canceling microphone is provided at a position adjacent to the side of the sound collection hole so as to be able to arrange a surface for sensing sound via a partition wall toward a rear part, and the noise canceling microphone and the sound amplification microphone are arranged close to each other. Can be held together.

According to the fourteenth aspect of the present invention, the noise canceling microphone is arranged on the circuit board closest to the loudspeaker microphone inside the housing, and the noise canceling microphone is confined inside the housing to obtain an acoustic environment. , And contributes to a loudspeaker having the effect of improving the call characteristics.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a loudspeaker according to the present invention.

FIG. 2 is a block diagram showing a configuration of a loudspeaker processing system of the loudspeaker according to the present invention.

FIG. 3 is a cross-sectional view of the loudspeaker according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a part of the loudspeaker according to the embodiment of the present invention, in which a loudspeaker microphone and a noise canceling microphone are attached.

FIG. 5 is a diagram showing an output value with respect to a frequency of a loudspeaker microphone amplifier of the loudspeaker according to the present invention.

FIG. 6 is a diagram showing an output value with respect to a frequency of a differential amplifier of the loudspeaker according to the embodiment of the present invention;

FIG. 7 is a diagram showing a frequency characteristic of acoustic coupling for explaining an effect of the loudspeaker according to the embodiment of the present invention;

FIG. 8 is a cross-sectional view of a first modified example of the embodiment of the loudspeaker according to the present invention.

FIG. 9 is a cross-sectional view of a second modified example of the loudspeaker according to the second embodiment of the present invention.

FIG. 10 is a cross-sectional view of a part of a second embodiment of the loudspeaker according to the present invention, in which a loudspeaker microphone and a noise canceling microphone are attached.

FIG. 11 is a cross-sectional view of a third modification of the loudspeaker according to the present invention.

FIG. 12 is a cross-sectional view of a third embodiment of the loudspeaker according to the present invention, in which a loudspeaker microphone and a noise canceling microphone are attached.

FIG. 13 is a block diagram showing a configuration of a conventional loudspeaker system of a loudspeaker.

FIG. 14 is a block diagram showing acoustic wraparound from a loudspeaker to a loudspeaker microphone in a conventional loudspeaker.

FIG. 15 is a perspective view showing the appearance of a conventional loudspeaker.

FIG. 16 is a cross-sectional view of the conventional loudspeaker of FIG. 14;

FIG. 17 is a longitudinal sectional view of a main part of the conventional loudspeaker of FIG. 14;

FIG. 18 is an enlarged sectional view of a mounting portion of a conventional loudspeaker for a loudspeaker.

[Explanation of symbols]

 2 Voice switch circuit 3 Loudspeaker amplifier 4 Loudspeaker 5 Loudspeaker microphone amplifier 6 Loudspeaker microphone 15 Housing 17 Sound collecting hole 25 Noise canceling microphone 26 Bandpass filter amplifier 27 Differential amplifier 30, 40, 44 Rubber case 31, 41, 45 Circuit board 35 Handset

Claims (14)

[Claims] 1. A speaker for loudspeaker for emitting a sound based on a received sound signal, a microphone for loudspeaker for inputting a user's voice, and an acoustic coupling component wrapping around the microphone for loudspeaker is detected and erased. Noise extracting microphone for obtaining an input for the same, extracting means for extracting a partial frequency component of a signal output from the noise canceling microphone, and a signal extracted by the extracting means being output from the loudspeaker microphone. A loudspeaker, comprising: an adding means for adding the signals in opposite phases to the signals. 2. The loudspeaker according to claim 1, wherein the loudspeaker microphone and the noise canceling microphone are arranged near each other. 3. The loudspeaker according to claim 1, wherein said extracting means extracts a signal in a frequency band having a large output level among all frequency bands of the signal output from the loudspeaker for loudspeaker. . 4. The loudspeaker according to claim 1, wherein the extracting means is a band-pass filter amplifier. 5. A loudspeaker and a noise elimination microphone are provided inside a housing, and the loudspeaker is configured to receive sound through a sound collection hole formed in the housing. Claim 1 characterized by the following:
The loudspeaker according to any one of claims 1 to 4. 6. A speaker amplifier according to claim 1, further comprising: a speaker amplifier for amplifying a received signal and supplying the amplified signal to a speaker for loudspeaker; and a microphone amplifier for amplifying an output of the microphone for loudspeaker. The loudspeaker described. 7. A portion which covers the microphone for noise enhancement and the microphone for noise reduction, and which faces a surface on the side for sensing the sound of the microphone for voice enhancement and a surface on the side for sensing the sound of the microphone for noise reduction. 7. A loudspeaker according to claim 1, further comprising an elastic material case having a hole. 8. A microphone for sound amplification, wherein a portion excluding a surface for sensing sound is covered with an elastic material case, and a surface for sensing sound is directed to a sound collection hole opened in the housing, and the inside of the housing is provided. The loudspeaker according to any one of claims 1 to 7, wherein the noise canceling microphone is provided on a circuit board inside a housing closest to the loudspeaker microphone. Phone. 9. The loudspeaker according to claim 1, wherein said adding means is a differential amplifier. 10. A system according to claim 1, further comprising means for attenuating a transmission signal from a loudspeaker during reception and attenuating a reception signal supplied to a loudspeaker during transmission. 10. The loudspeaker according to any one of claims 9 to 9. 11. A loudspeaker for emitting a sound based on a received sound signal, a loudspeaker for inputting a user's voice, and a sound component circulating around the loudspeaker for detecting and eliminating the sound component. A noise canceling microphone, extracting means for extracting a part of the frequency component of the signal output from the noise canceling microphone, and reversing the signal extracted by the extracting means into a signal output from the loudspeaker microphone. Used in a loudspeaker telephone having an adding means for adding a phase, wherein the loudspeaker microphone and the noise canceling microphone are covered, and a surface on the side of sensing the sound of the loudspeaker microphone and the sound of the noise canceling microphone are used. A micro-structure comprising an elastic material having a hole in a portion facing each of the sensing surfaces. Nkesu. 12. A microphone for covering a sound excluding a surface for detecting sound of a loudspeaker, and a surface for detecting sound is directed to a sound collection hole formed in a housing. The microphone case according to claim 11, wherein the microphone case is disposed so as to be disposed on the back surface of the microphone for voice. 13. A microphone for noise reduction, which covers a portion except for a sound sensing surface of a loudspeaker and directs a sound sensing surface to a sound collection hole formed in a housing. The microphone case according to claim 11, wherein a surface that senses sound is disposed at a position adjacent to a side of the microphone via a partition wall so as to be arranged toward a rear part. 14. A loudspeaker for sound emission based on a received sound signal, a loudspeaker microphone for inputting a user's voice, and a sound component wrapping around the loudspeaker microphone for detecting and eliminating the sound component. A noise canceling microphone, extracting means for extracting a part of the frequency component of the signal output from the noise canceling microphone, and reversing the signal extracted by the extracting means into a signal output from the loudspeaker microphone. When mounting the microphone on a loudspeaker equipped with an addition means for adding by phase, the sound collecting surface is provided with a portion excluding a surface for sensing the sound of the loudspeaker microphone and a surface for sensing the sound opened in a housing. The microphone for noise cancellation is disposed on a circuit board closest to the microphone for sound amplification inside the housing toward the hole. Mounting structure of.