JPH10294989A - Noise control head set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably control wide band random noise or cyclic noise and to provide a sufficient silencing effect by respectively adding noise signals from a first noise detection part near the mouth and second and third noise detectors provided in left and right headphones in first and second noise signal adders and turning the output to the reference signals of adaptive filters. SOLUTION: The output of microphones 1a and 1b is inputted to the first noise signal adder 2a and the output of the microphones 1a and 1c is inputted to the second noise signal adder 2b. The output of the microphone 1f and the reception signals of a radio or cable communication equipment 10 are inputted to a first output signal adder 2c and a second output signal adder 2d. The output of the adders 2a and 2b is respectively inputted to a first adaptive filter 3a and a second adaptive filter 3b (AFIR). Also, the output of the adders 2a and 2b is respectively inputted to a first transmission function correction device (Fx filter 4a) and a second transmission function correction device (Fx filter 4b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to active noise control.

[0002]

2. Description of the Related Art In recent years, a control method for actively silencing noise in a duct for air conditioning, for example, using a speaker has been put into practical use. In addition, noise control type headphones used in factories etc. to protect the hearing of workers
Various types of noise control headphones have been proposed.

[0003] A conventional noise control headphone will be described below with reference to the drawings. A conventional example is disclosed in JP-A-3-96199. FIG. 25 shows a block diagram of this conventional noise control headphone. In FIG. 25, a microphone 23 is attached to an outer casing of the earphone 25. A microphone 24 is attached to the inside of the earphone 25 facing the external auditory meatus 28A. When the earphone 25 is attached to the ear 28, the microphone 23 picks up external noise indicated by the arrow N, and the microphone 24 picks up sound in the external auditory canal 28 </ b> A.

[0004] The outputs of the microphones 23 and 24 are supplied to an adaptive processing system 26. In the adaptive processing system 26, the transfer characteristic from the microphone 23 to the earphone 25 is identified so as to be similar to the transfer characteristic until the external noise N detected by the microphone 24 reaches the ear canal 28A. The output of the adaptive processing system 26 is supplied to the earphone 25 via the amplifier 27. Earphone 25
Thus, the output signal of the amplifier 27 is converted into a sound, and this sound is supplied to the external auditory meatus 28A. The noise N enters the external auditory canal 28A from the outside. The adaptive processing system 26 controls the noise N to minimize the noise component.

That is, a closed loop adaptive system as shown in FIG. 26 is realized by the apparatus shown in FIG. 25 to remove a noise component. In FIG. 26, the adaptive processing system 26 operates to operate with characteristics similar to those of the signal processing system 30. That is, the signal S is supplied to the adaptive processing system 26 and the signal processing system 30. An error ε (ε = dy) between the output y of the adaptive processing system 26 and the output d of the signal processing system 30 is obtained by the subtracter 29. The error component ε is input to the adaptive processing system 26 and controlled so that the error ε is minimized. After the adaptive processing is completed, both systems are identified in the sense that the transfer function of the signal processing system 30 is equal to the transfer function of the adaptive processing system 26.

When the adaptive processing system of FIG. 26 is compared with the noise control headphone device of FIG. 25, the signal S corresponds to the external noise N, the error component ε corresponds to the signal detected by the microphone 24, The signal processing system 30 corresponds to a transmission system from the microphone 23 to the microphone 24. The sound pressure of the ear canal 28A corresponding to the error ε is detected by the microphone 24, and the adaptive processing system 26 is controlled based on the output of the microphone 24. As a result, the sound pressure of the noise component in the ear canal 28A is minimized.

As described above, since the transmission characteristics from the microphone 23 to the headphones 25 are always identified by the adaptive processing system 26 so as to be the same as the sound insulation characteristics when external noise enters the ear canal 28A, Ear canal 2
The noise component in 8A can be canceled. Therefore, even if the manner of wearing the earphone 25 changes or the earphone 25 or the microphone 23 undergoes aging, the sound insulation characteristics do not deteriorate.

Next, another conventional noise control headphone disclosed in JP-A-6-67679 will be described. FIG. 27 shows a block diagram of the conventional noise control headphones. In FIG. 27, a microphone 32 for error detection and a speaker 33 for control are provided inside the left and right housings of a personal portable headphone 31 composed of a pair of right and left. The microphone 32 and the speaker 33 are respectively connected to the left and right L channel and R channel error signal lines 32a and control signal lines 33a.
Via a, it is connected to a signal processing device 34 integrated with the headphones 31. A set of a detection sensor 35 for detecting vibration or sound generated from the machine 38 and an amplifier 35a for amplifying the output of the detection sensor 35 to a predetermined level are provided near the machine 38 serving as a vibration source or a sound source. Alternatively, if necessary, a plurality of sets are provided at positions that have been well investigated in advance in order to generate a reference signal highly relevant to the vibration or generated sound of the machine 38.

When a plurality of detection sensors 35 are provided, the outputs of the respective amplifiers 35a are mixed in a mixer 36 to obtain a reference signal representative of the machine 38.
The mixed signal resulting from the mixing is used as a reference signal of the machine 38. This reference signal is output to a plurality of output jacks 36a provided near the machine 38. Headphones 31
Is used near the machine 38, the signal processor 34
34b of connection cable 34a for inputting reference signal
Is attached to the output jack 36a, and the reference signal is taken into the signal processing device 34. Based on the reference signal, a signal that minimizes the output of the microphone 32 is output to the speaker 3.
3 to perform active silencing. Here, the reference signal is shared by both the L and R channels.

As described above, a plurality of detection sensors 35 are appropriately arranged and provided in the vicinity of the machine 38 as a sound source, and the outputs thereof are mixed (mixed) at an appropriate level. A reference signal highly relevant to the sound entering the ear is obtained, and a high noise reduction effect is obtained by using this reference signal. Further, since the detection sensor 35 is installed near the machine 38, which is a sound source, the difference between the time when the reference signal is taken into the signal processing device 34 and the time when the sound of the machine 38 directly enters the ear is sufficiently large. . Accordingly, it is possible to secure a processing time required for the signal processing device 34 to calculate the cancellation signal for silencing and to provide the signal to the speaker 33.
This makes it possible to accurately silence random sounds.

FIG. 28 shows a system for wirelessly transmitting a reference signal in the system shown in FIG. 27. A radio receiver 37a is provided on the side of a signal processing device 34 carried by a person, and
6 is provided with a wireless transmitter 37b on the output side. As a result, the reference signal representing the vibration and sound emitted from the machine 38 is transmitted to all the radio receivers 37a in the electric field of the predetermined strength via the radio transmitter 37b and becomes available.
Therefore, it is not necessary to connect the signal processing device 34 as shown in FIG. 27 to the output of the mixer 36 via the connection cable 34a, and the freedom of human action can be secured.

FIG. 29 shows a case where a plurality of machines as sound sources exist. Machines 38-1 to 38-38
A wireless transmitter 37b of the same frequency corresponding to -n;
The reference signal of each machine is transmitted from each wireless transmitter 37b to all wireless receivers 37a within an electric field of a predetermined strength. The radio receiver 37a connected to the signal processing device 34 carried by a person includes the machines 38-1 to 38-
n, receives a plurality of reference signals, and generates a control signal to be sent to the speaker 33 including the respective reference signals, based on the mixed received signals, and performs mute control. Therefore, a plurality of sound source machines 38-1
This is very effective when sound is heard from .about.38-n.

[0013]

However, in the conventional example shown in FIG.
Is very short, the time from when the microphone 23 detects the external noise to when the noise reaches the microphone 24 is shortened. In addition, since the user moves while wearing the headphones 25, the noise source and the microphone 2 are used.
The positional relationship between 3 and the microphone 24 is not always on a straight line. For this reason, although detailed description is omitted because it is well known in the art and necessary for the adaptive processing system 26 to operate properly, the collected external noise and the signal to be supplied from the amplifier to the earphones are omitted. May not be established. Therefore, it was difficult to control broadband random noise. Further, when there are a plurality of external noises, or in a reflective room or a large room with a long reverberation time, a single microphone cannot detect sounds from a plurality of sound sources equally, and the microphones 23 and 24 However, there is a problem that the degree of relevance of the noise signal detected by the above method is reduced, and a sufficient silencing effect cannot be obtained. Further, there is another problem that a conversation between a plurality of users cannot be performed because a microphone for detecting a user's voice is not attached.

Next, in the conventional examples shown in FIGS. 27, 28 and 29, a detection sensor 35 is provided near a machine 38 which is a noise source.
When the user moves while wearing the headphones 31, the characteristics to be realized by the signal processing device 34 greatly change, and the operation becomes unstable. The filter constituting the signal processing device 34 has a finite length FIR filter (finite impulse response filter, Fi
nite impulse response filter) or small-order IIR filter (infinite impulse response filter, Inf
In the case of an inite impulse response filter, a response to an impulse on the transmission path from the detection sensor 35 to the microphone 32 cannot be realized to a sufficient degree. Therefore, there is a problem that the noise reduction effect is deteriorated. Also, in the case of a reflective room or a large room having a long reverberation time, if a finite length FIR filter or a small-order IIR filter is used, the response to the impulse of the transmission path from the detection sensor 35 to the microphone 32 will be reduced. There is a problem that the noise reduction effect cannot be realized to a sufficient extent and the noise reduction effect deteriorates. Further, there is also a problem that a conversation between a plurality of users cannot be performed because a microphone for detecting voice is not attached.

A first object of the present invention is to control a noise source and a control point indicating a position of a noise control headset by moving headphones with a noise control headset integrated with a sound detector mounted thereon. Even if there is a change in the relative position, if there are multiple external noises, or in a reflective room or a large room with a long reverberation time, the control of the wideband random noise or the control of the periodic noise will be stable. Moreover, it is an object of the present invention to provide a sufficient noise reduction effect and to monitor the voice of the user and the voice of the other party via the communication device.

A second object of the present invention, in addition to the first object, is to prevent a malfunction at the time of mute control caused by monitoring of a user's own voice and a partner's voice. To transmit power to the communication device without transmitting voice to the communication device. A third object of the present invention is to
In addition to the second object, the present invention is to actively reduce the ambient noise included in the own audio signal using an adaptive filter to prevent a malfunction of the adaptive filter when the own audio is generated.

A fourth object of the present invention, in addition to the third object, is to compensate for a time required for discriminating the voice of the user's own voice, thereby causing a malfunction during the mute control by monitoring the user's voice and the voice of the user's own voice. An object of the present invention is to ensure prevention of a malfunction at the time of noise control of a signal, and to further prevent loss of a sound signal at the time of monitoring own sound and transmitting it to a communication device. A fifth object of the present invention is to realize the third object with higher accuracy. A sixth object of the present invention is to realize the fourth object with higher accuracy.

[0018]

In order to achieve the first object, a noise control headset according to the present invention, in which headphones and a sound detector are integrally formed, is provided in a cabinet which is a left or right headphone housing. An audio detector attached near the mouth of the user by a provided support arm; a first noise detector attached near the audio detector; and a second noise detector attached to a left cabinet of the headphones. A noise detector, a first noise signal adder for adding the outputs of the first noise detector and the second noise detector, and a second signal processor for processing the output of the first noise signal adder. 1, an adaptive filter, a first transfer function corrector for performing signal processing on an output of the first noise signal adder, an output of the first adaptive filter, an output of the voice detector, and the communication unit. A first output signal adder for adding a received signal, a left headphone for reproducing an output of the first output signal adder, and a first error detector mounted inside a cabinet of the left headphone. A first coefficient updater for calculating and updating a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector; A third noise detector attached to a cabinet, a second noise signal adder for adding outputs of the first noise detector and the third noise detector, and a second noise signal adder A second adaptive filter for processing the output signal of the second noise signal adder, a second transfer function corrector for processing the output signal of the second noise signal adder, an output of the second adaptive filter and a Output from the communication means A second output signal adder for adding an output signal, a right headphone for reproducing an output of the second output signal adder, a second error detector mounted inside a cabinet of the right headphone, A second coefficient updater for calculating and updating the coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector;

In order to achieve the second object, a noise control headset according to the present invention includes a sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet. A sound discriminator for judging the presence or absence of a sound based on the output of the sound detector, a reception signal discriminator for judging the presence or absence of a reception signal of the communication means, and a first noise detector attached near the sound detector. A second noise detector attached to a left cabinet of the headphones; a first noise signal adder for adding outputs of the first noise detector and the second noise detector; A first adaptive filter for processing an output signal of the first noise signal adder, a first transfer function corrector for processing an output signal of the first noise signal adder, and the first adaptive filter A first output signal adder for adding the output of the first audio signal, the output of the audio detector, and the received signal from the communication means; a left headphone for reproducing an output of the first output signal adder; A first error detector mounted inside a cabinet of
A first coefficient updater for calculating and updating the coefficient of the first adaptive filter from an output from the error detector and an output of the first transfer function corrector, and a first coefficient updater attached to a right cabinet of the headphones. A third noise detector;
A second noise signal adder for adding the outputs of the noise detector and the third noise detector; a second adaptive filter for processing an output signal of the second noise signal adder; A second transfer function corrector for processing an output signal of the noise signal adder of (a), and a second for adding an output of the second adaptive filter, an output of the voice detector, and a reception signal from the communication unit.
An output signal adder, a right headphone for reproducing an output of the second output signal adder, a second error detector mounted inside a cabinet of the right headphone, and the second error detector And a second coefficient updater that calculates and updates the coefficient of the second adaptive filter from the output of the second transfer function corrector and the output of the second transfer function corrector.

In order to achieve the third object, a noise control headset according to the present invention includes a sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet. A sound discriminator for judging the presence or absence of a sound based on the output of the sound detector, a reception signal discriminator for judging the presence or absence of a reception signal of the communication means, and a first noise detector attached near the sound detector A second noise detector attached to a left cabinet of the headphones; a first noise signal adder for adding outputs of the first noise detector and the second noise detector; A first adaptive filter for processing an output signal of the first noise signal adder, a first transfer function corrector for processing an output signal of the first noise signal adder, and the first adaptive filter A first output signal adder for adding an output of the first output signal adder and a reception signal from the communication means; a left headphone for reproducing an output of the first output signal adder; and a left headphone mounted inside a cabinet of the left headphone. A first error detector, and a first coefficient updater that calculates and updates the coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. When,
A third noise detector attached to a right cabinet of the headphones, a second noise signal adder for adding outputs of the first noise detector and the third noise detector,
A second adaptive filter for processing an output signal of the second noise signal adder, a second transfer function corrector for processing an output signal of the second noise signal adder, and the second adaptive filter A second output signal adder for adding an output of the second output signal adder and a reception signal from the communication means; a right headphone for reproducing an output of the second output signal adder; and a right headphone mounted inside a cabinet of the right headphone. A second error detector, and a second coefficient update for calculating and updating the coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector. A delay unit that delays the output of the voice detector, a third adaptive filter that processes the output signal of the first noise detector, and an output of the third adaptive filter from the output of the delay unit A subtractor for subtracting A third coefficient updater for calculating and updating the coefficient of the third adaptive filter from the output of the noise detector and the output of the subtractor, and controlling whether or not to pass the output of the subtractor. And a mute circuit.

In order to achieve the fourth object, a noise control headset according to the present invention comprises a sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet. A sound discriminator for judging the presence or absence of a sound based on the output of the sound detector, a reception signal discriminator for judging the presence or absence of a reception signal of the communication means, and attached near the sound detector; A first noise detector for detecting the noise of the headphone, a second noise detector attached to the left cabinet of the headphones, and an output of the first noise detector and an output of the second noise detector. A first noise signal adder;
A first adaptive filter that processes an output signal of the noise signal adder, a first transfer function corrector that processes an output signal of the first noise signal adder, and an output of the first adaptive filter. A first output signal adder for adding a signal received from the communication means, a left headphone for reproducing an output of the first output signal adder, and a first head mounted inside a cabinet of the left headphone. An error detector, a first coefficient updater that calculates and updates a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector; A third noise detector attached to a right cabinet of headphones, a second noise signal adder for adding outputs of the first noise detector and the third noise detector, and the second noise The output signal of the signal adder A second adaptive filter for processing, a second transfer function corrector for processing an output signal of the second noise signal adder, and adding an output of the second adaptive filter and a reception signal from the communication unit. A second output signal adder, a right headphone for reproducing an output of the second output signal adder, a second error detector mounted inside a cabinet of the right headphone, and a second error detector. A second coefficient updater for calculating and updating a coefficient of the second adaptive filter from an output from an error detector and an output from the second transfer function corrector; and a second coefficient updater for delaying an output of the voice detector. A first delay unit, a second delay unit for delaying an output of the first noise detector, a third adaptive filter for processing an output signal of the second delay unit, and the first delay unit From the output of the third adaptive filter A subtracter for subtracting, a third coefficient updater for calculating and updating a coefficient of the third adaptive filter from an output of the second delay and an output of the subtractor, and passing through an output of the subtractor It has a mute circuit for selecting whether or not to make it, and a mute control circuit for controlling the operation of the mute circuit.

According to a fifth aspect of the present invention, there is provided a noise control headset according to the present invention, wherein a sound detector attached near a mouth of a user by a support arm provided in a left or right headphone cabinet. A sound discriminator for judging the presence or absence of a sound based on the output of the sound detector, a reception signal discriminator for judging the presence or absence of a reception signal of the communication means, and a first noise attached near the sound detector A detector, a second noise detector attached to a left cabinet of the headphones, a first noise signal adder for adding outputs of the first noise detector and the second noise detector, A first adaptive filter that processes an output signal of the first noise signal adder, a first transfer function corrector that processes an output signal of the first noise signal adder, and the first adaptive filter. A first output signal adder for adding an output of the first output signal adder and a reception signal from the communication means; a left headphone for reproducing an output of the first output signal adder; and a left headphone mounted inside a cabinet of the left headphone. A first error detector, and a first coefficient update for calculating and updating a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. A third noise detector attached to a right cabinet of the headphones, a second noise signal adder for adding outputs of the first noise detector and the third noise detector, and A second adaptive filter that processes an output signal of the second noise signal adder, a second transfer function corrector that processes an output signal of the second noise signal adder, and a second adaptive filter that processes the output signal of the second adaptive filter. From the output and the communication means A second output signal adder for adding a received signal, a right headphone for reproducing an output of the second output signal adder, and a second error detector mounted inside a cabinet of the right headphone; The output from the second error detector and the second
A second coefficient updater for calculating and updating the coefficient of the second adaptive filter from the output of the transfer function corrector, a delayer for delaying the output of the voice detector, and the first noise detector A third adaptive filter for processing the output signal of the second noise detector, a fourth adaptive filter for processing the output signal of the second noise detector, and a fifth adaptive filter for processing the output signal of the third noise detector A filter, and a subtractor for subtracting an output of the third adaptive filter, an output of the fourth adaptive filter, and an output of the fifth adaptive filter from an output of the delay unit,
A third coefficient updater for calculating and updating a coefficient of the third adaptive filter from an output of the first noise detector and an output of the subtractor; and an output of the second noise detector and the subtraction. A fourth coefficient updater for calculating and updating the coefficient of the fourth adaptive filter from the output of the filter, and the coefficient of the fifth adaptive filter from the output of the third noise detector and the output of the subtractor. And a mute circuit for controlling whether the output of the subtractor is passed or not.

Similarly, in order to achieve the fifth object, the noise control headset of the present invention provides a sound control head set near the mouth of a user by a support arm provided on a left or right headphone cabinet. A detector, a sound discriminator for judging the presence or absence of a sound based on the output of the sound detector, a reception signal discriminator for judging the presence or absence of a reception signal of the communication means, and attached near the sound detector. A first noise detector mainly detecting ambient noise, a second noise detector attached to a left cabinet of the headphones, and a first noise detector and a second noise detector. A first noise signal adder for adding an output, a first adaptive filter for processing an output signal of the first noise signal adder, and a second adaptive filter for processing an output signal of the first noise signal adder Transfer function corrector, a first output signal adder for adding an output of the first adaptive filter and a received signal from the communication means, and a left headphone for reproducing an output of the first output signal adder. A first error detector mounted inside a cabinet of the left headphone; and a first error detection filter for the first adaptive filter based on an output from the first error detector and an output from the first transfer function corrector. A first coefficient updater for calculating and updating coefficients, a third noise detector attached to a right cabinet of the headphones, and outputs of the first noise detector and the third noise detector. A second noise signal adder for adding, a second adaptive filter for processing an output signal of the second noise signal adder, and a second transmission for processing an output signal of the second noise signal adder A function corrector; A second output signal adder for adding the output of the adaptive filter and the received signal from the communication means, a right headphone for reproducing the output of the second output signal adder, and a right headphone cabinet. A second error detector mounted;
A second coefficient updater for calculating and updating a coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; and an output from the speech detector. A first delay unit for delaying the first noise detector; a third adaptive filter for processing an output signal of the first noise detector;
A fourth adaptive filter that processes the output signal of the noise detector, a fifth adaptive filter that processes the output signal of the third noise detector, and the fourth adaptive filter that processes the output signal of the first delay unit.
A first subtracter for subtracting the output of the adaptive filter from the output of the fifth adaptive filter, a second delayer for delaying the output of the first subtractor, and a second delayer. A second subtractor for subtracting the output of the third adaptive filter from the output; and calculating a coefficient of the third adaptive filter from an output of the first noise detector and an output of the second subtractor. And a fourth coefficient updater for calculating and updating the coefficient of the fourth adaptive filter from the output of the second noise detector and the output of the first subtractor. A fifth coefficient updater that calculates and updates the coefficient of the fifth adaptive filter from the output of the third noise detector and the output of the first subtractor; A mute circuit for controlling whether the output is passed or not.

According to a sixth aspect of the present invention, there is provided a noise control headset according to the present invention, wherein a sound detector attached near a mouth of a user by a support arm provided in a left or right headphone cabinet. A sound discriminator for judging the presence or absence of a sound based on the output of the sound detector, a reception signal discriminator for judging the presence or absence of a reception signal of the communication means, and a first noise attached near the sound detector A detector, a second noise detector attached to a left cabinet of the headphones, a first noise signal adder for adding outputs of the first noise detector and the second noise detector, A first adaptive filter that processes an output signal of the first noise signal adder, a first transfer function corrector that processes an output signal of the first noise signal adder, and the first adaptive filter. A first output signal adder for adding an output of the first output signal adder and a reception signal from the communication means; a left headphone for reproducing an output of the first output signal adder; and a left headphone mounted inside a cabinet of the left headphone. A first error detector, and a first coefficient update for calculating and updating a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. A third noise detector attached to a right cabinet of the headphones, a second noise signal adder for adding outputs of the first noise detector and the third noise detector, and A second adaptive filter that processes an output signal of the second noise signal adder, a second transfer function corrector that processes an output signal of the second noise signal adder, and a second adaptive filter that processes the output signal of the second adaptive filter. From the output and the communication means A second output signal adder for adding a received signal, a right headphone for reproducing an output of the second output signal adder, and a second error detector mounted inside a cabinet of the right headphone; The output from the second error detector and the second
A second coefficient updater for calculating and updating the coefficient of the second adaptive filter from the output of the transfer function corrector, a first delayer for delaying the output of the speech detector, A second delay for delaying the output of the noise detector, a third adaptive filter for processing the output signal of the second delay, and a fourth for processing the output signal of the second noise detector An adaptive filter, a fifth adaptive filter for processing an output signal of the third noise detector, an output of the third adaptive filter and an output of the fourth adaptive filter from an output of the first delay unit And a subtractor for subtracting the output of the fifth adaptive filter and a third coefficient for calculating and updating the coefficient of the third adaptive filter from the output of the second delay unit and the output of the subtractor. Updater, output of the second noise detector and output of the subtractor A fourth coefficient updater for calculating and updating the coefficient of the fourth adaptive filter from the above, and calculating the coefficient of the fifth adaptive filter from the output of the third noise detector and the output of the subtractor. And a mute circuit for controlling whether or not to pass the output of the subtractor, and a mute control circuit for controlling the operation of the mute circuit.

Similarly, in order to achieve the sixth object, the noise control headset of the present invention provides a sound control head set near the mouth of a user by a support arm provided in a left or right headphone cabinet. A detector, a voice discriminator that determines the presence or absence of a voice based on the output of the voice detector, a reception signal discriminator that determines the presence or absence of a reception signal of the communication unit, and is attached near the voice detector A first noise detector that mainly detects ambient noise, a second noise detector attached to a left cabinet of the headphones, and outputs of the first noise detector and the second noise detector , A first adaptive filter for processing an output signal of the first noise signal adder, and a first for processing an output signal of the first noise signal adder. A transfer function corrector, a first output signal adder for adding an output of the first adaptive filter and a received signal from the communication means, and a left headphone for reproducing an output of the first output signal adder. A first error detector mounted inside the cabinet of the left headphone, and an output from the first error detector and the first error detector.
A first coefficient updater for calculating and updating the coefficient of the first adaptive filter from the output of the transfer function corrector, a third noise detector attached to a right cabinet of the headphones, A second noise signal adder for adding the outputs of the third and third noise detectors;
A second adaptive filter that processes the output signal of the noise signal adder, a second transfer function corrector that processes the output signal of the second noise signal adder, and an output of the second adaptive filter. A second output signal adder for adding a signal received from the communication means, a right headphone for reproducing an output of the second output signal adder, and a second error detector mounted inside the right headphone A second coefficient updater for calculating and updating the coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; The first to delay the output of
, A second delay for delaying the output of the first noise detector, a third adaptive filter for processing the output signal of the second delay, and the second noise detector A fourth adaptive filter for processing the output signal of the third noise detector, a fifth adaptive filter for processing the output signal of the third noise detector, and an output of the fourth adaptive filter from the output of the first delay unit. A first subtractor for subtracting the output of the third adaptive filter from the output of the fifth adaptive filter; a third delayer for delaying the output of the first subtractor; A second subtractor for subtracting the output of the adaptive filter of the above, and a third updating and calculating the coefficient of the third adaptive filter from the output of the second delay unit and the output of the second subtractor. A coefficient updater, and an output of the second noise detector and an output of the first subtractor, A fourth coefficient updater for calculating and updating the coefficient of the adaptive filter, and calculating the coefficient of the fifth adaptive filter from the output of the third noise detector and the output of the first subtractor. It has a fifth coefficient updater for updating, a mute circuit for controlling whether or not to pass the output of the second subtractor, and a mute control circuit for controlling the operation of the mute circuit.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

Embodiment 1 Embodiment 1 will be described with reference to FIGS. FIG. 1 is a block diagram of a noise control headset according to Embodiment 1 of the present invention. In FIG. 1, a noise control headset in which a headphone and a sound detector are integrally formed is provided outside a cabinet of a microphone 1a, which is a first noise detector arranged at a mouth of a user, and a left headphone 7a. The microphone 1b, which is the second noise detector disposed, and the third noise detector, which is disposed outside the cabinet of the right headphone 7b.
Microphone 1c as a noise detector, a microphone 1d as a first error detector disposed in a cabinet, a microphone 1e as a second error detector disposed in a cabinet, a mouth Has a microphone 1f, which is a voice detector arranged in. Outputs of the microphones 1a and 1b are input to an adder 2a which is a first noise signal adder, and outputs of the microphones 1a and 1c are input to an adder 2b which is a second noise signal adder. . The output of the microphone 1f and the reception signal of the wireless or wired communication device 10 are input to an adder 2c serving as a first output signal adder and an adder 2d serving as a second output signal adder. The outputs of the adders 2a and 2b are supplied to the first adaptive filter 3a and the second
Adaptive filter 3b (shown as AFIR in the figure),
Respectively. The outputs of the adders 2a and 2b are output from an Fx filter 4 which is a first transfer function corrector.
a, which is input to the Fx filter 4b which is the second transfer function corrector. The outputs of the Fx filters 4a and 4b are input to an LMS (least mean square) calculator 5a as a first coefficient updater and an LMS calculator 5b as a second coefficient updater. Outputs of the microphones 1d and 1e are input to LMS calculators 5a and 5b, respectively. Outputs of the LMS calculators 5a and 5b are input to adaptive filters 3a and 3b, respectively. Adaptive filter 3
The outputs of a and 3b are input to adders 2c and 2d, respectively. The outputs of the adders 2c and 2d are the speaker 6a and the right headphone 7b in the cabinet of the left headphone 7a.
Are input to the speakers 6b located in the cabinets. The left headphone 7a and the right headphone 7b are connected by a headband 8. The support arm 9 supports the microphones 1a and 1f so as to approach the mouth. For the noise control head head configured as above,
The operation will be described below. In the following description,
Suppressing the noise to reduce the sound pressure level at the ear of the sound emitted from the speakers 6a and 6b of the headset is called "noise control".

First, the ambient noises detected by the microphones 1a, 1b and 1c are added at a predetermined level ratio in adders 2a and 2b, respectively.
b and Fx filters 4a and 4b, respectively. The control signals output from the adaptive filters 3a and 3b are added at respective adders 2c and 2d to the audio signal from the microphone 1f and the received signal from the communication device 10 at a predetermined level ratio, and the respective headphones 7a And are applied to the speakers 6a and 6b installed in the speakers 7a and 7b and are reproduced as control sounds. The microphones 1d and 1e installed in the headphones 7a and 7b respectively detect the control sound from the speakers 6a and 6b and the noise entering the interior through the headphones 7a and 7b. Are input to the LMS operators 5a and 5b.

On the other hand, the noise signals from the adders 2a and 2b are subjected to convolution with the coefficients in the respective Fx filters 4a and 4b, and are input to the LMS calculators 5a and 5b, respectively. The LMS calculators 5a and 5b use the signals from the Fx filters 4a and 4b and the signals from the microphones 1d and 1e to minimize the output signals from the microphones 1d and 1e, respectively. And updates its value. Here, the Fx filter 4a is connected to the speaker 6a (more precisely, the adder 2c) and the microphone 1d.
The Fx filter 4b approximates the transfer function from the speaker 6b (more precisely, the adder 2d) to the microphone 1e as a coefficient.

This method is applied to the Filtered-x LMS algorithm (for example, see B. Widrowand S. Stearns, “A
daptive Signal Processing '' (Prentice-Hall, Englewood
Cliffs, NJ, 1985)). Then, the coefficient update operation of the Filtered-x LMS algorithm is represented by the following equation.

W (n + 1) = w (n) + μr (n) e (n) (1)

Where r (n) = x (n) ^T c (n)

W (n); adaptive filter 3a or 3b
Coefficient

C (n); Fx filter 4a or 4b
Coefficient

X (n); noise signal from adder 2c or 2d

E (n); microphone 1d or 1e
Error signal from

Μ: step parameter

T indicates transposition.

By repeating the above operation, noise in the space between the headphones 7a and 7b (that is, near the ears) is reduced.

By the way, each of the microphones 1a, 1b, 1
As shown in FIG. 2, the positional relationship between c, 1e and 1f is such that the microphone 1a is installed near the mouth of the user together with the microphone 1f. Microphone 1b is headphone 7a
2C, when the left headphone 7a is viewed from the outside of the cabinet as shown in FIG. 2C, the upper left corner is formed by a horizontal axis and a vertical axis passing through the center point P1 of the left headphone 7a. , The lower left, the upper right, and the lower right. As shown in FIG. 2A, when the microphone 1c is viewed from the side at the upper rear part outside the headphones 7b, that is, as shown in FIG.
It is installed in the upper left area divided into four areas of upper left, lower left, upper right and lower right by the horizontal axis and the vertical axis passing through the center point P2 of b. As shown in FIG. 1, the microphone 1d is installed near the outer ear hole on the front surface of the speaker 6a in the headphone 7a, and the microphone 1e is installed near the outer ear hole on the front surface of the speaker 6b in the headphone 7b. That is, as shown in FIG. 2C, the microphones 1a,
1d and 1b are installed so as to be located on approximately one straight line L1 when viewed from the side. Similarly, FIG.
As shown in the figure, the microphones 1a, 1e, and 1c are installed so as to be located on approximately one straight line L2 when viewed from the side.

With this arrangement, as shown in FIG. 3, when noise comes from the front of the user, the microphone 1a mainly detects the noise, and when noise comes from the left side, the microphone 1a detects the noise. 1b mainly performs noise detection. When noise comes from the right side of the user, the microphone 1c mainly detects noise, and when noise comes from behind, the microphones 1b and 1c mainly detect noise. Thus, no matter what direction the noise comes from, that is, where the noise source is, where there are multiple noise sources, or even in a space with a long reverberation time, , The noise can be accurately detected.

FIG. 4 is a graph showing the noise control effect when there are a plurality of noise sources actually measured in a reverberation room which is a diffuse sound field. The horizontal axis represents the frequency, and the vertical axis represents the sound pressure level at the ear. ing. Curve A is the sound pressure level when the headset is not worn. Curve B shows the headphones 7a and 7b when the headset is worn and noise control is not performed.
Shows the sound pressure level attenuated by the sound insulation characteristics of FIG. Curve C is the sound pressure level when a headset for noise control is mounted, and the difference between curves B and C is the adaptive filter 3a and 3b.
The effect of active noise control by means of is shown. When a plurality of noises are generated in the reverberation room, it is considered that the noises are coming from all directions as shown in FIG. Have been.

As described above, if the operation speed of the system is increased so as to satisfy the causality of noise control in the control band for low frequencies that cannot be completely shielded, the high frequencies are cut off by the sound insulation of the headphones 7a and 7b. Can be silenced stably like Also, the noise detection is performed not only with the microphone 1a but also with the microphones 1b and 1c.
By adding to the output of the microphone 1a by the adders 2a and 2b, not only a certain direction but also the surrounding noise can be detected all over, thereby making it possible to make some correction so as to satisfy causality.

FIG. 5 shows the noise control effect immediately before the noise source, that is, the noise control effect when only the front noise source in FIG. 3 is present. Curves A, B, and C in FIG. 5 show sound pressure levels under the same measurement conditions as in FIG. In this case, since the distance from the microphone 1a to the microphones 1d and 1e can be secured to some extent, it is possible to control up to a high frequency which is not controlled in FIG. This is because the frequency band satisfying the causality of noise control has been expanded. That is, the microphone 1
When the microphones 1a, 1b, and 1c for noise detection exist between the noise source and each of the microphones 1d and 1e in the microphone d or the microphone 1e, the time required for noise control approaches the noise transmission time. In other words, when the transmission time of the noise is the longest, a time margin for the noise control is created.

FIG. 6 shows the control effect of the 1 KHz sound. In the figure, curves A, B, and C represent sound pressure levels when no headset is mounted, when a headset without noise control is mounted, and when a headset with noise control is mounted. By using the adaptive filters 3a and 3b in this way, it is possible to control high-frequency sounds that were impossible with conventional analog noise control headphones. As described above, the noise control headset of the present embodiment can obtain a stable and sufficient noise reduction effect regardless of the noise source or the sound field. Further, by using a microphone 1f for voice detection that is bidirectional or unidirectional with directivity in the direction of the user's mouth, extraneous ambient noise other than voice is not detected as much as possible. Can be. Then, by adding this audio signal to the control signal and the reception signal from the communication device 10 in the adders 2c and 2d, it is possible to monitor the own voice and the voice of the other party while reducing noise. Naturally, since this voice signal is transmitted to the other party via the communication device 10, if both parties use the noise control headset, for example, it is possible to have a sufficient conversation even in a noise environment where ordinary conversation is not possible. Can communicate.

In this embodiment, the headphones 7a and 7
b is connected by the headband 8, but may be attached to the helmet 11 via the support portion 12 as shown in FIG. 7. Further, the headphones 7a and 7b may be of a closed type or an open type, and may be of an earphone type. The AD conversion of the outputs of the microphones 1a, 1b, and 1c may be performed before or after the adders 2a and 2b. If the analog addition signal is converted into a digital signal after the adders 2a and 2b, AD
The number of converters can be reduced.

Further, the LMS calculators 5a and 5b may use a well-known learning identification method for normalizing the error signals from the microphones 1d and 1e based on the outputs of the respective Fx filters 4a and 4b. Good. The communication device 10 may be built in the noise control headset, or an external communication device may be used.
Further, as shown in FIG. 8, the adders 2a and 2b may be configured to add all the detection signals of the microphones 1a, 1b and 1c.

Embodiment 2 Embodiment 2 will be described with reference to FIG. FIG. 9 is a block diagram showing a noise control headset according to the second embodiment of the present invention. In FIG. 9, a noise control headset in which a headphone and a sound detector are integrally formed is provided outside a cabinet of a microphone 1a, which is a first noise detector arranged at a mouth of a user, and a left headphone 7a. A microphone 1b as a second noise detector disposed, a microphone 1c as a third noise detector disposed outside the cabinet of the right headphone 7b, and a first error disposed in the cabinet. It has a microphone 1d as a detector, a microphone 1e as a second error detector disposed in the cabinet, and a microphone 1f as a voice detector disposed at the mouth.
The outputs of the microphones 1a and 1b are input to an adder 2a which is a first noise signal adder,
The outputs of a and 1c are input to an adder 2b which is a second noise signal adder. The reception signal of the wireless or wired communication device 10 is an adder 2c which is a first output signal adder, and an adder 2d which is a second output signal adder.
Is input to Outputs from the adders 2a and 2b are output to a first adaptive filter 3a and a second adaptive filter 3b (AF in the figure).
IR)). The outputs of the adders 2a and 2b are input to an Fx filter 4a as a first transfer function corrector and an Fx filter 4b as a second transfer function corrector. The outputs of the Fx filters 4a and 4b are input to an LMS (least mean square) calculator 5a as a first coefficient updater and an LMS calculator 5b as a second coefficient updater. The outputs of the microphones 1d and 1e are input to the LMS calculators 5a and 5b via the respective switches 15a and 15b. Outputs of the LMS calculators 5a and 5b are input to adaptive filters 3a and 3b, respectively. Adaptive filter 3
The outputs of a and 3b are input to adders 2c and 2d, respectively. The outputs of the adders 2c and 2d are the speaker 6a and the right headphone 7b in the cabinet of the left headphone 7a.
Are input to the speakers 6b located in the cabinets. The left headphone 7a and the right headphone 7b are connected by a headband 8. The support arm 9 supports the microphones 1a and 1f so as to approach the mouth. The output of the microphone 1f is input to the voice discriminator 13 and is input to the wireless communication device 10 via the switch 15c. The received signal is also input to the received signal discriminator 14. The noise control headset of the present embodiment includes a voice discriminator 13, a received signal discriminator 14, and a switch 15 in addition to the components of the noise control headset of Embodiment 1 in FIG.
a, 15b, and 15c, and the operation will be described below.

When the user utters a voice, the voice is detected by the microphone 1f, a voice signal is applied to the voice discriminator 13, and the voice discriminator 13 detects that the voice is generated. The switch 15c is turned on by the detection signal of the output of the audio discriminator 13, whereby the audio signal is
In addition to c and 2d, the own voice is reproduced by the speakers 6a and 6b. The audio signal is also input to the communication device 10. At this time, by turning on the transmission power supply of the communication device 10 in response to the detection signal from the audio discriminator 13, its own audio signal is transmitted to the other party. At the same time, the switches 15a and 15b are opened by this detection signal, and the error signal (e (n) in Equation 1) of the LMS calculators 5a and 5b becomes 0. Therefore, the coefficient updating operation of the adaptive filters 3a and 3b is performed. Stop.

When the user stops talking and there is no sound, the sound discriminator 13 detects that there is no sound, and the switch 15c is opened. Thus, the adders 2c and 2d and the communication device 10 have a microphone. The output signal from 1f is not input. At this time, by turning off the transmission power supply of the communication device 10 in response to the detection signal from the audio discriminator 13, the power consumption of the communication device 10 can be reduced.
At the same time, the switches 15a and 15b conduct, and L
The coefficient update operation of the MS calculators 5a to 5b is started again.

Thus, when sound is generated, the speaker 6a
And 6b are detected by the microphones 1d and 1e, which affect the coefficient update operations of the LMS calculators 5a and 5b, thereby preventing the adaptive filters 3a and 3b from becoming unstable. Further, by opening the switch 15c, it is possible to prevent the ambient noise from being transmitted to the other party when there is no voice without voice. The received signal discriminator 14 detects the presence or absence of a received signal applied from the communication device 10 and, if there is a received signal, adds the received signal to the adder 2.
The sound is reproduced by the speakers 6a and 6b via c and 2d. The switches 15a and 15b are opened to stop the coefficient update operation of the adaptive filters 3a to 3b.

Thus, it is possible to prevent the adaptive filters 3a and 3b from becoming unstable when receiving a radio signal.
As described above, the noise control headset of the present embodiment reduces noise at the ear of the user when there is no speech or when there is no reception signal from the communication device 10. In addition, when sound is generated or when there is a received signal from the communication device 10, noise can be reduced and the operations of the adaptive filters 3a and 3b can be prevented from becoming unstable. In addition, when the user is silent, the ambient noise is not transmitted to the other party, and the power consumption of the communication device 10 can be reduced.

In this embodiment, the headphones 7a and 7
b is connected by a headband 8, but FIG.
As shown in FIG. Further, the headphones 7a and 7b may be of a closed type or an open type, and may be of an earphone type. The AD conversion of the outputs of the microphones 1a, 1b and 1c may be performed before or after the adders 2a and 2b. If the analog addition signal is converted into a digital signal after the adders 2a and 2b, the number of AD converters can be reduced.

Further, the voice discriminator 13 and the received signal discriminator 14 digitize the voice signal from the microphone 1f and the received signal from the communication device 10, respectively, and determine the presence or absence of voice by a predetermined voice detection algorithm. Alternatively, for example, a configuration may be employed in which the audio signal is compared with a reference threshold value by a comparator and determined as an analog signal.

Further, the LMS calculators 5a and 5b provide Fx
A so-called learning identification method may be used in which the error signals from the microphones 1d and 1e are normalized by the outputs of the filters 4a and 4b. The communication device 10 may be built in the noise control headset, or an external communication device may be used. Further, as described with reference to FIG. 8, a configuration in which all the detection signals of the microphones 1a, 1b, and 1c are added by the adders 2a and 2b in FIG.

Third Embodiment FIG. 10 is a block diagram showing a noise control headset according to a third embodiment of the present invention. In FIG. 10, a noise control headset in which a headphone and a sound detector are integrally formed is provided outside a cabinet of a microphone 1a, which is a first noise detector arranged at the mouth of the user, and a left headphone 7a. Microphone 1b as a second noise detector disposed, and microphone 1 as a third noise detector disposed outside the cabinet of right headphone 7b
c, a microphone 1d as a first error detector disposed in the cabinet, and a microphone 1 as a second error detector disposed in the cabinet
e, a microphone 1f which is a voice detector arranged at the mouth. Outputs of the microphones 1a and 1b are input to an adder 2a which is a first noise signal adder, and outputs of the microphones 1a and 1c are input to an adder 2b which is a second noise signal adder. . The reception signal of the wireless or wired communication device 10 is input to an adder 2c which is a first output signal adder and an adder 2d which is a second output signal adder. Adders 2a, 2b
Are input to a first adaptive filter 3a and a second adaptive filter 3b (denoted as AFIR in the figure). The outputs of the adders 2a and 2b are input to an Fx filter 4a as a first transfer function corrector and an Fx filter 4b as a second transfer function corrector. The outputs of the Fx filters 4a and 4b are an LMS (least mean square) calculator 5a as a first coefficient updater and an LMS calculator 5 as a second coefficient updater.
b. The outputs of the microphones 1d and 1e are connected to the LMS through respective switches 15a and 15b.
The signals are input to the arithmetic units 5a and 5b. LMS calculators 5a, 5
The output of b is input to adaptive filters 3a and 3b, respectively. Outputs of the adaptive filters 3a and 3b are added to adders 2c and 2d.
And the outputs of the adders 2c and 2d are the speaker 6a in the cabinet of the left headphone 7a and the speaker 6b in the cabinet of the right headphone 7b.
Respectively. The left headphone 7a and the right headphone 7b are connected by a headband 8. The support arm 9 supports the microphones 1a and 1f so as to approach the mouth. The output of the microphone 1f is a voice discriminator 13
Is input to the delay unit 16. The received signal is also input to the received signal discriminator 14. The output of the delay unit 16 is input to the subtractor 17. The output of the microphone 1a is the third
Are also input to the adaptive filter 3c and the third LMS calculator 5c. The output of the third LMS operation unit 5c is input to the third adaptive filter 3c, and the output of the third adaptive filter 3c is input to the subtracter 17. The output of the subtractor 17 is input to the LMS calculator 5c via the switch 15c, and is input to the wireless communication device 10 via the switch 15d which is a mute circuit. The noise control headset of this embodiment further includes an adaptive filter 3c, an LMS operation unit 5c, switches 15c and 15d, a delay unit 16, and a subtractor 17 in addition to the components of the noise control headset in FIG. The operation will be described below.

The ambient noise signal detected by the microphone 1f is delayed by the delay unit 16 by a predetermined time during which the adaptive filter 3c satisfies causality, and is input to the subtractor 17. On the other hand, the noise signal detected by the microphone 1a is
The signal is processed by the adaptive filter 3c, and its output is
7 is input. In the subtracter 17, the output of the adaptive filter 3c is subtracted from the output of the delay unit 16, and the resulting output signal is input to the switches 15c and 16d. Then, the LMS calculator 5c uses the noise signal from the microphone 1a and the error signal input via the switch 15c,
The coefficient of the adaptive filter 3c is calculated and updated so as to minimize the error signal input via the switch 15c. Thereby, the noise component included in the output signal of the subtractor 17 is reduced.

As shown in FIGS. 11 and 12, the microphones 1a and 1f are unidirectional microphones having a directivity indicated by a dotted ellipse D1 in the direction of the mouth of the user. Is an omnidirectional microphone having a sound hole on the surface in the direction opposite to that of the microphone 1f, and is indicated by a dotted circle D2 placed right beside the microphone 1f.

FIG. 13 shows the noise control effect on the detection signal of the microphone 1f when sound is generated from a plurality of noise sources in a reverberation room which is a diffuse sound field. Curve B is the output level of the subtractor 17 when noise control is not performed, and curve C is the noise level at the output of the subtractor 17 when noise control is performed. FIG. 14 shows a change in an audio signal when a sound is emitted in the above-mentioned diffuse sound field. Curves B and C show the sound level at the output of the subtractor 17 when noise control is not performed and when noise control is performed, respectively.

As shown in FIG. 13, the noise component included in the audio signal detected by the microphone 1f is sufficiently attenuated, but the level change of the audio component hardly occurs as shown in FIG. FIG. 15 shows the noise control effect immediately before the noise source, that is, the control effect when only the forward noise source in FIG. 3 is present. As can be seen from the comparison between the curves B and C, when the noise control indicated by the curve C is performed, the noise output level is significantly reduced.

As described above, if control is performed immediately before the noise source,
It can be seen that the noise reduction amount increases. By the way, when the user utters a voice, the voice discriminator 13 detects that the voice is generated, and outputs a detection signal. This detection signal causes the switch 15d to conduct, whereby the audio signal is applied to the adders 2c and 2d, and the respective speakers 6a
And 6b reproduce the self-voice. Detection signal is communication device 1
It is also input to 0. At this time, the transmission power supply of the communication device 10 is turned on in response to the detection signal from the audio discriminator 13, and its own audio signal is transmitted to the other party. At the same time, the switches 15a to 15c are opened by this detection signal, and the error signals of the LMS calculators 5a to 5c become 0, thereby stopping the coefficient update operation of the adaptive filters 3a to 3c.

Next, when the user stops speaking and there is no sound, the sound discriminator 13 detects that there is no sound, and this causes the switch 15d to be opened. Output signal is not input. At this time, by turning off the transmission power of the communication device 10 by the detection signal from the voice discriminator 13,
The power consumption of the communication device 10 can be reduced. At this time, the switches 15a to 15c are turned on, whereby
The coefficient update operation of the MS calculators 5a to 5c is started again.

As a result, when the sound is generated, the speakers 6a and 6
b reproduces their own voices in the microphones 1d and 1e.
And affects the coefficient updating operation of the LMS calculators 5a and 5b, thereby preventing the operations of the adaptive filters 3a and 3b from becoming unstable. In addition, LMS
The audio signal remaining in the error signal of the arithmetic unit 5c affects the coefficient updating operation of the LMS arithmetic unit 5c, and the adaptive filter 3c
Can be prevented from becoming unstable. Further, when sound is mixed in the microphone 1a, it is possible to prevent the subtractor 17 from reducing the sound signal by the output of the adaptive filter 3c. The switch 15d makes it possible to prevent unnecessary ambient noise from being transmitted to the other party when the user is silent.

The received signal discriminator 14 detects the presence or absence of a received signal from the communication device 10. If there is a received signal, the received signal is reproduced by the speakers 6a and 6b via adders 2c and 2d. During that time, the switches 15a and 15b are opened to stop the coefficient updating operation of the adaptive filters 3a and 3b. Thereby, it is possible to prevent the operations of the adaptive filters 3a and 3b from becoming unstable during wireless reception.

As described above, the noise control headset of this embodiment reduces the noise at the user's ear as described with reference to FIG. At times, the adaptive filter 3c can reduce the ambient noise signal included in the detection signal from the microphone 1f. When sound is generated or when there is a received signal from the communication device 10, the operation of the adaptive filters 3a and 3b can be controlled so as not to be unstable while reducing noise. The control can be performed such that the adaptive filter 3c does not become unstable while reducing the noise component, or the audio signal is not reduced. In addition, it is possible to prevent unnecessary ambient noise from being transmitted to the other party and reduce the power consumption of the communication device 10 when the user is silent.

In this embodiment, the headphones 7a and 7
Although b is connected by the headband 8, it may be connected to the helmet 11 as shown in FIG. Further, the headphones 7a and 7b may be of a closed type or an open type, and may be of an earphone type. Further, if the analog addition signal is converted into a digital signal after the adders 2a and 2b, the number of AD converters can be reduced. Further, the voice discriminator 13 and the received signal discriminator 14 may digitize the voice signal from the microphone 1f and the received signal from the communication device 10 and discriminate the voice by a predetermined voice detection algorithm. A configuration may be used in which the analog signal is compared with a reference threshold value and determined by a comparator.

The microphone 1a and the microphone 1
The diaphragm diameter of the microphone 1f may be the same, but as a result of an experiment conducted by the inventor, the diaphragm diameter of the microphone 1f is
More preferably, it is at least twice as large as that of a. This is because the sensitivity of the microphone 1f is preferably higher than that of the microphone 1a. Further, as shown in FIG. 16, the microphones 1a and 1f are placed on the surface of the microphone 1a and the microphone 1f in the direction of the noise source (the surface opposite to the direction of the mouth).
A sound-absorbing material 18 such as a nonwoven fabric may be covered so as to cover the sound holes.

Further, the LMS calculators 5a, 5b and 5c
May be a learning identification method that normalizes the error signals from the microphones 1d and 1e and the subtractor 17 based on the outputs of the Fx filters 4a and 4b and the output of the microphone 1a. The communication device 10 may be built in the noise control headset, or an external communication device may be used. Further, as described with reference to FIG.
At 0, the adders 2a and 2b
A configuration in which all the detection signals b and 1c are added may be employed.

Embodiment 4 Embodiment 4 will be described with reference to FIG. FIG. 17 is a block diagram showing a noise control headset according to Embodiment 4 of the present invention. In FIG. 17, a noise control headset in which headphones and a voice detector are integrally formed is a first noise control headset arranged at the mouth of a user.
Microphone 1a, which is a noise detector, and microphone 1b, which is a second noise detector, disposed outside the cabinet of the left headphone 7a. Third noise, which is disposed outside the cabinet of the right headphone 7b. Microphone 1c as a detector, microphone 1d as a first error detector disposed in a cabinet, microphone 1e as a second error detector disposed in a cabinet, disposed at a mouth And a microphone 1f which is a sound detector. Outputs of the microphones 1a and 1b are input to an adder 2a which is a first noise signal adder, and outputs of the microphones 1a and 1c are input to an adder 2b which is a second noise signal adder. . Wireless or wired communication device 1
The received signal of 0 is input to an adder 2c which is a first output signal adder and an adder 2d which is a second output signal adder. The outputs of the adders 2a and 2b are input to a first adaptive filter 3a and a second adaptive filter 3b (denoted as AFIR in the figure). The outputs of the adders 2a and 2b are input to an Fx filter 4a as a first transfer function corrector and an Fx filter 4b as a second transfer function corrector. Fx
Outputs of the filters 4a and 4b are respectively input to an LMS (least mean square) calculator 5a as a first coefficient updater and an LMS calculator 5b as a second coefficient updater. The outputs of the microphones 1d and 1e are supplied to the LMS calculators 5a and 5b via the respective switches 15a and 15b.
Is input to Outputs of the LMS calculators 5a and 5b are input to adaptive filters 3a and 3b, respectively. The outputs of the adaptive filters 3a and 3b are input to adders 2c and 2d, respectively, and the outputs of the adders 2c and 2d are the speakers 6a and the right headphones 7b in the cabinet of the left headphone 7a.
Are input to the speakers 6b located in the cabinets. The left headphone 7a and the right headphone 7b are connected by a headband 8. The support arm 9 supports the microphones 1a and 1f so as to approach the mouth. The output of the microphone 1f is input to the voice discriminator 13 and the delay unit 16a. The received signal is received by a received signal discriminator 14.
Is also entered. The output of the delay unit 16a is input to the subtractor 17. The output of the microphone 1a is also input to the third adaptive filter 3c and the third LMS calculator 5c via the delay unit 16b. The output of the third LMS calculator 5c is input to the third adaptive filter 3c, and the third adaptive filter 3c
Is input to the subtractor 17. The output of the subtractor 17 is input to the LMS calculator 5c via the switch 15c.
The signal is input to the wireless communication device 10 via a switch 15d which is a mute circuit. The output of the audio discriminator 13 is input to the mute control circuit 19,
Is input to the wireless communication device 10. The noise control headset of the present embodiment includes a delay unit 16b and a mute control circuit 19 as components of the noise control headset in FIG.
The operation will be described below.

The ambient noise signal detected by the microphone 1f is delayed by the delay unit 16a by a predetermined time during which the adaptive filter 3c satisfies causality, and is input to the subtractor 17. On the other hand, the noise signal detected by the microphone 1a is
The delay 16b delays by a predetermined time required for the speech discriminator 13 to reliably discriminate the generation of speech, performs signal processing by the adaptive filter 3c, and inputs the output to the subtractor 17. In the subtractor 17, the output of the adaptive filter 3c is subtracted from the output of the delay unit 16a, and the resulting error signal is input to the switches 15c and 15d. The LMS operation unit 5c is configured to output the noise signal from the delay unit 16b and the switch 15c.
, The coefficient of the adaptive filter 3c is calculated and updated so as to minimize the error signal from the switch 15c. Thereby, the noise component included in the output signal of the subtractor 17 is reduced.

Here, the microphones 1a and 1f are configured as shown in FIG. 11 or 16 similarly to the case of the third embodiment, and the control effect at that time is as shown in FIG.
3, graphs shown in FIGS. 14 and 15 are obtained. FIG.
In step 7, when a voice is emitted, the voice discriminator 13 detects that the voice is generated, and outputs a detection signal. This detection signal is input to the mute control circuit 19. When receiving the detection signal from the sound discriminator 13, the mute control circuit 19 turns on the switch 15d. As a result, the audio signal is added to the adders 2c and 2d, and the own audio is reproduced by the speakers 6a and 6b, and is also input to the communication device 10. At this time, by turning on the transmission power supply of the communication device 10 in response to the detection signal from the audio discriminator 13, its own audio signal is transmitted to the other party. At the same time, the switches 15a, 15b and 15c are opened by the detection signal of the voice discriminator 13, whereby the LMS calculators 5a,
Since the error signals of 5b and 5c become 0, the updating of the coefficients of the adaptive filters 3a, 3b and 3c is stopped.

When there is no sound, the sound discriminator 13 detects that there is no sound, and the detection signal is input to the mute control circuit 19. The mute control circuit 19 opens the switch 15d a certain time after receiving this detection signal,
As a result, the output signals from the microphone 1f are not input to the adders 2c and 2d and the communication device 10. At this time, by turning off the transmission power of the communication device 10 by a signal from the mute control circuit 19, the power consumption of the communication device 10 can be reduced. At the same time, the switches 15a to 15c become conductive, whereby the coefficient updating operation of the LMS calculators 5a, 5b and 5c is started again.

Here, the voice discriminator 13 includes, for example, as shown in FIG.
1a and 21b and comparators 22a and 22b. The bandpass filter 20 is a microphone 1f
Only the audio band component of the signal detected in is passed,
It is input to the power calculators 21a and 21b. The power calculators 21a and 21b calculate the power (sum of squares) for a certain period.
1b operates out of phase. Next, the outputs of the power calculators 21a and 21b and the threshold setting unit 2
The comparators 22a and 22b compare the output with the predetermined threshold set in Step 2 and if the outputs of both power calculators 21a and 21b are smaller than the threshold, switch 15c is turned on. If it is larger, the switch 15c is opened. Further, the power calculators 21a and 21a
If any output of 1b is larger than the threshold value, the mute control circuit 19 turns on the switch 15d, and if both become smaller, the switch 15d is opened after a certain time.

By the way, when the voice discriminator 13 is configured as described above, the voice calculators 21a and 21
A certain time is required until the output of 1b becomes equal to or more than the threshold value. In other words, after emitting the voice, the switch 15
There will be a delay time until the detection signal is input from the voice discriminator 13 to c and the mute control circuit 19. Therefore, in order to correct this delay time, the output of the microphone 1a is delayed by the delay unit 16b.
The output of f is delayed by the time that the adaptive filter 3c satisfies the causality, including the delay time required for voice detection by the delay unit 16a (equal to the delay time of the delay unit 16b). As a result, during the time required for detecting the sound of the sound discriminator 13 in the early stage of the sound utterance, the adaptive filter 3c does not control the sound signal.

Further, the mute control circuit 19 opens the switch 15d after a certain period of time after the voice discriminator 13 determines that there is no voice. Portions can be input to the communication device 10 and the adders 2c and 2d without interruption. As a result, when the sound is generated, the own sound reproduced by the speakers 6a and 6b is detected by the microphones 1d and 1e, which affects the coefficient updating operation of the LMS calculators 5a and 5b, and the adaptive filters 3a and 3b
Can be prevented from becoming unstable. Further, it is possible to prevent the coefficient updating operation of the LMS computing unit 5c from being affected by the speech signal remaining in the error signal of the LMS computing unit 5c when the speech is generated, thereby preventing the operation of the adaptive filter 3c from becoming unstable.
Further, when sound is mixed in the microphone 1a, it is possible to prevent the subtractor 17 from reducing the sound signal by the output of the adaptive filter 3c. And switch 15
With d, it is possible to prevent unnecessary ambient noise from being transmitted to the other party when the user is silent.

The received signal discriminator 14 detects the presence or absence of a received signal from the communication device 10, and if there is a received signal, the signals are reproduced by the adders 2c and 2d on the speakers 6a and 6b, respectively. 15a and 15
b is released, and the coefficient updating operation of the adaptive filters 3a and 3b stops. This can prevent the operations of the adaptive filters 3a and 3b from becoming unstable during wireless reception.

As described above, when there is no speech or when there is no received signal from the communication device 10, the noise control headset of this embodiment reduces the noise at the ear as described in the first embodiment of FIG. Then, the surrounding noise signal included in the detection signal from the microphone 1f can be reduced by the adaptive filter 3c in a silent state. When sound is generated or when there is a received signal from the communication device 10, the operation of the adaptive filters 3a and 3b can be prevented from becoming unstable while reducing noise.
At the same time, it is possible to prevent the adaptive filter 3c from becoming unstable or reduce the audio signal while reducing the ambient noise component mixed into the audio signal when the audio is generated. Further, it is possible to prevent unnecessary ambient noise from being transmitted to the other party when the user is silent, and to reduce the power consumption of the communication device 10. Further, by controlling the transmission power supply of the communication device 10 by the output of the mute control circuit 19, the period in which the switch 15d is in the conductive state and the period in which the transmission power supply is on are the same, so that the audio signal is not interrupted. Can be sent to the other party.

Although the headphones 7a and 7b are connected by the headband 8 in the embodiment shown in FIG. 17, they may be attached to the helmet 11 as shown in FIG. Further, the headphones 7a and 7b may be of a closed type or an open type, and may be of an earphone type. Further, if the analog addition signal is converted into a digital signal after the adders 2a and 2b, the number of AD converters can be reduced.

Furthermore, the reception signal discriminator 14
The received signal from 0 may be digitized and the sound may be determined by a predetermined sound detection algorithm. Alternatively, the received sound signal may be compared with a reference threshold value by a comparator while the analog signal is being used. Similarly, the audio discriminator 13 may not be configured as shown in FIG. 18, and the audio signal may be compared with a reference threshold value by a comparator while the analog signal is an analog signal. The diaphragm diameters of the microphone 1a and the microphone 1f may be the same, but the diaphragm diameter of the microphone 1f is equal to that of the microphone 1a.
More preferably, it is more than twice.

Further, the LMS calculators 5a, 5b and 5c
Are the outputs of the Fx filters 4a and 4b and the delay 16
b, the microphones 1d and 1e and the subtractor 1
A so-called learning identification method for normalizing the error signal from the control unit 7 may be used. The communication device 10 may be built in as a noise control headset, or an external communication device may be used. Further, as described with reference to FIG.
, Adders 2a and 2b are microphones 1a, 1b
1c may be added.

Embodiment 5 Embodiment 5 will be described with reference to FIG. FIG. 19 is a block diagram showing a noise control headset according to the fifth embodiment of the present invention. In FIG. 19, a noise control headset in which a headphone and a voice detector are integrally formed is a first noise control headset arranged at a mouth of a user.
Microphone 1a, which is a noise detector, and microphone 1b, which is a second noise detector, disposed outside the cabinet of the left headphone 7a. Third noise, which is disposed outside the cabinet of the right headphone 7b. Microphone 1c as a detector, microphone 1d as a first error detector disposed in a cabinet, microphone 1e as a second error detector disposed in a cabinet, disposed at a mouth And a microphone 1f which is a sound detector. Outputs of the microphones 1a and 1b are input to an adder 2a which is a first noise signal adder, and outputs of the microphones 1a and 1c are input to an adder 2b which is a second noise signal adder. . Wireless or wired communication device 1
The received signal of 0 is input to an adder 2c which is a first output signal adder and an adder 2d which is a second output signal adder. The outputs of the adders 2a and 2b are input to a first adaptive filter 3a and a second adaptive filter 3b (denoted as AFIR in the figure). The outputs of the adders 2a and 2b are input to an Fx filter 4a as a first transfer function corrector and an Fx filter 4b as a second transfer function corrector. Fx
Outputs of the filters 4a and 4b are respectively input to an LMS (least mean square) calculator 5a as a first coefficient updater and an LMS calculator 5b as a second coefficient updater. The outputs of the microphones 1d and 1e are supplied to the LMS calculators 5a and 5b via the respective switches 15a and 15b.
Is input to Outputs of the LMS calculators 5a and 5b are input to adaptive filters 3a and 3b, respectively. The outputs of the adaptive filters 3a and 3b are input to adders 2c and 2d, respectively, and the outputs of the adders 2c and 2d are the speakers 6a and the right headphones 7b in the cabinet of the left headphone 7a.
Are input to the speakers 6b located in the cabinets. The left headphone 7a and the right headphone 7b are connected by a headband 8. The support arm 9 supports the microphones 1a and 1f so as to approach the mouth. The output of the microphone 1f is input to the voice discriminator 13 and the delay unit 16. The received signal is also input to the received signal discriminator 14. The output of the delay unit 16 is input to the subtractor 17. The output of the microphone 1a is the third adaptive filter 3
c and the third LMS calculator 5c. Third L
The output of the MS calculator 5c is input to the third adaptive filter 3c, and the output of the third adaptive filter 3c is input to the subtractor 17. The output of the subtractor 17 is input to the LMS computing unit 5c via a switch 15c, and the communication device 10 and the adder 2c via a switch 15d which is a mute circuit.
Input to 2d. The output of the microphone 1b is also input to the fourth adaptive filter 3d and the fourth LMS calculator 5d. The output of the microphone 1c is also input to the fifth adaptive filter 3e and the fifth LMS calculator 5e. Outputs of the adaptive filters 3d and 3e are input to a subtractor 17. L
The output of the MS calculator 5d is input to the adaptive filter 3d,
The output of the LMS calculator 5e is input to the adaptive filter 3e. The output of the subtractor 17 is input to the LMS calculators 5d and 5e. The noise control headset of the present embodiment includes fourth and fifth noise control headset components in FIG.
Adaptive filters 3d and 3e, and fourth and fifth LMSs
The operation is performed by adding arithmetic units 5d and 5e, and the operation thereof will be described below.

The ambient noise signal detected by the microphone 1f is delayed by the delay unit 16 by a predetermined time during which the adaptive filter 3c satisfies causality, and is input to the subtractor 17. On the other hand, the noise signal detected by the microphone 1a is
The signal is processed by the adaptive filter 3c, and its output is
7 is input. The noise signal detected by the microphone 1b is subjected to signal processing by the adaptive filter 3d, and the noise signal detected by the microphone 1c is processed by the adaptive filter 3e.
Signal processing. Outputs of the adaptive filters 3d and 3e are input to a subtractor 17. In the subtractor 17, the delay 16
Are subtracted from the outputs of the adaptive filters 3c, 3d and 3e, and the resulting error signal is
d and LMS calculators 5d and 5e. The LMS calculator 5c calculates and updates the coefficient of the adaptive filter 3c based on the noise signal from the microphone 1a and the error signal from the switch 15c so as to minimize the error signal from the switch 15c. Similarly, the LMS calculator 5d updates the coefficient of the adaptive filter 3d based on the noise signal from the microphone 1b and the error signal from the subtractor 17, so as to minimize the error signal from the subtractor 17. LMS calculator 5e
Updates the coefficient of the adaptive filter 3e based on the noise signal from the microphone 1c and the error signal from the subtractor 17 so as to minimize the error signal from the subtractor 17. Thereby, the noise component included in the output signal of the subtractor 17 is reduced.

Here, the microphones 1a and 1f are configured as shown in FIG. 11 or 16 similarly to the case of the third embodiment, and the control effect at that time is as shown in the graph of FIG. Become. Compare FIG. 20 with FIG.
It can be seen that the difference between the output level of the curve B when the noise control is not performed and the output level of the curve C when the noise control is performed is increased, and the noise control effect is improved. Also, adaptive filters 3a, 3b and 3 by the voice discriminator 13 and the received signal discriminator 14
The operation and effect of the control of the coefficient updating operation of c, the control of the switch 15d, and the control of the transmission power supply of the communication device 10 are the same as those of the third embodiment shown in FIG.

However, in the coefficient updating operation of the adaptive filters 3d and 3e, since the respective noise signals are detection signals from the microphones 1b and 1c which are hard to detect the sound because they are far from the mouth as shown in FIG. Not included. Therefore, the audio signal component at the output of the subtractor 17 does not decrease as shown in FIG.
The coefficient updating operation of d and 3e is not stopped.

As described above, the noise control headset of the present embodiment reduces the noise at the ear as described in the first embodiment of FIG. Then, the surrounding noise signal included in the detection signal from the microphone 1f can be reduced by the adaptive filters 3c to 3e in a silent state. When sound is generated or when there is a received signal from the communication device 10, the adaptive filters 3a and 3b can be prevented from becoming unstable while reducing noise.
Then, it is possible to prevent the adaptive filter 3c from becoming unstable or reduce the audio signal while reducing the ambient noise component mixed in the audio signal when the audio is generated. Further, it is possible to prevent unnecessary ambient noise from being transmitted to the other party when the user is silent, and to reduce the power consumption of the communication device 10.

In this embodiment, the headphones 7a and 7
b is connected by a headband 8, but FIG.
As shown in FIG. Further, the headphones 7a and 7b may be of a closed type or an open type, and may be of an earphone type. Further, if the analog addition signal is converted into a digital signal after the adders 2a and 2b, the number of AD converters can be reduced.

Further, the voice discriminator 13 and the received signal discriminator 14 may digitize the voice signal from the microphone 1f and the received signal from the communication device 10 and discriminate the voice by a predetermined voice detection algorithm. A configuration may be employed in which the audio signal is compared with a reference threshold value by a comparator and determined as an analog signal. The diaphragm diameters of the microphone 1a and the microphone 1f may be the same, but it is more preferable that the diaphragm diameter of the microphone 1f is at least twice as large as that of the microphone 1a.

Further, the LMS calculators 5a to 5c are so-called learning identification methods for normalizing error signals from the microphones 1d and 1e and the subtractor 17 with the outputs of the Fx filters 4a and 4b and the output of the microphone 1a. Is also good. In addition, as shown in FIG.
The error signals of d and 5e may be controlled by switches 15e and 15f. In this case, if the voice discriminator 13 determines that there is voice, the switches 15e and 15
f is released and switches 15e and 15
By conducting f, the adaptive filters 3d and 3e can be prevented from becoming unstable even when the audio level included in the subtractor 17 is large.

The communication device 10 may be built in as a noise control headset, or an external communication device may be used. Further, as described with reference to FIG. 8, the adders 2a and 2b in FIG. 19 may be configured to add all the detection signals of the microphones 1a, 1b and 1c.

Embodiment 6 Embodiment 6 will be described with reference to FIG. FIG. 22 is a block diagram showing a noise control headset according to the sixth embodiment of the present invention. In FIG. 22, a noise control headset in which headphones and a sound detector are integrally formed is a first noise control headset arranged at the mouth of a user.
Microphone 1a, which is a noise detector, and microphone 1b, which is a second noise detector, disposed outside the cabinet of the left headphone 7a. Third noise, which is disposed outside the cabinet of the right headphone 7b. Microphone 1c as a detector, microphone 1d as a first error detector disposed in a cabinet, microphone 1e as a second error detector disposed in a cabinet, disposed at a mouth And a microphone 1f which is a sound detector. Outputs of the microphones 1a and 1b are input to an adder 2a which is a first noise signal adder, and outputs of the microphones 1a and 1c are input to an adder 2b which is a second noise signal adder. . Wireless or wired communication device 1
The received signal of 0 is input to an adder 2c which is a first output signal adder and an adder 2d which is a second output signal adder. The outputs of the adders 2a and 2b are input to a first adaptive filter 3a and a second adaptive filter 3b (denoted as AFIR in the figure). The outputs of the adders 2a and 2b are input to an Fx filter 4a as a first transfer function corrector and an Fx filter 4b as a second transfer function corrector. Fx
Outputs of the filters 4a and 4b are respectively input to an LMS (least mean square) calculator 5a as a first coefficient updater and an LMS calculator 5b as a second coefficient updater. The outputs of the microphones 1d and 1e are supplied to the LMS calculators 5a and 5b via the respective switches 15a and 15b.
Is input to Outputs of the LMS calculators 5a and 5b are input to adaptive filters 3a and 3b, respectively. The outputs of the adaptive filters 3a and 3b are input to adders 2c and 2d, respectively, and the outputs of the adders 2c and 2d are the speakers 6a and the right headphones 7b in the cabinet of the left headphone 7a.
Are input to the speakers 6b located in the cabinets. The left headphone 7a and the right headphone 7b are connected by a headband 8. The support arm 9 supports the microphones 1a and 1f so as to approach the mouth. The output of the microphone 1f is input to the voice discriminator 13 and the delay unit 16a. The received signal is received by a received signal discriminator 14.
Is also entered. The output of the delay unit 16a is input to the subtractor 17a. The output of the microphone 1a is also input to the third adaptive filter 3c and the third LMS calculator 5c. The output of the third LMS calculator 5c is the third adaptive filter 3c
And the output of the third adaptive filter 3c is
7b. The output of the subtractor 17b is the switch 15
The signal is input to the LMS computing unit 5c via the switch c, and is input to the communication device 10 and the adders 2c and 2d via the switch 15d which is a mute circuit. The output of the microphone 1b is also input to the fourth adaptive filter 3d and the fourth LMS calculator 5d. The output of the microphone 1c is also input to the fifth adaptive filter 3e and the fifth LMS calculator 5e. Outputs of the adaptive filters 3d and 3e are input to a subtractor 17a. The output of the LMS calculator 5d is an adaptive filter 3d
And the output of the LMS computing unit 5e is
e. The output of the subtractor 17a is the LMS operator 5
d, 5e, and through the delay unit 16b, the subtractor 1
7b. The noise control headset of the present embodiment is obtained by adding a delay unit 16a and a subtractor 17a to the components of the noise control headset in FIG. 19, and the operation thereof will be described below.

The ambient noise signal detected by the microphone 1f is supplied to the adaptive filter 3d for a predetermined time by the delay 16a.
And 3e are delayed by the time that the causality is satisfied, and the subtractor 1
7a. On the other hand, the noise signal detected by the microphone 1b is processed by the adaptive filter 3d. The noise signal detected by the microphone 1c is processed by the adaptive filter 3e. Outputs of the adaptive filters 3d and 3e are input to a subtractor 17a. In the subtracter 17a, the outputs of the adaptive filters 3d and 3e are subtracted from the output of the delay unit 16a. The LMS computing unit 5d includes the microphone 1b
And the error signal from the subtractor 17a,
The coefficient of the adaptive filter 3d is updated so that the error signal from the subtractor 17a is minimized. Also, the LMS calculator 5e
Updates the coefficient of the adaptive filter 3e based on the noise signal from the microphone 1c and the error signal from the subtractor 17a so as to minimize the error signal from the subtractor 17a. Thereby, the noise component included in the output signal of the subtractor 17a is reduced.

Next, the output of the subtractor 17a is
, The adaptive filter 3c is delayed by a time that satisfies the causality, and is input to the subtractor 17b. On the other hand, the noise signal detected by the microphone 1a is subjected to signal processing by the adaptive filter 3c, and the output is input to the subtractor 17b. In the subtractor 17b, the output of the adaptive filter 3c is subtracted from the output of the delay unit 16b, and the resulting output signal is input to the switches 15c and 15d. The LMS calculator 5c is
Based on the noise signal from the microphone 1a and the error signal from the switch 15c, the coefficient of the adaptive filter 3c is calculated and updated so as to minimize the error signal from the switch 15c. Thereby, the noise component included in the output signal of the subtractor 17b is reduced.

Here, the microphones 1a and 1f are configured as shown in FIG. 11 or FIG. 16 similarly to the case of the third embodiment, and the control effect at that time is as shown in the graph of FIG. . In FIG. 20, a curve B is the output level of the subtractor 17 when the noise control is not performed, and a curve C is the same output level when the noise control is performed. The control of the updating of the coefficients of the adaptive filters 3a, 3b and 3c by the voice discriminator 13 and the reception signal discriminator 14, the control of the switch 15d, and the control of the transmission power supply of the communication device 10 have the same operations and effects. Is the same as in the fifth embodiment.

As described above, the noise control headset of this embodiment reduces noise at the ear as described in the first embodiment in FIG. 1 when there is no signal or when there is no reception signal from the communication device 10. Then, the surrounding noise signal included in the detection signal from the microphone 1f can be reduced by the adaptive filters 3c, 3d, and 3e in a silent state. When sound is generated or when there is a received signal from the communication device 10, the adaptive filters 3a and 3b can be prevented from becoming unstable while reducing noise. Then, it is possible to prevent the adaptive filter 3c from becoming unstable or reduce the audio signal while reducing the ambient noise component mixed in the audio signal when the audio is generated. Further, it is possible to prevent unnecessary ambient noise from being transmitted to the other party when the user is silent, and to reduce the power consumption of the communication device 10.

The delay units 16a and 16b and the subtractor 1
7a and 17b, the adaptive filter 3
The impulse responses of the coefficients to be realized for c, 3d and 3e can be optimally adjusted. In this embodiment, the headphones 7a and 7b are connected by the headband 8, but may be attached to the helmet 11 as shown in FIG. Further, the headphones 7a and 7b may be of a closed type or an open type, and may be of an earphone type.

If the analog addition signal is converted into a digital signal after the adders 2a and 2b, the number of AD converters can be reduced. Further, the voice discriminator 13 and the received signal discriminator 14 may digitize the voice signal from the microphone 1f and the received signal from the communication device 10 and discriminate the voice by a predetermined voice detection algorithm. A configuration may be used in which the analog signal is compared with a reference threshold value and determined by a comparator.

The microphone 1a and the microphone 1
f may have the same diaphragm diameter, but the microphone 1f
It is more preferable that the diameter of the diaphragm is at least twice as large as that of the microphone 1a. Further, the LMS computing units 5a, 5b and 5c may use a so-called learning identification method in which the outputs of the Fx filters 4a and 4b and the output of the microphone 1a are used to normalize the error signals from the microphones 1d and 1e and the subtractor 17. Good.

In addition, as described in the fifth embodiment shown in FIG. 21, the error signals of the LMS calculators 5d and 5e in FIG. 22 may be controlled by providing switches 15e and 15f. Further, as described with reference to FIG.
2, the adders 2a and 2b include the microphones 1a,
A configuration in which all the detection signals 1b and 1c are added may be used.
The communication device 10 may be built in as a noise control headset, or an external communication device may be used.

Embodiment 7 Embodiment 7 will be described with reference to FIG. FIG. 23 is a block diagram showing a noise control headset according to Embodiment 7 of the present invention. In FIG. 23, a noise control headset in which a headphone and a sound detector are integrally formed is a first noise control headset arranged at a mouth of a user.
Microphone 1a, which is a noise detector, and microphone 1b, which is a second noise detector, disposed outside the cabinet of the left headphone 7a. Third noise, which is disposed outside the cabinet of the right headphone 7b. Microphone 1c as a detector, microphone 1d as a first error detector disposed in a cabinet, microphone 1e as a second error detector disposed in a cabinet, disposed at a mouth And a microphone 1f which is a sound detector. Outputs of the microphones 1a and 1b are input to an adder 2a which is a first noise signal adder, and outputs of the microphones 1a and 1c are input to an adder 2b which is a second noise signal adder. . Wireless or wired communication device 1
The received signal of 0 is input to an adder 2c which is a first output signal adder and an adder 2d which is a second output signal adder. The outputs of the adders 2a and 2b are input to a first adaptive filter 3a and a second adaptive filter 3b (denoted as AFIR in the figure). The outputs of the adders 2a and 2b are input to an Fx filter 4a as a first transfer function corrector and an Fx filter 4b as a second transfer function corrector. Fx
Outputs of the filters 4a and 4b are respectively input to an LMS (least mean square) calculator 5a as a first coefficient updater and an LMS calculator 5b as a second coefficient updater. The outputs of the microphones 1d and 1e are supplied to the LMS calculators 5a and 5b via the respective switches 15a and 15b.
Is input to Outputs of the LMS calculators 5a and 5b are input to adaptive filters 3a and 3b, respectively. Outputs of the adaptive filters 3a and 3b are input to adders 2c and 2d, respectively, and outputs of the adders 2c and 2d are output to a speaker 6a in a cabinet 27a of a left headphone 7a and a speaker 6b in a cabinet 27b of a right headphone 7b. Each is entered. The left headphone 7a and the right headphone 7b are connected by a headband 8. The support arm 9 supports the microphones 1a and 1f so as to approach the mouth. The output of the microphone 1f is input to the voice discriminator 13 and the delay unit 16a. The received signal is also input to the received signal discriminator 14. The output of the delay unit 16a is input to the subtractor 17. The output of the microphone 1a is passed through a delay unit 16b to a third adaptive filter 3c and a third LMS.
It is also input to the arithmetic unit 5c. The output of the third LMS operation unit 5c is input to the third adaptive filter 3c, and the output of the third adaptive filter 3c is input to the subtracter 17. The output of the subtractor 17 is supplied to the LMS calculator 5c via the switch 15c.
To the switch 15 which is a mute circuit
The data is input to the wireless communication device 10 through the line d. Voice discriminator 1
The output of 3 is input to the mute control circuit 19, and the output of the mute control circuit 19 is input to the wireless communication device 10. The output of the microphone 1b is connected to the fourth adaptive filter 3d and the fourth
Is input also to the LMS calculator 5d. The output of the microphone 1c is also input to the fifth adaptive filter 3e and the fifth LMS calculator 5e. Outputs of the LMS calculators 5d and 5e are input to adaptive filters 3d and 3e, respectively. Outputs of the adaptive filters 3d and 3e are input to a subtractor 17. The noise control headset of the present embodiment is obtained by adding fourth and fifth adaptive filters 3d and 3e and fourth and fifth LMS operators 5d and 5e to the components of the noise control headset in FIG. The operation will be described below.

The ambient noise signal detected by the microphone 1f is delayed by the delay unit 16a by a predetermined time during which the adaptive filter 3c satisfies causality, and is input to the subtractor 17. On the other hand, the noise signal detected by the microphone 1a is
The delay 16b is delayed by a predetermined time required for the voice discriminator 13 to reliably discriminate the voice.
The signal is processed at c, and the output is input to the subtractor 17. The noise signal detected by the microphone 1b is subjected to signal processing by the adaptive filter 3d, and the noise signal detected by the microphone 1c is subjected to signal processing by the adaptive filter 3e. In the subtracter 17, the outputs of the adaptive filters 3c, 3d and 3e are subtracted from the output of the delay unit 16a, and the resulting output signals are input to the switches 15c and 15d and the LMS operators 5d and 5e. The LMS calculator 5c calculates and updates the coefficient of the adaptive filter 3c based on the noise signal from the delay unit 16b and the error signal from the switch 15c so as to minimize the error signal from the switch 15c. Similarly, the LMS calculator 5
“d” updates the coefficient of the adaptive filter 3 d based on the noise signal from the microphone 1 b and the error signal from the subtractor 17 so as to minimize the error signal from the subtractor 17. LM
The S calculator 5e updates the coefficient of the adaptive filter 3e based on the noise signal from the microphone 1c and the error signal from the subtractor 17, so as to minimize the error signal from the subtractor 17. Thereby, the noise component included in the output signal of the subtractor 17 is reduced.

Here, the microphones 1a and 1f are shown in FIG.
1 or FIG. 16, and the control effect at that time is as shown in the graph of FIG. The control of the coefficient update operation of the adaptive filters 3a, 3b and 3c by the voice discriminator 13 and the received signal discriminator 14, the control of the mute control circuit 19 and the switch 15d, and the control of the transmission power supply of the communication device 10 are described. ,
The operation and effect are the same as those of the fourth embodiment shown in FIG.

As described above, the noise control headset of the present embodiment reduces the noise at the ear as described in the first embodiment when there is no signal or when there is no reception signal from the communication device 10. Then, the surrounding noise signal included in the detection signal from the microphone 1f can be reduced by the adaptive filters 3c, 3b and 3e in a silent state. When sound is generated or when there is a received signal from the communication device 10, the adaptive filters 3a and 3b can be prevented from becoming unstable while reducing noise. Then, it is possible to prevent the adaptive filter 3c from becoming unstable or reduce the audio signal while reducing the ambient noise component mixed in the audio signal when the audio is generated. Further, it is possible to prevent unnecessary ambient noise from being transmitted to the other party when the user is silent, and to reduce the power consumption of the communication device 10. Further, by controlling the transmission power supply of the communication device 10 by the output of the mute control circuit 19, the period in which the switch 15d is in the conductive state and the period in which the transmission power supply is on are the same, so that the audio signal is not interrupted. Can be sent to the other party.

In this embodiment, the headphones 7a and 7
b is connected by a headband 8, but FIG.
As shown in FIG. Further, the headphones 7a and 7b may be of a closed type or an open type, and may be of an earphone type. Further, if the analog addition signal is converted into a digital signal after the adders 2a and 2b, the number of AD converters can be reduced.

Further, the voice discriminator 13 and the received signal discriminator 14 are adapted to transmit the voice signal from the microphone 1f and the communication device 10
The received signal may be digitized and the sound may be determined by a predetermined sound detection algorithm. For example, a structure may be used in which the sound signal is compared with a reference threshold value by a comparator while the analog signal remains as an analog signal. The diaphragm diameters of the microphone 1a and the microphone 1f may be the same, but it is more preferable that the diaphragm diameter of the microphone 1f is at least twice as large as that of the microphone 1a.

Further, the LMS calculators 5a, 5b and 5c
Are the outputs of the Fx filters 4a and 4b and the delay 16
b, the microphones 1d and 1e and the subtractor 1
A so-called learning identification method for normalizing the error signal from the control unit 7 may be used. The communication device 10 may be built in as a noise control headset, or an external communication device may be used.

In addition, as described with reference to FIG.
In, the error signals of the LMS operators 5d and 5e may be controlled by providing switches 15e and 15f. Further, as described with reference to FIG.
, Adders 2a and 2b are connected to microphones 1a and 1
A configuration in which all the detection signals of c are added may be employed.

Eighth Embodiment An eighth embodiment will be described with reference to FIG. FIG. 24 is a block diagram showing a noise control headset according to the eighth embodiment of the present invention. In FIG. 24, a noise control headset in which a headphone and a voice detector are integrally formed is a first noise control headset arranged at a mouth of a user.
Microphone 1a, which is a noise detector, and microphone 1b, which is a second noise detector, disposed outside the cabinet of the left headphone 7a. Third noise, which is disposed outside the cabinet of the right headphone 7b. Microphone 1c as a detector, microphone 1d as a first error detector disposed in a cabinet, microphone 1e as a second error detector disposed in a cabinet, disposed at a mouth And a microphone 1f which is a sound detector. Outputs of the microphones 1a and 1b are input to an adder 2a which is a first noise signal adder, and outputs of the microphones 1a and 1c are input to an adder 2b which is a second noise signal adder. . Wireless or wired communication device 1
The received signal of 0 is input to an adder 2c which is a first output signal adder and an adder 2d which is a second output signal adder. The outputs of the adders 2a and 2b are input to a first adaptive filter 3a and a second adaptive filter 3b (denoted as AFIR in the figure). The outputs of the adders 2a and 2b are input to an Fx filter 4a as a first transfer function corrector and an Fx filter 4b as a second transfer function corrector. Fx
Outputs of the filters 4a and 4b are respectively input to an LMS (least mean square) calculator 5a as a first coefficient updater and an LMS calculator 5b as a second coefficient updater. The outputs of the microphones 1d and 1e are supplied to the LMS calculators 5a and 5b via the respective switches 15a and 15b.
Is input to Outputs of the LMS calculators 5a and 5b are input to adaptive filters 3a and 3b, respectively. The outputs of the adaptive filters 3a and 3b are input to adders 2c and 2d, respectively, and the outputs of the adders 2c and 2d are the speakers 6a and the right headphones 7b in the cabinet of the left headphone 7a.
Are input to the speakers 6b located in the cabinets. The left headphone 7a and the right headphone 7b are connected by a headband 8. The support arm 9 supports the microphones 1a and 1f so as to approach the mouth. The output of the microphone 1f is input to the voice discriminator 13 and the delay unit 16a. The received signal is received by a received signal discriminator 14.
Is also entered. The output of the delay unit 16a is input to the subtractor 17a. The output of the microphone 1a passes through a delay unit 16b to a third adaptive filter 3c and a third LMS calculator 5c.
Is also entered. The output of the third LMS calculator 5c is the third
Of the third adaptive filter 3c.
The output of c is input to the subtractor 17b. The output of the subtractor 17b is input to the LMS calculator 5c via the switch 15c, and is input to the communication device 10 via the switch 15d which is a mute circuit. The output of the audio discriminator 13 is input to the mute control circuit 19, and the mute control circuit 1
The output of 9 is input to the communication device 10. Microphone 1b
Is also input to the fourth adaptive filter 3d and the fourth LMS calculator 5d. The output of the microphone 1c is also input to the fifth adaptive filter 3e and the fifth LMS calculator 5e. Outputs of the LMS calculators 5d and 5e are input to adaptive filters 3d and 3e, respectively. Adaptive filter 3
Outputs of d and 3e are input to a subtractor 17a. Subtractor 1
The output of 7a is input to the subtractor 17b via the delay 16c. The noise control headset of the present embodiment includes a delay unit 16a as a component of the noise control headset in FIG.
And a subtracter 17a, and the operation thereof will be described below.

The ambient noise signal detected by the microphone 1f is applied to the adaptive filter 3d for a predetermined time by the delay unit 16a.
And 3e are delayed by the time that the causality is satisfied, and the subtractor 1
7a. On the other hand, the noise signal detected by the microphone 1b is processed by the adaptive filter 3d, and the noise signal detected by the microphone 1c is processed by the adaptive filter 3e.
Is input to In the subtracter 17a, the outputs of the adaptive filters 3d and 3e are subtracted from the output of the delay unit 16a, and the resulting outputs are input to the LMS calculators 5d and 5e. The LMS computing unit 5d uses the noise signal from the microphone 1b and the error signal from the subtractor 17a to generate the subtractor 17a.
The coefficient of the adaptive filter 3d is updated so as to minimize the error signal from. Further, the LMS calculator 5e updates the coefficient of the adaptive filter 3e based on the noise signal from the microphone 1c and the error signal from the subtractor 17a so as to minimize the error signal from the subtractor 17a. Thereby, the noise component included in the output signal of the subtractor 17a is reduced.

Next, the output of the subtractor 17a is
At c, the adaptive filter 3c is delayed by a predetermined time that satisfies causality, and is input to the subtractor 17b. On the other hand, the noise signal detected by the microphone 1a is
Is delayed for a predetermined time required for the voice discriminator 13 to reliably discriminate the voice, the signal is processed by the adaptive filter 3c, and its output is input to the subtractor 17b. In the subtractor 17b, the adaptive filter 3c is output from the output of the delay unit 16c.
Are subtracted, and the resulting signal is input to switches 15c and 15d. Thereby, the noise component included in the output signal of the subtractor 17b is reduced.

Here, the microphones 1a and 1f are configured as shown in FIG. 11 or FIG. Becomes Further, the control of the coefficient update operation of the adaptive filters 3a, 3b and 3c by the voice discriminator 13 and the received signal discriminator 14, and the mute control circuit 19
The operation and effect of the control of the switch 15d and the control of the transmission power supply of the communication device 10 are the same as those of the seventh embodiment shown in FIG.

As described above, the noise control headset of this embodiment reduces noise at the ear as described in the first embodiment in FIG. 1 when there is no signal or when there is no reception signal from the communication device 10. Then, the surrounding noise signal included in the detection signal from the microphone 1f can be reduced by the adaptive filters 3c, 3d, and 3e in a silent state. When sound is generated or when there is a received signal from the communication device 10, the adaptive filters 3a and 3b can be prevented from becoming unstable while reducing noise. Then, it is possible to prevent the adaptive filter 3c from becoming unstable or reduce the audio signal while reducing the ambient noise component mixed in the audio signal when the audio is generated. Further, it is possible to prevent unnecessary ambient noise from being transmitted to the other party when the user is silent, and to reduce the power consumption of the communication device 10. Further, by controlling the transmission power supply of the communication device 10 by the output of the mute control circuit 19, the period in which the switch 15d is in the conductive state and the period in which the transmission power supply is on are the same, so that the audio signal is not interrupted. Can be sent to the other party.

The delay units 16a and 16c and the subtractor 1
7a and 17b, the adaptive filter 3
The impulse responses of the coefficients to be realized for c, 3d and 3e can be adjusted optimally. In this embodiment, the headphones 7a and 7b are connected by the headband 8, but they may be attached to the helmet 11 as shown in FIG. Further, the headphones 7a and 7b may be of a closed type or an open type, and may be of an earphone type.

If the analog addition signal is converted into a digital signal after the processing by the adders 2a and 2b, the number of AD converters can be reduced. Further, the voice discriminator 13 and the received signal discriminator 14 may digitize the voice signal from the microphone 1f and the received signal from the communication device 10 and discriminate the voice by a predetermined voice detection algorithm. A configuration in which the analog signal is compared with a reference threshold value and determined by a comparator may be used.

Further, the microphone 1a and the microphone 1
f may have the same diaphragm diameter, but the microphone 1f
It is more preferable that the diameter of the diaphragm is at least twice as large as that of the microphone 1a. Further, the LMS calculators 5a, 5b and 5c are so-called learning identification methods for normalizing error signals from the microphones 1d and 1e and the subtractor 17 with the outputs of the Fx filters 4a and 4b and the output of the delay unit 16b. Is also good.

The communication device 10 may be built in as a noise control headset, or an external communication device may be used. In addition, as described with reference to FIG. 21, the error signals of the LMS operators 5d and 5e in FIG.
e and 15f may be provided for control. Further, as described with reference to FIG. 8 of the first embodiment, in FIG. 24, the adders 2a and 2b may be configured to add all the detection signals of the microphones 1a and 1c.

[0116]

As described above, according to the first embodiment described with reference to the embodiment of FIG. 1, the first noise detector near the mouth and the second and third noise detectors installed on the left and right headphones are provided. The noise signals from the filters are added by first and second noise signal adders, respectively, and the output is used as a reference signal for the first and second adaptive filters. As a result, when the user moves while wearing the noise control headset, the relative position between the noise source and the control point changes, when there are multiple external noises, or when the reverberation time is long. Even in the case of a room or a large room, the control of the broadband random noise or the control of the periodic noise can be stably performed, and a sufficient noise reduction effect can be obtained. Further, the output of the voice detector and the first and second
The output of the adaptive filter and the received signal from the communication device are added by the first and second output signal adders, and reproduced from the left headphone and the right headphone. This makes it possible to monitor the own voice and the voice of the other party via the communication device.

According to the second invention described with reference to the embodiment of FIG. 9, in addition to the effects of the first invention, the sound discriminator and the received signal discriminator can be used when the own sound is generated or the received signal is detected. By stopping the coefficient update operations of the first and second coefficient updaters of the first and second adaptive filters, a malfunction during silence control by the monitor of the own voice and the partner voice is prevented. In addition, it does not transmit its own voice to the communication device except when its own voice is generated, thereby enabling further power saving of the communication device. Further, according to the third invention described with reference to the embodiment of FIG. 10, in addition to the effect of the second invention, the third adaptive filter actively reduces the ambient noise included in the own audio signal, The speech discriminator can prevent the third adaptive filter from malfunctioning when its own speech is generated.

Further, according to the fourth aspect of the invention described with reference to the embodiment of FIG. 17, in addition to the effect of the third aspect, the time that the first and second delay units have for determining the voice of the own voice is provided. To compensate. As a result, it is possible to reliably prevent a malfunction at the time of silencing control by monitoring the own voice and a malfunction at the time of noise control of the own voice signal.
In addition, the mute control circuit mutes the own sound after a certain period of time after the sound detection signal from the sound discriminator disappears, thereby preventing loss of the sound signal when monitoring the own sound and transmitting to the communication device. It is.

The fifth embodiment described with reference to FIG.
According to the invention, in order to reduce the ambient noise included in the audio signal, the signals of the first, second and third noise detectors are used as reference signals of the third, fourth and fifth adaptive filters, respectively. By controlling the output from the voice detector used, the effect of the third invention can be realized with higher accuracy. According to the sixth aspect of the present invention, in addition to the effect of the fourth aspect, in order to reduce the ambient noise signal included in the audio signal, the signals of the first, second and third noise detectors are reduced. Are used as reference signals of the third, fourth and fifth adaptive filters, respectively, to control the output from the speech detector, whereby the effect of the fourth invention can be realized with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a noise control headset according to a first embodiment of the present invention.

FIG. 2A is a right side view showing an installation location of each microphone. (B) is a plan view showing the installation location of each microphone. (C) is a left view which shows the installation location of each microphone.

FIG. 3 is a diagram showing a positional relationship between each microphone and a noise arrival direction.

FIG. 4 is a graph showing a noise control effect of headphones in a diffuse sound field.

FIG. 5 is a graph showing a noise control effect of headphones in a direct sound field.

FIG. 6 is a graph showing a noise control effect of headphones in a sound field having a periodic noise of 1 KHz.

FIG. 7A is a plan view showing an application of the present invention to a helmet. (B) is a left side view showing the application of the present invention to a helmet.

FIG. 8 is a block diagram illustrating another example of the first embodiment.

FIG. 9 is a block diagram illustrating a noise control headset according to a second embodiment of the present invention.

FIG. 10 is a block diagram illustrating a noise control headset according to a third embodiment of the present invention.

FIG. 11A shows a microphone 1a according to the third embodiment.
FIG. 5 is a front view showing a positional relationship between the microphone and a microphone 1f.
(B) is a side view showing a positional relationship between the microphone 1a and the microphone 1f in the third embodiment. (C) is a rear view showing the positional relationship between the microphone 1a and the microphone 1f in the third embodiment.

FIG. 12 is a diagram illustrating the directivity of a microphone 1a and a microphone 1f according to the third embodiment.

FIG. 13 is a graph showing a noise control effect of a voice microphone in a diffuse sound field.

FIG. 14 is a graph showing a change in characteristics of a voice microphone due to the influence of noise control.

FIG. 15 is a graph showing a noise control effect of a voice microphone in a direct sound field.

FIG. 16A is a front view illustrating a positional relationship between a microphone 1a and a microphone 1f according to another example of the third embodiment. (B) is a side view showing a positional relationship between the microphone 1a and the microphone 1f in another example of the third embodiment. (C) shows a microphone 1 in another example of the third embodiment.
FIG. 6 is a rear view showing a positional relationship between a and a microphone 1f.

FIG. 17 is a block diagram showing a noise control headset according to Embodiment 4 of the present invention.

FIG. 18 is a block diagram illustrating an example of a voice discrimination circuit according to a fourth embodiment.

FIG. 19 is a block diagram showing a noise control headset according to Embodiment 5 of the present invention.

FIG. 20 is a graph showing a noise control effect of a voice microphone in a diffuse sound field.

FIG. 21 is a block diagram showing another example of the fifth embodiment.

FIG. 22 is a block diagram showing a noise control headset according to Embodiment 6 of the present invention.

FIG. 23 is a block diagram showing a noise control headset according to Embodiment 7 of the present invention.

FIG. 24 is a block diagram showing a noise control headset according to Embodiment 8 of the present invention.

FIG. 25 is a block diagram showing a conventional noise control headphone.

FIG. 26 is a block diagram showing a conventional adaptive filter.

FIG. 27 is a block diagram showing another example of a conventional noise control headphone.

FIG. 28 is a block diagram showing still another example of the conventional noise control headphones.

FIG. 29 is a block diagram showing still another example of the conventional noise control headphones.

[Explanation of symbols]

1a, 1b, 1c, 1d, 1e, 1f Microphones 2a, 2b, 2c, 2d Adders 3a, 3b, 3c, 3d, 3e Adaptive filters 4a, 4b Fx filters 5a, 5b, 5c, 5d, 5e LMS calculator 6a , 6b Speakers 7a, 7b Headphones 8 Headband 9 Support arm 10 Communication device 11 Helmet 13 Voice discriminator 14 Received signal discriminator 15a, 15b, 15c, 15d, 15e, 15f Switch 16, 16a, 16b, 16c Delay device 17, 17a, 17b Subtractor 18 Sound absorbing material 19 Mute control circuit 20 Band-pass filter 21a, 21b Power calculator 22a, 22b Comparator 23 Microphone 24 Microphone 25 Headphone 26 Adaptive processing system 27 Amplifier 28 Ear 28A External auditory canal 29 Subtractor 30 System 3 Headphone 32 microphone 32a error signal line 33 speakers 33a control signal line 34 signal processor 34a connected cable 34b plug 35 detecting sensor 35a amplifier 36 mixer 36a outputs jacks 37a radio receiver 37b wireless transmitter 38-l, 38-n Machinery

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H04R 1/10 101 H04R 5/033 Z 5/033 G10K 11/16 H (72) Inventor Tetsuya Mohri 1006 Kadoma Kadoma, Kadoma, Osaka Address Matsushita Electric Industrial Co., Ltd.

Claims (65)

[Claims] 1. A sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet, and a sound detector attached near the sound detector to mainly detect ambient noise. A first noise detector, a second noise detector attached to the outside of a left cabinet of the headphones, and a first adding the outputs of the first noise detector and the second noise detector. A noise signal adder, a first adaptive filter that processes an output signal of the first noise signal adder, and a first transfer function corrector that processes an output signal of the first noise signal adder. A first output signal adder that adds an output of the first adaptive filter, an output of the voice detector, and a reception signal from a communication unit that performs communication with another person; Signal addition Left headphone for reproducing the output of the first headphone, a first error detector mounted inside the cabinet of the left headphone, and an output from the first error detector and an output of the first transfer function corrector. A first coefficient updater for calculating and updating the coefficient of the first adaptive filter; a third noise detector mounted outside a right cabinet of the headphones; the first noise detector; A second noise signal adder for adding an output of the third noise detector, a second adaptive filter for processing an output signal of the second noise signal adder, and a second noise signal adder for processing the output signal of the second noise signal adder. A second transfer function corrector that processes an output signal; a second output signal adder that adds an output of the second adaptive filter, an output of the voice detector, and a reception signal from the communication unit; Second output signal A right headphone reproducing the output of the arithmetic unit, a second error detector mounted inside a cabinet of the right headphone, and an output of the second error detector and the second transfer function corrector. A second coefficient updater that calculates and updates the coefficient of the second adaptive filter from an output, wherein the voice detector has a strong directivity in a direction of a user's mouth. And the output signal is used as the transmission signal of the communication means, and the coefficient of the first transfer function corrector is approximated to the transfer function from the left headphone to the first error detector. The noise control headset, wherein the coefficient of the second transfer function corrector is configured to approximate a transfer function from the right headphone to the second error detector. 2. In a state in which a noise control headset is mounted so that the voice detector is located near a mouth of a user, the second noise detector moves an outside of a left headphone cabinet toward a side of the user. When viewed from above, it is attached to an upper-right area divided into four parts by a horizontal axis and a vertical axis from a center point of the left headphone to an upper left part, a lower left part, an upper right part, and a lower right part. 2. The noise control headset according to 1. 3. In a state in which the noise control headset is mounted so that the voice detector comes to the mouth of the user, the third noise detector moves the outside of the cabinet of the right headphone to the side of the user. When viewed from above, it is attached to an upper left area divided into four parts by a horizontal axis and a vertical axis from a center point of the right headphone to an upper left part, a lower left part, an upper right part, and a lower right part. 2. The noise control headset according to 1. 4. A sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet, and a sound discriminator for judging presence or absence of sound based on an output of the sound detector. A reception signal discriminator for judging the presence or absence of a reception signal of a communication means for communicating with another person; a first noise detection device attached near the voice detector and mainly detecting ambient noise A second noise detector attached to the outside of the left cabinet of the headphones; a first noise signal adder for adding outputs of the first noise detector and the second noise detector. A first adaptive filter that processes an output signal of the first noise signal adder; a first transfer function corrector that processes an output signal of the first noise signal adder; A first output signal adder for adding an output of the filter, an output of the audio detector, and a reception signal from the communication unit; a left headphone for reproducing an output of the first output signal adder; A first error detector mounted inside a headphone cabinet; and calculating a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. A first coefficient updater that updates the first and second noise detectors; a third noise detector attached outside the right cabinet of the headphones; and an output of the first noise detector and the third noise detector. A second noise signal adder, a second adaptive filter for processing an output signal of the second noise signal adder, and a second transfer function correction for processing an output signal of the second noise signal adder Vessel and the second A second output signal adder for adding an output of the adaptive filter, an output of the audio detector, and a reception signal from the communication unit; a right headphone for reproducing an output of the second output signal adder; A second error detector mounted inside the cabinet of the right headphone; calculating a coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; And a second coefficient updater for updating, wherein the voice detector has unidirectionality or bidirectionality having a strong directivity in the direction of the mouth of the user, and is provided by the voice discriminator. The output signal is used as a transmission signal of the communication means and an input signal to the first and second output signal adders only while it is determined that a sound is being generated, and the first transfer function corrector is used. The coefficient of And a coefficient of the second transfer function corrector is approximated to a transfer function from the right headphone to the second error detector. Wherein the first and second coefficient updaters determine at least one of a case where a sound is generated by the sound discriminator and a case where the received signal discriminator determines that a received signal is present. The noise control headset, wherein the updating of the coefficients of the first and second adaptive filters is stopped only during such a case. 5. In a state in which a noise control headset is mounted so that the voice detector comes to the mouth of the user, the second noise detector is configured to move the outside of the cabinet of the left headphone from the side of the user. When viewed from the center of the left headphone, it is attached to an upper right area divided into four parts by a horizontal axis and a vertical axis from an upper left part, a lower left part, an upper right part, and a lower right part. The described noise control headset. 6. In a state in which the noise control headset is mounted so that the voice detector comes to the mouth of the user, the third noise detector moves the outside of the right headphone cabinet to the side of the user. When viewed from above, it is attached to an upper left area divided into four parts by a horizontal axis and a vertical axis from a center point of the right headphone to an upper left part, a lower left part, an upper right part, and a lower right part. 5. The noise control headset according to 4. 7. A period in which a voice discriminator detects a voice,
5. The noise control headset according to claim 4, wherein the control is performed such that the transmission power of the communication unit is turned on. 8. A sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet, and a sound discriminator for judging presence or absence of sound based on an output of the sound detector. A reception signal discriminator for judging the presence or absence of a reception signal of a communication means for communicating with another person; a first noise detection device attached near the voice detector and mainly detecting ambient noise A second noise detector attached to the outside of the left cabinet of the headphones; a first noise signal adder for adding outputs of the first noise detector and the second noise detector. A first adaptive filter that processes an output signal of the first noise signal adder; a first transfer function corrector that processes an output signal of the first noise signal adder; A first output signal adder for adding an output of the filter and a reception signal from the communication means; a left headphone for reproducing an output of the first output signal adder; and a left headphone mounted inside a cabinet of the left headphone. A first error detector, and a first coefficient updating unit that calculates and updates a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. A third noise detector attached to the outside of a right cabinet of the headphones; a second noise signal adder for adding outputs of the first noise detector and the third noise detector. A second adaptive filter that processes an output signal of the second noise signal adder; a second transfer function corrector that processes an output signal of the second noise signal adder; Filter output and previous A second output signal adder for adding a signal received from the communication means; a right headphone for reproducing an output of the second output signal adder; a second head mounted inside a cabinet of the right headphone. An error detector; a second coefficient updater that calculates and updates the coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; A delay unit for delaying an output of the voice detector; a third adaptive filter for processing an output signal of the first noise detector; and subtracting an output of the third adaptive filter from an output of the delay unit. A subtractor; a third coefficient updater for calculating and updating the coefficient of the third adaptive filter from the output of the first noise detector and the output of the subtractor; and passing the output of the subtractor. Control whether or not And a chute circuit, however, the speech classifier first its output in the conducting state the mute circuit only while it is determined that the speech is occurring
And a second output signal adder. The first output signal adder adds the output of the first adaptive filter, the received signal from the communication means, and the output of the mute circuit, and adds the second output signal. The output of the second adaptive filter, the received signal from the communication means and the output of the mute circuit are added together, and the output of the mute circuit is used as the transmission signal of the communication means. The coefficient of the first transfer function corrector Is adapted to approximate a transfer function from the left headphone to the first error detector, and the coefficient of the second transfer function corrector approximates a transfer function from the right headphone to the second error detector. The first and second coefficient updaters are configured to determine whether a voice is being generated by the voice discriminator or to determine whether a received signal is received by the received signal discriminator. Stops updating the coefficients of the first and second adaptive filters only during at least one of the cases where it is determined that there is a sound. The third coefficient updater generates a sound by the sound discriminator. A noise control headset configured to stop updating the coefficients of the third adaptive filter only while it is determined that the noise is present. 9. In a state where the noise control headset is mounted so that the voice detector is located near a user's mouth, the second noise detector moves the outside of the cabinet of the left headphone to the side of the user. When viewed from above, it is attached to an upper-right area divided into four parts by a horizontal axis and a vertical axis from a center point of the left headphone to an upper left part, a lower left part, an upper right part, and a lower right part. A noise control headset according to claim 8. 10. In a state where a noise control headset is mounted so that the voice detector comes to a mouth of a user,
The third noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the right headphone when the outside of the cabinet of the right headphone is viewed from the side of the user. The noise control headset according to claim 8, wherein the noise control headset is attached to an upper left area divided into four parts at a lower part. 11. The noise control headset according to claim 8, wherein the first noise detector is omnidirectional, and the voice detector has directivity. 12. The noise control headset according to claim 8, wherein the diaphragm diameter of the voice detector is at least twice as large as the diaphragm diameter of the first noise detector. 13. The sound detector is mounted so as to have directivity in the direction of a user's mouth, the first noise detector is omni-directional, and the directivity of the sound detector is provided. The sound detector is mounted so that the sound hole faces in a direction directly opposite to the direction having the sound detector, and the first detector is located right beside the sound detector on an axis perpendicular to the direction having directivity of the sound detector. The noise control headset according to claim 8, wherein a noise control headset is provided. 14. The noise control headset according to claim 13, wherein a sound hole on a surface of the voice detector on a surface directly opposite to a surface facing a user's mouth is covered with a sound absorbing material. 15. A sound hole in a sound hole on a surface diametrically opposite to a surface of the voice detector facing a mouth of a user and a sound hole in the first noise detector on the same surface as the diametrically opposite surface. The noise control headset according to claim 13, which is covered with a material. 16. The noise control headset according to claim 8, wherein control is performed such that a transmission power supply of a communication unit is turned on during a period in which the voice discriminator is detecting voice. 17. A sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet, and a sound discriminator for judging presence or absence of sound based on an output of the sound detector. A reception signal discriminator for judging the presence or absence of a reception signal of a communication means for communicating with another person; a first noise detection device attached near the voice detector and mainly detecting ambient noise A second noise detector attached to the outside of the left cabinet of the headphones; a first noise signal adder for adding outputs of the first noise detector and the second noise detector. A first adaptive filter that processes an output signal of the first noise signal adder; a first transfer function corrector that processes an output signal of the first noise signal adder; A first output signal adder for adding an output of the filter and a reception signal from the communication unit; a left headphone for reproducing an output of the first output signal adder; and a left headphone mounted inside a cabinet of the left headphone. A first error detector, and a first coefficient updating unit that calculates and updates a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. A third noise detector attached to the outside of a right cabinet of the headphones; a second noise signal adder for adding outputs of the first noise detector and the third noise detector. A second adaptive filter that processes an output signal of the second noise signal adder; a second transfer function corrector that processes an output signal of the second noise signal adder; Filter output and A second output signal adder for adding a reception signal from the communication unit; a right headphone for reproducing an output of the second output signal adder; a second head mounted inside a cabinet of the right headphone An error detector; a second coefficient updater that calculates and updates the coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; A first delay for delaying the output of the voice detector; a second delay for delaying the output of the first noise detector; and a third adaptation for processing an output signal of the second delay. A filter; a subtractor for subtracting an output of the third adaptive filter from an output of the first delay unit; and a coefficient of the third adaptive filter from an output of the second delay unit and an output of the subtractor. Update the third coefficient , A mute circuit for controlling whether or not to allow the output of the subtractor to pass, and a mute control circuit for controlling the operation of the mute circuit, provided that the voice discriminator generates a voice. The mute control circuit inputs a sound generation signal to the mute control circuit only while it is determined that the mute circuit has been input. A mute control signal is generated, and the output of the mute circuit is input to the first and second output signal adders while the signal is being input to the mute circuit, and the first output signal is added. The output of the first adaptive filter, the received signal from the communication means and the output of the mute circuit are added in the adder, and the output of the second adaptive filter is added in the second output signal adder. The reception signal from the communication means and the output of the mute circuit are added, and the output of the mute circuit is used as the transmission signal of the communication means. The coefficient of the first transfer function corrector is from the left headphone to the first error detector. Wherein the coefficient of the second transfer function corrector is adapted to approximate a transfer function from the right headphone to the second error detector; and The second coefficient updater is configured to output the second coefficient only when at least one of the case where it is determined that the voice is generated by the voice discriminator or the case where the reception signal discriminator determines that the received signal is present. Updating of the coefficients of the first and second adaptive filters is stopped, and the third coefficient updater performs the third adaptive filter only while the speech discriminator determines that speech is being generated. To stop the coefficient update of the data, as the noise control headset, characterized by being configured. 18. In a state in which a noise control headset is mounted so that the voice detector comes to a mouth of a user,
The second noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the left headphone when the outside of the cabinet of the left headphone is viewed from the side of the user. The noise control headset according to claim 17, wherein the noise control headset is attached to an upper right area divided into four parts at a lower part. 19. In a state where the noise control headset is mounted so that the voice detector comes to the mouth of a user,
The third noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the right headphone when the outside of the cabinet of the right headphone is viewed from the side of the user. The noise control headset according to claim 17, wherein the noise control headset is attached to an upper left area divided into four parts at a lower part. 20. The noise control headset according to claim 17, wherein said first noise detector is omnidirectional, and said voice detector has directivity. 21. The noise control headset according to claim 17, wherein the diaphragm diameter of the voice detector is at least twice as large as the diaphragm diameter of the first noise detector. 22. The sound detector is mounted so as to have directivity in the direction of a user's mouth, the first noise detector is non-directional, and the sound detector has directivity. The first detection is carried out on an axis perpendicular to a direction having directivity of the sound detector and directly beside the sound detector. The noise control headset according to claim 17, wherein a device is installed. 23. The noise control headset according to claim 22, wherein a sound hole on a surface of the voice detector on a surface directly opposite to a surface facing a mouth of a user is covered with a sound absorbing material. 24. A sound hole on the surface of the sound detector opposite to the surface facing the mouth of the user and a sound hole of the first noise detector on the same surface as the surface opposite to the mouth. The noise control headset according to claim 22, wherein the headset is covered with a material. 25. The noise control head according to claim 17, wherein the control is performed such that the transmission power of the communication unit is turned on only while the mute control signal from the mute control circuit is being generated. set. 26. A sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet, and a sound discriminator for judging presence or absence of sound based on an output of the sound detector. A reception signal discriminator for judging the presence or absence of a reception signal of a communication means for communicating with another person; a first noise detection device attached near the voice detector and mainly detecting ambient noise A second noise detector attached to the outside of the left cabinet of the headphones; a first noise signal adder for adding outputs of the first noise detector and the second noise detector. A first adaptive filter that processes an output signal of the first noise signal adder; a first transfer function corrector that processes an output signal of the first noise signal adder; A first output signal adder for adding an output of the filter and a reception signal from the communication unit; a left headphone for reproducing an output of the first output signal adder; and a left headphone mounted inside a cabinet of the left headphone. A first error detector, and a first coefficient updating unit that calculates and updates a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. A third noise detector attached to the outside of a right cabinet of the headphones; a second noise signal adder for adding outputs of the first noise detector and the third noise detector. A second adaptive filter that processes an output signal of the second noise signal adder; a second transfer function corrector that processes an output signal of the second noise signal adder; Filter output and A second output signal adder for adding a reception signal from the communication unit; a right headphone for reproducing an output of the second output signal adder; a second head mounted inside a cabinet of the right headphone An error detector; a second coefficient updater that calculates and updates the coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; A delay unit for delaying the output of the voice detector, a third adaptive filter for processing the output signal of the first noise detector, and a fourth adaptive filter for processing the output signal of the second noise detector A fifth adaptive filter that processes an output signal of the third noise detector; an output of the third adaptive filter, an output of the fourth adaptive filter, and the fifth Output of adaptive filter A third coefficient updater for calculating and updating a coefficient of the third adaptive filter from an output of the first noise detector and an output of the subtractor, and a second noise. A fourth coefficient updater for calculating and updating the coefficient of the fourth adaptive filter from the output of the detector and the output of the subtractor; and the fourth coefficient updater calculating the coefficient from the output of the third noise detector and the output of the subtractor. A fifth coefficient updater for calculating and updating the coefficient of the fifth adaptive filter, and a mute circuit for controlling whether or not to allow the output of the subtractor to pass, wherein the audio discriminator is The mute circuit is made conductive only while it is determined that a sound is being generated, and its output is output to the first
And a second output signal adder. The first output signal adder adds the output of the first adaptive filter, the received signal from the communication means, and the output of the mute circuit, and adds the second output signal. The output of the second adaptive filter, the received signal from the communication means and the output of the mute circuit are added together, and the output of the mute circuit is used as the transmission signal of the communication means. The coefficient of the first transfer function corrector Is adapted to approximate a transfer function from the left headphone to the first error detector, and the coefficient of the second transfer function corrector approximates a transfer function from the right headphone to the second error detector. The first and second coefficient updaters determine that a voice is being generated by the voice discriminator, or the received signal is determined by the received signal discriminator. The updating of the coefficients of the first and second adaptive filters is stopped only during at least one of the cases where it is determined that there is a sound, and the third coefficient updating unit is generating sound by the sound discriminator. The noise control headset is configured to stop updating the coefficient of the third adaptive filter only during the determination. 27. In a state in which the noise control headset is mounted so that the voice detector comes to the mouth of a user,
The second noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the left headphone when the outside of the cabinet of the left headphone is viewed from the side of the user. 27. The noise control headset according to claim 26, wherein the noise control headset is attached to an upper right area divided into four parts at a lower part. 28. In a state where a noise control headset is mounted so that the voice detector comes to a mouth of a user,
The third noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the right headphone when the outside of the cabinet of the right headphone is viewed from the side of the user. 27. The noise control headset according to claim 26, wherein the headset is attached to an upper left area divided into four parts at a lower part. 29. The fourth and fifth coefficient updaters,
27. The noise control headset according to claim 26, wherein the updating of the coefficients of the fourth and fifth adaptive filters is stopped only while the sound discriminator determines that sound is being generated. 30. The noise control headset according to claim 26, wherein the first noise detector is omnidirectional, and the voice detector has directivity. 31. The noise control headset according to claim 26, wherein the diaphragm diameter of the voice detector is at least twice as large as the diaphragm diameter of the first noise detector. 32. The sound detector is mounted so as to have directivity in the direction of a user's mouth, the first noise detector is omni-directional, and the directivity of the sound detector is The first detection is carried out on an axis perpendicular to a direction having directivity of the sound detector and directly beside the sound detector. 27. The noise control headset according to claim 26, further comprising a heater. 33. The noise control headset according to claim 32, wherein a sound hole on a surface of the voice detector on a surface directly opposite to a surface facing a mouth of a user is covered with a sound absorbing material. 34. A sound-absorbing material comprising: a sound hole on a surface diametrically opposite to a surface of the voice detector facing a mouth of a user; 33. The noise control headset according to claim 32, wherein the headset is covered by a noise control headset. 35. The noise control headset according to claim 26, wherein control is performed such that a transmission power supply of said communication means is turned on during a period in which said voice discriminator is detecting voice. 36. A sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet, and a sound discriminator for judging presence / absence of sound based on an output of the sound detector. A reception signal discriminator for judging the presence or absence of a reception signal of the communication means; a first noise detector attached near the voice detector and mainly detecting ambient noise; and a left side of the headphones. A second noise detector mounted outside the cabinet; a first noise signal adder for adding outputs of the first noise detector and the second noise detector; and a first noise signal. A first adaptive filter that processes an output signal of the adder, a first transfer function corrector that processes an output signal of the first noise signal adder, and an output of the first adaptive filter. A first output signal adder for adding a signal received from the communication means; a left headphone for reproducing an output of the first output signal adder; a first head mounted inside a cabinet of the left headphone. An error detector; a first coefficient updater that calculates and updates a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector; A third noise detector attached to the outside of the right cabinet of the headphone, a second noise signal adder for adding outputs of the first noise detector and the third noise detector, and a second noise detector. A second adaptive filter that processes an output signal of the noise signal adder, a second transfer function corrector that processes an output signal of the second noise signal adder, and an output of the second adaptive filter. From the communication means A second output signal adder for adding a received signal; a right headphone for reproducing an output of the second output signal adder; a second error detector mounted inside a cabinet of the right headphone; A second coefficient updater for calculating and updating a coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; and an output from the voice detector. A first delay unit that delays the output of the first noise detector, a third adaptive filter that processes the output signal of the first noise detector, and a fourth adaptive filter that processes the output signal of the second noise detector. A fifth adaptive filter that processes an output signal of the third noise detector; and subtracting an output of the fourth adaptive filter and an output of the fifth adaptive filter from an output of the first delay unit. First
A second delayer that delays the output of the first subtractor; a second subtractor that subtracts the output of the third adaptive filter from the output of the second delayer; A third coefficient updater for calculating and updating a coefficient of the third adaptive filter from an output of the first noise detector and an output of the second subtractor; and an output of the second noise detector. And a fourth coefficient updater for calculating and updating the coefficient of the fourth adaptive filter from the output of the first subtractor; an output of the third noise detector and an output of the first subtractor. A fifth coefficient updater that calculates and updates the coefficient of the fifth adaptive filter from and a mute circuit that controls whether or not to allow the output of the second subtractor to pass, The sound discriminator conducts the mute circuit only while determining that sound is being generated. Wherein the output in the state first
And a second output signal adder. The first output signal adder adds the output of the first adaptive filter, the received signal from the communication means, and the output of the mute circuit, and adds the second output signal. The output of the second adaptive filter, the received signal from the communication means and the output of the mute circuit are added together, and the output of the mute circuit is used as the transmission signal of the communication means. The coefficient of the first transfer function corrector Is adapted to approximate a transfer function from the left headphone to the first error detector, and the coefficient of the second transfer function corrector approximates a transfer function from the right headphone to the second error detector. The first and second coefficient updaters determine that a voice is being generated by the voice discriminator, or the received signal is determined by the received signal discriminator. Stopping the coefficient update of the first and second adaptive filters only during at least one of the cases where it is determined that there is a voice, the third coefficient updater generates a voice by the voice discriminator, A noise control headset configured to stop updating the coefficients of the third adaptive filter only while it is determined that the noise is present. 37. In a state where the noise control headset is mounted so that the voice detector comes to the mouth of a user,
The second noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the left headphone when the outside of the cabinet of the left headphone is viewed from the side of the user. 37. The noise control headset according to claim 36, wherein the headset is attached to an upper right area divided into four parts at a lower part. 38. In a state where the noise control headset is mounted so that the voice detector comes to the mouth of a user,
The third noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the right headphone when the outside of the cabinet of the right headphone is viewed from the side of the user. 37. The noise control headset according to claim 36, wherein the headset is attached to an upper left area divided into four parts at a lower part. 39. The fourth and fifth coefficient updaters,
37. The noise control headset according to claim 36, wherein updating of the coefficients of the fourth and fifth adaptive filters is stopped only while the sound discriminator determines that sound is being generated. 40. The noise control headset according to claim 36, wherein the first noise detector is non-directional, and the voice detector has directivity. 41. The noise control headset according to claim 36, wherein the diaphragm diameter of the voice detector is at least twice the diaphragm diameter of the first noise detector. 42. The sound detector is mounted so as to have directivity in the direction of a user's mouth, the first noise detector is non-directional, and the direction of the sound detector is changed. The sound detector is attached so that the sound hole faces in a direction directly opposite to the direction in which the first detector is located right beside the sound detector on an axis perpendicular to a direction having directivity of the sound detector. 37. The noise control headset according to claim 36, wherein the headset is installed. 43. The noise control headset according to claim 42, wherein a sound hole on a surface of the voice detector, which is directly opposite to a surface facing a mouth of a user, is covered with a sound absorbing material. 44. A sound hole in a sound hole on a surface directly opposite to a surface of the sound detector facing a user's mouth and a sound hole in the first noise detector on the same surface as the surface opposite to the mouth. 43. The noise control headset according to claim 42, wherein the headset is covered with a material. 45. The noise control headset according to claim 36, wherein control is performed such that a transmission power supply of a communication unit is turned on during a period in which the voice discriminator is detecting voice. 46. A voice detector attached near the mouth of a user by a support arm provided on a left or right headphone cabinet, and a voice discriminator for judging presence / absence of voice based on an output of the voice detector. A received signal discriminator for judging the presence or absence of a received signal of a communication means for communicating with another person; a first noise detector attached near the voice detector and mainly detecting ambient noise A second noise detector attached to the outside of the left cabinet of the headphones; a first noise signal adder for adding outputs of the first noise detector and the second noise detector; A first adaptive filter for processing an output signal of the first noise signal adder, a first transfer function corrector for processing an output signal of the first noise signal adder, and a first adaptive filter. A first output signal adder for adding the output of the first output signal adder and a reception signal from the communication unit; a left headphone for reproducing an output of the first output signal adder; and a left headphone mounted inside a cabinet of the left headphone. A first error detector, and a first coefficient updating unit that calculates and updates a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. A third noise detector attached to the outside of a right cabinet of the headphones; a second noise signal adder for adding outputs of the first noise detector and the third noise detector. A second adaptive filter that processes an output signal of the second noise signal adder; a second transfer function corrector that processes an output signal of the second noise signal adder; Filter output and the A second output signal adder for adding a received signal from the communication means, a right headphone for reproducing an output of the second output signal adder, and a second error mounted inside a cabinet of the right headphone. A second coefficient updater for calculating and updating the coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; A first delay unit for delaying the output of the detector, a second delay unit for delaying the output of the first noise detector, and a third adaptive filter for processing an output signal of the second delay unit A fourth adaptive filter that processes an output signal of the second noise detector; a fifth adaptive filter that processes an output signal of the third noise detector; and an output of the first delay unit From the output of the third adaptive filter and A subtracter for subtracting the output of the fourth adaptive filter from the output of the fifth adaptive filter; and calculating the coefficient of the third adaptive filter from the output of the second delay unit and the output of the subtractor. A third coefficient updater for calculating and updating a coefficient of the fourth adaptive filter from an output of the second noise detector and an output of the subtractor; A fifth coefficient updater for calculating and updating the coefficient of the fifth adaptive filter from the output of the third noise detector and the output of the subtractor; and controlling whether the output of the subtractor is passed or not. And a mute control circuit that controls the operation of the mute circuit, provided that the sound discriminator inputs a sound generation signal to the mute control circuit only while determining that sound is being generated. The mute control circuit While the signal is being input and within a certain period of time after the sound generation signal disappears, a mute control signal for making the mute circuit conductive is generated, and while the signal is being input to the mute circuit, the mute circuit is turned off. The output of the mute circuit is input to the first and second output signal adders in the conductive state, and the output of the first adaptive filter, the reception signal from the communication means, and the output of the mute circuit are input to the first output signal adder. The outputs are added, and the output of the second adaptive filter, the received signal from the communication means and the output of the mute circuit are added in the second output signal adder, and the output of the mute circuit is used as the transmission signal of the communication means. The coefficient of the first transfer function corrector is designed to approximate a transfer function from the left headphone to the first error detector, and the second transfer function corrector Are approximated to a transfer function from the right headphone to the second error detector, and the first and second coefficient updaters determine that a voice is being generated by the voice discriminator. And stopping the coefficient update of the first and second adaptive filters only during at least one of the cases or when the received signal discriminator determines that a received signal is present, the third coefficient updater A noise control headset configured to stop updating the coefficients of the third adaptive filter only while the voice discriminator determines that voice is being generated. 47. In a state where the noise control headset is mounted so that the voice detector comes to the mouth of the user, the second noise detector looks at the outside of the cabinet of the left headphone from the side of use. 47. In a case where the headphone is left, it is attached to an upper right area divided into four parts by a horizontal axis and a vertical axis from a center point of the left headphone to an upper left part, a lower left part, an upper right part, and a lower right part. Noise control headset. 48. In a state in which the noise control headset is mounted so that the voice detector comes to the mouth of the user, the third noise detector moves the outside of the cabinet of the right headphone to the side of the user. When viewed from above, from the center point of the right headphone, it is divided into four parts by a horizontal axis and a vertical axis into an upper left part, a lower left part, an upper right part, and a lower right part, and attached to an upper left area. 46. The noise control headset according to 46. 49. A fourth and fifth coefficient updater stops updating the coefficients of the fourth and fifth adaptive filters only while the sound discriminator determines that a sound is being generated. 47. The noise control headset according to claim 46. 50. The noise control headset according to claim 46, wherein the first noise detector is omni-directional, and the voice detector has directivity. 51. The noise control headset according to claim 46, wherein the diaphragm diameter of the sound detector is at least twice as large as the diaphragm diameter of the first noise detector. 52. The sound detector is mounted so as to have directivity in the direction of the mouth of the user, the first noise detector is non-directional, and the directivity of the sound detector is The first noise is mounted on an axis perpendicular to a direction having directivity of the sound detector and directly beside the sound detector. The noise control headset according to claim 46, further comprising a detector. 53. The noise control headset according to claim 52, wherein a sound hole on a surface of the voice detector on a surface directly opposite to a surface facing a user's mouth is covered with a sound absorbing material. 54. A sound hole on a surface of the sound detector opposite to a surface facing a user's mouth and a sound hole of the first noise detector on the same surface are covered with a sound absorbing material. 53. The noise control headset according to claim 52. 55. The noise control headset according to claim 46, wherein control is performed such that the transmission power supply of the communication unit is turned on only while the mute control signal from the mute control circuit is being generated. 56. A sound detector attached near a mouth of a user by a support arm provided on a left or right headphone cabinet, and a sound discriminator for judging presence or absence of sound based on an output of the sound detector. A reception signal discriminator for judging the presence or absence of a reception signal of a communication means for communicating with another person; a first noise detection device attached near the voice detector and mainly detecting ambient noise A second noise detector mounted outside the left cabinet of the headphones; a first noise signal adder for adding the outputs of the first noise detector and the second noise detector; A first adaptive filter that processes an output signal of the first noise signal adder; a first transfer function corrector that processes an output signal of the first noise signal adder; A first output signal adder for adding an output of the filter and a reception signal from the communication means; a left headphone for reproducing an output of the first output signal adder; and a left headphone mounted inside a cabinet of the left headphone. A first error detector, and a first coefficient updating unit that calculates and updates a coefficient of the first adaptive filter from an output from the first error detector and an output from the first transfer function corrector. A third noise detector attached to the outside of a right cabinet of the headphones; a second noise signal adder for adding outputs of the first noise detector and the third noise detector. A second adaptive filter that processes an output signal of the second noise signal adder; a second transfer function corrector that processes an output signal of the second noise signal adder; Filter output and previous A second output signal adder for adding a received signal from the communication means; a right headphone for reproducing an output of the second output signal adder; a second error detector mounted inside the right headphone A second coefficient updater that calculates and updates the coefficient of the second adaptive filter from an output from the second error detector and an output from the second transfer function corrector; and the voice detector. A first delay device that delays the output of the first noise detector, a second delay device that delays the output of the first noise detector, and a third adaptive filter that processes an output signal of the second delay device. A fourth adaptive filter that processes an output signal of the second noise detector; a fifth adaptive filter that processes an output signal of the third noise detector; The output of a fourth adaptive filter and the fifth adaptive filter First subtracting the output of the filter
A third delayer that delays the output of the first subtractor; a second subtractor that subtracts the output of the third adaptive filter from the output of the third delayer; Calculating and updating a coefficient of the third adaptive filter from an output of the second delay unit and an output of the second subtractor;
A fourth coefficient updater that calculates and updates the coefficient of the fourth adaptive filter from the output of the second noise detector and the output of the first subtractor; A fifth coefficient updater for calculating and updating the coefficient of the fifth adaptive filter from the output of the noise detector and the output of the first subtractor; and determining whether to pass the output of the second subtractor. A mute circuit that controls whether or not to make the mute circuit operate, and a mute control circuit that controls the operation of the mute circuit. However, the sound discriminator only outputs sound to the mute control circuit while determining that sound is being generated. A mute control circuit generates a mute control signal for turning on the mute circuit while the signal is being input and for a certain period of time after the sound generation signal disappears, and mutes the signal. Input to circuit While the mute circuit is in a conductive state, the output of the mute circuit is input to the first and second output signal adders, and the output of the first adaptive filter and the communication means in the first output signal adder The output of the mute circuit is added to the output of the mute circuit, the output of the second adaptive filter is added to the output of the second adaptive filter in the second output signal adder, and the output of the mute circuit is added to the output of the mute circuit. A transmission signal of the communication means, wherein a coefficient of the first transfer function corrector is adapted to approximate a transfer function from a left headphone to a first error detector; and a second transfer function corrector. Are approximated to a transfer function from the right headphone to the second error detector. The first and second coefficient updaters generate sound by the sound discriminator. The first and second signals only during at least one of the cases where it is determined that the received signal is present or when the received signal discriminator determines that the received signal is present.
The third coefficient updater is configured to stop updating the coefficient of the third adaptive filter only while the voice discriminator determines that a voice is being generated. A noise control headset, comprising: 57. In a state where the noise control headset is mounted so that the voice detector comes to the mouth of the user,
The second noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the left headphone when the outside of the cabinet of the left headphone is viewed from the side of the user. 57. The noise control headset according to claim 56, wherein the headset is attached to an upper right area divided into four parts at a lower part. 58. In a state where the noise control headset is mounted so that the voice detector comes to the mouth of a user,
The third noise detector includes an upper left part, a lower left part, an upper right part, and a right part based on a horizontal axis and a vertical axis from a center point of the right headphone when the outside of the cabinet of the right headphone is viewed from the side of the user. 57. The noise control headset according to claim 56, wherein the headset is attached to an upper left area divided into four parts at a lower part. 59. The fourth and fifth coefficient updaters,
57. The noise control headset according to claim 56, wherein updating of the coefficients of the fourth and fifth adaptive filters is stopped only while the sound discriminator determines that sound is being generated. 60. The noise control headset according to claim 56, wherein the first noise detector is omni-directional, and the voice detector has directivity. 61. The noise control headset according to claim 56, wherein the diaphragm diameter of the voice detector is at least twice the diaphragm diameter of the first noise detector. 62. The sound detector is mounted so as to have directivity in the direction of a user's mouth, the first noise detector is non-directional, and the sound detector has directivity. The first detector is mounted on an axis perpendicular to the direction of the directivity of the sound detector and directly beside the sound detector. 57. The noise control headset according to claim 56, wherein: 63. The noise control headset according to claim 62, wherein a sound hole on a surface of the voice detector on a surface directly opposite to a direction surface facing a mouth of a user is covered with a sound absorbing material. 64. A sound hole on a surface diametrically opposite to a direction surface facing a mouth of a user of the voice detector, and a sound hole of the first noise detector on the same surface as the diametrically opposite surface. 63. The noise control headset according to claim 62, wherein the headset is covered with a sound absorbing material. 65. The noise control head according to claim 56, wherein the control is performed such that the transmission power of the communication means is turned on only while the mute control signal from the mute control circuit is being generated. set.