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JP2008241899

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Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2008241899
A noise cancellation device capable of coping with occurrence of relatively loud noise that does
not normally occur and capable of being easily installed in various places, and a noise
cancellation method that can be realized in various places are provided. Kind Code: A1 Noise
information collected by a microphone device is wirelessly sent to a control box, and its sound
pressure and frequency are analyzed. If the sound pressure is equal to or higher than a
predetermined threshold value, check whether it corresponds to a warning sound, and generate a
sound of the same phase as the sound pressure of the sound to be canceled in the noncorresponding frequency region, and accordion It is sent to the flat speaker 201 included in the
curtain 214 to cancel the noise. A cancellation sound may be generated so that a continuous
sound whose sound pressure is equal to or higher than a predetermined threshold value is
canceled except for the start portion. [Selected figure] Figure 1
Noise cancellation device and noise cancellation method
[0001]
The present invention relates to a noise cancellation device and a noise cancellation method for
canceling noise from a space such as a room.
[0002]
2. Description of the Related Art An active noise control device has conventionally been proposed
in which a compensation sound of equal sound pressure is output from a speaker in a phase
opposite to that of a noise generated from a sound source to cancel the noise.
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(See, for example, Patent Document 1).
[0003]
FIG. 6 shows an outline of the configuration of the noise cancellation device of this proposal. The
noise cancellation device 100 includes a cancellation sound generation speaker 101 for
canceling noise, and a noise collection microphone 102 for detecting and feeding back a residual
sound from which the noise is canceled. An adaptive filter 104, first and second low pass filters
105 and 106, a sampling frequency varying unit 107, and a transfer characteristic simulating
unit 108 are provided in the control unit 103 that controls the entire noise canceling apparatus
100. It is connected.
[0004]
Among these, the adaptive filter 104 is provided to form a compensation sound and to make the
filter length variable. The adaptive filter 104 is adapted to receive the filter coefficient update
from the coefficient update unit 111. The first and second low pass filters 105 and 106 have
variable cutoff frequencies, and aliasing (a phenomenon in which the original signal can not be
correctly reproduced from the sampling point due to a change in sampling frequency) (aliasing)
can be prevented. The sampling frequency variable unit 107 converts an analog signal obtained
by amplifying the sound picked up by the noise collection microphone 102 by the first amplifier
circuit 112 into a digital signal, and outputs the output of the AD converter circuit 113. Sampling
frequency of the D / A conversion circuit 114 for converting the digital signal of the cancellation
sound obtained sequentially through the low pass filter 105, the coefficient updating unit 111,
the adaptive filter 104, and the second low pass filter 106 into It is supposed to change. The
output of the DA conversion circuit 114 is amplified by the second amplification circuit 115 and
output from the cancellation sound generation speaker 101. The transfer characteristic
simulation unit 108 simulates the transfer characteristic corresponding to the variable sampling
frequency.
[0005]
With such a configuration, the conventional noise cancellation apparatus 100 shown in FIG. 6
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outputs the noise of the noise and the negative phase equal sound pressure from the cancellation
sound generation speaker 101, and the noise is effectively generated according to the change of
the noise frequency. Can be canceled. JP-A-06-167986 (Paragraph 0014, FIG. 1)
[0006]
Such a conventional noise cancellation device 100 is mainly used to cancel the loud noise level
noise such as the noise generated by the internal combustion engine, for example. For this
reason, the cancellation sound generation speaker 101 is a relatively large and large output
speaker among ordinary speakers provided with a voice coil and a diaphragm using cone paper.
Therefore, the size of the cancellation sound generation speaker 101 itself is large, and it is
necessary to secure an installation space. In addition, there is a restriction that secures the
appearance of the installation place of the cancellation sound generation speaker 101, and there
is a problem that many cases can not be installed.
[0007]
In addition, when noise cancellation equipment is used for traffic vehicles such as private
vehicles and work use vehicles such as heavy equipment for construction, even warning sounds
such as horns may be canceled as noise, which may lead to personal injury. There was a risk of
Therefore, there is a problem that the noise cancellation device 100 can not be easily installed in
a space such as inside a car.
[0008]
Therefore, a first object of the present invention is to provide a noise cancellation device and a
noise cancellation method capable of coping with the occurrence of a relatively loud noise that is
not normally generated.
[0009]
A second object of the present invention is to provide a noise cancellation device that can be
easily installed in various places and a noise cancellation method that can be realized in various
places.
[0010]
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In the invention according to claim 1, (a) a microphone for inputting surrounding sound, and (b)
sound pressure according to frequency for discriminating whether the sound inputted from the
microphone is equal to or more than a preset sound pressure according to frequency
Discrimination means, (C) cancellation sound generation means for generating cancellation
sound for canceling the sound of the frequency lower than the previously set sound pressure
discriminated by the frequency-specific sound pressure discrimination means, The noise
cancellation device is equipped with a speaker that outputs the sound generated by the
cancellation sound generation means.
[0011]
That is, in the present invention, whether the sound input from the microphone is equal to or
more than the preset sound pressure is determined by frequency by the frequency-specific sound
pressure determination means.
Then, the cancellation sound generation means generates a cancellation sound for canceling the
sound of the frequency lower than the preset sound pressure and outputs the generated
cancellation sound from the speaker.
This makes it possible to cope with the occurrence of relatively loud sounds that do not normally
occur.
The speakers are not limited to flat speakers, and may be of any type.
[0012]
In the invention according to claim 2, (a) a microphone for inputting surrounding sound, and (b)
sound pressure for each frequency for discriminating whether the sound input from the
microphone is equal to or more than a preset sound pressure for each frequency Discrimination
means; (C) Warning sound registration discrimination means for discriminating whether a sound
of a frequency equal to or higher than the above-mentioned preset sound pressure discriminated
by this frequency-specific sound pressure discrimination means is registered as a warning sound
(D) Sounds of frequencies less than the previously set sound pressure determined by the sound
pressure discrimination means according to frequency and sounds registered as warning sound
by the warning sound judgment means are not less than the previously set sound pressure
Cancellation sound generation means for generating cancellation sound for canceling the sound
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of the frequency of (1) and (e) a speaker for outputting the sound generated by the cancellation
sound generation means It is provided in Yanseru device.
[0013]
That is, in the present invention, whether the sound input from the microphone is equal to or
more than the preset sound pressure is determined by frequency by the frequency-specific sound
pressure determination means.
Further, it is determined by the warning sound registration determining means whether the
sound of the frequency equal to or higher than the above-mentioned preset sound pressure
determined by the frequency-specific sound pressure determining means is registered as the
warning sound. Sounds of frequencies less than the previously set sound pressure determined by
the sound pressure determination means and sounds registered as warning sounds by the
warning sound determination means other than sounds registered as warning sound It is decided
to cancel the sound using a speaker. As a result, since a relatively loud warning sound is
reproduced from the speaker, the warning can be dealt with. The speakers are not limited to flat
speakers, and may be of any type.
[0014]
In the invention according to claim 3, (a) a microphone for inputting surrounding sound, and (b)
sound pressure by frequency for discriminating whether the sound inputted from the
microphone is equal to or more than a preset sound pressure for each frequency Discrimination
means and (C) Continuation to determine whether sound of a frequency equal to or higher than
the above-mentioned preset sound pressure discriminated by the frequency-specific sound
pressure discrimination means is continuously input from the microphone for a predetermined
time or more Sound discrimination means, and (d) sound of frequency less than the previously
set sound pressure discriminated by the frequency-specific sound pressure discrimination means
and the sound of that frequency after the time discriminated as the continuous sound by the
continuous sound discrimination means And a speaker for outputting the sound generated by the
cancellation sound generation means, as a noise cancellation device. To Bei.
[0015]
That is, in the present invention, whether the sound input from the microphone is equal to or
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more than the preset sound pressure is determined by frequency by the frequency-specific sound
pressure determination means.
Further, the continuous sound discrimination means determines a relatively loud continuous
sound, and for such sound, the sound of that frequency after the time determined as the
continuous sound is canceled using the speaker. Therefore, since such a sound is output from the
speaker as a normal sound until it is determined as a continuous sound, it can be noticed and
dealt with. The speakers are not limited to flat speakers, and may be of any type.
[0016]
In the invention according to claim 4, (a) a microphone for inputting surrounding sound, (b)
cancellation sound generating means for generating a cancellation sound for canceling the sound
input from the microphone, and (c) this The noise cancellation device is equipped with a giant
magnetostrictive element that expands and contracts in response to the frequency of the sound
generated by the cancellation sound generation means, and (d) a plate member that is attached
and vibrates the giant magnetostrictive element.
[0017]
That is, in the present invention, the cancellation sound generation means generates a
cancellation sound for canceling the sound input from the microphone, and the cancellation
sound is used to cancel the noise by vibrating the plate member using the super magnetostrictive
element. I'm thinking.
Therefore, for example, a curtain or window glass can be used as a speaker, so that the noise
cancellation device can be easily installed in various places.
[0018]
In the invention according to claim 6, (a) sound pressure discrimination step according to
frequency for judging whether the sound inputted from the microphone is equal to or more than
a preset sound pressure according to frequency, (ii) sound pressure judgment according to the
frequency The noise cancellation method includes a cancellation sound output step of generating
a cancellation sound for canceling a sound of a frequency lower than the previously set sound
pressure determined in the step and outputting the cancellation sound from the flat speaker.
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[0019]
That is, in the present invention, it is determined whether the sound input from the microphone
at the frequency-specific sound pressure determination step is equal to or higher than the preset
sound pressure for each frequency, and the sound of the frequency lower than the preset sound
pressure is canceled. It was decided to generate a cancellation sound to do this and output it
from a flat speaker.
This makes it possible to cope with the occurrence of relatively loud sounds that do not normally
occur. Moreover, since the speaker is a flat speaker, members for partitioning the space such as
curtains, walls, ceilings, floors, and window glass can also be used, and it is possible to avoid
trouble in the placement place.
[0020]
In the invention according to claim 7, (a) sound pressure discrimination step according to
frequency for judging whether the sound inputted from the microphone is equal to or more than
a preset sound pressure according to frequency, (ii) sound pressure judgment according to the
frequency A warning sound registration determining step of determining whether a sound having
a frequency equal to or higher than the above-described preset sound pressure determined in the
step is registered as a warning sound; Canceling for canceling the sound of the frequency above
the previously set sound pressure other than the sound of the frequency lower than the
previously set sound pressure and the sound registered as the warning sound in the warning
sound determination step The noise cancellation method includes a cancellation sound output
step of generating a sound and outputting the generated cancellation sound from the flat
speaker.
[0021]
That is, in the present invention, in addition to the invention according to claim 6, in the case
where the sound of the frequency which is equal to or higher than the preset sound pressure is a
warning sound, this is not canceled and other preset sounds are set. I have decided to cancel the
overpressure sound.
As a result, since a relatively loud sound other than the warning sound is also a target of
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cancellation, noise removal can be performed more effectively.
[0022]
As described above, according to the present invention, since the sound pressure and frequency
of the sound input from the microphone are analyzed to select the sound to be canceled, the
occurrence of a situation where a necessary sound can not be heard Can be prevented, and noise
cancellation technology can be extended to various applications. Further, by configuring the flat
speaker with a member that divides the space such as furniture, the cancellation sound can be
output from a wide area, and the noise can be canceled effectively.
[0023]
The present invention will be described in detail by way of the following examples.
[0024]
FIG. 1 shows a main part of a room using a noise cancellation device according to an
embodiment of the present invention.
In this embodiment, the noise cancellation apparatus 200 includes a plurality of strip-shaped flat
speakers 201, 201, ..., a control box 203 connected to the flat speakers 201, 201, ... by a cable
202, and the control box 203. The microphone device 205 communicates with an antenna 204
attached to the microphone.
[0025]
Here, the flat speakers 201, 201,... Are accommodated by providing a pocket (not shown) on the
lining side of the accordion curtain 214 suspended on the curtain rail 211 via the runner 212
and the hook 213. Further, the flat speakers 201, 201,... Are connected by a cable 202 so as not
to be noticeable on the lining side of the accordion curtain 214.
[0026]
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The microphone device 205 is possessed when the user 216 of this room wants to cancel the
noise indoors, picks up the surrounding sound and transmits it as noise information to the
control box 203 by near field communication. There is. The microphone device 205 itself may be
attached to, for example, a strap of a mobile phone (not shown), or may be configured as an
accessory such as a necklace.
[0027]
FIG. 2 shows the configuration of the flat loudspeaker of this embodiment. The flat speaker 201
has a structure in which an exciter 232 is attached to the upper end of a rectangular acrylic plate
231, and a connector 233 for connecting a cable 202 is disposed near the exciter 232. By
adopting a structure for connecting the cable 202 to the connector 233, as shown in FIG. 1, it is
possible to connect the flat speakers 201 by an arbitrary number. Moreover, the addition of the
flat speaker 201 is also easy. Furthermore, when the cable 202 is broken for any reason, the
cable 202 can be easily repaired by replacing the connector 233 including the broken portion
with a new one.
[0028]
Securing the rigidity of the acrylic plate 231 is important for transmitting vibration, but it can be
made flexible by reducing its thickness to a certain extent. Therefore, even when the accordion
curtain 214 shown in FIG. 1 swings due to an external force such as wind, a movement close to
natural can be realized. Moreover, by incorporating the acrylic plate 231 into the accordion
curtain 214, the fold of the fabric is stabilized for a long time.
[0029]
The exciter 232 has a structure in which a giant magnetostrictive element (not shown) made of
an intermetallic compound based on a lanthanoid element and an iron group element is
processed into a cylindrical shape and a coil (not shown) is wound therearound. When a noise
cancellation signal for generating a noise for canceling noise from the cable 202 flows, the
exciter 232 expands and contracts, and the acrylic plate 231 vibrates accordingly. Thereby, a
sound is generated from the flat speaker 201. The exciter 232 does not have to be attached to
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the upper end of the acrylic plate 231, and may be attached to other places where vibrations
occur efficiently.
[0030]
FIG. 3 shows the configuration of the control box of this embodiment. The control box 203
includes a control unit 243 including a central processing unit (CPU) 241 and a control program
storage unit 242. The control program storage portion 242 is constituted by, for example, a ROM
(Read Only Memory) or a RAM (Random Access Memory), and the CPU 241 executes the control
program stored therein to perform noise cancellation processing. ing. A part of the memory area
of the control program etc. storage unit 242 is a working memory.
[0031]
The control unit 243 is connected to each unit of the control box 203 to perform control thereof.
Among these, the first amplification unit 245 amplifies noise information from the microphone
device 205 (FIG. 1) received by the noise collection unit 246 including the antenna 204. The AD
conversion unit 247 performs sampling and quantization for converting the analog level noise
information amplified by the first amplification unit 245 into digital information. The frequency
analysis / sound pressure measurement unit 248 performs frequency analysis on the digital
noise information input from the AD conversion unit 247 and measures the sound pressure level.
Then, the controller 243 is notified of the analyzed frequency component and the sound pressure
level of each frequency component.
[0032]
The band elimination filter unit 249 is a filter that removes a signal component of a
predetermined frequency band instructed by the control unit 243 from the digital noise
information input from the frequency analysis / sound pressure measurement unit 248. The
number of simultaneously removable frequency bands of the band elimination filter unit 249 is
arbitrary, and there may be no frequency band to be removed, or a plurality of frequency bands
may be set to be simultaneously removed. The band elimination filter unit 249 and the frequency
analysis / sound pressure measurement unit 248 constitute a circuit portion which is a feature of
the present embodiment.
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[0033]
The anti-phase cancellation sound generation unit 250 is configured to generate digital antiphase noise information that is in anti-phase with the digital noise information input from the
band elimination filter unit 249. The DA conversion unit 251 converts the digital antiphase noise
information input from the antiphase cancellation sound generation unit 250 into analog
antiphase noise information. The second amplification unit 252 is an amplifier that amplifies the
analog antiphase noise information input from the DA conversion unit 251. The amplification
factor of the second amplification unit 252 can be controlled by the control unit 243. The cable
202 is connected to the output side of the second amplification unit 252, and the amplified
analog antiphase noise information is sent to this.
[0034]
The display unit 253 is a display such as a liquid crystal display, and various visual information
such as the operation status, the operation status and the setting status of the noise cancellation
device 200 is displayed here. The operation unit 254 is an input unit used by the user 216 of the
room shown in FIG. 1 or a maintenance inspector to input various information as needed, and
has a plurality of input keys (not shown).
[0035]
In the control box 203 of this embodiment, the audio input unit 255 is also connected to the
control unit 243. The audio input unit 255 changes the frequency characteristic by inputting an
audio signal such as music input from the input terminals 256 and 257 while the control unit
243 is in the audio output mode by the operation of the operation unit 254. The signal is output
to the second amplification unit 252. This is because the flat speakers 201, 201,... Shown in FIG.
1 are used as speakers for audio. Even when the control unit 243 is in the audio output mode,
noise cancellation is performed. In this embodiment, a noise signal input from the microphone
261 and an audio signal such as music input from the audio input terminals 256 and 257 are
input to the control box 203 as signals of different systems. In addition, the output from the
audio input unit 255 is caused to reach the second amplification unit 252 at the same time as not
passing through the antiphase cancellation sound generation unit 250 and also to the antiphase
cancellation sound generation unit 250. At this time, the antiphase cancellation sound generation
unit 250 subtracts the signal component input through the audio input unit 255 from the signal
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input through the microphone 261 path. This is because the noise signal input through the
microphone 261 path already includes an audio signal component such as music generated from
the flat speakers 201, 201,... Of course, the sound pressure level of the audio signal to be
subtracted can be appropriately adjusted using the operation unit 254. Next, on the basis of the
signal after subtracting the audio signal component, an antiphase cancellation sound is
generated. The cancellation sound generated in this manner hardly contains an antiphase
component that becomes a cancellation sound for the signal input via the audio input unit 255.
Therefore, the signal input via the audio input unit 255 can be left as an audible sound as the
original sound, and it is possible to listen to music or enjoy karaoke, for example, in a situation
where the noise is canceled.
[0036]
FIG. 4 shows the configuration of the microphone device. The microphone device 205 includes a
microphone 261, an amplifier 262 that amplifies the noise information collected by the
microphone 261, and a transmission unit 264 that transmits the noise information output from
the amplifier 262 by the built-in antenna 263. The amplifier 262 and the transmission unit 264
are connected to the operation unit 265. The operation unit 265 is connected to the battery 266,
and supplies power to the amplifier 262 and the transmission unit 264 when noise cancellation
is performed, and adjusts the amplification factor. Here, the microphone 261 collects, as noise
information, a mixture of the surrounding sound and the sound output from the flat speakers
201, 201,... Shown in FIG.
[0037]
The operation when the noise cancellation apparatus 200 configured as described above is set to
the noise cancellation mode as a mode other than the audio output mode will be described with
reference to FIGS. 1 to 4. The accordion curtain 214 shown in FIG. 1 is disposed just inside the
window glass (not shown), and noise is supposed to enter the room from the outside of the
window.
[0038]
The microphone 261 of the microphone device 205 collects the sound in a state in which the
analog antiphase noise output from the flat speakers 201, 201, ... and the ambient noise
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including the noise intruding from the outside are mixed in the air Do. The amplifier 262
amplifies these sounds and sends them to the transmitting unit 264, and the transmitting unit
264 outputs this as noise information from the built-in antenna 263.
[0039]
In the control box 203, the noise collection unit 246 receives the noise information. The control
unit 243 amplifies the received analog level noise information to an appropriate level according
to the setting value of the volume (not shown) of the operation unit 254. The AD converter 247
converts this analog signal into a digital signal by sampling and quantizing. The frequency
analysis / sound pressure measurement unit 248 performs frequency analysis on digital noise
information, and measures the sound pressure level for each frequency. Then, these results are
notified to the control unit 243 in a predetermined cycle.
[0040]
Every time notification is given from the frequency analysis / sound pressure measurement unit
248, the control unit 243 determines whether or not the frequency at which the sound pressure
exceeds a predetermined threshold matches a specific condition. The band attenuation setting
information is output to the band elimination filter unit 249 according to each determination
result.
[0041]
FIG. 5 shows a state of output control of band attenuation setting information by the control unit.
Description will be made with reference to FIG. When the control unit 243 receives the
notification from the frequency analysis / sound pressure measurement unit 248 (step S301: Y),
the sound of sound pressure exceeding a predetermined threshold is included in the notification
at a specific frequency registered in advance. It is checked whether or not there is (step S302). If
a sound of such a specific frequency and sound pressure is present (Y), it is determined to be a
warning sound, and signal attenuation is prohibited for the corresponding specific frequency
(step S303). The sound pressure serving as the threshold can be adjusted by the user 216 using
the operation unit 254. The user 216 can also perform new registration of a specific frequency
and deletion of the registered specific frequency using the operation unit 254. Of course,
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maintenance and inspection personnel can also make such adjustments based on the request of
the user 216.
[0042]
After the above processing is performed, the control unit 243 determines whether the sound
with the sound pressure exceeding the above-described threshold is continued at frequencies
other than the specific frequency (step S304). This determination is made in the working
memory of the control program storage unit 242 when there is a sound with a sound pressure
that exceeds the threshold at a frequency other than the specific frequency each time the
notification is received in step S301. This process is performed by storing and continuing the
sound of the same frequency when the same frequency is continuously stored a predetermined
number of times. When it is determined that the sound of the sound pressure exceeding the
threshold is continued at a frequency other than the specific frequency as a result of the
determination (Y), the frequency of the sound is stored in the working memory and step S301.
Attenuation of the signal of that frequency is performed with a predetermined length that is
equal to or longer than the period in which the notification is received (step S305). The
information on the sounds stored in the working memory may be deleted when the sounds no
longer continue.
[0043]
Next, the control unit 243 creates band attenuation setting information incorporating the content
of the attenuation inhibition determined in step S303 and the content of the attenuation
determined in step S305 in this way, and sends it to the band elimination filter unit 249. (Step
S306).
[0044]
The band elimination filter unit 249 receives the band attenuation setting information at the
notification period of step S301 in FIG.
Then, the frequency that inhibits the attenuation and the frequency that performs the attenuation
are set, and the digital noise information that has passed through the frequency analysis and
sound pressure measurement unit 248 is filtered according to the setting contents, and the
reverse phase cancellation sound generation unit Supply to 250. Therefore, when the warning
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sound of the sound pressure exceeding the above-mentioned threshold is heard, the warning
sound is outputted from the flat speakers 201, 201,... As it is and gives a warning to the room
user 216.
[0045]
Also, if a sound of sound pressure exceeding the above threshold suddenly occurs and continues
for a predetermined time or more, the start portion of the sound is not canceled from the flat
speakers 201, 201, ... It is output and recognized by the user 216 of the room, but in the
subsequent part of the sound, the flat speakers 201, 201,... Output the sound of the opposite
phase and cancel the sound of the actual frequency. Thus, the room user 216 recognizes the
beginning of the sound but no longer hears the sound. The reason for the recognition of the start
part of the sound is that when a sound with a sound pressure exceeding the above-mentioned
threshold newly arrives, it is impossible to cope with the occurrence of various hazards when the
sound is completely shut off. In consideration of things. It can be adjusted by the operation unit
254 as to which time length the sound start part is left.
[0046]
The anti-phase cancellation sound generation unit 250 generates digital anti-phase noise
information that is in anti-phase with the input digital audio signal, and supplies the digital antiphase noise information to the DA conversion unit 251. The DA conversion unit 251 converts the
digital antiphase noise information into analog antiphase noise information, and the second
amplification unit 252 amplifies this and outputs it to the cable 202.
[0047]
Thereby, the flat speakers 201, 201,... Output the noise information of the same sound pressure
level in the opposite phase to the noise, at the window which is likely to be the entrance of the
noise. For this reason, the noise actually generated and the noise information output from the flat
speakers 201, 201,... Are mixed in the air and mutually cancel each other to obtain the noise
cancellation effect.
[0048]
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Of course, the cancellation sound outputted from the flat speakers 201, 201,... In this
embodiment is a sound subjected to processing of antiphase processing after removing the sound
component that satisfies the specific condition from the original noise. There is. Therefore, noises
that satisfy specific conditions, such as warning sounds of registered frequencies, do not include
antiphase components that become cancellation sounds, and these sounds can be left as audible
sounds as original sounds. Similarly, since the sound input from other than the microphone is not
targeted for cancellation, for example, it is possible to play music as a normal reproduction sound
from the flat speakers 201, 201,.
[0049]
As described above, according to the noise cancellation apparatus of the present embodiment,
the exciter 232 shown in FIG. 2 is used for the flat speakers 201, 201,... Which output analog
antiphase noise information of antiphase to noise. Then, since the sound is output by causing the
acrylic plate 231 by the exciter 232, the flat speakers 201, 201,... Can be included in the curtain,
there is no need to newly provide an installation space, and the appearance is not lost. Noise can
be canceled in the state.
[0050]
Moreover, the curtain is usually disposed on the window side of a room where noise often
intrudes, and the area occupied by the room is often large. Therefore, compared with the case
where a conventional box-type loudspeaker is used, it is possible to output noise and anti-phase
analog anti-phase noise information from a wide area with an essentially nondirectional radiation
characteristic. For this reason, since the listening angle can be spread, flat frequency
characteristics, and uniform sound pressure distribution can be made, a natural sound spread
space can be obtained, and a noise-cancelled sound field with less discomfort can be created over
a wide area. it can.
[0051]
Further, in the present embodiment, measurement of noise and sound pressure and duration of
the noise and frequency analysis are performed so that cancellation noise of opposite phase is
04-05-2019
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not generated for noise that satisfies specific conditions. Therefore, a sound such as a warning
sound that is undesirable to cancel can be excluded from cancellation.
[0052]
Furthermore, in the embodiment, even if it is not the sound of the frequency registered in
advance, the sound generated continuously at the sound pressure exceeding the predetermined
threshold value is erased except for the start time point. Therefore, even when the generation of
sound has an important meaning, it can be heard without missing it. In addition, when sounds
other than the registered frequency are continuously generated as noise, there are many cases
where the noise is generated due to work, so it is possible to cancel this sound from a certain
point in time and ensure a quiet environment. .
[0053]
Further, in the embodiment, since the audio input unit 255 is provided in the control box 203, it
is possible to reproduce music or enjoy karaoke using the flat speakers 201, 201,. In addition,
when using a plurality of flat speakers 201, 201, ... as in the embodiment, in addition to stereo
reproduction, enjoyment of reproduction of audio using a large number of speakers such as 5.1
channel etc. it can. Of course, in the case of outputting different sounds from a plurality of
speakers, it is necessary to increase the number of circuits and cables for amplification.
[0054]
Although the flat speaker 201 is included in the accordion curtain 214 in the embodiment, the
flat speaker may be similarly incorporated into the strip-like member constituting the blind. In
addition, by dividing the flat speaker into smaller pieces and incorporating them in curtains other
than the accordion curtain 214, sound output can be performed without disturbing the
movement of the curtain fabric.
[0055]
Furthermore, the exciter 232 shown in FIG. 2 can be attached to a partition member such as a
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window glass, a floor or a ceiling that divides a space in a place such as a house, a car, an
airplane or a rail car without worrying about the installation space. The noise can be eliminated.
Thereby, for example, noise can be eliminated near the window of the meeting room, the lobby of
the hotel, the room of the Shinkansen, the window of the study, the window of the store facing
the road, and the window of the passenger car.
[0056]
In addition, even when such a partition member is used as a flat speaker, frequency analysis is
performed as in the present embodiment so that cancellation noise of opposite phase is not
generated for noise that satisfies a specific condition. Thus, for example, it is possible to ensure
that a warning sound such as a horn of another vehicle when the present invention is applied to
the vehicle is sufficiently audible. As a result, even the warning sound is not deleted as noise or
suppressed to a small sound that is hard to hear, and the risk of causing a serious accident
related to the human body can be avoided.
[0057]
Further, although the control box 203 and the microphone device 205 are wirelessly connected
in the embodiment, for example, the microphone may be attached to a table or a stool (not
shown) and wired to the control box 203. As a result, the problem of battery exhaustion when
using the microphone device 205 is eliminated, and since no microphone is worn, privacy can be
protected.
[0058]
Furthermore, in the embodiment, for the sound pressure before the threshold is exceeded, the
noise cancellation processing is performed as usual for noise, and the warning sound and the
continuing sound are dealt with for the part exceeding this. It is also possible to process only the
warning sound for the sound pressure exceeding the value or to perform the cancellation process
only for the sound continuing for a predetermined time or more.
[0059]
It is the principal part perspective view showing the principal part of the room which used the
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noise cancellation device in one example of the present invention.
It is a top view showing composition of a plane speaker used by a present example. It is a block
diagram showing composition of a control box of this example. It is a block diagram showing
composition of a microphone device of this example. It is the flowchart showing the mode of
output control of band attenuation setting information by the control part of a present Example.
It is a block diagram showing the outline of the composition of the noise cancellation device
proposed conventionally.
Explanation of sign
[0060]
DESCRIPTION OF SYMBOLS 200 noise cancellation apparatus 201 plane speaker 203 control
box 205 microphone apparatus 214 accordion curtain 216 room user 231 acrylic board 232
exciter 241 CPU 242 control program storage part 243 control part 246 noise collection
reception part 248 frequency analysis and sound pressure measurement Part 249 Band
elimination filter part 250 Inverse phase cancellation sound generation part 255 Audio input
part 261 Microphone
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