JP2007159042A - Acoustic apparatus - Google Patents

Acoustic apparatus Download PDF

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JP2007159042A
JP2007159042A JP2005355177A JP2005355177A JP2007159042A JP 2007159042 A JP2007159042 A JP 2007159042A JP 2005355177 A JP2005355177 A JP 2005355177A JP 2005355177 A JP2005355177 A JP 2005355177A JP 2007159042 A JP2007159042 A JP 2007159042A
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sound
background noise
signal
microphone
output
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Koji Nagai
宏治 永井
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Mitsubishi Electric Engineering Co Ltd
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Mitsubishi Electric Engineering Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To measure a backgound noise level in a narrow audible area generated by audio demodulated from ultrasound and adjust an output volume of audio, depending on the background noise level, even during outputting of the audio. <P>SOLUTION: An audio signal from a sound source 1 is modulated by a modulator 2 to generate a super directional audio signal indicating audio in which ultrasound is a carrier. A sound field 7 of demodulated audio is generated by emitting ultrasound from a parametric loudspeaker 4 based on the super directional audio signal amplified by an amplifier 3. A microphone 5 is provided in the sound field 7, and a background noise detection/volume controller 6 extracts background noise 8 from an output signal of the microphone 5 using the audio signal from the sound source 1 and controls the modulator 2 to generate the super directional audio signal having a volume, depending on a level of the background noise 8, while the microphone 5 is prevented from collecting ambient ultrasound using an acoustic filter 9 which attenuates ultrasound. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

この発明は、パラメトリックスピーカを利用して、案内音声や警報音などを狭いエリア内のみで聴こえるように放送し、このとき生じる可聴エリア内の暗騒音レベルを測定してパラメトリックスピーカの出力音声の音量を調整する音響装置に関するものである。   The present invention uses a parametric speaker to broadcast a guidance voice or an alarm sound so that it can be heard only in a narrow area, and measures the background noise level in the audible area and the volume of the output sound of the parametric speaker. The present invention relates to an acoustic device that adjusts the frequency.

従来の音声の音量を制御する装置として、増幅手段によって通知音声信号を増幅して音声出力手段へ出力するとき、マイクロホンの出力信号に基づいて音声出力手段の周囲の騒音レベルを求める騒音レベル測定手段と、騒音レベル測定手段の出力信号に基づいて上記の増幅手段へ増幅率を指定する増幅率指定手段とを備え、一般的なスピーカを使用して通知音声を出力するものがある。その動作は、例えばマイクロホンの出力ピーク値を周囲の騒音レベルとして取り扱い、上記の騒音レベル測定手段を成すピークホールド回路がマイクロホンの出力信号のピーク値を保持する。上記の増幅率指定手段を成す比較部が、閾値とピークホールド回路によって保持されている値とを比較して、同じく増幅指定手段を成す増幅率決定部が比較結果に対応する増幅率を求める。上記の増幅手段を成す増幅器は、増幅率決定部の求めた増幅率を用いて通知音声信号を増幅して、スピーカから出力される通知音声の音量を調整している。   As a conventional device for controlling the volume of sound, a noise level measuring means for obtaining a noise level around the sound output means based on the output signal of the microphone when the notification sound signal is amplified by the amplifying means and outputted to the sound output means. And an amplification factor designating unit that designates the amplification factor to the amplification unit based on the output signal of the noise level measuring unit, and outputs a notification voice using a general speaker. In the operation, for example, the output peak value of the microphone is treated as the ambient noise level, and the peak hold circuit constituting the noise level measuring means holds the peak value of the output signal of the microphone. The comparison unit that constitutes the amplification factor designating unit compares the threshold value with the value held by the peak hold circuit, and the amplification factor determination unit that also constitutes the amplification designation unit obtains the amplification factor corresponding to the comparison result. The amplifier constituting the amplification means amplifies the notification sound signal using the amplification factor obtained by the amplification factor determination unit, and adjusts the volume of the notification sound output from the speaker.

上記のように一般的なスピーカを使用した装置では、スピーカから出力された通知音声が不確定な範囲に拡散して暗騒音と共にマイクに集音されてしまう。そこで、暗騒音と通知音声とを分別して暗騒音レベルを測定するため、スピーカから通知音声を出力する直前の暗騒音レベルをピーク検出回路に保持させ、この暗騒音レベルを基準に通知音声の出力レベルを調整している（例えば、特許文献１参照）。   In the apparatus using a general speaker as described above, the notification sound output from the speaker is diffused in an indeterminate range and collected by the microphone together with background noise. Therefore, in order to measure the background noise level by separating the background noise from the notification sound, the background noise level immediately before the notification sound is output from the speaker is held in the peak detection circuit, and the notification sound is output based on the background noise level. The level is adjusted (see, for example, Patent Document 1).

特開平５−１７２６１９号公報（第３，４頁、図１，図３）Japanese Patent Laid-Open No. 5-172619 (pages 3 and 4, FIGS. 1 and 3)

従来の音響装置は以上のように構成されているので、音声出力中は、マイクロホンが周囲の騒音と共に当該音声を集音してしまうことから、このようなときの暗騒音レベル測定を避けている。そのため音声出力中に周囲の暗騒音レベルが変化したとき、その変化に対応してスピーカの出力音量を調整／制御することができないという課題があった。   Since the conventional acoustic apparatus is configured as described above, the microphone collects the sound together with the surrounding noise during the sound output, and thus avoids the background noise level measurement in such a case. . Therefore, when the background noise level changes during audio output, there is a problem that the output volume of the speaker cannot be adjusted / controlled in response to the change.

この発明は上記のような課題を解決するためになされたもので、超音波から復調した音声によって生じる狭い可聴エリア内の暗騒音レベルを測定し、音声出力中においても暗騒音レベルに応じて音声の出力音量を調整する音響装置を得ることを目的とする。   The present invention has been made to solve the above-described problems, and measures the background noise level in a narrow audible area caused by the sound demodulated from the ultrasonic wave. An object of the present invention is to obtain an acoustic device that adjusts the output volume of the sound.

この発明に係る音響装置は、パラメトリックスピーカの放射した超音波から復調した音声の可聴エリア内に配置されたマイクロホンと、マイクロホンの周囲の超音波を減衰する音響フィルタと、マイクロホンから出力された集音信号から暗騒音を抽出し、当該暗騒音のレベルに応じた音量を有する超指向性音声信号を生成するように変調手段を制御する暗騒音検出／音量制御手段とを備えたものである。   An acoustic device according to the present invention includes a microphone disposed in an audible area of sound demodulated from ultrasonic waves emitted from a parametric speaker, an acoustic filter that attenuates ultrasonic waves around the microphone, and a sound collection output from the microphone. Background noise is extracted from the signal, and background noise detection / volume control means for controlling the modulation means so as to generate a super-directional audio signal having a volume corresponding to the level of the background noise is provided.

この発明によれば、パラメトリックスピーカの放射した超音波から復調した音声の可聴エリア内にマイクロホンを配置し、マイクロホンの周囲の超音波を音響フィルタによって減衰し、暗騒音検出／音量制御手段がマイクロホンから出力された集音信号から暗騒音を抽出して当該暗騒音のレベルに応じた音量を有する超指向性音声信号を生成するように変調手段を制御するようにしたので、可聴エリア内の暗騒音レベルに応じて出力音声の音量を適切に調整することができるという効果がある。   According to the present invention, the microphone is arranged in the audible area of the sound demodulated from the ultrasonic wave radiated from the parametric speaker, the ultrasonic wave around the microphone is attenuated by the acoustic filter, and the background noise detection / volume control means is provided from the microphone. The background noise in the audible area is controlled by extracting the background noise from the output sound collection signal and controlling the modulation means so as to generate a super-directional voice signal having a volume corresponding to the level of the background noise. There is an effect that the volume of the output sound can be adjusted appropriately according to the level.

以下、この発明の実施の一形態を説明する。
実施の形態１．
図１は、この発明の実施の形態１による音響装置の構成を示す説明図である。この図は、実施の形態１による音響装置の概略構成ならびに当該装置のパラメトリックスピーカ４及びマイクロホン５を設置した様子を示したものである。図示した音響装置は、通知音声などを表す音声信号を出力する音源１、音源１からの音声信号を入力して当該信号を変調して超音波帯域の超指向性音声信号を生成する変調器（変調手段）２、変調器２から出力された超指向性音声信号を増幅する増幅器３、増幅器３によって増幅された信号に基づいて超音波を発生させ、空気中へ放射するパラメトリックスピーカ４、パラメトリックスピーカ４から放射された超音波によって生じる音場（可聴エリア）７内に存在する暗騒音８を集音するマイクロホン５、マイクロホン５の出力信号から暗騒音８を検出して増幅率信号を生成し、この増幅率信号を用いて変調器２の動作を制御する暗騒音検出／音量制御器（暗騒音検出／音量制御手段）６を備えている。 An embodiment of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is an explanatory diagram showing a configuration of an acoustic device according to Embodiment 1 of the present invention. This figure shows a schematic configuration of the acoustic apparatus according to the first embodiment and a state in which the parametric speaker 4 and the microphone 5 of the apparatus are installed. The illustrated acoustic device includes a sound source 1 that outputs a sound signal representing a notification sound and the like, a modulator that inputs a sound signal from the sound source 1 and modulates the signal to generate a super-directional sound signal in an ultrasonic band. Modulation means 2, an amplifier 3 for amplifying the superdirective audio signal output from the modulator 2, a parametric speaker 4 for generating an ultrasonic wave based on the signal amplified by the amplifier 3, and radiating it into the air, a parametric speaker A microphone 5 that collects background noise 8 present in the sound field (audible area) 7 generated by the ultrasonic waves radiated from 4, detects the background noise 8 from the output signal of the microphone 5, and generates an amplification factor signal; A background noise detection / volume controller (background noise detection / volume control means) 6 for controlling the operation of the modulator 2 using the amplification factor signal is provided.

パラメトリックスピーカ４は、聴取者が存在する位置へ、もしくは音場７を生じさせたい所望の位置へ超音波の放射面を向けて設置されている。
マイクロホン５は、パラメトリックスピーカ４から放射された超音波によって生じる音場７の内部であって、該音場７内に存在する暗騒音８を集音することが可能な位置に設置されている。また、マイクロホン５には、当該マイクロホン５が周囲の超音波を集音しないように、自らの集音部分を覆うように例えばウレタン部材から成る音響フィルタ９を装着している。
また、上記の暗騒音検出／音量制御器６は音源１に接続され、音声信号を入力するように構成されている。 The parametric speaker 4 is installed with the radiation surface of the ultrasonic wave directed to a position where a listener is present or a desired position where a sound field 7 is desired.
The microphone 5 is installed inside the sound field 7 generated by the ultrasonic waves radiated from the parametric speaker 4 at a position where the background noise 8 existing in the sound field 7 can be collected. In addition, an acoustic filter 9 made of, for example, a urethane member is attached to the microphone 5 so as to cover its own sound collection portion so that the microphone 5 does not collect surrounding ultrasonic waves.
The background noise detection / volume controller 6 is connected to the sound source 1 and configured to input an audio signal.

図２は、実施の形態１による音響装置の構成を示すブロック図である。図１に示したものと同一あるいは相当する部分に同じ符号を使用し、その説明を省略する。この図は、図１に示した音響装置のブロック構成を示したものである。
音源１は、例えば警告や音声案内などの通知音声を表す音声信号１４を発生するもので、このような可聴音声を表す信号を、前述のように変調器２へ出力するように接続されている。
変調器２は、音声信号１４を変調する変調部１１、搬送波として使用する超音波を示す搬送波信号を生成する搬送波生成部１２、変調部１１から出力される音声変調信号と搬送波生成部１２からの搬送波信号と後述する暗騒音検出／音量制御器６から出力された増幅率信号１５とを用いて超指向性音声信号を生成する乗算部１３を備えている。 FIG. 2 is a block diagram showing the configuration of the acoustic device according to the first embodiment. The same reference numerals are used for the same or corresponding parts as shown in FIG. This figure shows a block configuration of the acoustic apparatus shown in FIG.
The sound source 1 generates a sound signal 14 representing a notification sound such as a warning or voice guidance, and is connected to output a signal representing such an audible sound to the modulator 2 as described above. .
The modulator 2 includes a modulation unit 11 that modulates the audio signal 14, a carrier wave generation unit 12 that generates a carrier wave signal indicating an ultrasonic wave to be used as a carrier wave, and the audio modulation signal output from the modulation unit 11 and the carrier wave generation unit 12. A multiplication unit 13 is provided that generates a superdirectional audio signal using a carrier wave signal and an amplification factor signal 15 output from a background noise detection / volume controller 6 described later.

暗騒音検出／音量制御器６は、前述のようにマイクロホン５と接続され、当該マイクロホン５から出力された集音信号から可聴音声帯域を示す信号のみを通過させるローパスフィルタ２１、ローパスフィルタ２１の出力信号から音源１の音声信号１４を減算する減算部（減算手段）２２、減算部２２の出力信号から暗騒音８のレベルを検出する暗騒音レベル検出部２３、暗騒音レベル検出部２３の出力信号に応じて増幅率信号１５を生成する音量制御部２４から成る。
なお、上記の乗算部１３から出力された超指向性音声信号を増幅器３へ入力するように、当該乗算部１３を有する変調器２と増幅器３が接続されている。また、増幅器３の出力信号によりパラメトリックスピーカ４が駆動されるように、当該増幅器３とパラメトリックスピーカ４が接続されている。 The background noise detection / volume controller 6 is connected to the microphone 5 as described above, and outputs from the low-pass filter 21 and the low-pass filter 21 that pass only a signal indicating an audible voice band from the collected sound signal output from the microphone 5. A subtracting unit (subtracting means) 22 that subtracts the audio signal 14 of the sound source 1 from the signal, a background noise level detecting unit 23 that detects the level of the background noise 8 from the output signal of the subtracting unit 22, and an output signal of the background noise level detecting unit 23 The volume control unit 24 generates the amplification factor signal 15 according to the above.
Note that the modulator 2 having the multiplier 13 and the amplifier 3 are connected so that the super-directional audio signal output from the multiplier 13 is input to the amplifier 3. The amplifier 3 and the parametric speaker 4 are connected so that the parametric speaker 4 is driven by the output signal of the amplifier 3.

次に動作について説明する。
音源１から出力される音声信号１４は、前述のように変調器２の変調部１１へ入力される。変調部１１は、入力した音声信号１４に、例えば係数の乗算、バイアス値の加算、さらに平方根を求める演算処理などを施して音声変調信号を生成する。搬送波生成部１２は、超音波帯域の搬送波を表す搬送波信号を生成する。
乗算部１３は、変調部１１からの音声変調信号と搬送波生成部１２からの搬送波信号とを入力し、また、暗騒音検出／音量制御器６から増幅率信号１５を入力して、これらの信号の乗算を行う。この乗算処理によって、通知音声と超音波の搬送波とを合成し、また増幅率信号１５の表している増幅率を加味することにより通知音声の出力音量を設定した超指向性音声信号を生成する。
増幅器３は、変調器２詳しくは乗算部１３から出力された超指向性音声信号を、パラメトリックスピーカ４の駆動に要するレベルへ増幅する。パラメトリックスピーカ４は、入力した信号に応じて超音波を発生し、パラメトリックスピーカ４の正面においてビーム状の狭い範囲の音場７が形成されるように放射する。パラメトリックスピーカ４から放射された超音波は、音場７内において可聴音声帯域の音波に自己復調し、狭く限られた可聴エリア内のみで聴こえる通知音声が当該音響装置から出力される。 Next, the operation will be described.
The audio signal 14 output from the sound source 1 is input to the modulation unit 11 of the modulator 2 as described above. The modulation unit 11 generates an audio modulation signal by performing, for example, coefficient multiplication, addition of a bias value, arithmetic processing for obtaining a square root, and the like on the input audio signal 14. The carrier wave generation unit 12 generates a carrier wave signal representing a carrier wave in the ultrasonic band.
The multiplier 13 receives the audio modulation signal from the modulation unit 11 and the carrier signal from the carrier wave generation unit 12, and receives the amplification factor signal 15 from the background noise detection / volume controller 6, and receives these signals. Multiply By this multiplication processing, the notification voice and the ultrasonic carrier wave are synthesized, and the superdirective voice signal in which the output volume of the notification voice is set is generated by adding the amplification factor represented by the amplification factor signal 15.
The amplifier 3 amplifies the super-directional audio signal output from the modulator 2, specifically the multiplier 13, to a level required for driving the parametric speaker 4. The parametric speaker 4 generates an ultrasonic wave according to the input signal and radiates it so that a beam-like narrow sound field 7 is formed in front of the parametric speaker 4. The ultrasonic waves radiated from the parametric speaker 4 are self-demodulated into sound waves in the audible sound band in the sound field 7, and notification sound that can be heard only in a narrow and limited audible area is output from the acoustic device.

マイクロホン５は、前述のように音場７の内部であって、音場７に存在する暗騒音８を集音することのできる場所に設置されている。このマイクロホン５の集音部分には前述のように超音波の減衰作用を有する材質から成る音響フィルタ９が備えられ、超音波帯域の例えば２０ｋＨｚ以上の周波数をカットして、主にパラメトリックスピーカ４から放射された超音波を集音しないようにしている。このようにして音場７に存在する可聴音声帯域の暗騒音８などを集音したマイクロホン５から出力される集音信号は、前述のように暗騒音検出／音量制御器６のローパスフィルタ２１へ出力される。ローパスフィルタ２１は、マイクロホン５から入力した音声信号１４をデジタル処理によって超音波帯域等の周波数成分をカットもしくは減衰させ、可聴音声帯域の可聴音声成分から成る集音信号を生成し減算器２２へ出力する。   As described above, the microphone 5 is installed inside the sound field 7 and in a place where the background noise 8 existing in the sound field 7 can be collected. As described above, the sound collecting portion of the microphone 5 is provided with the acoustic filter 9 made of a material having an ultrasonic attenuating action, and cuts a frequency of, for example, 20 kHz or more in the ultrasonic band, mainly from the parametric speaker 4. The radiated ultrasonic waves are not collected. The sound collection signal output from the microphone 5 that collects the background noise 8 in the audible voice band existing in the sound field 7 in this way is sent to the low-pass filter 21 of the background noise detection / volume controller 6 as described above. Is output. The low-pass filter 21 cuts or attenuates a frequency component such as an ultrasonic band by digital processing of the sound signal 14 input from the microphone 5, generates a sound collection signal composed of an audible sound component in the audible sound band, and outputs it to the subtractor 22. To do.

減算器２２は、前述のように音源１から音声信号１４を入力し、またローパスフィルタ２１から集音信号を入力し、この集音信号から音声信号１４を減算する。この処理は、ローパスフィルタ２１の出力信号即ちマイクロホン５の集音した信号には、可聴音声帯域の信号として暗騒音８と共に音場７に出力された通知音声の成分が含まれているため、当該通知音声を示す成分を除去し、可聴音声帯域の暗騒音８の成分を抽出するものである。減算器２２は、このように通知音声の成分を除去した信号を暗騒音レベル検出部２３へ出力する。   The subtractor 22 receives the audio signal 14 from the sound source 1 as described above, receives the sound collection signal from the low-pass filter 21, and subtracts the sound signal 14 from the sound collection signal. In this processing, since the output signal of the low-pass filter 21, that is, the signal collected by the microphone 5, includes the component of the notification sound output to the sound field 7 together with the background noise 8 as a signal in the audible sound band, The component indicating the notification voice is removed, and the component of the background noise 8 in the audible voice band is extracted. The subtractor 22 outputs the signal from which the notification sound component is removed in this manner to the background noise level detection unit 23.

暗騒音レベル検出部２３は、例えば暗騒音８の振幅の大きさを検出し、この大きさを暗騒音８のレベルとして表現した暗騒音レベル信号を生成して音量制御部２４へ出力する。
音量制御部２４は、前述のように暗騒音８のレベルに応じてパラメトリックスピーカ４の出力音声即ち通知音声の音量を設定するもので、予め暗騒音８のレベルに対応させて増幅率を定めており、暗騒音検出部２３からの暗騒音レベル信号に応じた増幅率を表す増幅率信号１５を前述の乗算部１３へ出力する。暗騒音に対して聴き取り可能な音声には、暗騒音よりも概ね１０ｄＢ以上の音量レベルが必要になる。そのため、音量制御部２４は、暗騒音レベル信号よりも１０ｄＢ〜１５ｄＢ程度高い音量レベルを有する通知音声が得られるように増幅率を設定し、当該増幅率を示す増幅率信号１５を出力する。 The background noise level detection unit 23 detects, for example, the magnitude of the amplitude of the background noise 8, generates a background noise level signal expressing the magnitude as the level of the background noise 8, and outputs the signal to the volume control unit 24.
The volume control unit 24 sets the volume of the output sound of the parametric speaker 4, that is, the notification sound according to the level of the background noise 8 as described above, and determines the amplification factor corresponding to the level of the background noise 8 in advance. The amplification factor signal 15 representing the amplification factor corresponding to the background noise level signal from the background noise detection unit 23 is output to the multiplication unit 13 described above. Sound that can be heard against background noise requires a volume level of approximately 10 dB or higher than background noise. Therefore, the volume control unit 24 sets an amplification factor so that a notification voice having a volume level higher by about 10 dB to 15 dB than the background noise level signal is obtained, and outputs the amplification factor signal 15 indicating the amplification factor.

このように本発明の音響装置は、狭い音場７内の暗騒音８を直接集音するように、音場７内にマイクロホン５を配置し、またマイクロホン５が音場７内の超音波を集音しないように音響フィルタ９を備え、パラメトリックスピーカ４の超音波放射動作によって生じる音場７内の可聴音声を集音するようにしている。また、マイクロホン５の出力信号からローパスフィルタ２１を用いて可聴音声帯域の成分を抽出し、さらにマイクロホン５が音場７内において集音した通知音声の成分を減算部２２を用いて除去して暗騒音８のみを抽出することができることから、音声出力動作中でも、狭い音場７内に存在する暗騒音レベルに応じて随時出力音声の音量を調整している。   As described above, the acoustic device of the present invention arranges the microphone 5 in the sound field 7 so as to directly collect the background noise 8 in the narrow sound field 7, and the microphone 5 generates the ultrasonic waves in the sound field 7. An acoustic filter 9 is provided so as not to collect sound, and audible sound in the sound field 7 generated by the ultrasonic radiation operation of the parametric speaker 4 is collected. In addition, an audible voice band component is extracted from the output signal of the microphone 5 using the low-pass filter 21, and further, the notification voice component collected by the microphone 5 in the sound field 7 is removed using the subtractor 22 to darken it. Since only the noise 8 can be extracted, the volume of the output sound is adjusted at any time according to the background noise level existing in the narrow sound field 7 even during the sound output operation.

以上のように実施の形態１によれば、マイクロホン５の集音部分を。超音波を減衰する音響フィルタ９で覆い、マイクロホン５から出力された集音信号から可聴音声帯域の成分をローパスフィルタ２１によって抽出し、減算器２２によってローパスフィルタ２１の出力信号から音声信号１４を減算して暗騒音８を抽出し、暗騒音８のレベルに応じて出力音声の音量を調整するようにしたので、狭い音場７の内部に存在する暗騒音８のレベルを精度よく集音し、音場７内の暗騒音レベルに応じて出力音声の音量を適切に調整することができるという効果がある。
また、通知音声の出力中に音場７内の暗騒音８のレベルが変化したときでも、その変化した騒音レベルに追随して通知音声の出力音量を調整することができるという効果がある。 As described above, according to the first embodiment, the sound collecting portion of the microphone 5 is used. An acoustic filter 9 that attenuates the ultrasonic waves is covered, and an audible voice band component is extracted from the collected sound signal output from the microphone 5 by the low-pass filter 21. Since the background noise 8 is extracted and the volume of the output sound is adjusted according to the level of the background noise 8, the level of the background noise 8 existing in the narrow sound field 7 is accurately collected, There is an effect that the volume of the output sound can be appropriately adjusted according to the background noise level in the sound field 7.
In addition, even when the level of the background noise 8 in the sound field 7 changes during the output of the notification sound, there is an effect that the output volume of the notification sound can be adjusted following the changed noise level.

この発明の実施の形態１による音響装置の構成を示す説明図である。It is explanatory drawing which shows the structure of the audio equipment by Embodiment 1 of this invention. 実施の形態１による音響装置の構成を示すブロック図である。1 is a block diagram illustrating a configuration of an audio device according to Embodiment 1. FIG.

符号の説明Explanation of symbols

１ 音源、２ 変調器、３ 増幅器、４ パラメトリックスピーカ、５ マイクロホン、６ 暗騒音検出／音量制御器、７ 音場、８ 暗騒音、９ 音響フィルタ、１１ 変調部、１２ 搬送波生成部、１３ 乗算部、１４ 音声信号、１５ 増幅率信号、２１ ローパスフィルタ、２２ 減算部、２３ 暗騒音レベル検出部、２４ 音量制御部。   1 sound source, 2 modulator, 3 amplifier, 4 parametric speaker, 5 microphone, 6 background noise detection / volume controller, 7 sound field, 8 background noise, 9 acoustic filter, 11 modulation section, 12 carrier generation section, 13 multiplication section , 14 audio signal, 15 gain signal, 21 low-pass filter, 22 subtracting unit, 23 background noise level detecting unit, 24 volume control unit.

Claims (3)

音源からの音声信号を変調し超音波を搬送波とする音声を示す超指向性音声信号を生成する変調手段と、前記超指向性音声信号に基づいて音声に復調する超音波を放射するパラメトリックスピーカとを備えた音響装置において、
前記パラメトリックスピーカの放射した超音波から復調した音声の可聴エリア内に配置されたマイクロホンと、
前記マイクロホンの周囲の超音波を減衰する音響フィルタと、
前記マイクロホンから出力された集音信号から暗騒音を抽出し、当該暗騒音のレベルに応じた音量を有する超指向性音声信号を生成するように変調手段を制御する暗騒音検出／音量制御手段と、
を備えたことを特徴とする音響装置。 Modulating means for modulating a sound signal from a sound source and generating a super-directional sound signal indicating sound using ultrasonic waves as a carrier wave; and a parametric speaker for emitting ultrasonic waves to be demodulated into sound based on the super-directional sound signal; In an audio device comprising:
A microphone disposed in an audible area of sound demodulated from ultrasonic waves emitted from the parametric speaker;
An acoustic filter that attenuates the ultrasonic waves around the microphone;
Background noise detection / volume control means for extracting the background noise from the collected sound signal output from the microphone and controlling the modulation means so as to generate a super-directional voice signal having a volume corresponding to the level of the background noise; ,
An acoustic device comprising: 暗騒音検出／音量制御手段は、音源からの音声信号とマイクロホンからの集音信号とを入力し、当該集音信号から音声信号を減算して暗騒音を抽出する減算手段を備えたことを特徴とする請求項１記載の音響装置。   The background noise detection / volume control means includes subtracting means for inputting a sound signal from a sound source and a sound collection signal from a microphone, and subtracting the sound signal from the sound collection signal to extract background noise. The acoustic device according to claim 1. 暗騒音検出／音量制御手段は、マイクロホンから出力された集音信号の可聴音声成分を抽出するローパスフィルタを備え、当該ローパスフィルタの出力信号から暗騒音を抽出することを特徴とする請求項１または請求項２記載の音響装置。   The background noise detection / volume control means includes a low-pass filter that extracts an audible sound component of the collected sound signal output from the microphone, and extracts the background noise from the output signal of the low-pass filter. The acoustic device according to claim 2.
JP2005355177A 2005-12-08 2005-12-08 Acoustic apparatus Pending JP2007159042A (en)

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