JP2007228402A - Super-directional sound device - Google Patents

Super-directional sound device Download PDF

Info

Publication number
JP2007228402A
JP2007228402A JP2006048805A JP2006048805A JP2007228402A JP 2007228402 A JP2007228402 A JP 2007228402A JP 2006048805 A JP2006048805 A JP 2006048805A JP 2006048805 A JP2006048805 A JP 2006048805A JP 2007228402 A JP2007228402 A JP 2007228402A
Authority
JP
Japan
Prior art keywords
signal
frequency
carrier wave
carrier
sound
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2006048805A
Other languages
Japanese (ja)
Inventor
Kentaro Yasutake
憲太郎 安武
Shinichi Sakai
新一 酒井
Original Assignee
Mitsubishi Electric Engineering Co Ltd
三菱電機エンジニアリング株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Engineering Co Ltd, 三菱電機エンジニアリング株式会社 filed Critical Mitsubishi Electric Engineering Co Ltd
Priority to JP2006048805A priority Critical patent/JP2007228402A/en
Publication of JP2007228402A publication Critical patent/JP2007228402A/en
Pending legal-status Critical Current

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a sound pressure increase of audible voice which demodulates itself from emitted super sound, by using a plurality of resonance frequencies specific to a super-directional speaker for carrier waves. <P>SOLUTION: An amplitude modulator 2 is provided with carrier wave generators 11 and 13 generating carrier wave signals whose frequencies are different from each other, a multiplier 12 multiplying a voice signal from a voice generator 1 by the carrier wave signal from the carrier wave generator 11 to generate a multiplication signal S1, a multiplier 14 multiplying the voice signal by the carrier wave signal from the carrier wave generator 13 to generate a multiplication signal S2, and an adder 15 adding the multiplication signal S1 to the multiplication signal S2 to generate a modulation signal which generates super sound in a super-directional speaker 4. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

この発明は、可聴音声を狭いエリア内のみで聴こえるように放射する超指向性音響装置に関するものである。   The present invention relates to a superdirective acoustic device that radiates audible sound so that it can be heard only in a narrow area.

空気中において可聴音声に復調する超音波を放射する超指向性音響装置は、音源が生成した音声信号と搬送波生成部が生成した超音波帯域に属する搬送波を示す信号とを合成し、超音波帯域の搬送波を可聴音声で振幅変調した変調信号を生成する。この変調信号を増幅器が増幅して超指向性スピーカを駆動し、超音波を発生させている。超指向性スピーカから放射された超音波は、空気中を伝搬するとき非線形特性により可聴音声に自己復調する。このようにして超音波の放射エリア内、即ち狭いエリアのみに可聴音声の放射を行っている。ここで使用されている超指向性スピーカは、複数の音圧ピークを有する、即ち複数の共振周波数を有するものである(例えば、特許文献1参照)。   A super-directional acoustic device that emits ultrasonic waves that are demodulated into audible sound in the air, combines an audio signal generated by a sound source and a signal indicating a carrier wave belonging to the ultrasonic band generated by a carrier wave generation unit, A modulation signal is generated by amplitude-modulating the carrier wave with audible sound. The modulation signal is amplified by an amplifier to drive a super-directional speaker and generate ultrasonic waves. The ultrasonic wave radiated from the super-directional speaker is self-demodulated into audible sound due to nonlinear characteristics when propagating through the air. In this way, audible sound is radiated only in the ultrasonic radiation area, that is, in a narrow area. The super-directional speaker used here has a plurality of sound pressure peaks, that is, a plurality of resonance frequencies (see, for example, Patent Document 1).

特開2004−112212号公報(第4頁、図2,図3)JP 2004-112212 A (page 4, FIGS. 2 and 3)

従来の超指向性音響装置は以上のように構成されているので、複数の共振周波数を有する超指向性スピーカを駆動するとき、一つの共振周波数のみを搬送波として使用しているため超音波の発生効率を高めることに限界があり、大きな音圧の可聴音声を放射することが難しいという課題があった。   Since the conventional super directional acoustic device is configured as described above, when driving a super directional speaker having a plurality of resonance frequencies, only one resonance frequency is used as a carrier wave, so that an ultrasonic wave is generated. There has been a problem that it is difficult to radiate an audible sound with a large sound pressure because there is a limit to increasing the efficiency.

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、超指向性スピーカの複数の共振周波数を搬送波に使用することにより放射される超音波から自己復調する可聴音声の音圧増大を図ることを目的とする。   The present invention has been made in order to solve the above-described problems. By using a plurality of resonance frequencies of a superdirective speaker as a carrier wave, the sound pressure of an audible sound that is self-demodulated from ultrasonic waves radiated is increased. The purpose is to plan.

この発明に係る超指向性音響装置は、変調手段に、周波数の異なる複数の搬送波信号を生成する搬送波生成手段と、音声生成手段からの音声信号と搬送波生成手段からの各搬送波信号とを各々乗算して各乗算信号を生成する乗算手段と、乗算手段が生成した全ての乗算信号を加算して変調信号を生成する加算手段とを備えるものである。   The superdirective acoustic device according to the present invention multiplies the modulation means by a carrier generation means for generating a plurality of carrier signals having different frequencies, an audio signal from the sound generation means, and each carrier signal from the carrier generation means. The multiplication means for generating each multiplication signal and the addition means for adding all the multiplication signals generated by the multiplication means to generate the modulation signal are provided.

この発明によれば、搬送波生成手段が周波数の異なる複数の搬送波信号を生成し、音声生成手段からの音声信号と搬送波生成手段からの各搬送波信号とを各々乗算してこれらを全て加算して変調信号を生成するようにしたので、この変調信号を超指向性スピーカに入力して超音波を発生させると超音波帯域の複数の搬送波から同一の可聴音声が復調し、狭いエリア内に大きな音圧の可聴音声を放射することができるという効果がある。   According to this invention, the carrier wave generating means generates a plurality of carrier signals having different frequencies, and multiplies each of the audio signal from the sound generating means and each carrier signal from the carrier wave generating means, and adds all of them to modulate. Since the signal is generated, when the modulated signal is input to a super directional speaker and an ultrasonic wave is generated, the same audible sound is demodulated from a plurality of carriers in the ultrasonic band, and a large sound pressure is generated in a narrow area. The audible sound can be radiated.

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による超指向性音響装置の構成を示すブロック図である。可聴音声を示す音声信号を出力する音声生成器1は、変調信号を生成する振幅変調器2へ接続されている。増幅器3は、振幅変調器2から変調信号を入力し、増幅した変調信号を超指向性スピーカ4へ出力するように接続されている。
振幅変調器2は、搬送波として使用する超音波を発生する搬送波生成部11、及び、搬送波生成部11の出力信号と音声生成器1から入力した音声信号とを合成する乗算部12を備えている。また、超音波帯域の搬送波を発生する搬送波生成部13、及び、搬送波生成部13の出力信号と音声生成器1からの音声信号とを合成する乗算部14を備えている。さらに、乗算部12の出力信号と乗算部14の出力信号とを加算する加算部15を備えている。増幅器3は、振幅変調器2から出力された変調信号を増幅するもので、超指向性スピーカ4は、圧電セラミック素子を使用しているパラメトリックスピーカである。
An embodiment of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a superdirective acoustic device according to Embodiment 1 of the present invention. A sound generator 1 that outputs a sound signal indicating audible sound is connected to an amplitude modulator 2 that generates a modulation signal. The amplifier 3 is connected so as to receive the modulation signal from the amplitude modulator 2 and output the amplified modulation signal to the superdirective speaker 4.
The amplitude modulator 2 includes a carrier wave generation unit 11 that generates an ultrasonic wave used as a carrier wave, and a multiplication unit 12 that synthesizes the output signal of the carrier wave generation unit 11 and the audio signal input from the audio generator 1. . In addition, a carrier wave generation unit 13 that generates a carrier wave in the ultrasonic band, and a multiplication unit 14 that synthesizes the output signal of the carrier wave generation unit 13 and the audio signal from the audio generator 1 are provided. Further, an adder 15 for adding the output signal of the multiplier 12 and the output signal of the multiplier 14 is provided. The amplifier 3 amplifies the modulation signal output from the amplitude modulator 2, and the super-directional speaker 4 is a parametric speaker using a piezoelectric ceramic element.

次に動作について説明する。
図2は、超指向性スピーカの音圧周波数特性を示す説明図である。この図は、超指向性スピーカ4が超音波を発生するときの音圧と周波数との関係、即ち超指向性スピーカ4の音圧周波数特性を示したグラフで、図中縦軸は出力音圧レベル[dB]を表し、横軸は超指向性スピーカ4が発生する超音波の周波数[Hz]を表している。圧電セラミック素子を超音波振動子として備えた超指向性スピーカ4は、図2に示したように音圧ピークが生じる複数の共振周波数を有する。ここでは、前述のように二つの搬送波生成部11,13を振幅変調器2に備え、超指向性スピーカ4の複数の共振周波数の中から図2に示した二つの周波数f1,f2を用いる動作を例示して説明する。なお、本発明の超指向性音響装置を構成する搬送波生成部及び乗算部の数、即ち搬送波として使用する超指向性スピーカの共振周波数は二つに限定されない。
Next, the operation will be described.
FIG. 2 is an explanatory diagram showing sound pressure frequency characteristics of the superdirective speaker. This figure is a graph showing the relationship between the sound pressure and frequency when the superdirective speaker 4 generates ultrasonic waves, that is, the sound pressure frequency characteristic of the superdirective speaker 4. In the figure, the vertical axis represents the output sound pressure. The level [dB] is represented, and the horizontal axis represents the frequency [Hz] of the ultrasonic wave generated by the super-directional speaker 4. The super-directional speaker 4 provided with a piezoelectric ceramic element as an ultrasonic transducer has a plurality of resonance frequencies at which sound pressure peaks occur as shown in FIG. Here, as described above, the two carrier generation units 11 and 13 are provided in the amplitude modulator 2, and the operation using the two frequencies f1 and f2 shown in FIG. An example will be described. Note that the number of carrier generation units and multiplication units constituting the superdirective acoustic device of the present invention, that is, the resonance frequency of the superdirective speaker used as the carrier wave is not limited to two.

図1の音声生成器1は、前述のように可聴音声を示す音声信号を生成して振幅変調器2へ出力する。振幅変調器2は、この音声信号を自ら備える乗算部12及び乗算部14へ入力する。
搬送波生成部11は、例えば図2に示した周波数f1の超音波を示す搬送波信号を生成する。周波数f1は、前述のように超指向性スピーカ4の音圧周波数特性における共振周波数のひとつで、図2に示したように当該特性の中で最も大きな出力音圧が得られる、即ち最大の音圧ピークが生じる共振周波数である。乗算部12は、搬送波生成部11から搬送波信号を入力し、この搬送波信号と音声生成器1から入力した音声信号との乗算処理を行って、周波数f1の超音波を可聴音声で振幅変調した、即ち周波数f1の超音波を搬送波とした可聴音声を表す乗算信号S1を生成する。
The sound generator 1 in FIG. 1 generates a sound signal indicating audible sound as described above and outputs the sound signal to the amplitude modulator 2. The amplitude modulator 2 inputs this audio signal to the multiplying unit 12 and the multiplying unit 14 provided with the sound signal.
The carrier wave generation unit 11 generates a carrier wave signal indicating an ultrasonic wave having the frequency f1 shown in FIG. 2, for example. The frequency f1 is one of the resonance frequencies in the sound pressure frequency characteristic of the superdirective speaker 4 as described above. As shown in FIG. 2, the highest output sound pressure can be obtained, that is, the maximum sound pressure. This is the resonance frequency at which the pressure peak occurs. The multiplier 12 receives the carrier wave signal from the carrier wave generator 11, multiplies the carrier wave signal by the audio signal input from the audio generator 1, and amplitude-modulates the ultrasonic wave having the frequency f 1 with audible sound. That is, the multiplication signal S1 representing the audible sound using the ultrasonic wave of the frequency f1 as a carrier wave is generated.

搬送波生成部13は、図2に示した周波数f2の超音波を示す搬送波信号を生成する。周波数f2は、超指向性スピーカ4の音圧周波数特性において、図2に示したように二番目に大きな出力音圧が得られる、即ち二番目に大きな音圧ピークが生じる共振周波数である。乗算部14は、搬送波生成部13からの搬送波信号を入力し、この搬送波信号と音声生成器1からの音声信号とを乗算処理して、周波数f2の超音波を可聴音声で振幅変調した、即ち周波数f2の超音波を搬送波とした可聴音声を表す乗算信号S2を生成する。
なお、上記の周波数f1は周波数f2よりも低い周波数である。以下の説明で使用する周波数f1,f2も同様な関係を有する。
The carrier wave generation unit 13 generates a carrier wave signal indicating the ultrasonic wave having the frequency f2 shown in FIG. The frequency f2 is a resonance frequency at which the second largest output sound pressure is obtained as shown in FIG. 2 in the sound pressure frequency characteristics of the superdirective speaker 4, that is, the second largest sound pressure peak occurs. The multiplier 14 receives the carrier signal from the carrier generator 13, multiplies the carrier signal by the sound signal from the sound generator 1, and amplitude-modulates the ultrasonic wave having the frequency f2 with audible sound. A multiplication signal S2 representing audible sound using ultrasonic waves of frequency f2 as a carrier wave is generated.
The frequency f1 is lower than the frequency f2. The frequencies f1 and f2 used in the following description have a similar relationship.

振幅変調器2の加算部15は、乗算部12から出力された乗算信号S1と乗算部14から出力された乗算信号S2とを加算処理し、同一可聴音声によって振幅変調された周波数f1と周波数f2の二つの搬送波を表す変調信号を生成する。即ち、加算部15によって生成されている変調信号は、超指向性スピーカ4を用いて超音波を発生させたとき複数の超音波帯域の搬送波成分から同一の可聴音声成分が復調するように生成したものである。   The addition unit 15 of the amplitude modulator 2 adds the multiplication signal S1 output from the multiplication unit 12 and the multiplication signal S2 output from the multiplication unit 14, and the frequency f1 and the frequency f2 amplitude-modulated by the same audible sound. Modulation signals representing the two carrier waves are generated. That is, the modulation signal generated by the adder 15 is generated so that the same audible audio component is demodulated from the carrier wave components of a plurality of ultrasonic bands when the ultrasonic wave is generated using the superdirective speaker 4. Is.

図3は、実施の形態1による超指向性音響装置の動作を示す説明図である。この図は、超指向性スピーカ4から放射された周波数f1の超音波から復調する可聴音声成分の復調波a1と、周波数f2の超音波から復調する可聴音声成分の復調波a2とを示したもので、横軸方向に周波数[Hz]、縦軸方向に音圧レベル[dB]を表している。
前述のように生成された変調信号を増幅器3によって増幅して超指向性スピーカ4へ入力すると、超指向性スピーカ4は周波数f1と周波数f2、またこれらの周波数の側波帯からなる超音波を発生する。上記のように変調信号は振幅変調によって生成されていることから、超指向性スピーカ4の発生した超音波は、空気中を伝搬する際に可聴音声へ自己復調し、周波数f1を中心としてその両側波帯に復調波a1が生じ、また、周波数f2を中心としてその両側波帯に復調波a2が生じる。
FIG. 3 is an explanatory diagram showing the operation of the superdirective acoustic device according to the first embodiment. This figure shows a demodulated wave a1 of an audible audio component demodulated from an ultrasonic wave having a frequency f1 radiated from the superdirective speaker 4 and a demodulated wave a2 of an audible audio component demodulated from an ultrasonic wave having a frequency f2. The frequency [Hz] in the horizontal axis direction and the sound pressure level [dB] in the vertical axis direction.
When the modulation signal generated as described above is amplified by the amplifier 3 and input to the superdirective speaker 4, the superdirective speaker 4 receives the ultrasonic waves composed of the frequency f1 and the frequency f2 and sidebands of these frequencies. appear. Since the modulation signal is generated by amplitude modulation as described above, the ultrasonic wave generated by the superdirective speaker 4 is self-demodulated into audible sound when propagating through the air, and both sides thereof are centered on the frequency f1. A demodulated wave a1 is generated in the waveband, and a demodulated wave a2 is generated in both sidebands centered on the frequency f2.

超指向性音響装置で取り扱う可聴音声帯域の上限周波数を、即ち、音声生成器1からの音声信号が表す周波数の上限をfaとしたとき、図3に示したように周波数f1の上側波帯及び下側波帯の各々に周波数faの値を有する帯域幅の復調波a1が生じる。同様に、周波数f2の上側波帯及び下側波帯の各々に周波数faの値を有する帯域幅の復調波a2が生じる。
なお、復調波a1と復調波a2は同一の可聴音声成分からなり、上記の搬送波などの超音波成分は人の耳には聴こえないことから、超指向性スピーカ4から放射された復調波a1,a2は一つの音声となって高い音圧で聴こえるようになる。
When the upper limit frequency of the audible sound band handled by the superdirective acoustic device, that is, the upper limit of the frequency represented by the sound signal from the sound generator 1 is fa, the upper side band of the frequency f1 as shown in FIG. A demodulated wave a1 having a bandwidth having a value of the frequency fa is generated in each of the lower sidebands. Similarly, a demodulated wave a2 having a bandwidth having a value of the frequency fa is generated in each of the upper sideband and the lower sideband of the frequency f2.
Since the demodulated wave a1 and the demodulated wave a2 are composed of the same audible audio component, and the ultrasonic component such as the carrier wave cannot be heard by the human ear, the demodulated wave a1, radiated from the superdirective speaker 4 is used. a2 becomes one voice and can be heard with high sound pressure.

周波数f1と周波数f2の間隔は、超指向性スピーカ4から放射された超音波が、正確に聴取することのできる可聴音声へ自己復調するように、少なくとも可聴音声の上限周波数faの値よりも離間して、即ち可聴帯域よりも広い帯域幅を確保するように設定し、搬送波生成部11,13に上記のような周波数f1,f2の搬送波を表す信号を生成させる。可聴帯域は、概ね20〜20000[Hz]なので上限周波数faは最大でも20[kHz]程度になる。そこで、周波数f1と周波数f2の間隔、即ち、f2−f1の値が20[kHz]以上となるように各周波数f2,f1を設定する。また、当該超指向性音響装置で取り扱う可聴音声の帯域幅を狭くして動作する場合、即ち音声生成器1から出力される音声信号の上限周波数が上記の値よりも低くなる場合には、例えば10[kHz]を上限周波数とする場合には、周波数faは10[kHz]となって周波数f1と周波数f2の間隔が10[kHz]以上となるように設定する。   The interval between the frequency f1 and the frequency f2 is at least separated from the value of the upper limit frequency fa of the audible sound so that the ultrasonic wave radiated from the superdirective speaker 4 self-demodulates into an audible sound that can be accurately heard. That is, it is set so as to secure a wider bandwidth than the audible band, and the carrier wave generation units 11 and 13 are caused to generate signals representing the carrier waves of the frequencies f1 and f2 as described above. Since the audible band is approximately 20 to 20000 [Hz], the upper limit frequency fa is about 20 [kHz] at the maximum. Accordingly, the frequencies f2 and f1 are set so that the interval between the frequency f1 and the frequency f2, that is, the value of f2-f1 is 20 [kHz] or more. Further, when operating with a narrow bandwidth of audible sound handled by the superdirective acoustic device, that is, when the upper limit frequency of the audio signal output from the audio generator 1 is lower than the above value, for example, When the upper limit frequency is 10 [kHz], the frequency fa is set to 10 [kHz], and the interval between the frequency f1 and the frequency f2 is set to 10 [kHz] or more.

図4は、実施の形態1による超指向性音響装置の動作を示す説明図である。この図は、搬送波の周波数f1と周波数f2とを、前述の周波数faの2倍の値以上に離間して設定し、動作させたときに超指向性スピーカ4から放射される超音波、さらに当該超音波から復調する可聴音声成分を示したものである。横軸方向は周波数[Hz]を示し、縦軸方向は音圧レベル[dB]を示している。図4に示した周波数f1と周波数f2は、その間隔即ちf2−f1の値が上記の可聴音声の上限周波数faを2倍にした値よりも大きくなるように設定されている。   FIG. 4 is an explanatory diagram showing the operation of the superdirective acoustic device according to the first embodiment. This figure shows the ultrasonic wave radiated from superdirective speaker 4 when the frequency f1 and frequency f2 of the carrier wave are set apart from each other by a value more than twice the above-mentioned frequency fa and operated. The audible sound component demodulated from the ultrasonic wave is shown. The horizontal axis direction represents frequency [Hz], and the vertical axis direction represents sound pressure level [dB]. The frequency f1 and the frequency f2 shown in FIG. 4 are set so that the interval, that is, the value of f2-f1 is larger than the value obtained by doubling the upper limit frequency fa of the audible sound.

このように周波数f1と周波数f2とを離間すると、各搬送波から自己復調する可聴音声、即ち各搬送波の両側波帯に生じる復調波a1と復調波a2が重なり合うことがなくなり、可聴音声の復調が正常に行われる。図3に示した帯域fbのように、復調波a1と復調波a2が重なる部分が生じた場合でも聴取可能な音声が発生するが、不要な復調も含まれる。図4に示したように周波数f1と周波数f2との間を周波数faの2倍よりも離間して設定することにより、各搬送波の両側波帯に生じる復調波a1と復調波a2が重なることがなくなり、最も効率よく可聴音声を放射することができる。また、周波数f1と周波数f2には、前述のように超指向性スピーカ4の固有の共振周波数を用いている。そのため必ず上記のような間隔をおいて搬送波の周波数を設定することが困難な場合もある。搬送波の周波数f1,f2は、上記のように少なくとも可聴音声の上限となる周波数faよりも離間して、好ましくは周波数faの2倍の値よりも離間させ、なおかつ上記の超指向性スピーカ4の共振周波数と概ね同様な、好ましくは同一の周波数f1,f2を設定し、このような条件を満たす周波数f1の搬送波を搬送波生成部11に生成させ、また周波数f2の搬送波を搬送波生成部13に生成させる。   When the frequency f1 and the frequency f2 are separated from each other in this manner, the audible sound that is self-demodulated from each carrier wave, that is, the demodulated wave a1 and the demodulated wave a2 that are generated in both sidebands of each carrier do not overlap, and the demodulation of the audible sound is normal To be done. Although the audible sound is generated even when a portion where the demodulated wave a1 and the demodulated wave a2 overlap as shown in the band fb shown in FIG. 3, unnecessary demodulation is also included. As shown in FIG. 4, when the frequency f1 and the frequency f2 are set apart from twice the frequency fa, the demodulated wave a1 and the demodulated wave a2 generated in both sidebands of each carrier may overlap. The audible sound can be radiated most efficiently. Further, as described above, the unique resonance frequency of superdirective speaker 4 is used for frequency f1 and frequency f2. For this reason, it may be difficult to set the frequency of the carrier wave with an interval as described above. The frequencies f1 and f2 of the carrier waves are separated from at least the frequency fa that is the upper limit of the audible sound as described above, preferably more than twice the value of the frequency fa, and the superdirective speaker 4 Set substantially the same frequency f1, f2 as the resonance frequency, preferably cause the carrier wave generation unit 11 to generate a carrier wave of the frequency f1 that satisfies such conditions, and generate a carrier wave of the frequency f2 to the carrier wave generation unit 13 Let

以上のように実施の形態1によれば、搬送波生成部11で生成した超音波帯域の周波数f1を音声生成器1からの音声信号で振幅変調し、また搬送波生成部13で生成した超音波帯域の周波数f2を上記の音声信号で振幅変調し、これらの振幅変調によって生成した乗算信号S1,S2を加算部15で加算して超指向性スピーカ4を駆動する変調信号を生成するようにしたので、当該変調信号を超指向性スピーカ4に入力して超音波を発生させると、複数の超音波帯域の搬送波から同一の可聴音声が復調し、狭いエリアに超指向性放射した可聴音声の音圧を増大させることができるという効果がある。   As described above, according to the first embodiment, the frequency f1 of the ultrasonic band generated by the carrier generation unit 11 is amplitude-modulated with the audio signal from the audio generator 1, and the ultrasonic band generated by the carrier generation unit 13 is used. Frequency f2 is amplitude-modulated with the above-mentioned audio signal, and the multiplication signals S1 and S2 generated by the amplitude modulation are added by the adder 15 to generate a modulation signal for driving the superdirective speaker 4. When the modulation signal is input to the superdirective speaker 4 to generate ultrasonic waves, the same audible sound is demodulated from a plurality of ultrasonic band carriers, and the sound pressure of the audible sound radiated superdirectively in a narrow area There is an effect that can be increased.

実施の形態2.
図5は、この発明の実施の形態2による超指向性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。図5に示した超指向性音響装置は、図1に示した振幅変調器2に替えて、振幅変調器2aと振幅変調器2bとを備え、またさらにこれらの振幅変調器2a,2bの出力信号を加算して変調信号を生成する加算器25を備えて構成したものである。音声生成器1、増幅器3、及び、超指向性スピーカ4は、実施の形態1による超指向性音響装置と同様なものである。上記の振幅変調器2a,2bは、音声生成器1から同一の音声信号を入力するように接続されている。また、振幅変調器2a,2bから各々出力された信号は加算器25へ入力するように接続されている。加算器25は、出力信号が増幅器3へ入力するように接続されている。また、実施の形態1で説明したものと同様に、増幅器3の出力信号が超指向性スピーカ4へ供給されるように接続されている。
Embodiment 2. FIG.
FIG. 5 is a block diagram showing a configuration of a superdirective acoustic device according to Embodiment 2 of the present invention. The same reference numerals are used for the same or corresponding parts as shown in FIG. The superdirective acoustic device shown in FIG. 5 includes an amplitude modulator 2a and an amplitude modulator 2b instead of the amplitude modulator 2 shown in FIG. 1, and further outputs of these amplitude modulators 2a and 2b. An adder 25 for adding signals to generate a modulated signal is provided. The sound generator 1, the amplifier 3, and the superdirective speaker 4 are the same as those of the superdirective acoustic device according to the first embodiment. The amplitude modulators 2a and 2b are connected to input the same audio signal from the audio generator 1. The signals output from the amplitude modulators 2 a and 2 b are connected so as to be input to the adder 25. The adder 25 is connected so that the output signal is input to the amplifier 3. Further, similar to that described in the first embodiment, the output signal of the amplifier 3 is connected so as to be supplied to the superdirective speaker 4.

振幅変調器2aは、搬送波として使用する例えば前述の周波数f1の超音波を発生する搬送波生成部21、及び、搬送波生成部21から出力された搬送波信号と音声生成器1から入力した音声信号とを乗算処理する乗算部22を備えている。
振幅変調器2bは、搬送波として使用する例えば前述の周波数f2の超音波を発生する搬送波生成部23、及び、搬送波生成部23から出力された搬送波信号と音声生成器1から入力した音声信号とを乗算処理する乗算部24を備えている。
また、上記の加算器25は、振幅変調器2aの乗算部22から出力される乗算信号T1と振幅変調器2bの乗算部24から出力される乗算信号T2とを入力し、これらの加算処理を行うもので、実施の形態1で説明した加算部15と同様な機能を有するように構成されている。
The amplitude modulator 2a uses, for example, a carrier wave generation unit 21 that generates ultrasonic waves having the above-described frequency f1 to be used as a carrier wave, a carrier wave signal output from the carrier wave generation unit 21, and a sound signal input from the sound generator 1. A multiplication unit 22 for performing multiplication processing is provided.
The amplitude modulator 2b is used as a carrier wave, for example, a carrier wave generation unit 23 that generates an ultrasonic wave having the above-described frequency f2, and a carrier wave signal output from the carrier wave generation unit 23 and a sound signal input from the sound generator 1. A multiplication unit 24 for performing multiplication processing is provided.
The adder 25 receives the multiplication signal T1 output from the multiplication unit 22 of the amplitude modulator 2a and the multiplication signal T2 output from the multiplication unit 24 of the amplitude modulator 2b, and performs an addition process thereof. It is configured so as to have the same function as that of the adding unit 15 described in the first embodiment.

次に動作について説明する。
実施の形態1で説明した超指向性音響装置と同様な動作について重複説明を省略し、実施の形態2による超指向性音響装置の特徴となっている動作を説明する。
前述のように音声生成器1が生成した音声信号は、振幅変調器2aと振幅変調器2bへ入力される。振幅変調器2aは、搬送波生成部21が生成した周波数f1の搬送波を示す搬送波信号と、音声生成器1からの音声信号とを乗算部22へ入力して乗算処理を行う。この演算処理により周波数f1の搬送波が音声信号によって振幅変調される。乗算部22から演算結果の乗算信号T1が加算器25へ出力される。
また、振幅変調器2bは、搬送波生成部23が生成した周波数f2の搬送波を示す搬送波信号と、音声生成器1からの音声信号とを乗算部24へ入力して乗算処理を行う。この演算処理により周波数f2の搬送波が音声信号によって振幅変調される。乗算部24から演算結果の乗算信号T2が加算器25へ出力される。
Next, the operation will be described.
The same operations as those of the superdirective acoustic device described in the first embodiment are not described repeatedly, and the operations that are characteristic of the superdirective acoustic device according to the second embodiment will be described.
The audio signal generated by the audio generator 1 as described above is input to the amplitude modulator 2a and the amplitude modulator 2b. The amplitude modulator 2a performs a multiplication process by inputting the carrier signal indicating the carrier wave of the frequency f1 generated by the carrier wave generation unit 21 and the audio signal from the audio generator 1 to the multiplication unit 22. By this arithmetic processing, the carrier wave of frequency f1 is amplitude-modulated by the audio signal. A multiplication signal T 1 as a calculation result is output from the multiplier 22 to the adder 25.
In addition, the amplitude modulator 2b inputs the carrier signal indicating the carrier wave having the frequency f2 generated by the carrier wave generation unit 23 and the audio signal from the audio generator 1 to the multiplication unit 24 and performs multiplication processing. By this arithmetic processing, the carrier wave of frequency f2 is amplitude-modulated by the audio signal. A multiplication signal T2 as a calculation result is output from the multiplication unit 24 to the adder 25.

加算器25は、振幅変調器2aから出力された乗算信号T1と振幅変調器2bから出力された乗算信号T2とを加算し、この演算処理によって周波数f1及び周波数f2の各搬送波によって搬送される可聴音声を示す変調信号を生成する。この変調信号は、増幅器3へ入力されて超指向性スピーカ4を駆動できるように増幅され、当該超指向性スピーカ4から前述のような周波数の異なる複数の搬送波から自己復調した可聴音声が放射される。
なお、ここで説明した搬送波の周波数f1と周波数f2は、実施の形態1で説明したものと同様な間隔を有しており、また、超指向性スピーカ4固有の複数の共振周波数の中のいずれかと概ね同様な周波数で、好ましくは同一周波数である。
ここで説明した実施の形態2による超指向性音響装置は、二つの振幅変調器2a,2bを備えて周波数が異なる二つの搬送波を用いるようにしているが、音声生成器1と加算器25との間に並列に備えられる振幅変調器の数、即ち搬送波の数は二つに限定されるものではない。
The adder 25 adds the multiplication signal T1 output from the amplitude modulator 2a and the multiplication signal T2 output from the amplitude modulator 2b, and is audible carried by each carrier wave of the frequency f1 and the frequency f2 by this arithmetic processing. A modulation signal indicating sound is generated. This modulated signal is input to the amplifier 3 and amplified so that the super directional speaker 4 can be driven, and audible sound self-demodulated from a plurality of carriers having different frequencies as described above is emitted from the super directional speaker 4. The
The frequency f1 and the frequency f2 of the carrier wave described here have the same interval as that described in the first embodiment, and any of the resonance frequencies unique to the superdirective speaker 4 can be obtained. The frequency is generally the same, and preferably the same frequency.
The superdirective acoustic apparatus according to the second embodiment described here includes two amplitude modulators 2a and 2b and uses two carrier waves having different frequencies. However, the sound generator 1 and the adder 25 The number of amplitude modulators provided in parallel, i.e., the number of carrier waves, is not limited to two.

以上のように実施の形態2によれば、振幅変調器2a,2bと、振幅変調器2aの出力信号と振幅変調器2bの出力信号とを加算する加算器25とを備えたので、効率よく超指向性スピーカを動作させることができ、当該超指向性スピーカ4の放射した超音波から自己復調する可聴音声の音圧を大きくすることができるという効果がある。   As described above, according to the second embodiment, the amplitude modulators 2a and 2b and the adder 25 that adds the output signal of the amplitude modulator 2a and the output signal of the amplitude modulator 2b are provided. The super directional speaker can be operated, and the sound pressure of the audible sound that self-demodulates from the ultrasonic wave radiated from the super directional speaker 4 can be increased.

この発明の実施の形態1による超指向性音響装置の構成を示すブロック図である。It is a block diagram which shows the structure of the super-directional sound apparatus by Embodiment 1 of this invention. 超指向性スピーカの音圧周波数特性を示す説明図である。It is explanatory drawing which shows the sound pressure frequency characteristic of a super-directional speaker. 実施の形態1による超指向性音響装置の動作を示す説明図である。FIG. 6 is an explanatory diagram illustrating an operation of the superdirective acoustic device according to the first embodiment. 実施の形態1による超指向性音響装置の動作を示す説明図である。FIG. 6 is an explanatory diagram illustrating an operation of the superdirective acoustic device according to the first embodiment. この発明の実施の形態2による超指向性音響装置の構成を示すブロック図である。It is a block diagram which shows the structure of the super-directional sound apparatus by Embodiment 2 of this invention.

符号の説明Explanation of symbols

1 音声生成器、2,2a,2b 振幅変調器、3 増幅器、4 超指向性スピーカ、11,13,21,23 搬送波生成部、12,14,22,24 乗算部、15 加算部、25 加算器。   DESCRIPTION OF SYMBOLS 1 Sound generator, 2, 2a, 2b Amplitude modulator, 3 amplifier, 4 super directional speaker, 11, 13, 21, 23 Carrier generation part, 12, 14, 22, 24 Multiplication part, 15 addition part, 25 addition vessel.

Claims (4)

音声生成手段から入力した音声信号で超音波帯域の搬送波を変調する変調手段と、前記変調手段の生成した変調信号を増幅する増幅手段と、前記増幅手段の増幅した変調信号に基づいて超音波を発生する超指向性スピーカとを備えた超指向性音響装置において、
前記変調手段に、
周波数の異なる複数の搬送波信号を生成する搬送波生成手段と、
前記音声生成手段からの音声信号と前記搬送波生成手段からの各搬送波信号とを各々乗算して各乗算信号を生成する乗算手段と、
前記乗算手段が生成した全ての乗算信号を加算して変調信号を生成する加算手段と、
を備えることを特徴とする超指向性音響装置。
A modulation unit that modulates a carrier wave in an ultrasonic band with an audio signal input from the audio generation unit, an amplification unit that amplifies the modulation signal generated by the modulation unit, and an ultrasonic wave based on the modulation signal amplified by the amplification unit In a super directional acoustic device equipped with a super directional speaker that generates,
In the modulation means,
Carrier wave generating means for generating a plurality of carrier wave signals having different frequencies;
Multiplying means for multiplying the audio signal from the sound generating means and each carrier signal from the carrier generating means to generate each multiplied signal;
Adding means for adding all the multiplication signals generated by the multiplication means to generate a modulation signal;
A superdirective acoustic device comprising:
搬送波生成手段は、超指向性スピーカの固有の複数の共振周波数と同様な各周波数を各々搬送波の周波数として用いた搬送波信号を生成することを特徴とする請求項1記載の超指向性音響装置。   2. The superdirective acoustic device according to claim 1, wherein the carrier wave generating means generates a carrier wave signal using each frequency similar to a plurality of resonance frequencies unique to the superdirective speaker as a carrier frequency. 搬送波生成手段は、各搬送波の間隔を音声信号が表す帯域の上限周波数値よりも離間して各搬送波信号を生成することを特徴とする請求項1または請求項2記載の超指向性音響装置。   The superdirective acoustic device according to claim 1 or 2, wherein the carrier generation means generates each carrier signal with an interval between each carrier separated from an upper limit frequency value of a band represented by the audio signal. 搬送波生成手段は、音声信号が表す帯域の上限周波数の二倍の周波数値よりも離間した各搬送波信号を生成することを特徴とする請求項3記載の超指向性音響装置。   4. The superdirective acoustic device according to claim 3, wherein the carrier wave generating means generates each carrier wave signal separated from a frequency value that is twice the upper limit frequency of the band represented by the audio signal.
JP2006048805A 2006-02-24 2006-02-24 Super-directional sound device Pending JP2007228402A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2006048805A JP2007228402A (en) 2006-02-24 2006-02-24 Super-directional sound device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2006048805A JP2007228402A (en) 2006-02-24 2006-02-24 Super-directional sound device

Publications (1)

Publication Number Publication Date
JP2007228402A true JP2007228402A (en) 2007-09-06

Family

ID=38549740

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2006048805A Pending JP2007228402A (en) 2006-02-24 2006-02-24 Super-directional sound device

Country Status (1)

Country Link
JP (1) JP2007228402A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010032463A1 (en) * 2008-09-18 2010-03-25 パナソニック株式会社 Sound reproducing apparatus
JP2012217017A (en) * 2011-03-31 2012-11-08 Nec Casio Mobile Communications Ltd Loudspeaker device and electronic apparatus
WO2014041587A1 (en) * 2012-09-14 2014-03-20 Necカシオモバイルコミュニケーションズ株式会社 Speaker device and electronic equipment
KR101943384B1 (en) * 2017-08-08 2019-01-29 포항공과대학교 산학협력단 Active noise removing system and method for variable path using super-directional speaker

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62296698A (en) * 1986-06-17 1987-12-23 Matsushita Electric Ind Co Ltd Parametric speaker

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62296698A (en) * 1986-06-17 1987-12-23 Matsushita Electric Ind Co Ltd Parametric speaker

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010032463A1 (en) * 2008-09-18 2010-03-25 パナソニック株式会社 Sound reproducing apparatus
JP2010074488A (en) * 2008-09-18 2010-04-02 Panasonic Corp Sound reproducing device
KR101181188B1 (en) 2008-09-18 2012-09-18 파나소닉 주식회사 Sound reproducing apparatus
CN102160399B (en) * 2008-09-18 2013-11-27 松下电器产业株式会社 Sound reproducing apparatus
US9100755B2 (en) 2008-09-18 2015-08-04 Panasonic Intellectual Property Management Co., Ltd. Sound reproducing apparatus for sound reproduction using an ultrasonic transducer via mode-coupled vibration
JP2012217017A (en) * 2011-03-31 2012-11-08 Nec Casio Mobile Communications Ltd Loudspeaker device and electronic apparatus
WO2014041587A1 (en) * 2012-09-14 2014-03-20 Necカシオモバイルコミュニケーションズ株式会社 Speaker device and electronic equipment
KR101943384B1 (en) * 2017-08-08 2019-01-29 포항공과대학교 산학협력단 Active noise removing system and method for variable path using super-directional speaker

Similar Documents

Publication Publication Date Title
JP6274497B2 (en) Parametric speaker
JPH11164384A (en) Super directional speaker and speaker drive method
JP2005204288A (en) Method of driving directional speaker, and the directional speaker
JP2007228402A (en) Super-directional sound device
JP4535758B2 (en) Superdirective speaker modulator
JP2020010408A (en) Radiation method from parametric speaker, parametric speaker, signal processing device, and signal processing program
JP2007201624A (en) Modulator for super-directivity speaker
JP4799303B2 (en) Modulator and superdirective acoustic device
JP5821241B2 (en) Speaker device and electronic device
JP2005234203A (en) Silencing system and electronic equipment
JP3668180B2 (en) Ultrasonic reproduction method / Ultrasonic reproduction device
JP4783921B2 (en) Super directional speaker
JP2009290253A (en) Parametric speaker
JP2011041266A (en) Human body sound transmitting device and method for minimizing loss of signal
Sakai et al. Dynamic single sideband modulation for realizing parametric loudspeaker
US10750275B2 (en) Speaker device and control method for a speaker device
JP4785647B2 (en) Super directional acoustic device
JP6171752B2 (en) Noise reduction device
JP2009046236A (en) Post for man conveyor
CN101984555B (en) Parametric array audio play system
JPH08149592A (en) Parametric speaker controller
JP2005236420A (en) Modulator for super-directivity speaker
JP2006003405A (en) Projector and projector silencing control method
JP2008113194A (en) Ultrasonic element and ultra-directional speaker
JP3668187B2 (en) Sound reproduction method and sound reproduction apparatus

Legal Events

Date Code Title Description
RD04 Notification of resignation of power of attorney

Effective date: 20071105

Free format text: JAPANESE INTERMEDIATE CODE: A7424

RD04 Notification of resignation of power of attorney

Effective date: 20080909

Free format text: JAPANESE INTERMEDIATE CODE: A7424

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20081002

A977 Report on retrieval

Effective date: 20101129

Free format text: JAPANESE INTERMEDIATE CODE: A971007

A131 Notification of reasons for refusal

Effective date: 20101207

Free format text: JAPANESE INTERMEDIATE CODE: A131

A02 Decision of refusal

Effective date: 20110426

Free format text: JAPANESE INTERMEDIATE CODE: A02