JPH08331065A - Acoustic communication equipment - Google Patents
Acoustic communication equipmentInfo
- Publication number
- JPH08331065A JPH08331065A JP15706295A JP15706295A JPH08331065A JP H08331065 A JPH08331065 A JP H08331065A JP 15706295 A JP15706295 A JP 15706295A JP 15706295 A JP15706295 A JP 15706295A JP H08331065 A JPH08331065 A JP H08331065A
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- Prior art keywords
- reflected wave
- signal
- received
- unit
- wave
- 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.)
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- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、超音波を用いて通信を
行う音響通信装置に関し、特に水中のように反射波の干
渉が生ずる環境下における通信を行う超音波を用いた音
響通信装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acoustic communication device which uses ultrasonic waves for communication, and more particularly to an acoustic communication device which uses ultrasonic waves for communication in an environment where reflected waves interfere with each other, such as underwater. .
【０００２】[0002]
【従来の技術】水中に配置された観測ステーションや水
中移動体と水上の観測船や母船との間で通信を行う場
合、超音波を用いた音響通信装置が用いられている。2. Description of the Related Art An acoustic communication device using ultrasonic waves is used for communication between an observation station or an underwater moving body placed underwater and an observation ship or mother ship on the water.
【０００３】従来、この種の水中における通信を目的と
する超音波を用いた音響通信装置は、通信を行う両者の
相対位置が移動しても相互の送受波器のビーム範囲内に
存在するように、それぞれの送受波器のビーム幅を広く
している。このため、送受波器が広範囲からのノイズを
入力してしまうため通信品質の劣化を招来していた。ま
た、通信内容を秘密にしたい場合にも不都合であった。Conventionally, an acoustic communication device using ultrasonic waves for the purpose of underwater communication of this type seems to exist within the beam range of a mutual transceiver even if the relative positions of the two communicating with each other move. In addition, the beam width of each transducer is widened. For this reason, the transmitter / receiver inputs noise from a wide range, resulting in deterioration of communication quality. It is also inconvenient when it is desired to keep the communication contents secret.
【０００４】そこで、このような問題を回避するため、
ビームの指向範囲を狭めた狭ビームを用いて、ビームパ
ターンを互いの指向方向に向けて通信を行う音響通信装
置が提案されている。Therefore, in order to avoid such a problem,
An acoustic communication device has been proposed in which a narrow beam having a narrow beam directivity range is used to perform communication by directing beam patterns in mutually directing directions.
【０００５】水中に配置された観測ステーションと水上
の観測船との間の通信を例として説明すると、まず、観
測船がＧＰＳ（Ｇｌｏｂａｌ Ｐｏｓｉｔｉｏｎｉｎｇ
Ｓｙｓｔｅｍ）等の航法装置を用いて観測ステーショ
ンに近い位置に移動する。そして、観測船から観測ステ
ーションが存在すると考えられるいくつかの方向にセン
サーデータ要求コマンドを超音波信号として送波する。The communication between an observation station arranged underwater and an observation ship on the water will be described as an example. First, the observation ship is GPS (Global Positioning).
Use a navigation system such as System) to move to a position near the observation station. Then, the sensor data request command is transmitted as an ultrasonic signal from the observation ship in some directions in which the observation station is considered to exist.
【０００６】観測ステーションは、センサーデータ要求
コマンドの超音波信号を受波すると、まず、当該信号の
送波された方向を算出する。そして、観測結果であるセ
ンサーデータをＦＳＫ（Ｆｒｅｑｕｅｎｓｙ Ｓｈｉｆ
ｔ Ｋｅｙｉｎｇ）信号やＰＳＫ（Ｐｈａｓｅ Ｓｈｉ
ｆｔ Ｋｅｙｉｎｇ）信号に変換し、算出した観測船の
方向に向けて送波する。Upon receiving the ultrasonic signal of the sensor data request command, the observation station first calculates the direction in which the signal was transmitted. Then, the sensor data as the observation result is converted into FSK (Frequency Shift).
t Keying) signal or PSK (Phase Shi)
ft Keying) signal, and transmits toward the calculated direction of the observation ship.
【０００７】観測船は、センサーデータの超音波信号を
受波すると、当該信号の送波された方向を算出する。こ
れ以後の通信は、算出された観測ステーションの方向に
向けて行うこととなる。また、受波した超音波信号は、
復調してセンサーデータとして取得する。この種の技術
としては、例えば特許公開公報、平３−２４５６２５号
に開示された技術がある。Upon receiving the ultrasonic signal of the sensor data, the observation ship calculates the direction in which the signal is transmitted. Subsequent communications will be directed toward the calculated observation station. Also, the received ultrasonic signal is
Demodulate and acquire as sensor data. Examples of this type of technology include the technology disclosed in Japanese Patent Laid-Open No. 3-245625.
【０００８】[0008]
【発明が解決しようとする課題】しかし、上述した従来
の音響通信装置は、直接受信する信号と水面等で反射さ
れた反射波の信号との干渉により発生するデータエラー
を低減するため、超音波信号の送受波器のサイドローブ
を十分に抑え、かつ指向性ビームを可能な限り幅の狭い
ものにする必要がある。このため、観測船や観測ステー
ションに搭載する通信用のハードウェアの規模が大きく
なるという欠点があった。However, in the above-described conventional acoustic communication device, in order to reduce the data error caused by the interference between the signal directly received and the signal of the reflected wave reflected on the water surface or the like, the ultrasonic wave is generated. It is necessary to sufficiently suppress the side lobes of the signal transmitter / receiver and to make the directional beam as narrow as possible. For this reason, there is a drawback that the scale of communication hardware mounted on the observation ship or observation station becomes large.
【０００９】また、十分に幅の狭い指向性ビームを用い
るため、観測船と観測ステーションの指向性ビームを相
互に正確に向かい合わせることが困難であるという欠点
があった。Further, since a directional beam having a sufficiently narrow width is used, it is difficult to accurately cause the directional beams of the observation ship and the observation station to face each other.
【００１０】本発明は、上記従来の欠点を解消し、反射
波を原因とするデータエラーを低減し、かつ指向性ビー
ムの方向の決定が容易な音響通信装置を提供することを
目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional drawbacks, reduce a data error caused by a reflected wave, and provide an acoustic communication device in which the direction of a directional beam can be easily determined.
【００１１】[0011]
【課題を解決するための手段】上述した問題点を解決す
るため、本発明は、電気信号を超音波信号に変換して送
波し、受波した超音波信号を電気信号に変換する送受波
手段を備える音響通信装置において、受波した受信信号
のうち他の音響通信装置から送波された後１回以上の反
射を経て受波した反射波による受信信号の受信レベルを
低減する反射波低減手段を備える。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a transmission / reception in which an electric signal is converted into an ultrasonic signal for transmission and the received ultrasonic signal is converted into an electric signal. In an acoustic communication device provided with means, reflected wave reduction for reducing a reception level of a received signal by a reflected wave received after receiving at least one reflection after being transmitted from another acoustic communication device among received signals received Means are provided.
【００１２】また、他の態様では、前記反射波低減手段
が、受波した信号のうち既知の周波数およびパルス幅の
信号を解析して前記他の超音波通信装置から直接受波し
た直接波の入射時刻と反射波の入射時刻との間の遅延時
間および前記反射波の入射角を算出する手段と、前記算
出した反射波の遅延時間と入射角とに基づいて受信信号
のうち反射波による受信信号を区別して低減する手段と
を備える構成としている。[0012] In another aspect, the reflected wave reducing means analyzes a signal having a known frequency and a pulse width among the received signals and detects the direct wave directly received from the other ultrasonic communication device. Means for calculating the delay time between the incident time and the incident time of the reflected wave and the incident angle of the reflected wave, and reception by the reflected wave of the received signal based on the calculated delay time of the reflected wave and the incident angle And a means for distinguishing and reducing signals.
【００１３】また、他の態様では、指向性を備えた指向
性ビームと無指向性の無指向ビームとからなる受波ビー
ムを形成する手段をさらに備え、前記反射波低減手段
が、受波した信号のうち既知の周波数およびパルス幅の
信号を解析して前記他の超音波通信装置から直接受波し
た直接波の入射時刻と反射波の入射時刻との間の遅延時
間および前記反射波の入射角を算出する手段と、前記無
指向ビームにて受信した受信信号から前記指向性ビーム
にて受信した受信信号を減算して該受信信号中の反射波
成分を抽出する手段と、前記算出した反射波の遅延時間
と入射角とに基づいて前記抽出された反射波成分の受信
レベルを算出し前記受信信号から減算する手段とを備え
る構成としている。According to another aspect, there is further provided a means for forming a received beam composed of a directional beam having directivity and an omnidirectional omnidirectional beam, and the reflected wave reducing means receives the wave. The delay time between the incident time of the direct wave and the incident time of the reflected wave received directly from the other ultrasonic communication device by analyzing the signal of known frequency and pulse width among the signals and the incidence of the reflected wave Means for calculating an angle, means for subtracting a received signal received by the directional beam from a received signal received by the omnidirectional beam to extract a reflected wave component in the received signal, and the calculated reflection And a means for calculating the reception level of the extracted reflected wave component based on the delay time of the wave and the incident angle and subtracting the reception level from the reception signal.
【００１４】上記目的を達成する他の音響通信装置で
は、電気信号を超音波信号に変換して送波する送波手段
を備えた第１のユニットと該第１のユニットから送波し
た超音波信号を受波し電気信号に変換する受波手段を備
えた第２のユニットとからなる音響通信装置において、
前記第１のユニットが、あらかじめ設定された周波数お
よびパルス幅の試験信号を送信する試験信号送信手段
と、目的のデータを送信するデータ送信手段とを備え、
前記第２のユニットが、受波した受信信号のうち前記第
１のユニットから送波された後１回以上の反射を経て受
波した反射波による受信信号の受信レベルを低減する反
射波低減手段と、該反射波低減手段によって反射波を低
減された受信信号から前記目的のデータを取得するデー
タ取得手段とを備え、前記反射波低減手段が、前記第１
のユニットから送信された試験信号を解析して前記第１
のユニットから直接受波した直接波の入射時刻と反射波
の入射時刻との間の遅延時間および前記反射波の入射角
を算出する手段と、前記算出した反射波の遅延時間と入
射角とに基づいて前記第１のユニットから送信されたデ
ータの受信信号のうち反射波による受信信号を区別して
低減する手段とを備える。In another acoustic communication device that achieves the above object, a first unit having a wave transmitting means for converting an electric signal into an ultrasonic wave signal and transmitting the ultrasonic wave signal, and an ultrasonic wave transmitted from the first unit. An acoustic communication device comprising a second unit having a wave receiving means for receiving a signal and converting the signal into an electric signal,
The first unit includes a test signal transmitting unit that transmits a test signal having a preset frequency and a pulse width, and a data transmitting unit that transmits target data.
The reflected wave reducing means for reducing the reception level of the received signal by the reflected wave received by the second unit after having been transmitted at least once after being transmitted from the first unit among the received signals received by the second unit. And a data acquisition unit that acquires the target data from the received signal whose reflected wave is reduced by the reflected wave reducing unit, wherein the reflected wave reducing unit is the first
Analyzing the test signal transmitted from the unit of
Means for calculating the delay time between the incident time of the direct wave received directly from the unit and the incident time of the reflected wave and the incident angle of the reflected wave; and the calculated delay time and incident angle of the reflected wave. Based on the received signal of the data transmitted from the first unit, a means for distinguishing and reducing the received signal by the reflected wave is provided.
【００１５】また、他の態様では、前記第２のユニット
が、指向性を備えた指向性ビームと無指向性の無指向ビ
ームとからなる受波ビームを形成する手段をさらに備
え、前記反射波低減手段が、前記無指向ビームにて受信
した受信信号から前記指向性ビームにて受信した受信信
号を減算して前記データの受信信号中の反射波成分を抽
出する手段と、前記算出した反射波の遅延時間と入射角
とに基づいて前記抽出されたデータの受信信号における
反射波成分の受信レベルを算出し前記データの受信信号
から減算する手段とを備える構成としている。In another aspect, the second unit further includes means for forming a received beam including a directional beam having directivity and an omnidirectional beam having no directivity, and the reflected wave is provided. Reducing means subtracts the received signal received by the directional beam from the received signal received by the omnidirectional beam to extract a reflected wave component in the received signal of the data; and the calculated reflected wave Means for calculating the reception level of the reflected wave component in the received signal of the extracted data based on the delay time and the incident angle and subtracting it from the received signal of the data.
【００１６】[0016]
【作 用】本発明によれば、反射波低減手段が、既知の
周波数およびパルス幅の信号を用いて反射波の受波の遅
延時間と入射角とを算出し、これに基づいて受信信号か
ら反射波成分の受信レベルを低減することができる。ま
た、無指向ビームと指向性ビームとの受信信号を比較す
ることにより受信信号の中から反射波成分を容易に抽出
することができる。[Operation] According to the present invention, the reflected wave reducing means calculates the delay time and the incident angle of reception of the reflected wave using signals of known frequency and pulse width, and based on this, The reception level of the reflected wave component can be reduced. Further, the reflected wave component can be easily extracted from the received signal by comparing the received signals of the omnidirectional beam and the directional beam.
【００１７】[0017]
【実施例】次に、本発明の実施例について図面を参照し
て説明する。図１は、本発明の１実施例による音響通信
装置の構成を示すブロック図である。なお、本実施例で
は、図２に示す様に、音響通信装置を海底等の水中に配
置された観測ステーションと海上の観測船とに搭載し、
観測ステーションによる観測データ（センサーデータ）
を観測船に送信する場合を例として説明する。Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an acoustic communication device according to an embodiment of the present invention. In the present embodiment, as shown in FIG. 2, the acoustic communication device is mounted on an observation station placed underwater such as the seabed and an observation ship on the sea,
Observation data from the observation station (sensor data)
Will be described as an example.
【００１８】図示のように、本実施例の音響通信装置
は、観測船に搭載されたデータの受信を主目的とする音
響通信装置１０と、観測ステーションに搭載されたデー
タの送信を主目的とする音響通信装置２０とからなる。As shown in the figure, the acoustic communication device of the present embodiment has an acoustic communication device 10 mainly for receiving data mounted on an observation ship and an acoustic communication device 10 mainly for transmitting data mounted on an observation station. And the acoustic communication device 20.
【００１９】観測船に搭載された音響通信装置１０は、
超音波信号を送信および受信するＮチャンネル送受波器
アレイ１１と、観測ステーションから送られたセンサー
データを受信するためのＮチャンネルプリアンプ１２、
整相器１３、受信した超音波信号が送信された方向を算
出するビーム方向演算器１４、反射波の受信レベルを低
減する反射波低減回路１５、および復調器１６と、観測
ステーションにセンサーデータの送信を要求するセンサ
ーデータ要求コマンドを送信するための整相器１７およ
びＮチャンネルパワーアンプ１８とを備える。The acoustic communication device 10 mounted on the observation ship is
An N-channel transducer array 11 for transmitting and receiving ultrasonic signals, and an N-channel preamplifier 12 for receiving sensor data sent from the observation station,
The phase shifter 13, the beam direction calculator 14 for calculating the direction in which the received ultrasonic signal is transmitted, the reflected wave reduction circuit 15 for reducing the reception level of the reflected wave, and the demodulator 16, and the sensor data for the observation station. A phase adjuster 17 and an N-channel power amplifier 18 for transmitting a sensor data request command for requesting transmission are provided.
【００２０】Ｎチャンネル送受波器アレイ１１は、超音
波信号の送受を行う送受波器を配列して構成され、電気
信号を超音波信号にして送波したり、超音波信号を受波
して電気信号に変換したりする。チャンネル数Ｎの値
は、一般的に４（２×２）、９（３×３）、１６（４×
４）、２５（５×５）等である。幅の狭いシャープなビ
ームを得るためには大きな値をとることとなるが、本実
施例では、従来のビームパターンを互いの指向方向に向
けて通信を行う技術において必要とされるようなシャー
プなビームは必要ない。したがって、チャンネル数の値
も比較的小さい値であってもよい。The N-channel transducer array 11 is formed by arranging transducers for transmitting and receiving ultrasonic signals, and transmits and receives electric signals as ultrasonic signals and receives ultrasonic signals. It is converted into an electric signal. The number of channels N is generally 4 (2 × 2), 9 (3 × 3), 16 (4 ×).
4), 25 (5 × 5), etc. It takes a large value to obtain a narrow and sharp beam, but in the present embodiment, a sharp beam, which is required in the technique for communicating by directing beam patterns in the conventional directions to each other, is used. No beam required. Therefore, the value of the number of channels may be a relatively small value.
【００２１】Ｎチャンネルプリアンプ１２は、Ｎチャン
ネル送受波器アレイ１１で受波した受信信号を前置増幅
する。整相器１３は、一定の指向性を有する狭ビームと
無指向ビームとからなる受波ビームを形成する。そし
て、Ｎチャンネルプリアンプ１２で増幅した受信信号の
うち、当該超音波信号の送波元の方向を指向する狭ビー
ムで受波した信号（狭ビーム受信信号１０１）を抽出す
る。ビーム方向演算器１４は、Ｎチャンネルプリアンプ
１２、整相器１３を介して入力した受信信号に基づいて
当該超音波信号が送信された方向を算出する。なお、観
測船と観測ステーションとの相対位置は常に変化するの
で、整相器１３およびビーム方向演算器１４による狭ビ
ーム受信信号１０１のフィードバックと狭ビーム方向の
設定は随時行う。The N-channel preamplifier 12 preamplifies the reception signal received by the N-channel transmitter / receiver array 11. The phase shifter 13 forms a received beam composed of a narrow beam having a certain directivity and an omnidirectional beam. Then, of the reception signals amplified by the N-channel preamplifier 12, a signal (narrow beam reception signal 101) received by a narrow beam directed in the direction of the transmission source of the ultrasonic signal is extracted. The beam direction calculator 14 calculates the direction in which the ultrasonic signal is transmitted based on the reception signal input via the N-channel preamplifier 12 and the phase adjuster 13. Since the relative position between the observation ship and the observation station is constantly changing, the feedback of the narrow beam reception signal 101 and the setting of the narrow beam direction by the phase shifter 13 and the beam direction calculator 14 are performed at any time.
【００２２】反射波低減回路１５は、Ｎチャンネルプリ
アンプ１２で増幅された受信信号（無指向ビーム受信信
号１０２）と整相器１３にて抽出された狭ビーム受信信
号１０１とを入力し、受信信号のうち、観測ステーショ
ンの音響通信装置２０から直接受波した直接波による受
信信号と海面等で反射した後受波した反射波による受信
信号とを区別し、反射波による受信信号を低減する。反
射波による受信信号の低減の動作については後述する。The reflected wave reduction circuit 15 inputs the reception signal (omnidirectional beam reception signal 102) amplified by the N-channel preamplifier 12 and the narrow beam reception signal 101 extracted by the phase shifter 13, and receives the reception signal. Among them, the received signal by the direct wave directly received from the acoustic communication device 20 of the observation station and the received signal by the reflected wave received after being reflected by the sea surface etc. are distinguished and the received signal by the reflected wave is reduced. The operation of reducing the received signal by the reflected wave will be described later.
【００２３】復調器１６は、反射波低減回路１５によっ
て反射波を低減された信号を復調する。これによって観
測ステーションにおける観測結果であるセンサーデータ
を取得することができる。The demodulator 16 demodulates the signal whose reflected wave is reduced by the reflected wave reducing circuit 15. As a result, sensor data, which is the observation result at the observation station, can be acquired.
【００２４】整相器１７は、一定の指向性を有する送波
ビーム（狭ビーム）を形成し、観測ステーションにセン
サーデータの送信を要求するセンサーデータ要求コマン
ドを送信するためのビームフォーミングを行う。なお、
整相器１７によるビームフォーミングの方向は、整相器
１３およびビーム方向演算器１４による受波ビームの狭
ビーム方向の設定をフィードバックして制御する。Ｎチ
ャンネルパワーアンプ１８は、整相器１７でビームフォ
ーミングしたセンサーデータ要求コマンドの信号を電力
増幅してＮチャンネル送受波器アレイ１１に送る。The phase adjuster 17 forms a transmission beam (narrow beam) having a certain directivity and performs beam forming for transmitting a sensor data request command for requesting transmission of sensor data to the observation station. In addition,
The direction of the beam forming by the phase adjuster 17 is controlled by feeding back the setting of the narrow beam direction of the received beam by the phase adjuster 13 and the beam direction calculator 14. The N-channel power amplifier 18 power-amplifies the signal of the sensor data request command beamformed by the phase adjuster 17 and sends it to the N-channel transducer array 11.
【００２５】観測ステーションに搭載された音響通信装
置２０は、超音波信号を送信および受信するＮチャンネ
ル送受波器アレイ２１と、観測船から送られたセンサー
データ要求コマンドを受信するためのＮチャンネルプリ
アンプ２２、整相器２３、および受信した超音波信号が
送信された方向を算出するビーム方向演算器２４と、観
測船にセンサーデータを送信するための変調器２５、整
相器２６、およびＮチャンネルパワーアンプ２７と、観
測船の音響通信装置１０における反射波の低減を実行す
るために用いる反射波トレーニング信号を発生する反射
波トレーニング信号発生回路２８とを備える。The acoustic communication device 20 mounted on the observation station includes an N-channel transducer array 21 for transmitting and receiving ultrasonic signals and an N-channel preamplifier for receiving a sensor data request command transmitted from the observation ship. 22, a phase shifter 23, a beam direction calculator 24 for calculating the direction in which the received ultrasonic signal is transmitted, a modulator 25 for transmitting sensor data to the observation ship, a phase shifter 26, and N channels A power amplifier 27 and a reflected wave training signal generation circuit 28 that generates a reflected wave training signal used to reduce the reflected wave in the acoustic communication device 10 of the observation ship are provided.
【００２６】Ｎチャンネル送受波器アレイ２１、Ｎチャ
ンネルプリアンプ２２、整相器２３、ビーム方向演算器
２４、整相器２６、およびＮチャンネルパワーアンプ２
７は、それぞれ音響通信装置１０のＮチャンネル送受波
器アレイ１１、Ｎチャンネルプリアンプ１２、整相器１
３、ビーム方向演算器１４、整相器１７、およびＮチャ
ンネルパワーアンプ１８と同様である。N-channel transmitter / receiver array 21, N-channel preamplifier 22, phasing device 23, beam direction calculator 24, phasing device 26, and N-channel power amplifier 2
Reference numeral 7 denotes an N-channel transmitter / receiver array 11, an N-channel preamplifier 12, and a phase adjuster 1 of the acoustic communication device 10, respectively.
3, the beam direction calculator 14, the phase adjuster 17, and the N-channel power amplifier 18 are the same.
【００２７】変調器２５は、センサーデータをＦＳＫ
（Ｆｒｅｑｕｅｎｃｙ ＳｈｉｆｔＫｅｙｉｎｇ）信号
またはＰＳＫ（Ｐｈａｓｅ Ｓｈｉｆｔ Ｋｅｙｉｎ
ｇ）信号に変調する。変調されたセンサーデータの信号
は、整相器２６でビームフォーミングされ、Ｎチャンネ
ルパワーアンプ２７で電力増幅されてＮチャンネル送受
波器アレイ２１に送られる。The modulator 25 sends the sensor data to FSK.
(Frequency Shift Keying) signal or PSK (Phase Shift Keyin)
g) Modulate to signal. The modulated sensor data signal is beamformed by the phase adjuster 26, power-amplified by the N-channel power amplifier 27, and sent to the N-channel transceiver array 21.
【００２８】反射波トレーニング信号発生回路１７は、
観測船の音響通信装置１０の反射波低減回路１５による
反射波の低減を実行するために用いる反射波トレーニン
グ信号を発生する。反射波トレーニング信号は、あらか
じめ設定された周波数およびパルス幅のパルス波であ
る。この反射波トレーニング信号は、センサーデータと
同様に整相器２６およびＮチャンネルパワーアンプ２７
を介してＮチャンネル送受波器アレイ２１に送られる。The reflected wave training signal generation circuit 17 is
A reflected wave training signal used for executing the reflected wave reduction by the reflected wave reduction circuit 15 of the acoustic communication device 10 of the observation ship is generated. The reflected wave training signal is a pulse wave having a preset frequency and pulse width. This reflected wave training signal is similar to the sensor data in the phase adjuster 26 and the N channel power amplifier 27.
Is transmitted to the N-channel transducer array 21 via.
【００２９】ここで、音響通信装置１０の反射波低減回
路１５による反射波を低減する動作について説明する。
音響通信装置２０から反射波トレーニング信号が送波さ
れ、音響通信装置１０で受波すると、該反射波トレーニ
ング信号は、Ｎチャンネルプリアンプ１２から無指向ビ
ーム受信信号１０２として、整相器１３から狭ビーム受
信信号１０１として反射波低減回路１５に入力される。Here, the operation of reducing the reflected wave by the reflected wave reduction circuit 15 of the acoustic communication device 10 will be described.
When a reflected wave training signal is transmitted from the acoustic communication device 20 and received by the acoustic communication device 10, the reflected wave training signal is output from the N-channel preamplifier 12 as an omnidirectional beam reception signal 102 and from the phaser 13 to a narrow beam. The received signal 101 is input to the reflected wave reduction circuit 15.
【００３０】反射波低減回路１５は、まず、入力した反
射波トレーニング信号の受信信号を解析して直接波の受
波から反射波の受波までの遅延時間を算出する。反射波
は直接波よりも長い距離を経てＮチャンネル送受波器ア
レイ１１に受波されるため、図４に示すように、一定の
時間だけ遅れて受波される。反射波トレーニング信号
は、周波数およびパルス幅があらかじめ設定されている
ため、反射波の遅延時間Ｔｄを容易に算出することがで
きる。The reflected wave reduction circuit 15 first analyzes the received signal of the input reflected wave training signal and calculates the delay time from the reception of the direct wave to the reception of the reflected wave. Since the reflected wave is received by the N-channel transmitter / receiver array 11 after passing a longer distance than the direct wave, it is received with a delay of a certain time as shown in FIG. Since the frequency and pulse width of the reflected wave training signal are preset, the delay time Td of the reflected wave can be easily calculated.
【００３１】次に、無指向ビームにて受波する反射波の
受信レベルの値Ｒｍと狭ビームにて受波する反射波の受
信レベルの値Ｒｍ，ｎと狭ビームの指向性関数Ｄｎ
（θ）との関係、 Ｒｍ，ｎ＝Ｒｍ×Ｄｎ（θ） から反射波の入射角θを算出する。Next, the reception level value Rm of the reflected wave received by the omnidirectional beam, the reception level value Rm, n of the reflected wave received by the narrow beam, and the directivity function Dn of the narrow beam.
The incident angle θ of the reflected wave is calculated from the relationship with (θ) and Rm, n = Rm × Dn (θ).
【００３２】次に、音響通信装置２０からセンサーデー
タの超音波信号が送波され、音響通信装置１０で受波す
ると、該センサーデータの受信信号は、Ｎチャンネルプ
リアンプ１２から無指向ビーム受信信号１０２として、
整相器１３から狭ビーム受信信号１０１として反射波低
減回路１５に入力される。Next, when the ultrasonic signal of the sensor data is transmitted from the acoustic communication device 20 and received by the acoustic communication device 10, the received signal of the sensor data is the omnidirectional beam reception signal 102 from the N-channel preamplifier 12. As
The narrow beam reception signal 101 is input from the phase shifter 13 to the reflected wave reduction circuit 15.
【００３３】反射波低減回路１５は、まず、入力したセ
ンサーデータの受信信号のうち、無指向ビームの受信信
号Ｒｌ（ｔ）から狭ビームの受信信号Ｒｌ，ｎ（ｔ）を
減算する。図５に示すように、無指向ビームと狭ビーム
とでそれぞれ受信したセンサーデータの信号は、直接波
同士、反射波同士ではいずれも位相が一致している。ま
た、直接波の受信信号では、無指向ビーム受信信号の受
信レベルと狭ビーム受信信号の受信レベルとは原理的に
同一であるのに対し、反射波の受信信号では、狭ビーム
の指向性関数Ｄｎ（θ）によって、受信レベルが異な
る。したがって、無指向ビームの受信信号Ｒｌ（ｔ）か
ら狭ビームの受信信号Ｒｌ，ｎ（ｔ）を減算すれば、図
６に示すように、受信信号の反射波の成分のみを抽出す
ることができる。The reflected wave reduction circuit 15 first subtracts the reception signal Rl, n (t) of the narrow beam from the reception signal Rl (t) of the omnidirectional beam among the reception signals of the input sensor data. As shown in FIG. 5, the signals of the sensor data received by the omnidirectional beam and the narrow beam have the same phase between the direct waves and the reflected waves. In addition, in the direct wave reception signal, the reception level of the omnidirectional beam reception signal and the reception level of the narrow beam reception signal are theoretically the same, whereas in the reception signal of the reflected wave, the directivity function of the narrow beam is used. The reception level varies depending on Dn (θ). Therefore, if the reception signal Rl, n (t) of the narrow beam is subtracted from the reception signal Rl (t) of the omnidirectional beam, only the reflected wave component of the reception signal can be extracted as shown in FIG. .
【００３４】次に、反射波低減回路１５は、抽出した受
信信号の反射波成分を参照して、受信開始時刻ｔから遅
延時間Ｔｄだけ経過した後における狭ビーム受信信号Ｒ
ｌ，ｎ（ｔ＋Ｔｄ）の反射波成分の受信レベルＲｍ，ｎ
（ｔ＋Ｔｄ）を推定する。当該反射波成分の受信レベル
Ｒｍ，ｎ（ｔ＋Ｔｄ）は、 Ｒｍ，ｎ（ｔ＋Ｔｄ）＝｛Ｒｌ（ｔ＋Ｔｄ）−Ｒｌ，ｎ
（ｔ＋Ｔｄ）｝×Ｄｎ（θ）／｛１−Ｄｎ（θ）｝ で算出できる。Next, the reflected wave reduction circuit 15 refers to the extracted reflected wave component of the received signal, and receives the narrow beam received signal R after a delay time Td from the reception start time t.
Reception levels Rm, n of reflected wave components of l, n (t + Td)
Estimate (t + Td). The reception level Rm, n (t + Td) of the reflected wave component is Rm, n (t + Td) = {Rl (t + Td) -Rl, n
It can be calculated by (t + Td)} × Dn (θ) / {1-Dn (θ)}.
【００３５】そして、反射波低減回路１５は、狭ビーム
受信信号Ｒｌ，ｎ（ｔ）から反射波成分の推定値Ｒｍ，
ｎ（ｔ＋Ｔｄ）を減算することによって、反射波の受信
レベルの低減を行う。Then, the reflected wave reduction circuit 15 estimates the reflected wave component Rm, n from the narrow beam reception signal Rl, n (t).
The reception level of the reflected wave is reduced by subtracting n (t + Td).
【００３６】次に、図３のタイムチャートを参照して本
実施例の動作について説明する。まず、観測船がＧＢＳ
（Ｇｌｏｂａｌ Ｐｏｓｉｔｉｏｎｉｎｇ Ｓｙｓｔｅ
ｍ）等の航法装置を用いて観測ステーションの付近の海
上に移動する。そして、観測ステーションにセンサーデ
ータの送信を要求するセンサーデータ要求コマンドを生
成して、音響通信装置１０の整相器１７、Ｎチャンネル
パワーアンプ１８を介してＮチャンネル送受波器アレイ
１１に送り、観測ステーションが存在すると考えられる
いくつかの方向にセンサーデータ要求コマンドの超音波
信号を送波する。Next, the operation of this embodiment will be described with reference to the time chart of FIG. First, the observation ship is GBS
(Global Positioning System
Use the navigation device such as m) to move to the sea near the observation station. Then, a sensor data request command for requesting the transmission of sensor data to the observation station is generated and sent to the N-channel transducer array 11 via the phase shifter 17 and the N-channel power amplifier 18 of the acoustic communication device 10 for observation. The station sends out an ultrasonic signal of a sensor data request command in several directions in which it is considered that the station is present.
【００３７】観測ステーションは、音響通信装置２０の
Ｎチャンネル送受波器アレイ２１でセンサーデータ要求
コマンドの超音波信号を受波すると、当該信号をＮチャ
ンネルプリアンプ２２で増幅し、整相器２３およびビー
ム方向演算器２４によって当該超音波信号の送波元であ
る観測船の音響通信装置１０のＮチャンネル送受波器ア
レイ１１の方向を算出する。そして、算出された音響通
信装置１０の方向に基づいて整相器２６を調整し、ビー
ムフォーミングを制御する。When the N-channel transmitter / receiver array 21 of the acoustic communication device 20 receives the ultrasonic signal of the sensor data request command, the observation station amplifies the signal by the N-channel preamplifier 22, and the phase adjuster 23 and the beam. The direction calculator 24 calculates the direction of the N-channel transducer array 11 of the acoustic communication device 10 of the observation ship, which is the transmission source of the ultrasonic signal. Then, the phase adjuster 26 is adjusted based on the calculated direction of the acoustic communication device 10 to control the beamforming.
【００３８】次に、観測ステーションは、反射波トレー
ニング信号発生回路２８で反射波トレーニング信号を発
生し、整相器２６、Ｎチャンネルパワーアンプ２７を介
してＮチャンネル送受波器アレイ２１に送り、音響通信
装置１０に向けて送波する。そして、所定の時間をおい
た後、センサーデータを変調器２５でＦＳＫ信号または
ＰＳＫ信号に変換し、整相器２６、Ｎチャンネルパワー
アンプ２７を介してＮチャンネル送受波器アレイ２１か
ら音響通信装置１０に向けて送波する。Next, in the observation station, the reflected wave training signal generation circuit 28 generates a reflected wave training signal and sends it to the N channel transmitter / receiver array 21 via the phase rectifier 26 and the N channel power amplifier 27, and the acoustic wave is transmitted. The signal is transmitted to the communication device 10. Then, after a lapse of a predetermined time, the sensor data is converted into an FSK signal or a PSK signal by the modulator 25, and the acoustic communication device is transmitted from the N-channel transmitter / receiver array 21 via the phase adjuster 26 and the N-channel power amplifier 27. Transmit to 10.
【００３９】観測船は、音響通信装置１０のＮチャンネ
ル送受波器アレイ１１で反射波トレーニング信号を受波
すると、Ｎチャンネルプリアンプ１２、整相器１３を介
して反射波低減回路１５に受信信号を入力し、反射波の
遅延時間と入射角とを算出する。次に、Ｎチャンネル送
受波器アレイ１１でセンサーデータの超音波信号を受波
すると、Ｎチャンネルプリアンプ１２、整相器１３を介
して反射波低減回路１５に受信信号を入力し、反射波を
低減した後、復調器１６で受信信号を復調してセンサー
データを取得する。When the observation ship receives the reflected wave training signal at the N channel transmitter / receiver array 11 of the acoustic communication device 10, the received signal is sent to the reflected wave reduction circuit 15 via the N channel preamplifier 12 and the phase shifter 13. It is input, and the delay time of the reflected wave and the incident angle are calculated. Next, when the N channel transmitter / receiver array 11 receives the ultrasonic signal of the sensor data, the received signal is input to the reflected wave reduction circuit 15 via the N channel preamplifier 12 and the phase shifter 13 to reduce the reflected wave. After that, the demodulator 16 demodulates the received signal to obtain sensor data.
【００４０】以上好ましい実施例をあげて本発明を説明
したが、本発明は必ずしも上記実施例に限定されるもの
ではない。例えば、本実施例では、音響通信装置をデー
タの送信を主目的とする音響通信装置とデータの受信を
主目的とする音響通信装置とに分けて説明したが、各音
響通信装置において、データの送信および受信を相互に
行うようにしてもよい。この場合、いずれの音響通信装
置にも、送信するデータを変調する変調器と、反射波ト
レーニング信号を生成する反射波トレーニング信号発生
回路と、受信信号から反射波の信号を低減する反射波低
減回路と、受信信号を復調する復調器とを備えることと
なる。Although the present invention has been described above with reference to the preferred embodiments, the present invention is not necessarily limited to the above embodiments. For example, in the present embodiment, the acoustic communication device is described separately as an acoustic communication device whose main purpose is data transmission and an acoustic communication device whose main purpose is data reception. You may make it transmit and receive mutually. In this case, in any acoustic communication device, a modulator that modulates data to be transmitted, a reflected wave training signal generation circuit that generates a reflected wave training signal, and a reflected wave reduction circuit that reduces the reflected wave signal from the received signal And a demodulator for demodulating the received signal.
【００４１】さらに、本発明の音響通信装置は、本実施
例のように２個の音響通信装置間における所定のデータ
の送受信のみならず、３個以上の音響通信装置間での通
話等の目的で利用できるのは言うまでもない。Further, the acoustic communication device of the present invention is used not only for transmitting and receiving predetermined data between two acoustic communication devices as in this embodiment, but also for making a call between three or more acoustic communication devices. Needless to say, it can be used in.
【００４２】[0042]
【発明の効果】以上説明したように、本発明の音響通信
装置は、反射波の受波の遅延時間と入射角とを算出し、
これに基づいて受信信号から反射波成分の受信レベルを
低減することができるため、指向性ビーム（狭ビーム）
の幅が比較的広くても反射波の干渉等の影響によるデー
タエラーの発生が少ない。したがって、十分に狭い幅の
指向性ビームを形成するために観測船や観測ステーショ
ン等に搭載する通信用のハードウェアの規模が大きくな
ってしまうことを回避することができる。As described above, the acoustic communication device of the present invention calculates the delay time of the reflected wave and the incident angle,
Based on this, it is possible to reduce the reception level of the reflected wave component from the reception signal, so that the directional beam (narrow beam)
Even if the width is relatively wide, the occurrence of data error due to the influence of interference of reflected waves is small. Therefore, it is possible to prevent the scale of communication hardware mounted on an observation ship, an observation station, or the like from increasing in order to form a directional beam having a sufficiently narrow width.
【００４３】また、比較的幅の広い指向性ビームを用い
ることができるため、観測船と観測ステーションの指向
性ビームをあまり正確に向かい合わせる必要がなく、指
向性ビームの方向の設定が容易である。Since a directional beam having a relatively wide width can be used, it is not necessary to make the directional beams of the observation ship and the observation station face each other very accurately, and the direction of the directional beam can be easily set. .
【００４４】さらに、無指向ビームと指向性ビームとの
受信信号を比較することにより受信信号の中から反射波
成分を容易に抽出することができるため、受信信号中の
反射波の受信レベルの低減を容易に行うことができる。Furthermore, since the reflected wave component can be easily extracted from the received signal by comparing the received signals of the omnidirectional beam and the directional beam, the reception level of the reflected wave in the received signal can be reduced. Can be done easily.
【図面の簡単な説明】[Brief description of drawings]
【図１】 本発明の１実施例による音響通信装置の構成
を示すブロック図である。FIG. 1 is a block diagram showing a configuration of an acoustic communication device according to an embodiment of the present invention.
【図２】 本実施例による通信状態を示す概略図であ
る。FIG. 2 is a schematic diagram showing a communication state according to the present embodiment.
【図３】 本実施例の動作を示すタイムチャートであ
る。FIG. 3 is a time chart showing the operation of this embodiment.
【図４】 本実施例における反射波トレーニング信号の
送信信号と受信信号との関係を示すチャートである。FIG. 4 is a chart showing a relationship between a transmission signal and a reception signal of a reflected wave training signal in the present embodiment.
【図５】 本実施例における送信データと受信データと
の関係を示すチャートである。FIG. 5 is a chart showing the relationship between transmission data and reception data in this embodiment.
【図６】 本実施例における受信データのうち反射波に
よる受信データと受信データから反射波による受信デー
タを低減した状態と取得したデータとの関係を示すチャ
ートである。FIG. 6 is a chart showing the relationship between the received data by reflected waves and the state in which the received data by reflected waves is reduced from the received data and the acquired data in the received data in the present embodiment.
１０、２０ 音響通信装置 １１、２１ Ｎチャンネル送受波器アレイ １２、２２ Ｎチャンネルプリアンプ １３、１７、２３、２６ 整相器 １４、２４ ビーム方向演算器 １５ 反射波低減回路 １６ 復調器 １８、２７ Ｎチャンネルパワーアンプ ２５ 変調器 ２８ 反射波トレーニング信号発生回路 10, 20 Acoustic communication device 11, 21 N-channel transducer array 12, 22 N-channel preamplifier 13, 17, 23, 26 Phaser 14, 24 Beam direction calculator 15 Reflected wave reduction circuit 16 Demodulator 18, 27 N Channel power amplifier 25 Modulator 28 Reflected wave training signal generation circuit
Claims (5)
し、受波した超音波信号を電気信号に変換する送受波手
段を備える音響通信装置において、 受波した受信信号のうち他の音響通信装置から送波され
た後１回以上の反射を経て受波した反射波による受信信
号の受信レベルを低減する反射波低減手段を備えること
を特徴とする音響通信装置。1. An acoustic communication device comprising a wave transmitting / receiving means for converting an electric signal into an ultrasonic signal for transmission, and for converting the received ultrasonic signal into an electric signal. An acoustic communication device, comprising: a reflected wave reducing unit that reduces a reception level of a received signal by a reflected wave that has been transmitted from the acoustic communication device and then received through one or more reflections.
を解析することにより前記他の超音波通信装置から直接
受波した直接波の入射時刻と反射波の入射時刻との間の
遅延時間および前記反射波の入射角を算出する手段と、 前記算出した反射波の遅延時間と入射角とに基づいて受
信信号のうち反射波による受信信号を区別して低減する
手段とを備えることを特徴とする請求項１に記載の音響
通信装置。2. The reflected wave reducing means analyzes the signal having a known frequency and pulse width among the received signals to detect the incident time and reflection of the direct wave directly received from the other ultrasonic communication device. Means for calculating the delay time between the wave incident time and the incident angle of the reflected wave, and distinguishing the received signal of the reflected wave among the received signals based on the calculated delay time of the reflected wave and the incident angle The acoustic communication device according to claim 1, further comprising: a reducing unit.
の無指向ビームとからなる受波ビームを形成する手段を
さらに備え、 前記反射波低減手段が、 受波した信号のうち既知の周波数およびパルス幅の信号
を解析することにより前記他の超音波通信装置から直接
受波した直接波の入射時刻と反射波の入射時刻との間の
遅延時間および前記反射波の入射角を算出する手段と、 前記無指向ビームにて受信した受信信号から前記指向性
ビームにて受信した受信信号を減算することにより該受
信信号中の反射波成分を抽出する手段と、 前記算出した反射波の遅延時間と入射角とに基づいて前
記抽出された反射波成分の受信レベルを算出し前記受信
信号から減算する手段とを備えることを特徴とする請求
項１に記載の音響通信装置。3. A means for forming a received beam composed of a directional beam having directivity and an omnidirectional omnidirectional beam is further provided, and the reflected wave reducing means is a known signal among the received signals. The delay time between the incident time of the direct wave received directly from the other ultrasonic communication device and the incident time of the reflected wave and the incident angle of the reflected wave are calculated by analyzing the frequency and pulse width signals. Means, means for extracting a reflected wave component in the received signal by subtracting the received signal received by the directional beam from the received signal received by the omnidirectional beam, and delay of the calculated reflected wave The acoustic communication device according to claim 1, further comprising: a unit that calculates a reception level of the extracted reflected wave component based on time and an incident angle and subtracts the reception level from the reception signal.
る送波手段を備えた第１のユニットと該第１のユニット
から送波した超音波信号を受波し電気信号に変換する受
波手段を備えた第２のユニットとからなる音響通信装置
において、 前記第１のユニットが、あらかじめ設定された周波数お
よびパルス幅の試験信号を送信する試験信号送信手段
と、目的のデータを送信するデータ送信手段とを備え、 前記第２のユニットが、受波した受信信号のうち前記第
１のユニットから送波された後１回以上の反射を経て受
波した反射波による受信信号の受信レベルを低減する反
射波低減手段と、該反射波低減手段によって反射波を低
減された受信信号から前記目的のデータを取得するデー
タ取得手段とを備え、 前記反射波低減手段が、 前記第１のユニットから送信された試験信号を解析して
前記第１のユニットから直接受波した直接波の入射時刻
と反射波の入射時刻との間の遅延時間および前記反射波
の入射角を算出する手段と、 前記算出した反射波の遅延時間と入射角とに基づいて前
記第１のユニットから送信されたデータの受信信号のう
ち反射波による受信信号を区別して低減する手段とを備
えることを特徴とする音響通信装置。4. A first unit having a wave transmitting means for converting an electric signal into an ultrasonic wave signal and transmitting the ultrasonic wave signal, and an ultrasonic wave signal transmitted from the first unit is received and converted into an electric signal. In an acoustic communication device including a second unit including a wave receiving unit, the first unit transmits a test signal transmitting unit that transmits a test signal having a preset frequency and pulse width, and transmits target data. The second unit receives a received signal by a reflected wave received by the second unit after having been transmitted at least once after being transmitted from the first unit in the received signal received by the second unit. A reflected wave reducing unit that reduces the level; and a data acquisition unit that acquires the target data from the received signal whose reflected wave is reduced by the reflected wave reducing unit. Uni Means for analyzing the test signal transmitted from the first unit to calculate the delay time between the incident time of the direct wave received directly from the first unit and the incident time of the reflected wave and the incident angle of the reflected wave. A means for distinguishing and reducing a received signal due to the reflected wave among the received signals of the data transmitted from the first unit based on the calculated delay time of the reflected wave and the incident angle. Acoustic communication device.
指向性ビームと無指向性の無指向ビームとからなる受波
ビームを形成する手段をさらに備え、 前記反射波低減手段が、 前記無指向ビームにて受信した受信信号から前記指向性
ビームにて受信した受信信号を減算して前記データの受
信信号中の反射波成分を抽出する手段と、 前記算出した反射波の遅延時間と入射角とに基づいて前
記抽出されたデータの受信信号における反射波成分の受
信レベルを算出し前記データの受信信号から減算する手
段とを備えることを特徴とする請求項４に記載の音響通
信装置。5. The second unit further comprises means for forming a received beam composed of a directional beam having directivity and an omnidirectional omnidirectional beam, and the reflected wave reducing means, Means for extracting a reflected wave component in the received signal of the data by subtracting the received signal received by the directional beam from the received signal received by the omnidirectional beam; delay time and incidence of the calculated reflected wave The acoustic communication device according to claim 4, further comprising means for calculating a reception level of a reflected wave component in the received signal of the extracted data based on the angle and subtracting the received level from the received signal of the data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7157062A JP2720834B2 (en) | 1995-05-30 | 1995-05-30 | Acoustic communication device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7157062A JP2720834B2 (en) | 1995-05-30 | 1995-05-30 | Acoustic communication device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08331065A true JPH08331065A (en) | 1996-12-13 |
| JP2720834B2 JP2720834B2 (en) | 1998-03-04 |
Family
ID=15641385
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7157062A Expired - Lifetime JP2720834B2 (en) | 1995-05-30 | 1995-05-30 | Acoustic communication device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2720834B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011101821A (en) * | 1999-05-03 | 2011-05-26 | Remon Medical Technologies Ltd | Implantable acoustic biosensing system and method |
| US8934972B2 (en) | 2000-10-16 | 2015-01-13 | Remon Medical Technologies, Ltd. | Acoustically powered implantable stimulating device |
| US9024582B2 (en) | 2008-10-27 | 2015-05-05 | Cardiac Pacemakers, Inc. | Methods and systems for recharging an implanted device by delivering a section of a charging device adjacent the implanted device within a body |
| US9731141B2 (en) | 2007-06-14 | 2017-08-15 | Cardiac Pacemakers, Inc. | Multi-element acoustic recharging system |
| JP2019085703A (en) * | 2017-11-01 | 2019-06-06 | 古河機械金属株式会社 | Mining system of seabed deposit, mining machine and diving machine used for mining of the same, and mining method of the same |
| WO2020105538A1 (en) * | 2018-11-22 | 2020-05-28 | 日本電信電話株式会社 | Underwater acoustic communication system and receiving device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52454A (en) * | 1975-06-23 | 1977-01-05 | Nec Corp | Transponder installed in water |
-
1995
- 1995-05-30 JP JP7157062A patent/JP2720834B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52454A (en) * | 1975-06-23 | 1977-01-05 | Nec Corp | Transponder installed in water |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011101821A (en) * | 1999-05-03 | 2011-05-26 | Remon Medical Technologies Ltd | Implantable acoustic biosensing system and method |
| US8934972B2 (en) | 2000-10-16 | 2015-01-13 | Remon Medical Technologies, Ltd. | Acoustically powered implantable stimulating device |
| US9731141B2 (en) | 2007-06-14 | 2017-08-15 | Cardiac Pacemakers, Inc. | Multi-element acoustic recharging system |
| US9024582B2 (en) | 2008-10-27 | 2015-05-05 | Cardiac Pacemakers, Inc. | Methods and systems for recharging an implanted device by delivering a section of a charging device adjacent the implanted device within a body |
| JP2019085703A (en) * | 2017-11-01 | 2019-06-06 | 古河機械金属株式会社 | Mining system of seabed deposit, mining machine and diving machine used for mining of the same, and mining method of the same |
| WO2020105538A1 (en) * | 2018-11-22 | 2020-05-28 | 日本電信電話株式会社 | Underwater acoustic communication system and receiving device |
| JP2020088575A (en) * | 2018-11-22 | 2020-06-04 | 日本電信電話株式会社 | Underwater acoustic communication system and receiving device |
| US11923911B2 (en) | 2018-11-22 | 2024-03-05 | Nippon Telegraph And Telephone Corporation | Hydroacoustic communication system and receiving apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2720834B2 (en) | 1998-03-04 |
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