JP3759099B2 - Transceiver - Google Patents

Description

となる。ここでｊは虚数単位（−１）^1/2 、ωは印加電圧の角周波数を表している。
【００１１】
ＡＣ電源を利用する場合には、浮遊容量５３は無限大とみなすことができるので、式（１）からも明らかなようにＶ_b =Ｖ_s となり、信号は減衰することなく生体９に印加される。他方、ＡＣ電源を利用しない場合には、式（１）よりＶ_b ＜Ｖ_s となるため、生体９に印加される信号が減少するという問題があった。
【００１２】
本発明は上記に鑑みてなされたものであり、その目的は、電界伝達媒体に印加する電圧の減少を防止して、通信品質の向上を図ることのできるトランシーバを提供することにある。
【００１３】
【課題を解決するための手段】
上記目的を達成するために、請求項１記載の本発明は、送信すべき情報に基づく電界を電界伝達媒体に誘起し、この誘起した電界を用いて少なくとも情報の送信を行うトランシーバであって、所定の周波数を有する交流信号を発振して前記送信すべき情報を変調し、この変調した前記送信すべき情報に係る変調信号を送信する送信手段と、この送信手段のグランドと大地グランドの間に生じる浮遊容量と直列共振を起こす共振手段とを備えたことを要旨とする。
【００１４】
請求項１記載の本発明によれば、所定の周波数を有する交流信号を発振して送信すべき情報を変調した変調信号を送信する送信手段と、この送信手段のグランドと大地グランドの間に生じる浮遊容量と直列共振を起こす共振手段とを備えたトランシーバを提供することにより、電界伝達媒体に印加される電圧の減少を防止し、通信品質の向上を図ることができる。
【００１５】
請求項２記載の本発明は、送信すべき情報に基づく電界を電界伝達媒体に誘起し、この誘起した電界を用いて情報の送信を行う一方で、前記電界伝達媒体に誘起された受信すべき情報に基づく電界を受信することによって情報の受信を行うトランシーバであって、所定の周波数を有する交流信号を発振して前記送信すべき情報を変調し、この変調した前記送信すべき情報に係る変調信号を送信する送信手段と、前記送信すべき情報に基づく電界の誘起および前記受信すべき情報に基づく電界の受信を行う送受信電極と、前記送信手段のグランドと大地グランドの間に生じる浮遊容量と直列共振を起こすために前記送信手段および前記送受信電極と直列に接続される共振手段と、前記受信すべき情報に基づく電界を検出し、この検出した電界を電気信号に変換する電界検出手段と、この電界検出手段で変換した電気信号および前記変調信号に基づく基準信号を用いて前記共振手段が有する特性を制御する制御信号を出力する制御手段と、前記電界検出手段で変換した電気信号を復調する復調手段とを備えたことを要旨とする。
【００１６】
請求項２記載の本発明によれば、所定の周波数を有する交流信号を発振して送信すべき情報を変調した変調信号を送信する送信手段と、電界伝達媒体を伝達する電界の送受信を行う送受信電極と、送信手段のグランドと大地グランド間に生じる浮遊容量と直列共振を起こすために送信手段および送受信電極と直列に接続される共振手段と、受信した電界を検出して電気信号に変換する電界検出手段と、電気信号および変調信号に基づく基準信号を用いて共振手段が有する特性を制御する制御信号を出力する制御手段と、電界検出手段で変換した電気信号を復調する復調手段とを備えたトランシーバを提供することにより、共振手段の特性を制御して電界伝達媒体に印加される電圧の減少を防止し、通信品質の向上を図ることができる。
【００１７】
請求項３記載の本発明は、送信すべき情報に基づく電界を電界伝達媒体に誘起し、この誘起した電界を用いて情報の送信を行う一方で、前記電界伝達媒体に誘起された受信すべき情報に基づく電界を受信することによって情報の受信を行うトランシーバであって、所定の周波数を有する交流信号を発振して前記送信すべき情報を変調し、この変調した前記送信すべき情報に係る変調信号を送信する送信手段と、前記送信すべき情報に基づく電界の誘起および前記受信すべき情報に基づく電界の受信を行う送受信電極と、前記送信手段のグランドと大地グランドの間に生じる浮遊容量と直列共振を起こすために前記送信手段および前記送受信電極と直列に接続される共振手段と、前記受信すべき情報に基づく電界を前記送受信電極を介して検出し、この検出した電界を電気信号に変換する電界検出手段と、この電界検出手段で変換した電気信号および前記変調信号に基づく基準信号を用いて前記送信手段で発振する交流信号の周波数を制御する制御信号を出力する制御手段と、前記電界検出手段で変換した電気信号を復調する復調手段とを備えたことを要旨とする。
【００１８】
請求項３記載の本発明によれば、所定の周波数を有する交流信号を発振して送信すべき情報を変調した変調信号を送信する送信手段と、電界伝達媒体を伝達する電界の送受信を行う送受信電極と、送信手段のグランドと大地グランド間に生じる浮遊容量と直列共振を起こすために送信手段および送受信電極と直列に接続される共振手段と、受信した電界を検出して電気信号に変換する電界検出手段と、電気信号および変調信号に基づく基準信号を用いて送信手段で発振する交流信号の周波数を制御する制御信号を出力する制御手段と、電界検出手段で変換した電気信号を復調する復調手段とを備えたトランシーバを提供することにより、交流信号の周波数を制御して電界伝達媒体に印加される電圧の減少を防止し、通信品質の向上を図ることができる。
【００１９】
請求項４記載の本発明は、請求項２または３記載の発明において、前記制御手段は、前記電気信号を増幅する増幅器と、前記基準信号と前記増幅器の出力信号の差を求め、この差を増幅する差動増幅器と、この差動増幅器の出力信号と前記基準信号の積を求める乗算器と、この乗算器で求められた前記差動増幅器の出力信号と前記基準信号の積を与える信号の高調波成分を除去するフィルタと、このフィルタからの出力信号を積分した結果に基づいて前記制御信号を発生する第１の積分器とを有することを要旨とする。
【００２０】
請求項５記載の本発明は、請求項４記載の発明において、前記電界伝達媒体に電界を誘起して情報の送信を行うときには前記送信手段と前記共振手段を接続する一方で、前記送受信電極を介して前記電界伝達媒体に誘起された電界の受信を行うときには前記送信手段と前記共振手段の接続を切断する第１の接続手段と、前記情報の送信を行うときには前記電界検出手段と前記増幅器を接続する一方で、前記電界伝達媒体に誘起された電界の受信を行うときには前記電界検出手段と前記復調手段を接続する第２の接続手段とを備えたことを要旨とする。
【００２１】
請求項６記載の本発明は、請求項４記載の発明において、前記制御手段は、前記増幅器の利得を制御するための利得制御信号を発生する第２の積分器と、この第２の積分器から発生した利得制御信号によって制御された前記増幅器の利得を一定に保つために当該増幅器に一定の電圧を印加可能な固定電圧源とをさらに有することを要旨とする。
【００２２】
請求項７記載の本発明は、請求項６記載の発明において、前記電界伝達媒体に電界を誘起して情報の送信を行うときには前記送信手段と前記共振手段を接続し、前記増幅器の利得を調整するときには前記共振手段を介さずに前記送信手段と前記電界検出手段を接続し、前記送受信電極を介して前記電界伝達媒体に誘起された電界の受信を行うときには接続を行わない第１の接続手段と、前記情報の送信を行うとき並びに前記増幅器の利得を調整するときには前記電界検出手段と前記制御手段を接続する一方で、前記電界伝達媒体に誘起された電界の受信を行うときには前記電界検出手段と前記復調手段を接続する第２の接続手段と、前記増幅器の利得を調整するときには前記送信手段と前記電界検出光学部を接続する一方で、前記情報の送信を行うとき並びに前記電界の受信を行うときには前記送受信電極と前記電界検出手段を接続する第３の接続手段と、前記情報の送信を行うとき並びに前記電界の受信を行うときには前記フィルタと前記第１の積分器とを接続するとともに前記第２の積分器と前記固定電圧源を接続する一方で、前記増幅器の利得を調整するときには前記フィルタと前記第２の積分器を接続する第４の接続手段とを備えたことを要旨とする。
【００２３】
請求項８記載の本発明は、送信すべき情報に基づく電界を電界伝達媒体に誘起し、この誘起した電界を用いて情報の送信を行う一方で、前記電界伝達媒体に誘起された受信すべき情報に基づく電界を受信することによって情報の受信を行うトランシーバであって、所定の周波数を有する交流信号を発振して前記送信すべき情報を変調し、この変調した前記送信すべき情報に係る変調信号を送信する送信手段と、前記送信すべき情報に基づく電界の誘起および前記受信すべき情報に基づく電界の受信を行う送受信電極と、前記送信手段および前記送受信電極と直列に接続されるトランスと、前記送信手段のグランドと大地グランドの間に生じる浮遊容量と直列共振を起こすために前記トランスと並列に接続される共振手段と、前記受信すべき情報に基づく電界を検出し、この検出した電界を電気信号に変換する電界検出手段と、この電界検出手段で変換された電気信号および前記変調信号に基づく基準信号を用いて前記共振手段が有する特性を制御する制御信号を出力する制御手段と、前記電界検出手段で変換した電気信号を復調する復調手段とを備えたことを要旨とする。
【００２４】
請求項８記載の本発明によれば、所定の周波数を有する交流信号を発振して送信すべき情報を変調した変調信号を送信する送信手段と、電界伝達媒体を伝達する電界の送受信を行う送受信電極と、送信手段および送受信電極と直列に接続されるトランスと、送信手段のグランドと大地グランド間に生じる浮遊容量と直列共振を起こすためにトランスと並列に接続される共振手段と、受信した電界を検出して電気信号に変換する電界検出手段と、電気信号および変調信号に基づく基準信号を用いて共振手段が有する特性を制御する制御信号を出力する制御手段と、電気信号を復調する復調手段とを備えたトランシーバを提供することにより、共振手段の特性を制御して電界伝達媒体に印加される電圧の減少を防止し、通信品質の向上を図ることができる。
【００２５】
請求項９記載の本発明は、送信すべき情報に基づく電界を電界伝達媒体に誘起し、この誘起した電界を用いて情報の送信を行う一方で、前記電界伝達媒体に誘起された受信すべき情報に基づく電界を受信することによって情報の受信を行うトランシーバであって、所定の周波数を有する交流信号を発振して前記送信すべき情報を変調し、この変調した前記送信すべき情報に係る変調信号を送信する送信手段と、前記送信すべき情報に基づく電界の誘起および前記受信すべき情報に基づく電界の受信を行う送受信電極と、前記送信手段および前記送受信電極と直列に接続されるトランスと、前記送信手段のグランドと大地グランドの間に生じる浮遊容量と直列共振を起こすために前記トランスと並列に接続される共振手段と、前記受信すべき情報に基づく電界を検出し、この検出した電界を電気信号に変換する電界検出手段と、この電界検出手段で変換した電気信号および前記変調信号に基づく基準信号を用いて前記送信手段で発振する交流信号の周波数を制御する制御信号を出力する制御手段と、前記電界検出手段で変換した電気信号を復調する復調手段とを備えたことを要旨とする。
【００２６】
請求項９記載の本発明によれば、所定の周波数を有する交流信号を発振して送信すべき情報を変調した変調信号を送信する送信手段と、電界伝達媒体を伝達する電界の送受信を行う送受信電極と、送信手段および送受信電極と直列に接続されるトランスと、送信手段のグランドと大地グランド間に生じる浮遊容量と直列共振を起こすためにトランスと並列に接続される共振手段と、受信した電界を検出して電気信号に変換する電界検出手段と、電気信号および変調信号に基づく基準信号を用いて送信手段で発振する交流信号の周波数を制御する制御信号を出力する制御手段と、電界検出手段で変換した電気信号を復調する復調手段とを備えたトランシーバを提供することにより、交流信号の周波数を制御して電界伝達媒体に印加される電圧の減少を防止し、通信品質の向上を図ることができる。
【００２７】
請求項１０記載の本発明は、請求項８または９記載の発明において、前記制御手段は、前記基準信号と前記電気信号の積を求める乗算器と、この乗算器で求められた前記基準信号と前記電気信号の積を与える信号の高調波成分を除去するフィルタと、このフィルタからの出力信号を積分した結果に基づいて前記制御信号を発生する積分器とを有することを要旨とする。
【００２８】
請求項１１記載の本発明は、請求項１０記載の発明において、前記電界伝達媒体に電界を誘起して情報の送信を行うときには前記送信手段と前記トランスを接続する一方で、前記送受信電極を介して前記電界伝達媒体に誘起された電界の受信を行うときには前記送信手段と前記トランスの接続を切断する第１の接続手段と、前記情報の送信を行うときには前記電界検出手段と前記乗算器を接続する一方で、前記電界伝達媒体に誘起された電界の受信を行うときには前記電界検出手段と前記復調手段を接続する第２の接続手段と、前記情報の送信を行うときには前記共振手段と前記電界検出手段を接続する一方で、前記電界伝達媒体に誘起された電界の受信を行うときには前記送受信電極と前記電界検出手段を接続する第３の接続手段とを備えたことを要旨とする。
【００２９】
【発明の実施の形態】
次に、図面を参照して本発明の実施の形態を説明する。
【００３０】
以後の説明においては、ウェアラブルコンピュータがトランシーバを介して生体に電界を誘起してデータを送信する場合を「データ送信時」とし、生体に誘起された電界から検出されるデータをトランシーバを介してウェアラブルコンピュータが受信する場合を「データ受信時」とする。
【００３１】
（基本構成）
図１は、本発明の実施の形態に係るトランシーバ要部の構成を示す説明図である。同図においては、本発明に係る実施の形態に共通する構成を示すのが目的であるため、トランシーバ全体の詳細な構成については、後述する各実施形態で説明する。
【００３２】
図１に示すトランシーバは、ウェアラブルコンピュータ７から受信するデータ（情報）を出力するとともに受信した信号を受け取るＩ／Ｏ回路１１、この信号を変調して送信する送信回路１３、電界伝達媒体である生体９に電界を誘起するために導電性部材からなる送受信電極２１、および生体９に電流が流れるのを防止するとともに送受信電極２１による生体９の金属アレルギの危険性を除去するために送受信電極２１と生体９間に配置される絶縁体２３を少なくとも有する。
【００３３】
このうち送信手段としての送信回路１３は、所定の周波数の交流信号を発生する発振器１７と、発振器１７で発生した交流信号を搬送波としてＩ／Ｏ回路１１からの信号を変調する変調回路１５からなる。
【００３４】
本実施形態に係るトランシーバの特徴は、送信回路１３と送受信電極２１との間に共振手段であるリアクタンス部１９を挿入した点である。なお、ここで言う「リアクタンス部」とは、インダクタ（コイル）やコンデンサ等の複数の回路素子を接続して構成した回路網のことを意味している。このリアクタンス部１９は変調回路１５から見て直列に接続されるため、送信回路のグランド４１と大地グランド５１の間に生じる浮遊容量４３とリアクタンス部１９で直列共振回路が構成され、浮遊容量４３の変化による生体９への印加電圧の減衰を防止することが可能となる。
【００３５】
次に、本実施形態に係るトランシーバの作用について説明する。ウェアラブルコンピュータ７から送信され、Ｉ／Ｏ回路１１から出力されたデータは、発振器１７から発生する交流信号を搬送波として変調回路１５で変調された後、リアクタンス部１９から送受信電極２１に達し、絶縁体２３を介して生体９に誘起される電界を介して伝達される。
【００３６】
リアクタンス部１９、浮遊容量４３、および生体と大地グランド間に生じる浮遊容量５３は変調回路１５から見て直列に接続されているので、生体９に印加される電圧Ｖ_b は、浮遊容量４３および５３の値をそれぞれＣ_g およびＣ_b 、変調回路１５の出力電圧をＶ_s 、リアクタンス部１９が有するインピーダンスの虚数成分であるリアクタンスをＸとして次式で表される。
【数２】

【００３７】
この式（２）より、リアクタンス部１９のリアクタンスＸが
【数３】

を満たすときにＶ_b =Ｖ_s となり、信号は減衰せずに生体９に印加される。ここで、ｆは発振器１７の発振周波数を、πは円周率をそれぞれ表している。
【００３８】
なお、リアクタンス部１９をインダクタのみで構成することも勿論可能である。この場合、生体９に印加される電圧Ｖ_b は、インダクタが有するインダクタンス（リアクタンス）をＬとして、
【数４】

と表される。したがって、
【数５】

を満たすときにＶ_b =Ｖ_s となり、信号は減衰せずに生体９に印加される。
【００３９】
以上説明した本発明の実施の形態に係る基本構成に基づいて発振周波数ｆまたはリアクタンスＸを可変とすることにより、リアクタンス部１９と浮遊容量４３が直列共振を生じるように適宜制御を行い、生体９に印加される電圧の減少を防止して通信品質の向上を図ることが可能となる。
【００４０】
（第１の実施形態）
図２は、本発明の第１の実施形態に係るトランシーバの構成を示すブロック図である。同図に示すトランシーバ１において、Ｉ／Ｏ回路１０１、送信回路１０３、変調回路１０５、発振器１０７、送受信電極１１１、および絶縁体１１３については、図１を用いて説明した対応部位と同様の機能を有する。この点については、後述する実施形態においても同様である。なお、ここで送受信電極１１１を、送信用電極および受信用電極に分割して設けることも勿論可能である。その場合には、絶縁体もそれぞれの電極に対応して二つ設けられる。また、発振器１０７から発生する交流信号の周波数は、１０ｋＨｚ（キロヘルツ）〜１００ＭＨｚ（メガヘルツ）程度の値が想定されるが、１０ＭＨｚ程度であればより好ましい。ここで、１ｋＨｚ＝１０³ Ｈｚ、１ＭＨｚ＝１０⁶ Ｈｚである。
【００４１】
トランシーバ１に備えられた共振手段であるリアクタンス部は、発振周波数を一定に保つためにリアクタンスの変更が可能な可変リアクタンス部１０９であり、この可変リアクタンス部１０９と送信回路１０３の間には、生体９を介したデータ受信時に信号が送信側の回路に混入するのを防止するためにスイッチＳＷ１（第１の接続手段）が設けられている。図２では、スイッチＳＷ１が二つの端子ａ１とａ２を接続することによって閉成し、ウェアラブルコンピュータ７からのデータ送信時の状況を示している。
【００４２】
トランシーバ１は、以上に加えて、生体９に誘起された電界を受信してこの電界を光学的に検出した後、電気信号に変換する電界検出光学部１１５、低雑音増幅、雑音除去、および波形整形等の処理を行う信号処理回路１１７を有しており、これらが電界検出手段を構成している。
【００４３】
電界検出光学部１１５は、レーザ光と電気光学結晶を用いた電気光学的手法により電界を検出するものであり、少なくともレーザ光源を構成するレーザダイオードおよびＬｉＮｂＯ₃ やＬｉＴａＯ₃ 等の電気光学結晶（ＥＯ結晶：Electro Optic 結晶）からなる電気光学素子を有する（図示せず）。この電気光学素子として、例えば、レーザダイオードから発射されるレーザ光の進行方向に対して垂直な方向の電界成分のみに感度を有し、この電界強度によって光学特性、すなわち複屈折率が変化し、この複屈折率の変化によりレーザ光の偏光が変化するようなものを用いることができる。また、場合によっては電界によって電気光学素子の結晶が歪む逆圧電効果による偏光の変化も含まれる。
【００４４】
このような電気光学素子を通過して偏光が変化したレーザ光は、波長板を用いて偏光状態の調整を受けた後、偏光ビームスプリッタに入射することによりＰ波およびＳ波に分離され、光の強度変化に変換される。分離された各レーザ光は、コリメータ（集光レンズ）で集光されてから、光を電気信号に変換するためにそれぞれ設けられる二つのフォトダイオードに供給され、例えばその差を差動増幅することによって受信した電界に係る電気信号として出力される。
【００４５】
なお、以上説明した電界検出光学部１１５の構成および作用はあくまでも一例であり、本実施形態に係るトランシーバ１に適用される電界検出光学部が必ずしもこのような場合にのみ特有の効果を奏するわけではない。この点については、後述する実施形態においても同じことがいえる。
【００４６】
信号処理回路１１７から出力される信号は、隣接して設けられるスイッチＳＷ２（第２の接続手段）の接続状態に応じて送信先が変更される。図２に示すデータ送信時の場合、スイッチＳＷ２の３つの端子のうち端子ｂ１と端子ｂ３が接続され、信号処理回路１１７からの出力信号をモニタする振幅モニタ部１１９へ送信される。振幅モニタ部１１９では、信号処理回路１１７の出力信号と、送信回路１０３から送信される基準信号との差分を抽出してその抽出結果を制御信号発生部１２１へ送る。制御信号発生部１２１は、振幅モニタ部１１９の出力信号に基づいて、可変リアクタンス部１０９のリアクタンスを制御する制御信号を発生する。このようにデータ送信時には、振幅モニタ部１１９と制御信号発生部１２１を用いて負帰還回路を構成する。
【００４７】
他方、データ受信時には、スイッチＳＷ２では端子ｂ２と端子ｂ３が接続される。このときには、信号処理回路１１７からの出力信号が復調回路１２３（復調手段）で復調され、波形整形回路１２５で波形の整形が行われてＩ／Ｏ回路１０１に達し、ウェアラブルコンピュータ７にデータが送られる。このデータ受信時には、スイッチＳＷ１で端子ａ１−ａ２間の接続が切断され、送信回路１０３にデータが混入するのを防止する。
【００４８】
なお、上述したデータの送信時および受信時においては、スイッチＳＷ１およびＳＷ２の各々の端子間の接続が連動して切り替わる。図２ではこの切替を制御する切替制御手段として制御回路１４１をＩ／Ｏ回路１０１に接続することにより、制御信号を各スイッチに送信する構成を取る場合を示している。同図において、Ａの丸印で記載されている箇所同士は配線によって接続していることを示している。制御回路１４１から発せられるスイッチ切替のための制御信号は、ウェアラブルコンピュータ７から送信するようにしてもよいし、トランシーバ１に入力手段を設けてこの入力手段から送信するようにしてもよいが、接続切替手段としての各スイッチおよび制御回路の構成がここで説明したものに限られるわけでないことはいうまでもない。
【００４９】
図３は、図２の振幅モニタ部１１９の詳細な構成例を示すための構成を示すブロック図である。同図に示すトランシーバ１は、振幅モニタ部１１９の詳細な構成および制御信号発生部として積分器１２１が記載されている点を除いて、その構成は図２と同じである。したがって、図３に示すトランシーバ１は、ウェアラブルコンピュータ７からのデータ送信時の接続状況を示している。
【００５０】
振幅モニタ部１１９は、データ送信時に信号処理回路１１７の出力信号を増幅して出力する増幅器１２７、送信回路１０３から発生する基準信号と増幅器１２７の出力信号の差を取り出力する差動増幅器１２９、差動増幅器１２９の出力信号と基準信号を乗算し、その結果を出力する乗算器１３１、乗算器１３１の出力信号の高調波成分を除去するフィルタ１３３から構成される。
【００５１】
高調波成分が除去されたフィルタ１３３からの出力信号は制御信号発生部としての積分器１２１（第１の積分器）へ入力される。積分器１２１では、フィルタ１３３の出力信号を積分して可変リアクタンス部１０９に制御信号を出力する。より具体的には、式（３）から求められる発振周波数
【数６】

が浮遊容量４３（Ｃ_g ）の変化に伴って変化した分を可変リアクタンス部１０９への制御信号によって補償することにより、発振周波数ｆを元の値のまま保持する。
【００５２】
結局、これら振幅モニタ部１１９と制御信号発生部（積分器）１２１が、可変リアクタンス部１０９（共振手段）が有する特性としてのリアクタンスを制御する制御手段を構成している。
【００５３】
以上の構成を有するトランシーバ１の作用についてさらに詳細に説明する。Ｉ／Ｏ回路１０１から出力されたデータは変調回路１０５で変調された後、可変リアクタンス部１０９および送受信電極１１１を介して生体９へ印加される。変調回路１０５から見て可変リアクタンス部１０９と浮遊容量４３および５３は直列に接続されているので、生体９に印加される電圧Ｖ_b は、変調回路１０５の出力電圧をＶ_s 、可変リアクタンス部１０９のリアクタンスをＸとして、式（２）で表される。そこでこの式（２）でＶ_b =Ｖ_s を満たすように可変リアクタンス部１０９のリアクタンスＸを調整する（式（３）を参照）ために制御信号を送信する。
【００５４】
図１０は、データ送信時の制御信号発生までの振幅モニタ部１１９の各構成ユニットおよび積分器１２１の各々から出力される信号波形の例を示す説明図である。
【００５５】
このうち図１０（ａ）は送信回路と大地グランド間の浮遊容量４３が減少したときの信号波形の変化を示すものである。この場合、式（２）より生体９に印加される電圧Ｖ_b も減少するため、差動増幅器１２９の出力信号６１は送信回路１０３から送信される基準信号６３と同位相になる。このため、両者を乗算することによって得られる乗算器１３１の出力信号６５は正方向のみの変位を有する波形になる。この出力信号６５の高調波成分をフィルタ１３３によって除去したものが信号６７である。フィルタ１３３から出力される信号６７は積分器１２１で積分された結果、式（３）からも明らかなように、Ｖ_b =Ｖ_s とするために可変リアクタンス部１０９のリアクタンスＸを増加させる制御信号６９が積分器１２１から可変リアクタンス部１０９に出力され、この結果Ｖ_b =Ｖ_s の状態が保持される。
【００５６】
図１０（ｂ）は、浮遊容量４３が増加したときの信号波形の変化を示す説明図である。この場合には浮遊容量４３の増加に伴って生体９に印加される電圧Ｖ_b も増加するので、差動増幅器１２９の出力信号７１は基準信号７３と逆位相になる。このため、両者を乗算して得られる乗算器１３１の出力信号７５は負方向のみの変位を有し、この出力信号７５の高調波成分をフィルタ１３３によって除去した信号７７を積分器１２１で積分した結果、Ｖ_b =Ｖ_s とするために可変リアクタンス部１０９のリアクタンスＸを減少させる制御信号７９が積分器１２１から可変リアクタンス部１０９に出力されることになる。
【００５７】
なお、本実施形態においては、Ｖ_b =Ｖ_s のときに増幅器１２７の出力がＶ_s となるように増幅器１２７の利得が予め調整されているものとした。
【００５８】
以上説明した本発明の第１の実施形態によれば、信号処理回路１１７から出力され、増幅器１２７で増幅された出力信号と送信回路１０３からの基準信号の差分を取り、この差分に基づいて可変リアクタンス部１０９のリアクタンスを制御する制御信号を送信して直列共振を起こすような負帰還回路を振幅モニタ部１１９および制御信号発生部１２１を用いて構成することにより、生体９に印加される電圧の減少を防止して、通信品質の向上を図ることが可能になる。
【００５９】
本実施形態に係るトランシーバ１の具体的な利用形態については、図１４に示した従来技術と同様の利用形態が想定されることはいうまでもない。
【００６０】
（第１の実施形態の変形例）
前述した第１の実施形態においては、トランシーバ１に設けられる増幅器１２７の利得が既に調整されているものとして説明したが、この増幅器１２７の利得を可変とし、利得を自動的に調整する機能を付加することも可能である。
【００６１】
図４は、利得調整時のトランシーバ１の構成を示すブロック図である。同図に示すトランシーバ１は、振幅モニタ部１１９の詳細な構成、利得調整時に変調回路１０５と直接電界検出光学部１１５を可変リアクタンス部１０９を介さずに直接接続するための配線、およびこの配線に伴う新たなスイッチＳＷ３（第３の接続手段）が設けられている点を除けば、上記第１の実施形態と同様である。すなわち、利得調整時には、スイッチＳＷ３の端子ｃ１と端子ｃ２を閉成することで、変調回路１０５と電界検出光学部１１５を可変リアクタンス部１０９を介さずに直接接続し、電界検出光学部１１５に変調回路１０５の出力電圧Ｖ_s を減衰させずに印加することが可能となる。この場合、スイッチＳＷ１が端子ａ１−ａ２間を閉成していることはいうまでもない。
【００６２】
振幅モニタ部１１９には、利得の変更可能な可変利得増幅器１２７、この可変利得増幅器１２７に利得を制御するための制御信号を出力する積分器１３５（第２の積分器）、利得調整後のデータ送受信時に利得を一定に保つために積分器１３５の出力を一定にする信号を出力する固定電圧源１３７を新たに有している。固定電圧源１３７からは、通常零の信号が出力される。差動増幅器１２９、乗算器１３１、およびフィルタ１３３の機能については第１の実施形態と同様である。
【００６３】
また、振幅モニタ部１１９には新たに二つのスイッチＳＷ４およびＳＷ５が設けられ、これらが第４の接続手段を構成している。図４に示す利得調整時には、スイッチＳＷ４は端子ｄ１−ｄ２間が接続されるとともに、スイッチＳＷ５は端子ｅ１−ｅ２間が接続される。この結果、基準信号と差動増幅器１２９から出力信号を乗算器１３１で乗算後にフィルタ１３３で高調波成分が除去された信号は、積分器１３５で積分されて可変利得増幅器１２７に対する制御信号を発生して利得を変化させることができる。この際の利得は、電界検出光学部１１５にＶ_s の電圧が印加されたときに可変利得増幅器１２７の出力がＶ_s となるように調整する。なお、利得調整時にはデータ信号を一定にしておき、発振器１０７からの信号が変調されないようにしておく。
【００６４】
利得調整時の作用を、再び図１０を用いて説明する。利得が小さい場合、基準信号と差動増幅器１２９の出力信号が同位相となるため、乗算器１３１から出力され、フィルタ１３３により高調波が除去された信号を積分した結果、積分器１３５からは可変利得増幅器１２７における利得を増加させる制御信号（利得制御信号）が出力される。したがってこの場合には、振幅モニタ部１１９の各構成ユニットの出力波形は図１０（ａ）と本質的に同様なものになる。この際の制御信号６９は、差動増幅器１２９から出力される出力信号（基準信号６３と可変利得増幅器１２７の出力信号の差分）が０（ゼロ）になるまで利得を増加するような信号である。
【００６５】
一方、図１０（ｂ）は利得が大きい場合に振幅モニタ部１１９の各構成ユニットから出力される信号波形に対応している。この場合には基準信号７３と差動増幅器１２９の出力信号７１が逆位相となるため、積分器１３５からは差動増幅器１２９からの出力信号が０（ゼロ）となるまで利得を減少する制御信号７９が出力される。
【００６６】
以下、利得調整後のデータ送受信時の各スイッチの接続状態を説明する。
【００６７】
図５は、データ送信時のスイッチの接続状態を示すブロック図である。スイッチＳＷ１は、上述した第１の実施形態と同様に送信回路１０３からの出力を可変リアクタンス部１０９を介して生体９へ印加するように端子ａ２−ａ３間で接続される。スイッチＳＷ２は、利得調整時と同様に可変利得増幅器１２７側に接続されて負帰還回路を構成する（端子ｂ１−ｂ３間の接続）。スイッチＳＷ３は、生体９からの信号を受信するために送受信電極１１１側に接続する（端子ｃ２−ｃ３間の接続）。スイッチＳＷ４は、フィルタ１３３からの信号を積分して可変リアクタンス部１０９のリアクタンスを制御するために積分器１２１側に接続する（端子ｄ１−ｄ３間の接続）。スイッチＳＷ５は積分器１３５と固定電圧源１３７を接続する（端子ｅ２−ｅ３間の接続）。
【００６８】
一方、図６は、データ受信時のスイッチの接続状態を示すブロック図である。同図に示すように、データ受信時には第１の実施形態と同様に送信回路１０３への逆流を防止するために、スイッチＳＷ１を切断しておく。スイッチＳＷ２は、信号処理回路１１７から出力される信号を復調回路１２３に送信するように端子ｂ２−ｂ３間を接続する。それ以外のスイッチＳＷ３、ＳＷ４、およびＳＷ５の接続は、前述したデータ送信時と同じである。
【００６９】
なお、各スイッチの接続が、利得調整時、データ送信時、およびデータ受信時に応じた制御回路１４１からの切替制御信号によって連動して切り替えられる点については第１の実施形態と同様である。
【００７０】
以上説明した利得調整機能を有する本実施形態（第１の実施形態の変形例）が第１の実施形態と同様の効果を有するのは勿論である。加えて本実施形態によれば、振幅モニタ部１１９内に設けられる可変利得増幅器１２７の利得を自動的に調整することにより、状況に応じて最適な利得を得るように設定し、さらに安定した生体９への電圧の印加を行うことができる。
【００７１】
（第２の実施形態）
本発明の第２の実施形態に係るトランシーバは、送信回路と送受信電極の間に設けられるリアクタンス部のリアクタンスを可変とする代わりに発振器の発振周波数ｆを可変とし、生体９に印加される電圧の減少を防止するものである。
【００７２】
式（２）からも明らかなように、浮遊容量４３（Ｃ_g ）の変化に応じて変化する生体９への印加電圧Ｖ_b を送信回路からの出力電圧Ｖ_s に等しくするには、前述した第１の実施形態のようにリアクタンス部が有するリアクタンスＸを可変とする代わりに、発振器から発生する周波数ｆを変化させることによっても実現することができる。
【００７３】
図７は、本実施形態に係るトランシーバの構成を示すブロック図である。同図に示すトランシーバ２は、一定のリアクタンスを有するリアクタンス部２０９が送信回路２０３と送受信電極２１１の間に設けられる一方で、発振する交流信号の周波数を変更可能な周波数可変発振器２０７が送信回路２０３に設けられる。これにあわせて、振幅モニタ部２１９から出力される信号に基づいて制御信号を発生する制御信号発生部２２１が周波数可変発振器２０７に接続される。すなわち、本実施形態における制御信号は、周波数可変発振器２０７の周波数を制御するためのものである。これらの点を除いた各部位の機能構成については、上記第１の実施形態に係るトランシーバ１と同様である（各部位に付される符号の対応については、第１の実施形態における記載を参照のこと）。
【００７４】
図７は、トランシーバ２のデータ送信時の接続状態を示すブロック図である。同図においては、信号処理回路２１７から出力される信号が振幅モニタ部２１９を介して制御信号発生部２２１に送信され、この信号に基づいた制御信号が周波数可変発振器２０７に送られ、生体９への印加電圧が送信回路２０３の出力電圧Ｖ_s となるように制御される。具体的なスイッチの接続状態は、スイッチＳＷ１が端子ａ１−ａ２間、スイッチＳＷ２が端子ｂ１−ｂ３間の接続となる。
【００７５】
データ受信時については図示しないが、スイッチＳＷ１（第１の接続手段）の端子ａ１−ａ２間の接続が切断される一方で、スイッチＳＷ２（第２の接続手段）の接続が端子ｂ２−ｂ３間の接続に切り替わるのは第１の実施形態と同じである。これら二つのスイッチの切替が制御回路２４１からの切替制御信号を通じて行われる点についても第１の実施形態と同じである。
【００７６】
振幅モニタ部２１９の詳細な構成についても、図３に示した振幅モニタ部１１９の構成と同じである。すなわち、信号処理回路２１７からの出力信号は振幅モニタ部２１９内に設けられる増幅器２２７に出力され、この増幅器２２７からの出力信号と変調回路２０５からの基準信号を差動増幅して乗算器２３１において基準信号との乗算をとり、乗算した信号の高調波成分をフィルタ２３３で除去したものを制御信号発生部である積分器２２１を用いて積分することにより、周波数可変発振器２０７の周波数を制御する制御信号を発生する。なお、ここでは本実施形態で用いられる構成ユニットであることを明示するために、図３に示した振幅モニタ部１１９の各構成ユニットに付された符号の上１桁を「２」とした。
【００７７】
この場合にも増幅器２２７の利得は既に調整されているものとするが、増幅器２２７に自動的に利得を調整する機能を持たせた可変利得増幅器を用いた構成にすることも勿論可能である。図８は、増幅器として利得を調整する機能を備えた可変利得増幅器２２７を用いた利得調整時における振幅モニタ部２１９の詳細な構成およびスイッチの接続状況を表すブロック図である。
【００７８】
振幅モニタ部２１９を構成する構成ユニットおよびリアクタンス部２０９を介さずに送信回路２０３と電界検出光学部２１５を直接接続するための配線を施す点は、第１の実施形態の変形例で説明したものと同じである（図４を参照）。また、スイッチＳＷ１、ＳＷ２、ＳＷ３（第３の接続手段）、ＳＷ４およびＳＷ５（第４の接続手段）の各々に設けられる端子にそれぞれ付される符号は、第１の実施形態の各スイッチの端子に付される符号と対応している。より具体的には、送信回路２０３からの出力信号をリアクタンス部２０９を介さずに直接電界検出光学部２１５に送信するために、スイッチＳＷ１では端子ａ１−ａ２間を接続するとともにスイッチＳＷ３では端子ｃ１−ｃ２間を接続する。スイッチＳＷ２は信号処理回路２１７からの出力を可変利得増幅器２２７へ送るために端子ｂ１−ｂ３間を接続する。スイッチＳＷ４およびＳＷ５は、高調波成分が除去されたフィルタ２３３からの出力を積分器２３５へ送信するために、それぞれ端子ｄ１−ｄ２間および端子ｅ１−ｅ２間を接続する。
【００７９】
この結果、各構成ユニットから出力される信号波形についても、図１０に示したものと同様の波形になる。ただし本実施形態においては、制御信号発生部である積分器２２１からの制御信号が周波数可変発振器２０７に出力されることによってリアクタンス部２０９と直列共振を起こす周波数に変更されることはいうまでもない。
【００８０】
図９は、トランシーバ２のデータ送信時におけるスイッチの接続状態を示すブロック図である。同図における各スイッチの接続状況は次の通りである。スイッチＳＷ１は送信回路２０３からの出力をリアクタンス部２０９に送信するために、端子ａ２−ａ３間を接続する。スイッチＳＷ３は送受信電極２１１から信号を受信するために、端子ｃ２−ｃ３間を接続する。スイッチＳＷ２は利得調整時と同様である。スイッチＳＷ４は、フィルタ２３３からの出力を積分器２２１へ送るために端子ｄ１−ｄ３間の接続とする。スイッチＳＷ５は、利得調整後の可変利得増幅器２２７の利得を一定に保つため、固定電圧源２３７から積分器２３５に信号を送るように端子ｅ２−ｅ３間を接続する。
【００８１】
図示はしないが、データ受信時には、逆流防止のためにスイッチＳＷ１の端子間の接続を切断する。スイッチＳＷ２およびＳＷ３は、生体９に誘起された電界を電気信号に変換後、受信データとしてウェアラブルコンピュータ７に送信するために、それぞれ端子ｂ２−ｂ３間および端子ｃ２−ｃ３間の接続とする.。スイッチＳＷ４およびＳＷ５はデータ送信時と同じである。
【００８２】
以上説明した本発明の第２の実施形態によれば、第１の実施形態においてリアクタンス部のリアクタンスを可変とした代わりに発振器の周波数を可変とすることによって第１の実施形態と同じ効果を得ることができる。
【００８３】
また、利得可変な増幅器を用いて利得調整機能を加えた場合についても、第１の実施形態の変形例と同じ効果を得ることができるのは勿論である。
【００８４】
（第３の実施形態）
図１１は、本発明の第３の実施形態に係るトランシーバの構成を示すブロック図である。同図に示すトランシーバ３は、変調回路３０５と送受信電極３１１の間にトランス３１９を直列に接続し、このトランス３１９と並列に可変リアクタンス部３０９を接続している。この可変リアクタンス部３０９の一方の端点は大地グランド５１に接続される。このため、リアクタンスの値がＸ＝１／（ωＣ_g ）＝１／（２πｆ Ｃ_g ）である場合には、Ｖ_b＝Ｖ_s となるために節点Ａの電位は０（ゼロ）となる。この節点Ａをモニタし、その電位を０にする負帰還回路を構成するようにリアクタンスＸを変化させることによってＶ_b＝Ｖ_s の状態を保持することができる。なお、トランス３１９を設けることにより、送信時に生体９に誘起する電界強度を増加する効果を得ることができるのは勿論である。
【００８５】
次にトランシーバ３に設けられる三つのスイッチの接続形態について説明する。図１１に示すデータ送信時には、スイッチＳＷ１（第１の接続手段）は端子ａ１−ａ２が閉成される。スイッチＳＷ２（第２の接続手段）が乗算器３３１側に接続されて負帰還回路を構成する（端子ｂ１−ｂ３間の接続）。スイッチＳＷ３（第３の接続手段）は端子ｃ１−ｃ２間で接続され、トランス３１９と電界検出光学部３１５を直接接続する。
【００８６】
他方、データ受信時（図示せず）には、スイッチＳＷ１は生体９からの混入を防止するために端子間の接続が切断される。スイッチＳＷ３は生体９からの信号を受信するために送受信電極に接続され（端子ｃ２−ｃ３間の接続）、電界検出光学部３１５および信号処理回路３１７を介した信号がデータとしてウェアラブルコンピュータ７で受信されるように、スイッチＳＷ２は復調回路３２３側に接続される（端子ｂ２−ｂ３間の接続）。
【００８７】
制御信号発生までの各構成ユニットから出力される信号波形は、差動増幅器出力を示す出力信号６１および７１を信号処理回路３１７からの出力波形とみなす点を除いて、本質的に図１０と同じものである。すなわち、図１０（ａ）に示す場合が、送信回路と大地グランド５１間の浮遊容量４３（Ｃ_g ）が減少する場合である。このとき、式（２）よりＶ_b ＜Ｖ_s となり、節点Ａの電位は０より下がる。この結果、トランス３１９から電界検出光学部３１５および信号処理回路３１７を介して乗算器３３１へ入力される出力信号６１は、基準信号６３と同位相で減衰振動を起こす。したがって乗算器３３１の出力は正となり、この出力信号６５の高調波成分をフィルタ３３３で除去し、フィルタ３３３から出力された信号６７を積分器３２１で積分することにより、可変リアクタンス部３０９に対してＶ_b ＝Ｖ_s を満たすリアクタンスを与えるような制御信号（リアクタンスＸを増加する信号）６９を可変リアクタンス部３０９に送信する。
【００８８】
図１０（ｂ）は、浮遊容量４３が増加する場合に制御信号発生までの各構成ユニットから出力される信号波形を示す説明図である。同図に示す場合には、図１０（ａ）と状況が逆転する。すなわち、トランス３１９から電界検出光学部３１５および信号処理回路３１７を介して乗算器３３１へ入力される出力信号７１は、基準信号７３と逆位相で減衰振動を起こす。その結果、以後の各構成ユニットから出力される出力信号７５、信号７７、および制御信号７９は、全て図１０（ａ）に示すものと逆符号を有する。積分器３２１から出力される制御信号７９は、可変リアクタンス部３０９に対してＶ_b ＝Ｖ_s を満たすリアクタンスＸを与えるもの（リアクタンスＸを減少させる信号）である。
【００８９】
このように、本実施形態においては、第１および第２の実施形態における差動増幅器の役割を実質的にトランスが担っている。また、第１および第２の実施形態において差動増幅器の出力を０（ゼロ）とするように利得調整を行うことが、節点Ａの電位をモニタしてその電位を０（ゼロ）とするようにリアクタンスＸを調整することに対応している。したがって、節点Ａの電位が０（ゼロ）になることによりＶ_b ＝Ｖ_s が満たされるので、差動増幅器を用いる場合のように基準信号と比較する増幅器の利得を調整する必要が生じない。
【００９０】
なお、いうまでもないことであるが、上述した以外のトランシーバ３の各部位の機能については、上記各実施形態において対応する部位と特段の相違を持たないので、その説明は省略する。
【００９１】
以上説明した本発明の第３の実施形態によれば、上記第１および第２の実施形態と同様の効果を得ることができるのは勿論のこと、それら二つの実施形態に比べてトランシーバ内部の回路の簡略化を図ることが可能となる。
【００９２】
また、本実施形態によれば、利得調整を行う必要がないので、トランシーバを利用する上での予備的な操作が不要になり、さらに使い勝手がよくなるという効果を得ることもできる。
【００９３】
（第４の実施形態）
図１２は、本発明の第４の実施形態に係るトランシーバの構成を示すブロック図である。同図に示すトランシーバ４は、送信回路４０３と送受信電極４１１の間にトランス４１９を直列に接続し、このトランス４１９と並列にリアクタンス一定のリアクタンス部４０９を接続する一方、送信回路４０３内の発振器として、ウェアラブルコンピュータ７からのデータを搬送する搬送波（交流信号）の周波数を可変とする周波数可変発振器４０７を設けている。このため、周波数可変発振器４０７に対して周波数を制御する制御信号を発生するために、基準信号と信号処理回路４１７から出力される信号の乗算を行う乗算器４３１、乗算器４３１の出力信号の高調波成分を除去するフィルタ４３３、このフィルタ４３３の出力信号を積分することにより、制御信号を発生する積分器４２１を周波数可変発振器４０７に接続している。その他のトランシーバ４の構成については第３の実施形態と同様である。
【００９４】
本実施形態の作用は、本質的に前述した第３の実施形態と同様である。すなわち、リアクタンス部４０９の節点Ａの電位が０（ゼロ）となるように搬送波である交流信号の周波数を調整することにより、生体９への印加電圧Ｖ_b を変調回路４０５の出力電圧Ｖ_s になるように周波数を制御する制御信号が積分器４２１から発生する。したがって、各構成ユニット出力信号の波形は、実際の制御信号が周波数可変発振器４０７へ出力されて直列共振を起こす周波数に変更される点を除いて第３の実施形態と同様である（上記第３の実施形態において、図１０を用いた説明を参照）。
【００９５】
なお、３つのスイッチＳＷ１（第１の接続手段）、ＳＷ２（第２の接続手段）、およびＳＷ３（第３の接続手段）の接続形態については、データ送信時、受信時とも、上記第３の実施形態と同じである。すなわち、スイッチＳＷ１では端子ａ１−ａ２間が接続され、スイッチＳＷ２では端子ｂ１−ｂ３間が接続され、スイッチＳＷ３では端子ｃ１−ｃ２間が接続されている図１２が、データ送信時のトランシーバ４内部の構成および接続状態を示しているのは明らかである。また、図示していないデータ受信時においては、スイッチＳＷ１の端子間接続が切断され、スイッチＳＷ２では端子ｂ２−ｂ３間が、スイッチＳＷ３では端子ｃ２−ｃ３間が接続されることにより、生体９に誘起された電界を検出してウェアラブルコンピュータ７にデータを送る。
【００９６】
以上説明した本発明の第４の実施形態が上記第３の実施形態と同様の効果を奏するものであることはいうまでもない。
【００９７】
なお、上記各実施形態では、電界伝達媒体として生体を例に取り説明を行ったが、本発明に係るトランシーバの送受信時にデータに基づく電界を生じて伝達する電界伝達媒体は必ずしも生体に限定されるわけではない。
【００９８】
このように、本発明は上記同様の効果を奏する様々な実施の形態を含みうるものであることはいうまでもない。
【００９９】
【発明の効果】
以上説明した本発明によれば、電界伝達媒体に印加する電圧の減少を防止して、通信品質の向上を図ることのできるトランシーバを提供することができる。
【０１００】
これにより、ウェアラブルコンピュータがより実現性の高いものとなる。
【図面の簡単な説明】
【図１】本発明の実施の形態に係るトランシーバの基本構成を示す説明図である。
【図２】本発明の第１の実施形態に係るトランシーバにおけるデータ送信時の構成を示すブロック図である。
【図３】図２のトランシーバのさらに詳細な構成を示すブロック図である。
【図４】本発明の第１の実施形態に係るトランシーバが利得調整機能を有するときの利得調整時の構成を示すブロック図である。
【図５】図４のトランシーバのデータ送信時の構成を示すブロック図である。
【図６】図４のトランシーバのデータ受信時の構成を示すブロック図である。
【図７】本発明の第２の実施形態に係るトランシーバにおけるデータ送信時の構成を示すブロック図である。
【図８】本発明の第２の実施形態に係るトランシーバが利得調整機能を有するときの利得調整時の構成を示すブロック図である。
【図９】図８のトランシーバのデータ送信時の構成を示すブロック図である。
【図１０】利得調整時の振幅モニタ部の各構成ユニットおよび制御信号発生部からそれぞれ出力される信号を示す説明図である。
【図１１】本発明の第３の実施形態に係るトランシーバのデータ送信時の構成を示すブロック図である。
【図１２】本発明の第４の実施形態に係るトランシーバのデータ送信時の構成を示すブロック図である。
【図１３】従来法によるトランシーバの構成を示すブロック図である。
【図１４】トランシーバを介してウェアラブルコンピュータを人間に装着して使用するときの例を示す説明図である。
【図１５】従来法において生体に印加される電圧を説明する説明図である。
【符号の説明】
１、２、３、４、５ トランシーバ
７ ウェアラブルコンピュータ
９ 生体
１１、１０１、２０１、３０１、４０１、５０１ Ｉ／Ｏ回路
１３、１０３、２０３、３０３、４０３、５０３ 送信回路（送信手段）
１５、１０５、２０５、３０５、４０５、５０５ 変調回路
１７、１０７、３０７、５０７ 発振器
１９、２０９、４０９ リアクタンス部（共振手段）
２１、１１１、２１１、３１１、４１１、５１１ 送受信電極
２３、１１３、２１３、３１３、４１３、５１３ 絶縁体
４１ 送信回路のグランド
４３、５３ 浮遊容量
５１ 大地グランド
６１、６５、７１、７５ 出力信号
６３、７３ 基準信号
６７、７７ 信号
６９、７９ 制御信号
８０ 外部端末
９０ ケーブル
１０９、３０９ 可変リアクタンス部（共振手段）
１１５、２１５、３１５、４１５、５１５ 電界検出光学部（電界検出手段の一部）
１１７、２１７、３１７、４１７、５１７ 信号処理回路（電界検出手段の一部）
１１９、２１９ 振幅モニタ部（制御手段の一部）
１２１、２２１、３２１、４２１ 制御信号発生部または積分器（制御手段の一部）
１２３、２２３、３２３、４２３、５２３ 復調回路（復調手段）
１２５、２２５、３２５、４２５、５２５ 波形整形回路
１２７、２２７ （可変利得）増幅器
１２９、２２９ 差動増幅器
１３１、２３１、３３１、４３１ 乗算器
１３３、２３３、３３３、４３３ フィルタ
１３５、２３５ 積分器
１３７、２３７ 固定電圧源
１４１、２４１、３４１、４４１ 制御回路
２０７、４０７ 周波数可変発振器
３１９、４１９ トランス
ＳＷ１、ＳＷ２、ＳＷ３、ＳＷ４、ＳＷ５ スイッチ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transceiver that transmits and receives information using an electric field induced in an electric field transmission medium that transmits an electric field, and more specifically, is used in data communication using a wearable computer that can be worn on a human body. Related to transceivers.
[0002]
[Prior art]
Due to the miniaturization and high performance of portable terminals, wearable computers that can be attached to living bodies have been attracting attention.
[0003]
Conventionally, data communication between such wearable computers has been proposed to transmit and receive data by connecting a transceiver to the computer and transmitting the electric field induced by the transceiver to the inside of a living body which is an electric field transmission medium. (For example, refer to Patent Document 1).
[0004]
FIG. 13 is a block diagram showing a configuration of a conventional transceiver. The transceiver 5 shown in the figure is connected to the wearable computer 7 via an I / O circuit 501 for inputting and outputting signals, and a transmission / reception electrode 511 is provided close to the living body 9 via an insulator 513. Yes. Information (data) transmitted from the wearable computer 7 is modulated by the modulation circuit 505 in the transmission circuit 503 using the AC signal generated by the oscillator 507 as a carrier wave. The modulated modulation signal induces an electric field from the transmission / reception electrode 511 to the living body 9 through the insulator 513, and the electric field is transmitted through the living body 9 so that the transceiver 5 is provided in another part of the living body 9. Information transmitted from the wearable computer 7 is transmitted to the transceiver 5 that is electrically connected by contact with the living body 9.
[0005]
When another transceiver 5 receives the electric field transmitted through the transceiver 5 in this way, the electric field received by the transmission / reception electrode 511 through the insulator 513 is converted into an electric signal by the electric field detection optical unit 515. To the signal processing circuit 517. The signal processing circuit 517 performs signal processing such as filtering and amplification on the electric signal from the electric field detection optical unit 515. After the signal processing, data modulation and waveform shaping are further performed by the demodulation circuit 523 and the waveform shaping circuit 525, respectively, and the signal subjected to the series of processing is wearable from the I / O circuit 501 as received data of the wearable computer 7. It is transmitted to the computer 7.
[0006]
As described above, the transceiver 5 used for data communication between the wearable computers 7 induces an electric field based on information to be transmitted to the living body 9 which is an electric field transmission medium, and transmits information using the induced electric field. Thus, when receiving information, the transceiver 5 receives a signal using an electric field induced in the living body 9.
[0007]
FIG. 14 is an explanatory diagram illustrating an example in which the wearable computer 7 is used while being worn by a human being as an example of the living body 9. Wearable computers 7a, 7b, and 7c shown in the figure are attached to human arms, shoulders, trunks, and the like via correspondingly connected transceivers 5a, 5b, and 5c, and transmit / receive data to / from each other. Furthermore, when the tips of the limbs of the living body 9 come into contact with the transceivers 5′a and 5′b connected to the external terminal 80, which is an external device, via the cable 90, the wearable computers 7a, 7b, and 7c Data can be transmitted to and received from the external terminal 80.
[0008]
[Patent Document 1]
JP 2001-352298 A
[0009]
[Problems to be solved by the invention]
In the transceiver 5 described above, the transmission circuit 503 that is driven without using an AC power supply is separated from the ground ground 51 as shown in FIG. 15, and a stray capacitance 43 is generated between the ground 41 and the ground ground 51 of the transmission circuit. To do. A stray capacitance 53 also exists between the living body 9 and the ground 51, and these two stray capacitances (virtual capacitors having the same) are apparently connected in series when viewed from the modulation circuit 505.
[0010]
For this reason, the voltage V between the transmission circuit 503 and the ground 41 of the transmission circuit._sIs divided and applied to two stray capacitances 43 and 53. Among these, the voltage V applied to the living body 9_bIs the value of stray capacitance 43 and 53 respectively_gAnd C_bAfter all,
[Expression 1]

It becomes. Where j is the imaginary unit (-1)^1/2Ω represents the angular frequency of the applied voltage.
[0011]
When an AC power supply is used, the stray capacitance 53 can be regarded as infinite, and as is apparent from the equation (1), V_b= V_sThus, the signal is applied to the living body 9 without being attenuated. On the other hand, when AC power is not used, V is_b<V_sTherefore, there is a problem that the signal applied to the living body 9 decreases.
[0012]
The present invention has been made in view of the above, and an object of the present invention is to provide a transceiver capable of improving communication quality by preventing a decrease in voltage applied to an electric field transmission medium.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 is a transceiver for inducing an electric field based on information to be transmitted in an electric field transmission medium, and transmitting at least information using the induced electric field, A transmitting means for oscillating an alternating current signal having a predetermined frequency to modulate the information to be transmitted, and transmitting a modulated signal related to the modulated information to be transmitted; and between the ground of the transmitting means and the ground The gist of the present invention is to provide the stray capacitance generated and resonance means for causing series resonance.
[0014]
According to the first aspect of the present invention, a transmission means for transmitting a modulated signal obtained by modulating an information to be transmitted by oscillating an alternating current signal having a predetermined frequency is generated between the ground of the transmission means and the ground. By providing a transceiver including stray capacitance and resonance means that causes series resonance, it is possible to prevent a decrease in voltage applied to the electric field transmission medium and improve communication quality.
[0015]
According to the present invention of claim 2, an electric field based on information to be transmitted is induced in an electric field transmission medium, and information is transmitted using the induced electric field, while reception induced by the electric field transmission medium is to be performed. A transceiver that receives information by receiving an electric field based on information, oscillates an AC signal having a predetermined frequency, modulates the information to be transmitted, and modulates the modulated information to be transmitted A transmission means for transmitting a signal; a transmission / reception electrode for inducing an electric field based on the information to be transmitted and receiving an electric field based on the information to be received; and a stray capacitance generated between a ground and a ground of the transmission means Resonance means connected in series with the transmission means and the transmission / reception electrode to cause series resonance, and an electric field based on the information to be received is detected, and the detected electric field is An electric field detecting means for converting into an electric signal; an electric signal converted by the electric field detecting means; a control means for outputting a control signal for controlling characteristics of the resonance means using a reference signal based on the modulation signal; and the electric field The gist of the invention is that it comprises demodulation means for demodulating the electrical signal converted by the detection means.
[0016]
According to the second aspect of the present invention, transmission means for transmitting a modulated signal obtained by modulating information to be transmitted by oscillating an AC signal having a predetermined frequency, and transmission / reception for transmitting / receiving an electric field transmitted through an electric field transmission medium An electrode, a resonant means connected in series with the transmitting means and the transmitting / receiving electrode to cause series resonance with a stray capacitance generated between the ground of the transmitting means and the ground, and an electric field for detecting the received electric field and converting it into an electric signal A detection means; a control means for outputting a control signal for controlling characteristics of the resonance means using a reference signal based on the electric signal and the modulation signal; and a demodulation means for demodulating the electric signal converted by the electric field detection means. By providing the transceiver, it is possible to control the characteristics of the resonance means to prevent a decrease in the voltage applied to the electric field transmission medium and to improve the communication quality.
[0017]
According to the third aspect of the present invention, an electric field based on information to be transmitted is induced in the electric field transmission medium, and information is transmitted using the induced electric field, while reception induced by the electric field transmission medium is to be performed. A transceiver that receives information by receiving an electric field based on information, oscillates an AC signal having a predetermined frequency, modulates the information to be transmitted, and modulates the modulated information to be transmitted A transmission means for transmitting a signal; a transmission / reception electrode for inducing an electric field based on the information to be transmitted and receiving an electric field based on the information to be received; and a stray capacitance generated between a ground and a ground of the transmission means Resonance means connected in series with the transmission means and the transmission / reception electrode to cause series resonance, and an electric field based on the information to be received is detected via the transmission / reception electrode. Electric field detection means for converting the detected electric field into an electric signal, and control for controlling the frequency of the AC signal oscillated by the transmission means using the electric signal converted by the electric field detection means and the reference signal based on the modulation signal The gist is provided with control means for outputting a signal and demodulation means for demodulating the electrical signal converted by the electric field detection means.
[0018]
According to the third aspect of the present invention, transmission means for transmitting a modulated signal obtained by modulating information to be transmitted by oscillating an AC signal having a predetermined frequency, and transmission / reception for transmitting / receiving an electric field transmitted through an electric field transmission medium An electrode, a resonant means connected in series with the transmitting means and the transmitting / receiving electrode to cause series resonance with a stray capacitance generated between the ground of the transmitting means and the ground, and an electric field for detecting the received electric field and converting it into an electric signal Detection means, control means for outputting a control signal for controlling the frequency of an AC signal oscillated by the transmission means using a reference signal based on the electric signal and the modulation signal, and demodulation means for demodulating the electric signal converted by the electric field detection means By providing a transceiver including the above, the frequency of the AC signal is controlled to prevent a decrease in the voltage applied to the electric field transmission medium, thereby improving the communication quality. It can be.
[0019]
According to a fourth aspect of the present invention, in the invention according to the second or third aspect, the control means obtains a difference between an amplifier that amplifies the electrical signal, the reference signal, and an output signal of the amplifier, and calculates the difference. A differential amplifier for amplifying, a multiplier for obtaining a product of the output signal of the differential amplifier and the reference signal, and a signal for giving a product of the output signal of the differential amplifier and the reference signal obtained by the multiplier The gist of the invention is to have a filter that removes harmonic components and a first integrator that generates the control signal based on the result of integrating the output signal from the filter.
[0020]
According to a fifth aspect of the present invention, in the invention according to the fourth aspect, when transmitting information by inducing an electric field in the electric field transmission medium, the transmission means and the resonance means are connected while the transmission / reception electrodes are connected. A first connecting means for cutting off the connection between the transmitting means and the resonance means when receiving the electric field induced in the electric field transmission medium, and an electric field detecting means and the amplifier when transmitting the information. On the other hand, the gist of the present invention is to include a second connecting means for connecting the electric field detecting means and the demodulating means when receiving the electric field induced in the electric field transmission medium.
[0021]
According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the control means includes a second integrator that generates a gain control signal for controlling the gain of the amplifier, and the second integrator. In order to keep constant the gain of the amplifier controlled by the gain control signal generated from the above, it further includes a fixed voltage source capable of applying a constant voltage to the amplifier.
[0022]
According to a seventh aspect of the present invention, in the sixth aspect of the invention, when transmitting information by inducing an electric field in the electric field transmission medium, the transmission means and the resonance means are connected to adjust the gain of the amplifier. The transmitting means and the electric field detecting means are connected without going through the resonance means, and the first connecting means that does not make a connection when receiving the electric field induced in the electric field transmission medium through the transmitting / receiving electrodes. When the information is transmitted and when the gain of the amplifier is adjusted, the electric field detecting means and the control means are connected, while the electric field detecting means is received when receiving the electric field induced in the electric field transmission medium. And the second connecting means for connecting the demodulating means, and the transmission means and the electric field detecting optical unit when the gain of the amplifier is adjusted, while transmitting the information A third connecting means for connecting the transmission / reception electrode and the electric field detecting means, and a filter and the first time for transmitting the information and for receiving the electric field. A fourth connecting means for connecting the filter and the second integrator when adjusting the gain of the amplifier while connecting the integrator and the second integrator and the fixed voltage source; The main point is that
[0023]
According to the present invention of claim 8, an electric field based on information to be transmitted is induced in the electric field transmission medium, and information is transmitted using the induced electric field, while reception is induced in the electric field transmission medium. A transceiver that receives information by receiving an electric field based on information, oscillates an AC signal having a predetermined frequency, modulates the information to be transmitted, and modulates the modulated information to be transmitted A transmitting means for transmitting a signal; a transmission / reception electrode for inducing an electric field based on the information to be transmitted and receiving an electric field based on the information to be received; a transformer connected in series with the transmission means and the transmission / reception electrode; Resonance means connected in parallel with the transformer to cause series resonance with stray capacitance generated between the ground of the transmission means and the ground, and the information to be received. An electric field detecting means for detecting an electric field based on the electric field, converting the detected electric field into an electric signal, and a characteristic of the resonance means using the electric signal converted by the electric field detecting means and a reference signal based on the modulation signal. The gist of the invention is that it comprises control means for outputting a control signal to be controlled, and demodulation means for demodulating the electric signal converted by the electric field detection means.
[0024]
According to the eighth aspect of the present invention, transmission means for transmitting a modulated signal obtained by modulating information to be transmitted by oscillating an AC signal having a predetermined frequency, and transmission / reception for transmitting / receiving an electric field transmitted through an electric field transmission medium An electrode, a transformer connected in series with the transmitting means and the transmitting / receiving electrode, a resonant means connected in parallel with the transformer to cause a series resonance with a stray capacitance generated between the ground of the transmitting means and the ground, and a received electric field Electric field detection means for detecting and converting into an electric signal, control means for outputting a control signal for controlling the characteristics of the resonance means using a reference signal based on the electric signal and the modulation signal, and demodulation means for demodulating the electric signal By providing the transceiver with the above, the characteristic of the resonance means is controlled to prevent a decrease in the voltage applied to the electric field transmission medium, thereby improving the communication quality. It can be.
[0025]
According to the ninth aspect of the present invention, an electric field based on information to be transmitted is induced in the electric field transmission medium, and information is transmitted using the induced electric field, while reception is induced in the electric field transmission medium. A transceiver that receives information by receiving an electric field based on information, oscillates an AC signal having a predetermined frequency, modulates the information to be transmitted, and modulates the modulated information to be transmitted A transmitting means for transmitting a signal; a transmission / reception electrode for inducing an electric field based on the information to be transmitted and receiving an electric field based on the information to be received; a transformer connected in series with the transmission means and the transmission / reception electrode; Resonance means connected in parallel with the transformer to cause series resonance with stray capacitance generated between the ground of the transmission means and the ground, and the information to be received. An electric field detecting means for detecting an electric field based on the electric field and converting the detected electric field into an electric signal, and an AC signal oscillated by the transmitting means using the electric signal converted by the electric field detecting means and a reference signal based on the modulation signal And a demodulating unit for demodulating an electric signal converted by the electric field detecting unit.
[0026]
According to the ninth aspect of the present invention, the transmission means for transmitting the modulation signal obtained by modulating the information to be transmitted by oscillating the AC signal having a predetermined frequency, and the transmission / reception for transmitting / receiving the electric field transmitted through the electric field transmission medium An electrode, a transformer connected in series with the transmitting means and the transmitting / receiving electrode, a resonant means connected in parallel with the transformer to cause a series resonance with a stray capacitance generated between the ground of the transmitting means and the ground, and a received electric field An electric field detecting means for detecting an electric signal and converting it into an electric signal, a control means for outputting a control signal for controlling the frequency of an AC signal oscillated by the transmitting means using a reference signal based on the electric signal and the modulation signal, and an electric field detecting means By providing a transceiver comprising a demodulating means for demodulating the electric signal converted in step (b), the frequency of the AC signal is controlled by controlling the frequency of the AC signal. To prevent small, it is possible to improve the communication quality.
[0027]
According to a tenth aspect of the present invention, in the invention according to the eighth or ninth aspect, the control means includes a multiplier for obtaining a product of the reference signal and the electric signal, and the reference signal obtained by the multiplier. The gist of the invention is to include a filter that removes harmonic components of the signal that gives the product of the electrical signals, and an integrator that generates the control signal based on the result of integrating the output signals from the filter.
[0028]
The present invention according to claim 11 is the invention according to claim 10, wherein when transmitting information by inducing an electric field in the electric field transmission medium, the transmitting means and the transformer are connected, while the transmitting and receiving electrodes are interposed. When receiving the electric field induced in the electric field transmission medium, the transmission means and the transformer are disconnected from each other, and when transmitting the information, the electric field detection means and the multiplier are connected. On the other hand, when receiving the electric field induced in the electric field transmission medium, the second connecting means connecting the electric field detecting means and the demodulating means, and when transmitting the information, the resonant means and the electric field detection. A third connecting means for connecting the transmitting / receiving electrodes and the electric field detecting means when receiving the electric field induced in the electric field transmission medium. It is the gist of.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0030]
In the following description, the case where a wearable computer induces an electric field to a living body via a transceiver and transmits data is referred to as “data transmission”, and the data detected from the electric field induced in the living body is wearable via the transceiver. The case where the computer receives is “at the time of data reception”.
[0031]
(Basic configuration)
FIG. 1 is an explanatory diagram showing the configuration of the main part of the transceiver according to the embodiment of the present invention. In this figure, the purpose is to show a configuration common to the embodiments according to the present invention, and therefore the detailed configuration of the entire transceiver will be described in each embodiment to be described later.
[0032]
The transceiver shown in FIG. 1 outputs an I / O circuit 11 that outputs data (information) received from the wearable computer 7 and receives a received signal, a transmission circuit 13 that modulates and transmits the signal, and a biological body that is an electric field transmission medium. The transmission / reception electrode 21 made of a conductive member for inducing an electric field in the body 9 and the transmission / reception electrode 21 for preventing current from flowing through the living body 9 and removing the danger of the metal allergy of the living body 9 by the transmission / reception electrode 21. At least an insulator 23 disposed between the living bodies 9 is included.
[0033]
Among these, the transmission circuit 13 as a transmission means includes an oscillator 17 that generates an AC signal having a predetermined frequency, and a modulation circuit 15 that modulates a signal from the I / O circuit 11 using the AC signal generated by the oscillator 17 as a carrier wave. .
[0034]
A feature of the transceiver according to the present embodiment is that a reactance unit 19 as a resonance unit is inserted between the transmission circuit 13 and the transmission / reception electrode 21. Note that the “reactance portion” here means a circuit network configured by connecting a plurality of circuit elements such as inductors (coils) and capacitors. Since the reactance unit 19 is connected in series as viewed from the modulation circuit 15, a series resonance circuit is formed by the stray capacitance 43 generated between the ground 41 and the ground 51 of the transmission circuit and the reactance unit 19. It is possible to prevent the voltage applied to the living body 9 from being attenuated due to the change.
[0035]
Next, the operation of the transceiver according to this embodiment will be described. The data transmitted from the wearable computer 7 and output from the I / O circuit 11 is modulated by the modulation circuit 15 using the AC signal generated from the oscillator 17 as a carrier wave, and then reaches the transmission / reception electrode 21 from the reactance unit 19. The signal is transmitted through an electric field induced in the living body 9 through 23.
[0036]
The reactance unit 19, the stray capacitance 43, and the stray capacitance 53 generated between the living body and the ground are connected in series as viewed from the modulation circuit 15, and thus the voltage V applied to the living body 9._bIs the value of stray capacitance 43 and 53 respectively_gAnd C_bThe output voltage of the modulation circuit 15 is V_sThe reactance, which is an imaginary component of the impedance of the reactance unit 19, is represented by the following equation.
[Expression 2]

[0037]
From this equation (2), the reactance X of the reactance unit 19 is
[Equation 3]

V when satisfying_b= V_sThus, the signal is applied to the living body 9 without being attenuated. Here, f represents the oscillation frequency of the oscillator 17, and π represents the circular ratio.
[0038]
Of course, the reactance unit 19 may be formed of only an inductor. In this case, the voltage V applied to the living body 9_bIs the inductance (reactance) of the inductor is L,
[Expression 4]

It is expressed. Therefore,
[Equation 5]

V when satisfying_b= V_sThus, the signal is applied to the living body 9 without being attenuated.
[0039]
By making the oscillation frequency f or the reactance X variable based on the basic configuration according to the embodiment of the present invention described above, the reactance unit 19 and the stray capacitance 43 are appropriately controlled so as to cause series resonance, and the living body 9 It is possible to improve the communication quality by preventing a decrease in the voltage applied to the.
[0040]
(First embodiment)
FIG. 2 is a block diagram showing a configuration of the transceiver according to the first exemplary embodiment of the present invention. In the transceiver 1 shown in the figure, the I / O circuit 101, the transmission circuit 103, the modulation circuit 105, the oscillator 107, the transmission / reception electrode 111, and the insulator 113 have the same functions as the corresponding parts described with reference to FIG. Have. This also applies to the embodiments described later. Of course, the transmitting / receiving electrode 111 may be divided into a transmitting electrode and a receiving electrode. In that case, two insulators are also provided corresponding to each electrode. The frequency of the AC signal generated from the oscillator 107 is assumed to be about 10 kHz (kilohertz) to 100 MHz (megahertz), but is preferably about 10 MHz. Where 1 kHz = 10^ThreeHz, 1MHz = 10⁶Hz.
[0041]
The reactance unit, which is a resonance means provided in the transceiver 1, is a variable reactance unit 109 that can change the reactance in order to keep the oscillation frequency constant. Between the variable reactance unit 109 and the transmission circuit 103, there is a living body. A switch SW1 (first connecting means) is provided in order to prevent a signal from being mixed into the circuit on the transmission side when data is received via 9. In FIG. 2, the switch SW1 is closed by connecting the two terminals a1 and a2, and the situation at the time of data transmission from the wearable computer 7 is shown.
[0042]
In addition to the above, the transceiver 1 receives the electric field induced in the living body 9, optically detects the electric field, and then converts the electric field into an electric signal, low noise amplification, noise removal, and waveform A signal processing circuit 117 that performs processing such as shaping is provided, and these constitute electric field detection means.
[0043]
The electric field detection optical unit 115 detects an electric field by an electro-optic technique using laser light and an electro-optic crystal, and at least a laser diode and a LiNbO constituting a laser light source._ThreeAnd LiTaO_ThreeAnd an electro-optic element made of an electro-optic crystal (EO crystal: Electro Optic crystal) (not shown). As this electro-optic element, for example, it has sensitivity only to the electric field component in the direction perpendicular to the traveling direction of the laser light emitted from the laser diode, and the optical characteristics, that is, the birefringence index changes depending on the electric field strength, A laser beam whose polarization changes due to the change in birefringence can be used. In some cases, a change in polarization due to an inverse piezoelectric effect in which the crystal of the electro-optic element is distorted by an electric field is also included.
[0044]
The laser light whose polarization has been changed by passing through such an electro-optic element is subjected to polarization state adjustment using a wave plate, and then is incident on a polarization beam splitter to be separated into P-wave and S-wave. It is converted into intensity change. Each separated laser beam is condensed by a collimator (condensing lens) and then supplied to two photodiodes provided to convert the light into an electrical signal, for example, differentially amplifying the difference between them. Is output as an electrical signal related to the received electric field.
[0045]
Note that the configuration and operation of the electric field detection optical unit 115 described above are merely examples, and the electric field detection optical unit applied to the transceiver 1 according to the present embodiment does not necessarily exhibit a specific effect only in such a case. Absent. The same can be said for the embodiments described later.
[0046]
The transmission destination of the signal output from the signal processing circuit 117 is changed according to the connection state of the switch SW2 (second connection means) provided adjacently. In the case of data transmission shown in FIG. 2, the terminal b1 and the terminal b3 among the three terminals of the switch SW2 are connected and transmitted to the amplitude monitor unit 119 that monitors the output signal from the signal processing circuit 117. The amplitude monitor unit 119 extracts the difference between the output signal of the signal processing circuit 117 and the reference signal transmitted from the transmission circuit 103 and sends the extraction result to the control signal generation unit 121. The control signal generation unit 121 generates a control signal for controlling the reactance of the variable reactance unit 109 based on the output signal of the amplitude monitor unit 119. Thus, at the time of data transmission, a negative feedback circuit is configured using the amplitude monitor unit 119 and the control signal generator 121.
[0047]
On the other hand, at the time of data reception, the terminal b2 and the terminal b3 are connected in the switch SW2. At this time, the output signal from the signal processing circuit 117 is demodulated by the demodulation circuit 123 (demodulation means), the waveform shaping circuit 125 performs waveform shaping, reaches the I / O circuit 101, and data is sent to the wearable computer 7. It is done. At the time of data reception, the connection between the terminals a 1 and a 2 is disconnected by the switch SW 1 to prevent data from being mixed into the transmission circuit 103.
[0048]
At the time of data transmission and reception described above, the connection between the terminals of the switches SW1 and SW2 is switched in conjunction. FIG. 2 shows a case where a control circuit 141 is connected to the I / O circuit 101 as a switching control means for controlling the switching, and a control signal is transmitted to each switch. In the figure, the portions indicated by the circles A are connected by wiring. The control signal for switching the switch generated from the control circuit 141 may be transmitted from the wearable computer 7 or may be transmitted from the input unit provided in the transceiver 1. It goes without saying that the configuration of each switch and control circuit as the switching means is not limited to that described here.
[0049]
FIG. 3 is a block diagram showing a configuration for showing a detailed configuration example of the amplitude monitor unit 119 of FIG. The transceiver 1 shown in the figure is the same as that shown in FIG. 2 except that a detailed configuration of the amplitude monitor unit 119 and an integrator 121 are described as a control signal generator. Therefore, the transceiver 1 shown in FIG. 3 shows a connection state at the time of data transmission from the wearable computer 7.
[0050]
The amplitude monitor unit 119 amplifies and outputs the output signal of the signal processing circuit 117 during data transmission, a differential amplifier 129 that takes the difference between the reference signal generated from the transmission circuit 103 and the output signal of the amplifier 127, A multiplier 131 that multiplies the output signal of the differential amplifier 129 and a reference signal and outputs the result, and a filter 133 that removes harmonic components of the output signal of the multiplier 131.
[0051]
The output signal from the filter 133 from which the harmonic component has been removed is input to an integrator 121 (first integrator) serving as a control signal generator. The integrator 121 integrates the output signal of the filter 133 and outputs a control signal to the variable reactance unit 109. More specifically, the oscillation frequency obtained from Equation (3)
[Formula 6]

Is the stray capacitance 43 (C_g) Is compensated for by the control signal to the variable reactance unit 109, so that the oscillation frequency f is maintained at the original value.
[0052]
After all, the amplitude monitor unit 119 and the control signal generation unit (integrator) 121 constitute a control unit that controls reactance as a characteristic of the variable reactance unit 109 (resonance unit).
[0053]
The operation of the transceiver 1 having the above configuration will be described in more detail. The data output from the I / O circuit 101 is modulated by the modulation circuit 105 and then applied to the living body 9 via the variable reactance unit 109 and the transmission / reception electrode 111. Since the variable reactance unit 109 and the stray capacitances 43 and 53 are connected in series when viewed from the modulation circuit 105, the voltage V applied to the living body 9._bIs the output voltage of the modulation circuit 105 V_s, Where X is the reactance of the variable reactance unit 109, and is expressed by the equation (2). Therefore, V in this equation (2)_b= V_sA control signal is transmitted to adjust the reactance X of the variable reactance unit 109 so as to satisfy (see Expression (3)).
[0054]
FIG. 10 is an explanatory diagram illustrating an example of signal waveforms output from each component unit of the amplitude monitor unit 119 and each of the integrators 121 until generation of a control signal at the time of data transmission.
[0055]
Of these, FIG. 10A shows the change in signal waveform when the stray capacitance 43 between the transmission circuit and the ground is decreased. In this case, the voltage V applied to the living body 9 from the equation (2)._bTherefore, the output signal 61 of the differential amplifier 129 is in phase with the reference signal 63 transmitted from the transmission circuit 103. For this reason, the output signal 65 of the multiplier 131 obtained by multiplying both has a waveform having a displacement only in the positive direction. A signal 67 is obtained by removing the harmonic component of the output signal 65 by the filter 133. As a result of integration of the signal 67 output from the filter 133 by the integrator 121, as is apparent from the equation (3), V_b= V_sTherefore, a control signal 69 for increasing the reactance X of the variable reactance unit 109 is output from the integrator 121 to the variable reactance unit 109. As a result, V_b= V_sThis state is maintained.
[0056]
FIG. 10B is an explanatory diagram showing changes in the signal waveform when the stray capacitance 43 increases. In this case, the voltage V applied to the living body 9 as the stray capacitance 43 increases._bTherefore, the output signal 71 of the differential amplifier 129 has a phase opposite to that of the reference signal 73. Therefore, the output signal 75 of the multiplier 131 obtained by multiplying both has a displacement only in the negative direction, and the integrator 77 integrates the signal 77 obtained by removing the harmonic component of the output signal 75 by the filter 133. Result, V_b= V_sTherefore, the control signal 79 for reducing the reactance X of the variable reactance unit 109 is output from the integrator 121 to the variable reactance unit 109.
[0057]
In the present embodiment, V_b= V_sWhen the output of the amplifier 127 is V_sIt is assumed that the gain of the amplifier 127 is adjusted in advance so that
[0058]
According to the first embodiment of the present invention described above, the difference between the output signal output from the signal processing circuit 117 and amplified by the amplifier 127 and the reference signal from the transmission circuit 103 is taken and variable based on this difference. By constructing a negative feedback circuit that causes a series resonance by transmitting a control signal for controlling the reactance of the reactance unit 109 using the amplitude monitor unit 119 and the control signal generation unit 121, the voltage applied to the living body 9 can be reduced. It is possible to prevent the decrease and improve the communication quality.
[0059]
It goes without saying that the specific usage pattern of the transceiver 1 according to the present embodiment is assumed to be the same usage pattern as that of the conventional technique shown in FIG.
[0060]
(Modification of the first embodiment)
In the first embodiment described above, it has been described that the gain of the amplifier 127 provided in the transceiver 1 has already been adjusted. However, the gain of the amplifier 127 is variable and a function for automatically adjusting the gain is added. It is also possible to do.
[0061]
FIG. 4 is a block diagram showing the configuration of the transceiver 1 during gain adjustment. The transceiver 1 shown in the figure includes a detailed configuration of the amplitude monitor unit 119, wiring for directly connecting the modulation circuit 105 and the direct electric field detection optical unit 115 without adjusting the variable reactance unit 109 at the time of gain adjustment, and to this wiring Except for the point that a new switch SW3 (third connection means) is provided, it is the same as in the first embodiment. That is, at the time of gain adjustment, by closing the terminal c1 and the terminal c2 of the switch SW3, the modulation circuit 105 and the electric field detection optical unit 115 are directly connected without passing through the variable reactance unit 109, and modulated to the electric field detection optical unit 115. Output voltage V of circuit 105_sCan be applied without being attenuated. In this case, it goes without saying that the switch SW1 closes the terminal a1-a2.
[0062]
The amplitude monitor unit 119 includes a variable gain amplifier 127 whose gain can be changed, an integrator 135 (second integrator) that outputs a control signal for controlling the gain to the variable gain amplifier 127, and data after gain adjustment. In order to keep the gain constant at the time of transmission / reception, a fixed voltage source 137 that outputs a signal for making the output of the integrator 135 constant is newly provided. The fixed voltage source 137 normally outputs a zero signal. The functions of the differential amplifier 129, the multiplier 131, and the filter 133 are the same as in the first embodiment.
[0063]
Further, the amplitude monitor unit 119 is newly provided with two switches SW4 and SW5, which constitute a fourth connecting means. At the time of gain adjustment shown in FIG. 4, the switch SW4 is connected between the terminals d1 and d2, and the switch SW5 is connected between the terminals e1 and e2. As a result, the signal from which the harmonic component is removed by the filter 133 after multiplying the reference signal and the output signal from the differential amplifier 129 by the multiplier 131 is integrated by the integrator 135 to generate a control signal for the variable gain amplifier 127. The gain can be changed. The gain at this time is V in the electric field detection optical unit 115._sThe output of the variable gain amplifier 127 is V_sAdjust so that Note that the data signal is kept constant during gain adjustment so that the signal from the oscillator 107 is not modulated.
[0064]
The operation during gain adjustment will be described again with reference to FIG. When the gain is small, the reference signal and the output signal of the differential amplifier 129 have the same phase, so that the signal output from the multiplier 131 and the harmonics removed by the filter 133 is integrated. A control signal (gain control signal) for increasing the gain in gain amplifier 127 is output. Therefore, in this case, the output waveform of each component unit of the amplitude monitor unit 119 is essentially the same as that shown in FIG. The control signal 69 at this time is a signal that increases the gain until the output signal output from the differential amplifier 129 (the difference between the output signal of the reference signal 63 and the variable gain amplifier 127) becomes 0 (zero). .
[0065]
On the other hand, FIG. 10B corresponds to the signal waveform output from each component unit of the amplitude monitor unit 119 when the gain is large. In this case, since the reference signal 73 and the output signal 71 of the differential amplifier 129 are in opposite phases, the integrator 135 controls the gain until the output signal from the differential amplifier 129 becomes 0 (zero). 79 is output.
[0066]
The connection state of each switch at the time of data transmission / reception after gain adjustment will be described below.
[0067]
FIG. 5 is a block diagram showing the connection state of the switches during data transmission. The switch SW1 is connected between the terminals a2 to a3 so that the output from the transmission circuit 103 is applied to the living body 9 via the variable reactance unit 109 as in the first embodiment. The switch SW2 is connected to the variable gain amplifier 127 side in the same manner as the gain adjustment, and constitutes a negative feedback circuit (connection between terminals b1 and b3). The switch SW3 is connected to the transmission / reception electrode 111 side in order to receive a signal from the living body 9 (connection between terminals c2 and c3). The switch SW4 is connected to the integrator 121 side to integrate the signal from the filter 133 and control the reactance of the variable reactance unit 109 (connection between the terminals d1 to d3). The switch SW5 connects the integrator 135 and the fixed voltage source 137 (connection between terminals e2 and e3).
[0068]
On the other hand, FIG. 6 is a block diagram showing the connection state of the switches when receiving data. As shown in the figure, at the time of data reception, the switch SW1 is disconnected in order to prevent backflow to the transmission circuit 103 as in the first embodiment. The switch SW2 connects between the terminals b2 and b3 so as to transmit the signal output from the signal processing circuit 117 to the demodulation circuit 123. The other connections of the switches SW3, SW4, and SW5 are the same as in the data transmission described above.
[0069]
Note that the connection of each switch is switched in conjunction with a switching control signal from the control circuit 141 according to gain adjustment, data transmission, and data reception, as in the first embodiment.
[0070]
Of course, this embodiment (a modification of the first embodiment) having the gain adjustment function described above has the same effect as the first embodiment. In addition, according to the present embodiment, the gain of the variable gain amplifier 127 provided in the amplitude monitor unit 119 is automatically adjusted to be set so as to obtain an optimum gain according to the situation. Application of a voltage to 9 can be performed.
[0071]
(Second Embodiment)
In the transceiver according to the second embodiment of the present invention, instead of changing the reactance of the reactance unit provided between the transmission circuit and the transmission / reception electrode, the oscillation frequency f of the oscillator is made variable, and the voltage applied to the living body 9 is changed. This is to prevent a decrease.
[0072]
As apparent from the equation (2), the stray capacitance 43 (C_g) The applied voltage V to the living body 9 changes according to the change of_bOutput voltage V from the transmission circuit_sIt can be realized by changing the frequency f generated from the oscillator instead of making the reactance X of the reactance unit variable as in the first embodiment.
[0073]
FIG. 7 is a block diagram showing the configuration of the transceiver according to the present embodiment. In the transceiver 2 shown in the figure, a reactance unit 209 having a certain reactance is provided between the transmission circuit 203 and the transmission / reception electrode 211, while a frequency variable oscillator 207 capable of changing the frequency of the oscillating AC signal is provided in the transmission circuit 203. Is provided. In accordance with this, a control signal generator 221 that generates a control signal based on a signal output from the amplitude monitor 219 is connected to the variable frequency oscillator 207. That is, the control signal in this embodiment is for controlling the frequency of the frequency variable oscillator 207. The functional configuration of each part excluding these points is the same as that of the transceiver 1 according to the first embodiment (for the correspondence of the reference numerals given to each part, see the description in the first embodiment) )
[0074]
FIG. 7 is a block diagram illustrating a connection state of the transceiver 2 during data transmission. In the figure, a signal output from the signal processing circuit 217 is transmitted to the control signal generation unit 221 via the amplitude monitor unit 219, and a control signal based on this signal is transmitted to the frequency variable oscillator 207 to the living body 9. Is the output voltage V of the transmission circuit 203._sIt is controlled to become. Specifically, the switch SW1 is connected between the terminals a1 and a2, and the switch SW2 is connected between the terminals b1 and b3.
[0075]
Although not shown at the time of data reception, the connection between the terminals a1 and a2 of the switch SW1 (first connection means) is disconnected, while the connection of the switch SW2 (second connection means) is between the terminals b2 and b3. Switching to the connection is the same as in the first embodiment. The point that the switching of these two switches is performed through a switching control signal from the control circuit 241 is the same as in the first embodiment.
[0076]
The detailed configuration of the amplitude monitor unit 219 is also the same as the configuration of the amplitude monitor unit 119 shown in FIG. That is, an output signal from the signal processing circuit 217 is output to an amplifier 227 provided in the amplitude monitor unit 219, and the output signal from the amplifier 227 and the reference signal from the modulation circuit 205 are differentially amplified to be multiplied by the multiplier 231. Control for controlling the frequency of the frequency variable oscillator 207 by multiplying the reference signal and integrating the product obtained by removing the harmonic component of the multiplied signal by the filter 233 using the integrator 221 that is a control signal generator. Generate a signal. Here, in order to clearly indicate that this is a constituent unit used in the present embodiment, the first digit of the reference numeral assigned to each constituent unit of the amplitude monitor unit 119 shown in FIG.
[0077]
In this case as well, the gain of the amplifier 227 is already adjusted, but it is of course possible to use a variable gain amplifier in which the amplifier 227 has a function of automatically adjusting the gain. FIG. 8 is a block diagram showing a detailed configuration of the amplitude monitor unit 219 and a switch connection state at the time of gain adjustment using the variable gain amplifier 227 having a function of adjusting gain as an amplifier.
[0078]
The point that the wiring for directly connecting the transmission circuit 203 and the electric field detection optical unit 215 is provided without using the constituent unit constituting the amplitude monitor unit 219 and the reactance unit 209 is the one described in the modification of the first embodiment. (See FIG. 4). Also, the reference numerals assigned to the terminals provided in each of the switches SW1, SW2, SW3 (third connecting means), SW4 and SW5 (fourth connecting means) are the terminals of the respective switches of the first embodiment. Corresponding to the reference numerals attached to. More specifically, in order to transmit the output signal from the transmission circuit 203 directly to the electric field detection optical unit 215 without passing through the reactance unit 209, the switch SW1 connects the terminals a1-a2 and the switch SW3 connects the terminal c1. -Connect between c2. The switch SW2 connects between the terminals b1 and b3 in order to send the output from the signal processing circuit 217 to the variable gain amplifier 227. The switches SW4 and SW5 connect between the terminals d1 and d2 and between the terminals e1 and e2, respectively, in order to transmit the output from the filter 233 from which the harmonic component has been removed to the integrator 235.
[0079]
As a result, the signal waveform output from each component unit is the same as that shown in FIG. However, in the present embodiment, it goes without saying that the control signal from the integrator 221 that is the control signal generation unit is output to the frequency variable oscillator 207 so that the frequency is changed to a frequency causing series resonance with the reactance unit 209. .
[0080]
FIG. 9 is a block diagram illustrating a connection state of the switches when the transceiver 2 transmits data. The connection status of each switch in the figure is as follows. The switch SW1 connects the terminals a2 to a3 in order to transmit the output from the transmission circuit 203 to the reactance unit 209. The switch SW3 connects the terminals c2 to c3 in order to receive a signal from the transmission / reception electrode 211. The switch SW2 is the same as that at the time of gain adjustment. The switch SW4 is connected between the terminals d1 and d3 in order to send the output from the filter 233 to the integrator 221. The switch SW5 connects the terminals e2 to e3 so as to send a signal from the fixed voltage source 237 to the integrator 235 in order to keep the gain of the variable gain amplifier 227 after gain adjustment constant.
[0081]
Although not shown, at the time of data reception, the connection between the terminals of the switch SW1 is disconnected to prevent backflow. The switches SW2 and SW3 are connected between the terminals b2 and b3 and between the terminals c2 and c3, respectively, in order to transmit the electric field induced in the living body 9 to an electrical signal and then transmit the received data to the wearable computer 7. The switches SW4 and SW5 are the same as in data transmission.
[0082]
According to the second embodiment of the present invention described above, the same effect as that of the first embodiment is obtained by making the frequency of the oscillator variable instead of making the reactance of the reactance unit variable in the first embodiment. be able to.
[0083]
Of course, even when a gain adjustment function is added using a variable gain amplifier, the same effect as that of the modification of the first embodiment can be obtained.
[0084]
(Third embodiment)
FIG. 11 is a block diagram showing a configuration of a transceiver according to the third exemplary embodiment of the present invention. In the transceiver 3 shown in the figure, a transformer 319 is connected in series between the modulation circuit 305 and the transmission / reception electrode 311, and a variable reactance unit 309 is connected in parallel with the transformer 319. One end point of the variable reactance unit 309 is connected to the ground 51. Therefore, the reactance value is X = 1 / (ωC_g) = 1 / (2πf C_g), V_b= V_sTherefore, the potential of the node A becomes 0 (zero). By monitoring this node A and changing the reactance X so as to form a negative feedback circuit that makes its potential zero, V_b= V_sCan be maintained. Needless to say, the provision of the transformer 319 can increase the electric field strength induced in the living body 9 during transmission.
[0085]
Next, the connection form of the three switches provided in the transceiver 3 will be described. At the time of data transmission shown in FIG. 11, the terminals a1-a2 of the switch SW1 (first connecting means) are closed. A switch SW2 (second connection means) is connected to the multiplier 331 side to form a negative feedback circuit (connection between terminals b1 and b3). The switch SW3 (third connection means) is connected between the terminals c1 and c2, and directly connects the transformer 319 and the electric field detection optical unit 315.
[0086]
On the other hand, at the time of data reception (not shown), the switch SW1 is disconnected from the terminal in order to prevent contamination from the living body 9. The switch SW3 is connected to a transmission / reception electrode to receive a signal from the living body 9 (connection between terminals c2 and c3), and a signal via the electric field detection optical unit 315 and the signal processing circuit 317 is received by the wearable computer 7 as data. As described above, the switch SW2 is connected to the demodulation circuit 323 side (connection between the terminals b2 and b3).
[0087]
The signal waveforms output from each component unit until the generation of the control signal are essentially the same as those in FIG. 10 except that the output signals 61 and 71 indicating the differential amplifier output are regarded as the output waveforms from the signal processing circuit 317. Is. That is, in the case shown in FIG. 10A, the stray capacitance 43 (C_g) Decreases. At this time, V in accordance with Equation (2)_b<V_sThus, the potential of the node A falls below 0. As a result, the output signal 61 input from the transformer 319 to the multiplier 331 via the electric field detection optical unit 315 and the signal processing circuit 317 causes damped oscillation in the same phase as the reference signal 63. Therefore, the output of the multiplier 331 becomes positive, the harmonic component of the output signal 65 is removed by the filter 333, and the signal 67 output from the filter 333 is integrated by the integrator 321. V_b= V_sA control signal 69 (a signal for increasing the reactance X) 69 that gives a reactance satisfying the condition is transmitted to the variable reactance unit 309.
[0088]
FIG. 10B is an explanatory diagram showing signal waveforms output from each component unit until the control signal is generated when the stray capacitance 43 increases. In the case shown in the figure, the situation is reversed from FIG. That is, the output signal 71 input from the transformer 319 to the multiplier 331 via the electric field detection optical unit 315 and the signal processing circuit 317 causes a damped oscillation in the opposite phase to the reference signal 73. As a result, the output signal 75, the signal 77, and the control signal 79 output from the respective constituent units thereafter have the opposite signs to those shown in FIG. The control signal 79 output from the integrator 321 is V V to the variable reactance unit 309._b= V_sIs a signal that gives a reactance X satisfying (a signal that decreases the reactance X).
[0089]
As described above, in the present embodiment, the transformer substantially plays the role of the differential amplifier in the first and second embodiments. In the first and second embodiments, the gain adjustment is performed so that the output of the differential amplifier is 0 (zero), so that the potential at the node A is monitored and the potential is set to 0 (zero). This corresponds to adjusting the reactance X. Therefore, when the potential of the node A becomes 0 (zero), V_b= V_sTherefore, it is not necessary to adjust the gain of the amplifier compared with the reference signal as in the case of using the differential amplifier.
[0090]
Needless to say, the functions of the respective parts of the transceiver 3 other than those described above are not particularly different from the corresponding parts in the above-described embodiments, and thus the description thereof is omitted.
[0091]
According to the third embodiment of the present invention described above, it is possible to obtain the same effects as those of the first and second embodiments. It becomes possible to simplify the circuit.
[0092]
Further, according to the present embodiment, since it is not necessary to perform gain adjustment, a preliminary operation for using the transceiver is not necessary, and it is possible to obtain an effect that usability is further improved.
[0093]
(Fourth embodiment)
FIG. 12 is a block diagram showing a configuration of a transceiver according to the fourth exemplary embodiment of the present invention. In the transceiver 4 shown in the figure, a transformer 419 is connected in series between a transmission circuit 403 and a transmission / reception electrode 411, and a reactance unit 409 having a constant reactance is connected in parallel with the transformer 419. A variable frequency oscillator 407 is provided for changing the frequency of a carrier wave (AC signal) that carries data from the wearable computer 7. Therefore, in order to generate a control signal for controlling the frequency for the variable frequency oscillator 407, a multiplier 431 that multiplies the reference signal and the signal output from the signal processing circuit 417, and the harmonics of the output signal of the multiplier 431. A filter 433 for removing the wave component and an integrator 421 for generating a control signal by integrating the output signal of the filter 433 are connected to the frequency variable oscillator 407. Other configurations of the transceiver 4 are the same as those in the third embodiment.
[0094]
The operation of this embodiment is essentially the same as that of the third embodiment described above. That is, the voltage V applied to the living body 9 is adjusted by adjusting the frequency of the AC signal that is a carrier wave so that the potential of the node A of the reactance unit 409 becomes 0 (zero)._bThe output voltage V of the modulation circuit 405_sFrom the integrator 421, a control signal for controlling the frequency is generated. Therefore, the waveform of each component unit output signal is the same as that of the third embodiment except that the actual control signal is output to the frequency variable oscillator 407 and changed to a frequency causing series resonance (the third embodiment described above). In the embodiment, refer to the description using FIG.
[0095]
As for the connection form of the three switches SW1 (first connection means), SW2 (second connection means), and SW3 (third connection means), the third switch SW1 (first connection means) is used for both the data transmission and reception. This is the same as the embodiment. That is, the switch a1 is connected between the terminals a1 and a2, the switch SW2 is connected between the terminals b1 and b3, and the switch SW3 is connected between the terminals c1 and c2. FIG. It is clear that the configuration and the connection state are shown. Further, at the time of data reception (not shown), the connection between the terminals of the switch SW1 is disconnected, the terminals b2 and b3 are connected with the switch SW2, and the terminals c2 and c3 are connected with the switch SW3. The induced electric field is detected and data is sent to the wearable computer 7.
[0096]
It goes without saying that the fourth embodiment of the present invention described above has the same effects as those of the third embodiment.
[0097]
In each of the above-described embodiments, the living body is taken as an example of the electric field transmission medium. However, the electric field transmission medium that generates and transmits an electric field based on data during transmission / reception of the transceiver according to the present invention is not necessarily limited to the living body. Do not mean.
[0098]
Thus, it goes without saying that the present invention can include various embodiments that exhibit the same effects as described above.
[0099]
【The invention's effect】
According to the present invention described above, it is possible to provide a transceiver capable of preventing a decrease in voltage applied to an electric field transmission medium and improving communication quality.
[0100]
This makes the wearable computer more feasible.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a basic configuration of a transceiver according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration at the time of data transmission in the transceiver according to the first embodiment of the present invention.
FIG. 3 is a block diagram showing a more detailed configuration of the transceiver of FIG. 2;
FIG. 4 is a block diagram showing a configuration at the time of gain adjustment when the transceiver according to the first embodiment of the present invention has a gain adjustment function;
5 is a block diagram showing a configuration at the time of data transmission of the transceiver of FIG. 4; FIG.
6 is a block diagram showing a configuration of the transceiver of FIG. 4 when receiving data.
FIG. 7 is a block diagram showing a configuration at the time of data transmission in the transceiver according to the second embodiment of the present invention.
FIG. 8 is a block diagram showing a configuration at the time of gain adjustment when the transceiver according to the second embodiment of the present invention has a gain adjustment function;
9 is a block diagram showing a configuration at the time of data transmission of the transceiver of FIG. 8. FIG.
FIG. 10 is an explanatory diagram showing signals output from each component unit of the amplitude monitor unit and the control signal generation unit during gain adjustment;
FIG. 11 is a block diagram showing a configuration at the time of data transmission of a transceiver according to a third embodiment of the present invention.
FIG. 12 is a block diagram showing a configuration at the time of data transmission of a transceiver according to a fourth embodiment of the present invention.
FIG. 13 is a block diagram showing a configuration of a transceiver according to a conventional method.
FIG. 14 is an explanatory diagram showing an example when a wearable computer is worn and used by a person via a transceiver.
FIG. 15 is an explanatory diagram illustrating a voltage applied to a living body in a conventional method.
[Explanation of symbols]
1, 2, 3, 4, 5 transceiver
7 Wearable computers
9 Living body
11, 101, 201, 301, 401, 501 I / O circuit
13, 103, 203, 303, 403, 503 Transmission circuit (transmission means)
15, 105, 205, 305, 405, 505 Modulation circuit
17, 107, 307, 507 Oscillator
19, 209, 409 Reactance part (resonance means)
21, 111, 211, 311, 411, 511 Transmission / reception electrode
23, 113, 213, 313, 413, 513 insulator
41 Transmitter ground
43, 53 stray capacitance
51 Earth Ground
61, 65, 71, 75 Output signal
63, 73 Reference signal
67, 77 signals
69, 79 Control signal
80 External terminal
90 cable
109, 309 Variable reactance section (resonance means)
115, 215, 315, 415, 515 Electric field detection optical unit (part of electric field detection means)
117, 217, 317, 417, 517 Signal processing circuit (part of electric field detection means)
119, 219 Amplitude monitor (part of control means)
121, 221, 321, 421 Control signal generator or integrator (part of control means)
123, 223, 323, 423, 523 Demodulation circuit (demodulation means)
125, 225, 325, 425, 525 Waveform shaping circuit
127, 227 (variable gain) amplifier
129, 229 Differential amplifier
131,231,331,431 multipliers
133, 233, 333, 433 Filter
135, 235 integrator
137, 237 Fixed voltage source
141, 241, 341, 441 control circuit
207, 407 Frequency variable oscillator
319, 419 Transformer
SW1, SW2, SW3, SW4, SW5 switch

Claims (11)

A transceiver that induces an electric field based on information to be transmitted in an electric field transmission medium and transmits at least information using the induced electric field,
Transmitting means for oscillating an AC signal having a predetermined frequency to modulate the information to be transmitted, and transmitting a modulated signal related to the modulated information to be transmitted;
A transceiver comprising stray capacitance generated between the ground of the transmitting means and the ground and resonance means for causing series resonance. By inducing an electric field based on information to be transmitted in the electric field transmission medium and transmitting information using the induced electric field, while receiving an electric field based on the information to be received induced in the electric field transmission medium. A transceiver for receiving information,
Transmitting means for oscillating an AC signal having a predetermined frequency to modulate the information to be transmitted, and transmitting a modulated signal related to the modulated information to be transmitted;
Transmitting and receiving electrodes for inducing an electric field based on the information to be transmitted and receiving an electric field based on the information to be received;
Resonance means connected in series with the transmission means and the transmitting and receiving electrodes to cause series resonance with stray capacitance generated between the ground of the transmission means and the ground;
An electric field detection means for detecting an electric field based on the information to be received and converting the detected electric field into an electric signal;
Control means for outputting a control signal for controlling the characteristics of the resonance means by using an electric signal converted by the electric field detection means and a reference signal based on the modulation signal;
A transceiver comprising: demodulating means for demodulating the electric signal converted by the electric field detecting means. By inducing an electric field based on information to be transmitted in the electric field transmission medium and transmitting information using the induced electric field, while receiving an electric field based on the information to be received induced in the electric field transmission medium. A transceiver for receiving information,
Transmitting means for oscillating an AC signal having a predetermined frequency to modulate the information to be transmitted, and transmitting a modulated signal related to the modulated information to be transmitted;
Transmitting and receiving electrodes for inducing an electric field based on the information to be transmitted and receiving an electric field based on the information to be received;
Resonance means connected in series with the transmission means and the transmitting and receiving electrodes to cause series resonance with stray capacitance generated between the ground of the transmission means and the ground;
An electric field detecting means for detecting an electric field based on the information to be received through the transmission / reception electrode and converting the detected electric field into an electric signal;
Control means for outputting a control signal for controlling the frequency of an alternating current signal oscillated by the transmission means using a reference signal based on the electric signal converted by the electric field detection means and the modulation signal;
A transceiver comprising: demodulating means for demodulating the electric signal converted by the electric field detecting means. The control means includes
An amplifier for amplifying the electrical signal;
Obtaining a difference between the reference signal and the output signal of the amplifier, and a differential amplifier for amplifying the difference;
A multiplier for obtaining a product of the output signal of the differential amplifier and the reference signal;
A filter that removes the harmonic component of the signal that gives the product of the output signal of the differential amplifier and the reference signal obtained by the multiplier;
4. The transceiver according to claim 2, further comprising: a first integrator that generates the control signal based on a result obtained by integrating the output signal from the filter. When transmitting information by inducing an electric field in the electric field transmission medium, the transmitting means and the resonance means are connected, while receiving the electric field induced in the electric field transmission medium via the transmission / reception electrode. First connection means for disconnecting connection between the transmission means and the resonance means;
The electric field detection means and the amplifier are connected when transmitting the information, while the electric field detection means and the demodulation means are connected when receiving the electric field induced in the electric field transmission medium. 5. The transceiver of claim 4, further comprising: The control means includes
A second integrator for generating a gain control signal for controlling the gain of the amplifier;
A fixed voltage source capable of applying a constant voltage to the amplifier in order to keep the gain of the amplifier controlled by a gain control signal generated from the second integrator constant. 4. The transceiver according to 4. When transmitting information by inducing an electric field in the electric field transmission medium, the transmission unit and the resonance unit are connected, and when adjusting the gain of the amplifier, the transmission unit and the electric field detection unit are not provided via the resonance unit. A first connection means that does not perform connection when receiving an electric field induced in the electric field transmission medium via the transmission / reception electrode;
When transmitting the information and adjusting the gain of the amplifier, the electric field detection means and the control means are connected, while when receiving the electric field induced in the electric field transmission medium, the electric field detection means and the control means Second connection means for connecting the demodulation means;
When adjusting the gain of the amplifier, the transmission means and the electric field detection optical unit are connected, while when transmitting the information and when receiving the electric field, the transmission / reception electrode and the electric field detection means are connected. 3 connection means;
When transmitting the information and receiving the electric field, the filter and the first integrator are connected and the second integrator and the fixed voltage source are connected, while the gain of the amplifier is 7. The transceiver according to claim 6, further comprising fourth connecting means for connecting the filter and the second integrator when adjusting the frequency. By inducing an electric field based on information to be transmitted in the electric field transmission medium and transmitting information using the induced electric field, while receiving an electric field based on the information to be received induced in the electric field transmission medium. A transceiver for receiving information,
Transmitting means for oscillating an AC signal having a predetermined frequency to modulate the information to be transmitted, and transmitting a modulated signal related to the modulated information to be transmitted;
Transmitting and receiving electrodes for inducing an electric field based on the information to be transmitted and receiving an electric field based on the information to be received;
A transformer connected in series with the transmitting means and the transmitting and receiving electrodes;
Resonance means connected in parallel with the transformer to cause series resonance with stray capacitance generated between the ground of the transmission means and the ground;
An electric field detection means for detecting an electric field based on the information to be received and converting the detected electric field into an electric signal;
Control means for outputting a control signal for controlling characteristics of the resonance means using a reference signal based on the electric signal converted by the electric field detection means and the modulation signal;
A transceiver comprising: demodulating means for demodulating the electric signal converted by the electric field detecting means. By inducing an electric field based on information to be transmitted in the electric field transmission medium and transmitting information using the induced electric field, while receiving an electric field based on the information to be received induced in the electric field transmission medium. A transceiver for receiving information,
Transmitting means for oscillating an AC signal having a predetermined frequency to modulate the information to be transmitted, and transmitting a modulated signal related to the modulated information to be transmitted;
Transmitting and receiving electrodes for inducing an electric field based on the information to be transmitted and receiving an electric field based on the information to be received;
A transformer connected in series with the transmitting means and the transmitting and receiving electrodes;
Resonance means connected in parallel with the transformer to cause series resonance with stray capacitance generated between the ground of the transmission means and the ground;
An electric field detection means for detecting an electric field based on the information to be received and converting the detected electric field into an electric signal;
Control means for outputting a control signal for controlling the frequency of an alternating current signal oscillated by the transmission means using a reference signal based on the electric signal converted by the electric field detection means and the modulation signal;
A transceiver comprising: demodulating means for demodulating the electric signal converted by the electric field detecting means. The control means includes
A multiplier for obtaining a product of the reference signal and the electrical signal;
A filter that removes a harmonic component of a signal that gives a product of the reference signal and the electrical signal obtained by the multiplier;
10. The transceiver according to claim 8, further comprising an integrator that generates the control signal based on a result obtained by integrating an output signal from the filter. When transmitting information by inducing an electric field in the electric field transmission medium, the transmitter is connected to the transformer, while transmitting the electric field induced in the electric field transmission medium via the transmission / reception electrodes. First connecting means for disconnecting the means and the transformer;
A second connection for connecting the electric field detecting means and the demodulating means when receiving the electric field induced in the electric field transmission medium while connecting the electric field detecting means and the multiplier when transmitting the information Means,
A third connection for connecting the transmitting / receiving electrode and the electric field detecting means for receiving the electric field induced in the electric field transmission medium while connecting the resonance means and the electric field detecting means for transmitting the information. 11. The transceiver of claim 10, further comprising: means.

Images