JP3892563B2

JP3892563B2 - Information storage medium

Info

Publication number: JP3892563B2
Application number: JP01065898A
Authority: JP
Inventors: 芳美佐々木; 雅史横田
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 1998-01-22
Filing date: 1998-01-22
Publication date: 2007-03-14
Anticipated expiration: 2018-01-22
Also published as: JPH11215026A

Description

【０００１】
【発明の属する技術分野】
本発明は、たとえば、無電池式の無線カードや無線タグなど、携帯可能な無線通信機能を有した無電池式の情報記憶媒体に関する。
【０００２】
【従来の技術】
最近、携帯可能な無線通信機能を有した無電池式の情報記憶媒体として、いわゆる無電池式の無線カードが開発され、実用化されつつある。この種の無線カードを用いた無線カードシステムでは、無線カードリーダ・ライタを用いて、無線カードとの間で無線による送受信を行なうことにより、無線カードに対して電力の送信やデータの送信および受信など、所定の情報処理を行なうようになっている。
【０００３】
ところで、このような無線カードにおいて、無線カードリーダ・ライタから送信される電波による電力を受信しながら、無線カードリーダ・ライタに対してデータを変調して送信を行なう方式として、たとえば、図５に示す回路が知られている。
【０００４】
図５の回路について説明すると、１は無線カードの送受信アンテナコイルで、その両端には同調コンデンサ２が接続されるとともに、ダイオードＤ１〜Ｄ４をブリッジ接続してなる全波整流回路３の交流入力端が接続される。全波整流回路３の一方の直流出力端（負側）は接地され、他方の直流出力端（正側）はシリーズレギュレータあるいはシャントレギュレータからなる安定化電源回路４に接続され、この安定化電源回路４で無線カード内の各回路に供給する電源が生成される。
【０００５】
送受信アンテナコイル１の一端は復調回路５の入力端に接続され、復調回路５の出力端は制御ロジック回路６に接続されている。制御ロジック回路６には、受信データや送信データなどを記憶するメモリ７が接続されている。
【０００６】
送受信アンテナコイル１の両端には、抵抗８とアナログスイッチング素子９との直列回路が接続される。アナログスイッチング素子９は、変調回路１０からの変調された送信データによってオン、オフ制御される。変調回路１０の入力端は制御ロジック回路６に接続されている。
【０００７】
このような構成において、送受信アンテナコイル１で受信した搬送波は全波整流回路３で整流され、この整流出力に基づき安定化電源回路４で電源が生成され、各回路に供給されるとともに、復調回路５は、送受信アンテナコイル１の一端から得られる受信電圧を復調し、制御ロジック回路６へ送る。
【０００８】
一方、制御ロジック回路６は、メモリ７から送信データを読出して変調回路１０へ送り、変調回路１０で変調し、変調した送信データに応じてアナログスイッチング素子９をオン、オフ制御することにより、送信を行なう。
【０００９】
【発明が解決しようとする課題】
安定化電源回路をシリーズレギュレータで構成した場合、無線カードリーダ・ライタと無線カードとの通信距離が短くなると、無線カードリーダ・ライタから無線カードへ放射される電波の磁界強度Ｅは、距離をｄとすると、Ｅ∝１／ｄ³ の関係があり、送受信アンテナコイルでの搬送波受信電圧が非常に高くなり、ワンチップＬＳＩで構成される回路の耐圧が大きな問題となる。
【００１０】
また、安定化電源回路をシャントレギュレータで構成した場合、送受信アンテナコイルでの搬送波受信電圧はシャントレギュレータの電圧にクランプされ、この結果、低変調度の振幅変調信号の受信検波や送信がうまく行なえないという問題を有している。
【００１１】
そこで、本発明は、ワンチップＬＳＩ化した場合の耐圧問題を解決するとともに、低変調度の振幅変調信号の検波を確実に行なうことができるとともに、送信を効率よく行なうことができ、さらに、全二重通信を確実に行なうことができる無線通信機能を有した無電池式の情報記憶媒体を提供することを目的とする。
【００１２】
【課題を解決するための手段】
本発明の情報記憶媒体は、１つの送受信アンテナにより、外部から送信される電波を受信しながら外部へのデータ送信を行なう無線通信機能を有した無電池式の情報記憶媒体において、送受信を行なうための１つの送受信アンテナコイルと、この送受信アンテナコイルの両端に接続され、第１の搬送波に同調させるための同調素子と、前記送受信アンテナコイルの両端に接続され、前記第１の搬送波を整流する、４つの整流素子をブリッジ接続してなる全波整流回路と、この全波整流回路の出力に接続され、電流電圧変換手段を介して前記全波整流回路の出力を所定の電圧にクランプすることにより、該情報記憶媒体内で用いる安定化した電源を生成する電源生成手段と、前記全波整流回路の出力に接続され、前記全波整流回路の出力の包絡線検波を行なうことにより受信信号を検出する包絡線検波手段とを具備している。
【００１３】
また、本発明の情報記憶媒体は、１つの送受信アンテナにより、外部から送信される電波を受信しながら外部へのデータ送信を行なう無線通信機能を有した無電池式の情報記憶媒体において、送受信を行なうための１つの送受信アンテナコイルと、この送受信アンテナコイルの両端に接続され、第１の搬送波に同調させるための同調素子と、前記送受信アンテナコイルの両端に接続され、前記第１の搬送波を整流する、４つの整流素子をブリッジ接続してなる全波整流回路と、この全波整流回路の出力に接続され、電流電圧変換手段を介して前記全波整流回路の出力を所定の電圧にクランプすることにより、該情報記憶媒体内で用いる安定化した電源を生成する電源生成手段と、前記全波整流回路の出力に接続され、前記全波整流回路の出力の包絡線検波を行なうことにより受信信号を検出する包絡線検波手段と、この包絡線検波手段の出力から直流成分を除去する直流分除去手段と、この直流分除去手段で直流成分を除去された前記包絡線検波手段の出力を所定の増幅度で増幅する増幅手段と、この増幅手段の出力から第１の搬送波成分を除去するフィルタ手段と、このフィルタ手段で第１の搬送波成分を除去された前記増幅手段の出力を２値化する２値化手段とを具備している。
【００１４】
さらに、本発明の情報記憶媒体は、１つの送受信アンテナにより、外部から送信される電波を受信しながら外部へのデータ送信を行なう無線通信機能を有した無電池式の情報記憶媒体において、送受信を行なうための１つの送受信アンテナコイルと、この送受信アンテナコイルの両端に接続され、第１の搬送波に同調させるための同調素子と、前記送受信アンテナコイルの両端に接続され、前記第１の搬送波を整流する、４つの整流素子をブリッジ接続してなる全波整流回路と、この全波整流回路の出力に接続され、電流電圧変換手段を介して前記全波整流回路の出力を所定の電圧にクランプすることにより、該情報記憶媒体内で用いる安定化した電源を生成する電源生成手段と、前記送受信アンテナコイルで第１の搬送波を受信し、この第１の搬送波の整数分の１の周波数をもつ第３の搬送波を生成する第３の搬送波生成手段と、この第３の搬送波生成手段で生成された第３の搬送波と送信データとの排他的論理和をとることにより位相変調信号を得る排他的論理和手段と、この排他的論理和手段で得られる位相変調信号、および、それをインバータで反転させた反転位相変調信号の各電圧をそれぞれ所定の電流値に変換する定電流回路を前記送受信アンテナコイルの両端にそれぞれ接続してなり、前記第１の搬送波を受信中に前記位相変調信号に応じた所定の電流で前記送受信アンテナコイルの両端をプッシュプル駆動することにより送信を行なわせる定電流駆動手段とを具備している。
【００１５】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照して説明する。
図１は、本発明に係る情報記憶媒体としての無線カードが適用される無線カードシステムの構成を示すものである。この無線カードシステムは、携帯可能な無線通信機能を有する無電池式の無線カード１００と、外部装置としての無線カードリーダ・ライタ２００とに大別される。
【００１６】
無線カード１００は、無線カードリーダ・ライタ２００からのコマンドの解読、データの書込み、データの送信などを行なうもので、ループ状の送受信アンテナコイル１０１、無線カード１００内の各回路に与える安定化電源を生成する電源回路１０２、受信データの復調を行なう復調回路１０３、送信データの変調を行なう変調回路１０４、送信データや受信データなどを記憶する不揮発性のメモリ１０５、および、これらの制御を行なうＣＰＵなどからなる制御ロジック回路１０６などによって構成されている。
【００１７】
無線カードリーダ・ライタ２００は、無線カード１００への読出し、書込みコマンドの送信、読出しデータの処理、書込みデータの送信、電力波の送信などを行なうもので、送信アンテナコイル２０１、送信アンテナコイル２０１を駆動するドライバ２０２、送信データの変調を行なう変調回路２０３、受信アンテナコイル２０４、受信アンテナコイル２０４の出力を増幅する増幅回路２０５、受信データの復調を行なう復調回路２０６、および、これらの制御を行なうＣＰＵなどからなる制御回路２０７によって構成されている。
【００１８】
このような構成において、まず、無線カード１００側の動作について説明する。送受信アンテナ１０１で受信された受信信号は、電源回路１０２で整流、平滑、安定化されることにより安定化電源が生成され、各回路に供給される。また、この受信信号は、復調回路１０３で復調された後、制御ロジック回路１０６に送られ、制御ロジック回路１０６でコマンドの解読とともにデータの読出しや書込みが行なわれる。
【００１９】
また、制御ロジック回路１０６は、メモリ１０５から送信データを読出して変調回路１０４へ送り、変調回路１０４で変調した後、送受信アンテナ１０１に供給することにより、送信を行なう。
【００２０】
次に、無線カードリーダ・ライタ２００側の動作について説明する。制御回路２０７は、読出しコマンドあるいは書込みコマンドおよび書込みデータ（送信データ）を生成し、変調回路２０３へ送る。変調回路２０３では、制御回路２０７からの送信データを任意の変調方式で変調し、その変調データをドライバ２０２へ送る。ドライバ２０２では、変調データを放射するに充分な強度まで増幅した後、無線カード１００内の電源生成用の電力信号とともに、変調波として送信アンテナコイル２０１へ送り、送信を行なう。
【００２１】
また、無線カード１００からの送信電波は、受信アンテナ２０４で受信され、増幅回路２０５で増幅された後、復調回路２０６に送られる。復調回路２０６では受信信号を復調し、この復調されたデータは制御回路２０７へ送られ、ここで必要な処理（たとえば、正常に受信できたか、エラーは無いかなど）が行なわれた後、必要に応じて外部へ出力される。
【００２２】
次に、本発明の要部である無線カード１００における電源回路１０２、復調回路１０３、および、変調回路１０４の部分について、図２を参照して詳細に説明する。
【００２３】
図２において、送受信アンテナコイル１０１の両端には、第１の搬送波の周波数に同調させるための同調素子としての同調コンデンサ１１が接続されるとともに、整流素子としてのダイオードＤ１１〜Ｄ１４をブリッジ接続してなる全波整流回路１２の交流入力端ａ，ｂが接続される。全波整流回路１２の一方の直流出力端（負側）ｃは接地され、他方の直流出力端（正側）ｄは、電流電圧変換手段としての抵抗などで構成される電流電圧変換回路１３を介して、クランプ手段としてのシャントレギュレータなどで構成されるクランプ回路１４に接続され、このクランプ回路１４で無線カード１００内の各回路に供給する安定化電源が生成される。
【００２４】
クランプ回路１４には、クランプされた電圧を平滑する平滑手段としての平滑コンデンサ１５が接続されている。
また、全波整流回路１２の他方の直流出力端（正側）ｄは、包絡線検波手段としての包絡線検波回路１６の入力端に接続される。包絡線検波回路１６の出力端は、直流分除去手段としてのコンデンサ１７を介して、増幅手段としての増幅回路１８の入力端に接続される。増幅回路１８の出力端は、フィルタ手段としてのローパスフィルタ（ＬＰＦ）１９を介して、２値化手段としての２値化回路２０の入力端に接続される。２値化回路２０の出力端は、制御ロジック回路１０６に接続されている。
【００２５】
送受信アンテナコイル１０１の一端と接地点との間には、定電流回路を構成するＭＯＳトランジスタ（ＦＥＴ）２１と抵抗２２との直列回路が接続され、送受信アンテナコイル１０１の他端と接地点との間には、同じく定電流回路を構成するＭＯＳトランジスタ（ＦＥＴ）２３と抵抗２４との直列回路が接続される。
【００２６】
トランジスタ２１，２３の各ゲートには、それぞれフィルタ手段としてのローパスフィルタ（ＬＰＦ）２５，２６を介してアンド回路２７，２８の各出力端がそれぞれ接続される。
【００２７】
アンド回路２７の一方の入力端には、排他的論理和回路２９の出力が入力され、他方の入力端には、制御ロジック回路１０６からの送信制御信号が入力される。アンド回路２８の一方の入力端には、排他的論理和回路２９の出力がインバータ回路３０を介して入力され、他方の入力端には、制御ロジック回路１０６からの送信制御信号が入力される。
【００２８】
排他的論理和回路２９の各入力端には、制御ロジック回路１０６からの送信データ、および、受信した第１の搬送波を整数分の１に分周した第３の搬送波信号がそれぞれ入力される。
【００２９】
また、送受信アンテナコイル１０１の他端は、２値化手段としての２値化回路３１の入力端に接続される。２値化回路３１の出力端は、制御ロジック回路１０６に接続されている。
【００３０】
次に、このような構成において、図３および図４に示す要部の信号波形図を参照して図２の動作を説明する。
送受信アンテナコイル１０１で受信された第１の搬送波の低変調度の振幅変調受信電圧Ａ（あるいはＢ）の波形を図３（ａ）に示している。同調コンデンサ１１は、送受信アンテナコイル１０１とで第１の搬送波の周波数に同調している。
【００３１】
送受信アンテナコイル１０１で受信された第１の搬送波の受信電圧Ａ（あるいはＢ）は、全波整流回路１２で整流された後、抵抗などで構成される電流電圧変換回路１３を介して、シャントレギュレータなどで構成されるクランプ回路１４に入力され、クランプ回路１４で所定の定電圧が生成され、平滑コンデンサ１５で平滑されて、各回路の電源として用いられる。
【００３２】
ここで、クランプ回路１４は、無線カードリーダ・ライタ２００との通信可能距離が最大のときには、クランプ回路１４自身の消費電流がほぼ「０」となるように動作し、通信距離が無線カードリーダ・ライタ２００と近づくにつれて、クランプ回路１４自身の消費電流が増大し、クランプ回路１４の出力は所定の定電圧に保持されるようになっている。
【００３３】
なお、通信可能距離が最大のときの電流電圧変換回路１３による電圧降下は、クランプ回路１４から出力される所定の定電圧の１０分の１から５分の１程度が望ましい。
【００３４】
このように構成することによって、全波整流回路１２の出力電圧（受信電圧）Ｃは図３（ｂ）に示すような波形となる。この出力電圧Ｃは包絡線検波回路１６に入力され、図３（ｃ）に示すような波形の検波出力Ｄが得られる。この検波出力Ｄは、第１の搬送波の整数分の１の周波数をもつ第２の搬送波で２相位相（ＢＰＳＫ）変調された変調信号であり、クランプ回路１４から出力される所定の定電圧を越えるような直流電圧成分を有している。
【００３５】
包絡線検波回路１６の出力は、コンデンサ１７を介して増幅回路１８に入力されることにより、上記直流成分がコンデンサ１７で除去された後、所定の増幅度を有した増幅回路１８で増幅が行なわれる。
【００３６】
増幅回路１８の出力は、ローパスフィルタ１９を介して２値化回路２０に入力されることにより、ローパスフィルタ１９で第１の搬送波成分の充分な除去や、全二重通信時の第３の搬送波成分の除去も合せて行なわれた後、２値化回路２０で２値化されて図３（ｄ）に示す２値化出力Ｅが得られる。
【００３７】
こうして２値化回路２０から得られる２値化出力Ｅと、２値化回路３１から得られる第１の搬送波の２値化出力とから、２相位相変調信号の復調を制御ロジック回路１０６で行なうことができる。ここで、第２の搬送波の周波数＜第３の搬送波の周波数として、全二重通信を可能となるよう構成されている。
【００３８】
以上のように構成したので、クランプ回路１４の出力は、無線カードリーダ・ライタ２００との通信距離が変わっても所定の定電圧に安定化され、電流電圧変換回路１３によって低変調度の振幅変調受信信号が電圧に変換されることにより検波できる。
【００３９】
また、この電流電圧変換回路１３としての抵抗の値を充分に小さく設定してあるので、無線カードリーダ・ライタ２００との通信距離が近づいても、送受信アンテナコイル１０１の受信電圧は充分に抑制される。
【００４０】
次に、無線カード１００からの送信に関する動作について説明する。送受信アンテナコイル１０１で第１の搬送波を受信し、２値化回路３１でその受信した第１の搬送波の２値化信号を得て、制御ロジック回路１０６でその２値化信号の分周を行なうことにより、第１の搬送波の整数分の１の周波数をもつ第３の搬送波を得るとともに、メモリ１０５から送信データを読出し、これら第３の搬送波信号および送信データを排他的論理和回路２９に送り、両信号の排他的論理和をとることにより、２相位相（ＢＰＳＫ）変調信号を得る。
【００４１】
この２相位相変調信号（排他的論理和回路２９の出力）をアンド回路２７に入力するとともに、インバータ回路３０を介して反転させ、反転２相位相変調信号を得て、アンド回路２８に入力する。ここで、制御ロジック回路１０６から、データ送信時は“１”とし、それ以外では“０”とする送信制御信号をアンド回路２７，２８に入力し、２相位相変調信号と論理積をとることにより、送信時以外ではアンド回路２７，２８の各出力は“０”となり、電圧電流変換を行なうＭＯＳトランジスタ２１，２３をオフさせる。
【００４２】
ローパスフィルタ２５，２６は、アンド回路２７，２８にそれぞれ接続され、第３の搬送波の高調波成分を除くように構成される。ローパスフィルタ２５の出力（２相位相変調信号）は、電圧信号としてＭＯＳトランジスタ２１と抵抗２２とで構成された電圧電流変換を行なう定電流回路に入力され、抵抗２２によって所定の送信電流が送受信アンテナコイル１０１の一端に供給される。
【００４３】
また、ローパスフィルタ２６の出力（反転２相位相変調信号）は、電圧信号としてＭＯＳトランジスタ２３と抵抗２４とで構成された電圧電流変換を行なう定電流回路に入力され、抵抗２４によって所定の送信電流が送受信アンテナコイル１０１の他端に供給される。これにより、送受信アンテナコイル１０１への送信電流としてプッシュプル動作が行なわれる。
【００４４】
ここで、第３の搬送波の周波数ｆ3 による送受信アンテナコイル１０１のインピーダンスを、［送受信アンテナコイル１０１のインピーダンス（２πｆ3 Ｌ）＜（電流電圧変換回路１３の抵抗値）］とすることにより、効率の良い送信電流を送受信アンテナコイル１０１に流し、送信を行なうことができる。
【００４５】
プッシュプル送信を行なっているときの送受信アンテナコイル１０１の両端における各送信電圧Ａ，Ｂの波形を図４（ａ），（ｂ）に示す。プッシュプル送信を行なっているため、図４（ａ），（ｂ）の送信電圧波形は位相が反転したものとなる。この結果、全波整流回路１２の出力に現われる送信出力電圧Ｃは、図４（ｃ）に示すようになり、相殺されて受信の包絡線検波回路１６の出力には現われない。
【００４６】
また、（第１の搬送波の周波数ｆ1 ）＞（第３の搬送波の周波数ｆ3 ）＞（第２の搬送波の周波数ｆ2 ）となるように構成されているので、（第３の搬送波の周波数ｆ3 ）×２≫（第２の搬送波の周波数ｆ2 ）となる。したがって、ローパスフィルタ１９で送信搬送波は充分に除去できる。
【００４７】
この結果、本実施の形態の構成で全二重通信が安定に行なうことができる。
以上説明したように、上記した実施の形態によれば、従来の問題点であったワンチップＬＳＩ化した場合の耐圧問題を解決するとともに、１０％あるいはそれ以下の低変調度の振幅変調信号の検波を確実に行なうことができるとともに、送信を効率よく行なうことができ、さらに、全二重通信を確実に行なうことができる。
【００４８】
すなわち、シャントレギュレータとシリーズレギュレータとの中間の動作を行なわせるように構成したので、両レギュレータのそれぞれの欠点を共に回避できる。
【００４９】
また、全波整流回路の出力に直接平滑コンデンサを接続しないで、電流電圧変換回路としての抵抗を介して平滑コンデンサを接続し、平滑安定化を行なわせるようにしたので、１０％あるいはそれ以下の低変調度の振幅変調信号の波形が正しく全波整流回路の出力に保存される。したがって、この全波整流回路の出力を検波することにより、確実に低変調度の振幅変調信号の検波を行なうことができる。
【００５０】
また、全波整流回路の出力後の信号は両波整流のため、受信した第１の搬送波の周波数の２倍の周波数となるので検波が容易となる。
また、検波後は位相変調信号となるので、発生している直流分を容易にカットでき、安定した増幅が低い電源電圧で行なうことができる。
【００５１】
また、全波整流回路の出力後の信号は、第１の搬送波の周波数に対しても、第３の搬送波の周波数に対しても２倍とするので、検波後のもれ込みに対してもローパスフィルタでの除去が容易となる。
【００５２】
送信についても、送受信アンテナコイルの端部に出力インピーダンスが充分に高い定電流回路を接続して、定電流ドライブを行なうようにしたので、効率のよい送信が行なえる。
【００５３】
また、プッシュプル送信としたので、全波整流回路の出力には相殺されて受信検波出力には現われないので、全二重通信を確実に行なえる。
また、送信時以外には定電流ドライバをオフとしたので、効率のよい受信が行なえる。
【００５４】
また、定電流回路の入力部に第３の搬送波の高調波除去フィルタを挿入したので、不要な成分の送出が抑制できる。
さらに、送受信アンテナコイルの第３の搬送波の周波数でのインピーダンスが全波整流回路の出力に接続された電流電圧変換回路のインピーダンスよりも小となるようにしたので、効率のよい送信が行なえる。
【００５５】
【発明の効果】
以上詳述したように本発明によれば、ワンチップＬＳＩ化した場合の耐圧問題を解決するとともに、低変調度の振幅変調信号の検波を確実に行なうことができるとともに、送信を効率よく行なうことができ、さらに、全二重通信を確実に行なうことができる無線通信機能を有した無電池式の情報記憶媒体を提供できる。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る情報記憶媒体としての無線カードが適用される無線カードシステムの構成を示すブロック図。
【図２】無線カードの電源回路、復調回路および変調回路の部分を詳細に示す構成図。
【図３】動作を説明するための要部の信号波形を示す図。
【図４】動作を説明するための要部の信号波形を示す図。
【図５】従来の無線カードの構成を示す構成図。
【符号の説明】
１００……無線カード（情報記憶媒体）、２００……無線カードリーダ・ライタ、１０１……送受信アンテナ、１０２……電源回路、１０３……復調回路、１０４……変調回路、１０５……メモリ、１０６……制御ロジック回路、１１……同調コンデンサ（同調素子）、Ｄ１１〜Ｄ１４……ダイオード（整流素子）、１２……全波整流回路、１３……電流電圧変換回路（電流電圧変換手段）、１４……クランプ回路（クランプ手段）、１５……平滑コンデンサ（平滑手段）、１４……包絡線検波回路（包絡線検波手段）、１７……コンデンサ（直流分除去手段）、１８……増幅回路（増幅手段）、１９……ローパスフィルタ（フィルタ手段）、２０……２値化回路（２値化手段）、２１，２３……トランジスタ（定電流回路）、２２，２４……抵抗（定電流回路）、２５，２６……ローパスフィルタ（フィルタ手段）、２７，２８……アンド回路、２９……排他的論理和回路（排他的論理和手段）、３０……インバータ回路、３１……２値化回路（２値化手段）。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a batteryless information storage medium having a portable wireless communication function, such as a batteryless wireless card or a wireless tag.
[0002]
[Prior art]
Recently, a so-called battery-less wireless card has been developed and put into practical use as a battery-less information storage medium having a portable wireless communication function. In a wireless card system using this type of wireless card, the wireless card reader / writer is used to perform wireless transmission and reception with the wireless card, thereby transmitting power to the wireless card and transmitting and receiving data. For example, predetermined information processing is performed.
[0003]
By the way, in such a wireless card, a method for modulating and transmitting data to a wireless card reader / writer while receiving power from a radio wave transmitted from the wireless card reader / writer is shown in FIG. The circuit shown is known.
[0004]
The circuit shown in FIG. 5 will be described. Reference numeral 1 denotes a transmission / reception antenna coil of a wireless card. A tuning capacitor 2 is connected to both ends of the coil, and an AC input terminal of a full-wave rectifier circuit 3 formed by bridge-connecting diodes D1 to D4 Is connected. One DC output terminal (negative side) of the full-wave rectifier circuit 3 is grounded, and the other DC output terminal (positive side) is connected to a stabilized power circuit 4 composed of a series regulator or a shunt regulator. In step 4, power to be supplied to each circuit in the wireless card is generated.
[0005]
One end of the transmission / reception antenna coil 1 is connected to the input end of the demodulation circuit 5, and the output end of the demodulation circuit 5 is connected to the control logic circuit 6. The control logic circuit 6 is connected to a memory 7 that stores reception data, transmission data, and the like.
[0006]
A series circuit of a resistor 8 and an analog switching element 9 is connected to both ends of the transmission / reception antenna coil 1. The analog switching element 9 is ON / OFF controlled by the modulated transmission data from the modulation circuit 10. The input end of the modulation circuit 10 is connected to the control logic circuit 6.
[0007]
In such a configuration, the carrier wave received by the transmission / reception antenna coil 1 is rectified by the full-wave rectification circuit 3, and power is generated by the stabilized power supply circuit 4 based on the rectified output and supplied to each circuit. 5 demodulates the received voltage obtained from one end of the transmitting / receiving antenna coil 1 and sends it to the control logic circuit 6.
[0008]
On the other hand, the control logic circuit 6 reads transmission data from the memory 7, sends it to the modulation circuit 10, modulates it by the modulation circuit 10, and controls on / off of the analog switching element 9 according to the modulated transmission data, thereby transmitting data. To do.
[0009]
[Problems to be solved by the invention]
When the stabilized power supply circuit is composed of a series regulator, when the communication distance between the wireless card reader / writer and the wireless card becomes shorter, the magnetic field intensity E of the radio wave radiated from the wireless card reader / writer to the wireless card becomes the distance d. Then, there is a relationship of E∝1 / d ³ , the carrier wave reception voltage at the transmission / reception antenna coil becomes very high, and the breakdown voltage of the circuit constituted by the one-chip LSI becomes a serious problem.
[0010]
In addition, when the stabilized power supply circuit is configured with a shunt regulator, the carrier wave reception voltage at the transmit / receive antenna coil is clamped to the voltage of the shunt regulator, and as a result, reception detection and transmission of an amplitude modulation signal with a low modulation degree cannot be performed well. Has the problem.
[0011]
Therefore, the present invention solves the withstand voltage problem in the case of a one-chip LSI, can reliably detect an amplitude modulation signal with a low modulation degree, can perform transmission efficiently, An object of the present invention is to provide a battery-less information storage medium having a wireless communication function capable of reliably performing dual communication.
[0012]
[Means for Solving the Problems]
The information storage medium of the present invention is a battery-less information storage medium having a wireless communication function for transmitting data to the outside while receiving radio waves transmitted from the outside by one transmission / reception antenna. A transmitting / receiving antenna coil, a tuning element connected to both ends of the transmitting / receiving antenna coil and tuned to a first carrier wave, connected to both ends of the transmitting / receiving antenna coil, and rectifying the first carrier wave; A full-wave rectifier circuit formed by bridge-connecting four rectifier elements and an output of the full-wave rectifier circuit are connected to each other, and the output of the full-wave rectifier circuit is clamped to a predetermined voltage via a current-voltage converter. A power generation means for generating a stabilized power source used in the information storage medium, and an output envelope of the full-wave rectifier circuit connected to the output of the full-wave rectifier circuit It is provided with an envelope detector means for detecting the received signals by performing a detection.
[0013]
The information storage medium of the present invention is a battery-less information storage medium having a wireless communication function for transmitting data to the outside while receiving radio waves transmitted from the outside by one transmission / reception antenna. One transmitting / receiving antenna coil for performing, a tuning element connected to both ends of the transmitting / receiving antenna coil and tuned to a first carrier wave, connected to both ends of the transmitting / receiving antenna coil, and rectifying the first carrier wave The full-wave rectifier circuit formed by bridge-connecting four rectifier elements and the output of the full-wave rectifier circuit are connected to each other, and the output of the full-wave rectifier circuit is clamped to a predetermined voltage via the current-voltage conversion means. A power source generating means for generating a stabilized power source used in the information storage medium, and an output of the full-wave rectifier circuit connected to the output of the full-wave rectifier circuit Envelope detection means for detecting a received signal by performing envelope detection, DC component removal means for removing a DC component from the output of the envelope detection means, and DC component removed by the DC component removal means Amplifying means for amplifying the output of the envelope detecting means with a predetermined amplification degree, filter means for removing the first carrier component from the output of the amplifying means, and the first carrier component removed by the filter means Binarizing means for binarizing the output of the amplifying means.
[0014]
Furthermore, the information storage medium of the present invention is a battery-less information storage medium having a wireless communication function for transmitting data to the outside while receiving radio waves transmitted from the outside by one transmission / reception antenna. One transmitting / receiving antenna coil for performing, a tuning element connected to both ends of the transmitting / receiving antenna coil and tuned to a first carrier wave, connected to both ends of the transmitting / receiving antenna coil, and rectifying the first carrier wave The full-wave rectifier circuit formed by bridge-connecting four rectifier elements and the output of the full-wave rectifier circuit are connected to each other, and the output of the full-wave rectifier circuit is clamped to a predetermined voltage via the current-voltage conversion means. Thus, the first carrier wave is received by the power generation means for generating the stabilized power source used in the information storage medium and the transmission / reception antenna coil, and the first carrier wave is received. Third carrier generation means for generating a third carrier wave having a frequency that is 1 / integer of the carrier wave, and an exclusive OR of the third carrier wave generated by the third carrier wave generation means and the transmission data Each of the voltages of the exclusive OR means for obtaining the phase modulation signal, the phase modulation signal obtained by the exclusive OR means, and the inverted phase modulation signal obtained by inverting the phase modulation signal by the inverter, respectively. A constant current circuit that converts the value into a value is connected to both ends of the transmission / reception antenna coil, and both ends of the transmission / reception antenna coil are pushed and pulled with a predetermined current according to the phase modulation signal during reception of the first carrier wave. Constant current driving means for transmitting by driving.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a configuration of a wireless card system to which a wireless card as an information storage medium according to the present invention is applied. This wireless card system is roughly classified into a battery-less wireless card 100 having a portable wireless communication function and a wireless card reader / writer 200 as an external device.
[0016]
The wireless card 100 decodes commands from the wireless card reader / writer 200, writes data, transmits data, and the like, and includes a looped transmission / reception antenna coil 101 and a stabilized power supply to each circuit in the wireless card 100. The power supply circuit 102 for generating the received data, the demodulating circuit 103 for demodulating the received data, the modulating circuit 104 for modulating the transmission data, the non-volatile memory 105 for storing the transmission data and the received data, and the CPU for controlling these The control logic circuit 106 is composed of the above.
[0017]
The wireless card reader / writer 200 performs reading to the wireless card 100, transmission of a write command, processing of read data, transmission of write data, transmission of a power wave, and the like. A driver 202 to be driven, a modulation circuit 203 that modulates transmission data, a reception antenna coil 204, an amplification circuit 205 that amplifies the output of the reception antenna coil 204, a demodulation circuit 206 that demodulates reception data, and controls these The control circuit 207 is composed of a CPU or the like.
[0018]
In such a configuration, the operation on the wireless card 100 side will be described first. A reception signal received by the transmission / reception antenna 101 is rectified, smoothed, and stabilized by the power supply circuit 102 to generate a stabilized power supply, which is supplied to each circuit. The received signal is demodulated by the demodulation circuit 103 and then sent to the control logic circuit 106. The control logic circuit 106 reads and writes data as well as decoding the command.
[0019]
Further, the control logic circuit 106 reads out transmission data from the memory 105, sends it to the modulation circuit 104, modulates it by the modulation circuit 104, and then supplies it to the transmission / reception antenna 101 to perform transmission.
[0020]
Next, the operation on the wireless card reader / writer 200 side will be described. The control circuit 207 generates a read command or write command and write data (transmission data) and sends it to the modulation circuit 203. The modulation circuit 203 modulates transmission data from the control circuit 207 by an arbitrary modulation method, and sends the modulation data to the driver 202. The driver 202 amplifies the modulated data to an intensity sufficient to radiate the modulated data, and then sends it to the transmitting antenna coil 201 as a modulated wave together with the power signal for generating power in the wireless card 100 for transmission.
[0021]
A transmission radio wave from the wireless card 100 is received by the reception antenna 204, amplified by the amplification circuit 205, and then sent to the demodulation circuit 206. The demodulating circuit 206 demodulates the received signal, and the demodulated data is sent to the control circuit 207, where it is necessary after necessary processing (for example, whether it has been normally received or there is no error). Depending on the output.
[0022]
Next, the power supply circuit 102, demodulation circuit 103, and modulation circuit 104 in the wireless card 100, which is the main part of the present invention, will be described in detail with reference to FIG.
[0023]
In FIG. 2, a tuning capacitor 11 as a tuning element for tuning to the frequency of the first carrier wave is connected to both ends of the transmission / reception antenna coil 101, and diodes D11 to D14 as rectification elements are bridge-connected. The AC input terminals a and b of the full-wave rectifier circuit 12 are connected. One DC output terminal (negative side) c of the full-wave rectifier circuit 12 is grounded, and the other DC output terminal (positive side) d is connected to a current-voltage conversion circuit 13 constituted by a resistor as a current-voltage conversion means. To the clamp circuit 14 configured by a shunt regulator or the like as a clamp means, and the clamp circuit 14 generates a stabilized power supply to be supplied to each circuit in the wireless card 100.
[0024]
A smoothing capacitor 15 is connected to the clamp circuit 14 as smoothing means for smoothing the clamped voltage.
The other DC output terminal (positive side) d of the full-wave rectifier circuit 12 is connected to an input terminal of an envelope detection circuit 16 as envelope detection means. An output terminal of the envelope detection circuit 16 is connected to an input terminal of an amplifier circuit 18 as an amplifying means via a capacitor 17 as a direct current removing means. An output terminal of the amplifier circuit 18 is connected to an input terminal of a binarization circuit 20 serving as a binarization unit via a low pass filter (LPF) 19 serving as a filter unit. The output terminal of the binarization circuit 20 is connected to the control logic circuit 106.
[0025]
A series circuit of a MOS transistor (FET) 21 and a resistor 22 constituting a constant current circuit is connected between one end of the transmission / reception antenna coil 101 and a ground point, and the other end of the transmission / reception antenna coil 101 and the ground point are connected. In between, a series circuit of a MOS transistor (FET) 23 and a resistor 24, which also constitutes a constant current circuit, is connected.
[0026]
The output terminals of the AND circuits 27 and 28 are connected to the gates of the transistors 21 and 23 via low-pass filters (LPF) 25 and 26, respectively, as filter means.
[0027]
The output of the exclusive OR circuit 29 is input to one input terminal of the AND circuit 27, and the transmission control signal from the control logic circuit 106 is input to the other input terminal. The output of the exclusive OR circuit 29 is input to one input terminal of the AND circuit 28 via the inverter circuit 30, and the transmission control signal from the control logic circuit 106 is input to the other input terminal.
[0028]
To each input terminal of the exclusive OR circuit 29, transmission data from the control logic circuit 106 and a third carrier signal obtained by dividing the received first carrier by 1 / integer are input.
[0029]
The other end of the transmission / reception antenna coil 101 is connected to the input end of a binarization circuit 31 as binarization means. The output terminal of the binarization circuit 31 is connected to the control logic circuit 106.
[0030]
Next, the operation of FIG. 2 will be described with reference to signal waveform diagrams of the main part shown in FIGS. 3 and 4 in such a configuration.
FIG. 3A shows a waveform of the low modulation degree amplitude modulation reception voltage A (or B) of the first carrier wave received by the transmission / reception antenna coil 101. The tuning capacitor 11 is tuned to the frequency of the first carrier wave with the transmission / reception antenna coil 101.
[0031]
The received voltage A (or B) of the first carrier wave received by the transmission / reception antenna coil 101 is rectified by the full-wave rectifier circuit 12, and then the current-voltage conversion circuit 13 composed of a resistor or the like, and then the shunt regulator. The constant voltage is generated by the clamp circuit 14, smoothed by the smoothing capacitor 15, and used as a power source for each circuit.
[0032]
Here, when the communicable distance with the wireless card reader / writer 200 is the maximum, the clamp circuit 14 operates so that the current consumption of the clamp circuit 14 is almost “0”. As the writer 200 is approached, the current consumption of the clamp circuit 14 increases and the output of the clamp circuit 14 is held at a predetermined constant voltage.
[0033]
The voltage drop by the current-voltage conversion circuit 13 when the communicable distance is maximum is preferably about 1/10 to 1/5 of the predetermined constant voltage output from the clamp circuit 14.
[0034]
With this configuration, the output voltage (reception voltage) C of the full-wave rectifier circuit 12 has a waveform as shown in FIG. The output voltage C is input to the envelope detection circuit 16 to obtain a detection output D having a waveform as shown in FIG. This detection output D is a modulated signal that is two-phase phase (BPSK) modulated by a second carrier having a frequency that is 1 / integer of the first carrier, and a predetermined constant voltage output from the clamp circuit 14 is obtained. It has a DC voltage component that exceeds.
[0035]
The output of the envelope detection circuit 16 is input to the amplifier circuit 18 through the capacitor 17 so that the DC component is removed by the capacitor 17 and then amplified by the amplifier circuit 18 having a predetermined amplification degree. It is.
[0036]
The output of the amplifier circuit 18 is input to the binarization circuit 20 via the low-pass filter 19, so that the low-pass filter 19 sufficiently removes the first carrier component and the third carrier wave during full-duplex communication. After the components are also removed, the binarization circuit 20 binarizes and obtains a binarized output E shown in FIG.
[0037]
The control logic circuit 106 demodulates the two-phase phase modulation signal from the binarized output E obtained from the binarization circuit 20 and the binarized output of the first carrier wave obtained from the binarization circuit 31 in this way. be able to. Here, full-duplex communication is made possible by setting the frequency of the second carrier wave to the frequency of the third carrier wave.
[0038]
With the configuration described above, the output of the clamp circuit 14 is stabilized to a predetermined constant voltage even if the communication distance with the wireless card reader / writer 200 changes, and the current voltage conversion circuit 13 performs amplitude modulation with a low modulation degree. Detection is possible by converting the received signal into voltage.
[0039]
Further, since the resistance value of the current-voltage conversion circuit 13 is set to be sufficiently small, the reception voltage of the transmission / reception antenna coil 101 is sufficiently suppressed even when the communication distance to the wireless card reader / writer 200 is short. The
[0040]
Next, operations related to transmission from the wireless card 100 will be described. The transmitting / receiving antenna coil 101 receives the first carrier wave, the binarization circuit 31 obtains the received binary signal of the first carrier wave, and the control logic circuit 106 divides the binary signal. As a result, a third carrier wave having a frequency that is 1 / integer of the first carrier wave is obtained, transmission data is read from the memory 105, and these third carrier signal and transmission data are sent to the exclusive OR circuit 29. The two-phase (BPSK) modulated signal is obtained by taking the exclusive OR of both signals.
[0041]
The two-phase phase modulation signal (the output of the exclusive OR circuit 29) is input to the AND circuit 27 and inverted through the inverter circuit 30 to obtain an inverted two-phase phase modulation signal and input to the AND circuit 28. . Here, the control logic circuit 106 inputs a transmission control signal, which is set to “1” at the time of data transmission and “0” otherwise, to the AND circuits 27 and 28 and takes a logical product with the two-phase phase modulation signal. Thus, the outputs of the AND circuits 27 and 28 become “0” except during transmission, and the MOS transistors 21 and 23 that perform voltage-current conversion are turned off.
[0042]
Low-pass filters 25 and 26 are connected to AND circuits 27 and 28, respectively, and are configured to remove the harmonic component of the third carrier wave. The output of the low-pass filter 25 (two-phase phase modulation signal) is input as a voltage signal to a constant current circuit configured by a MOS transistor 21 and a resistor 22 that performs voltage-current conversion. It is supplied to one end of the coil 101.
[0043]
The output (inverted two-phase phase modulation signal) of the low-pass filter 26 is input as a voltage signal to a constant current circuit that performs voltage-current conversion including a MOS transistor 23 and a resistor 24. The resistor 24 outputs a predetermined transmission current. Is supplied to the other end of the transmitting / receiving antenna coil 101. As a result, a push-pull operation is performed as a transmission current to the transmission / reception antenna coil 101.
[0044]
Here, the impedance of the transmission / reception antenna coil 101 at the frequency f3 of the third carrier wave is set to [impedance of the transmission / reception antenna coil 101 (2πf3 L) <(resistance value of the current-voltage conversion circuit 13)]. Transmission can be performed by passing a transmission current through the transmission / reception antenna coil 101.
[0045]
The waveforms of the transmission voltages A and B at both ends of the transmission / reception antenna coil 101 during push-pull transmission are shown in FIGS. Since push-pull transmission is performed, the transmission voltage waveforms in FIGS. 4A and 4B are inverted in phase. As a result, the transmission output voltage C appearing at the output of the full-wave rectifier circuit 12 is as shown in FIG. 4C and is canceled and does not appear at the output of the reception envelope detection circuit 16.
[0046]
In addition, since the configuration is such that (the frequency f1 of the first carrier)> (the frequency f3 of the third carrier)> (the frequency f2 of the second carrier), (the frequency f3 of the third carrier) X2 >> (the frequency f2 of the second carrier wave). Therefore, the transmission carrier can be sufficiently removed by the low-pass filter 19.
[0047]
As a result, full-duplex communication can be performed stably with the configuration of the present embodiment.
As described above, according to the above-described embodiment, the problem of withstand voltage in the case of the one-chip LSI, which has been a conventional problem, is solved, and the amplitude modulation signal with a low modulation degree of 10% or less is used. Detection can be performed reliably, transmission can be performed efficiently, and full-duplex communication can be performed reliably.
[0048]
That is, since it is configured to perform an intermediate operation between the shunt regulator and the series regulator, both of the disadvantages of both regulators can be avoided.
[0049]
In addition, since a smoothing capacitor is connected to the output of the full-wave rectifier circuit directly through a resistor as a current-voltage conversion circuit without being connected directly to the output of the full-wave rectifier circuit, smoothing stabilization is performed. The waveform of the amplitude modulation signal having a low modulation degree is correctly stored in the output of the full-wave rectifier circuit. Therefore, by detecting the output of the full-wave rectifier circuit, it is possible to reliably detect an amplitude modulation signal with a low modulation degree.
[0050]
Further, since the signal after the output of the full-wave rectifier circuit is double-wave rectified, the frequency becomes twice the frequency of the received first carrier wave, so that detection is easy.
Moreover, since it becomes a phase modulation signal after detection, the generated direct current component can be easily cut, and stable amplification can be performed with a low power supply voltage.
[0051]
In addition, since the signal after the output of the full-wave rectifier circuit is doubled with respect to the frequency of the first carrier wave and the frequency of the third carrier wave, it is possible to prevent leakage after detection. Removal with a low-pass filter is facilitated.
[0052]
With regard to transmission, since a constant current circuit having a sufficiently high output impedance is connected to the end of the transmission / reception antenna coil to perform constant current driving, efficient transmission can be performed.
[0053]
Further, since push-pull transmission is used, it is canceled out by the output of the full-wave rectifier circuit and does not appear in the reception detection output, so that full-duplex communication can be performed reliably.
In addition, since the constant current driver is turned off except during transmission, efficient reception can be performed.
[0054]
In addition, since the third carrier wave harmonic elimination filter is inserted in the input section of the constant current circuit, it is possible to suppress the transmission of unnecessary components.
Furthermore, since the impedance at the frequency of the third carrier wave of the transmission / reception antenna coil is made smaller than the impedance of the current-voltage conversion circuit connected to the output of the full-wave rectification circuit, efficient transmission can be performed.
[0055]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to solve the withstand voltage problem in the case of a one-chip LSI, to reliably detect an amplitude modulation signal with a low modulation degree, and to perform transmission efficiently. In addition, a battery-less information storage medium having a wireless communication function capable of reliably performing full-duplex communication can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a wireless card system to which a wireless card as an information storage medium according to an embodiment of the present invention is applied.
FIG. 2 is a configuration diagram showing in detail a power supply circuit, a demodulation circuit, and a modulation circuit of a wireless card.
FIG. 3 is a diagram showing signal waveforms of main parts for explaining the operation.
FIG. 4 is a diagram showing signal waveforms of main parts for explaining the operation.
FIG. 5 is a configuration diagram showing a configuration of a conventional wireless card.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Wireless card (information storage medium) 200 ... Wireless card reader / writer, 101 ... Transmission / reception antenna, 102 ... Power supply circuit, 103 ... Demodulation circuit, 104 ... Modulation circuit, 105 ... Memory, 106 ... Control logic circuit, 11... Tuning capacitor (tuning element), D11 to D14... Diode (rectifier element), 12. Full wave rectifier circuit, 13. Current-voltage conversion circuit (current-voltage conversion means), 14 ...... Clamp circuit (clamping means) 15 ...... Smoothing capacitor (smoothing means) 14 ...... Envelope detection circuit (envelope detection means) 17 ...... Capacitor (DC component removal means) 18 ...... Amplification circuit ( Amplifying means), 19... Low pass filter (filter means), 20... Binarization circuit (binarization means), 21, 23... Transistor (constant current circuit), 22, 24. Resistance (constant current circuit), 25, 26 .. Low pass filter (filter means), 27, 28... AND circuit, 29... Exclusive OR circuit (exclusive OR means), 30. ... Binarization circuit (binarization means).

Claims

In a battery-less information storage medium having a wireless communication function for transmitting data to the outside while receiving radio waves transmitted from the outside by one transmission / reception antenna,
One transmit / receive antenna coil for transmitting and receiving;
A tuning element connected to both ends of the transmission / reception antenna coil for tuning to the first carrier;
A full-wave rectifier circuit that is connected to both ends of the transmitting / receiving antenna coil and bridges four rectifier elements that rectifies the first carrier wave;
A power supply that is connected to the output of the full-wave rectifier circuit and generates a stabilized power supply for use in the information storage medium by clamping the output of the full-wave rectifier circuit to a predetermined voltage via a current-voltage converter. Generating means;
Envelope detection means connected to the output of the full-wave rectifier circuit and detecting a received signal by performing envelope detection of the output of the full-wave rectifier circuit;
An information storage medium comprising:

The power generation means includes a current-voltage conversion means connected to the output of the full-wave rectification circuit, a clamp means for clamping the output of the full-wave rectification circuit to a predetermined voltage via the current-voltage conversion means, 2. The information storage medium according to claim 1, comprising smoothing means for smoothing the voltage clamped by the clamping means.

The received signal is a signal obtained by phase-modulating a signal that is phase-modulated with a subcarrier of a second carrier having a frequency that is 1 / integer of the first carrier, and amplitude-modulating with a low modulation degree with the first carrier. 2. The information storage medium according to claim 1, wherein the received signal is detected by the envelope detection means.

The current-voltage conversion means is constituted by a resistor, and a voltage drop at the maximum communicable distance of the current-voltage conversion means is smaller than a voltage of the power supply generated by the power supply generation means. The information storage medium according to 1 or 2.

In a battery-less information storage medium having a wireless communication function for transmitting data to the outside while receiving radio waves transmitted from the outside by one transmission / reception antenna,
One transmit / receive antenna coil for transmitting and receiving;
A tuning element connected to both ends of the transmission / reception antenna coil for tuning to the first carrier;
A full-wave rectifier circuit that is connected to both ends of the transmitting / receiving antenna coil and bridges four rectifier elements that rectifies the first carrier wave;
A power supply that is connected to the output of the full-wave rectifier circuit and generates a stabilized power supply for use in the information storage medium by clamping the output of the full-wave rectifier circuit to a predetermined voltage via a current-voltage converter. Generating means;
Envelope detection means connected to the output of the full-wave rectifier circuit and detecting a received signal by performing envelope detection of the output of the full-wave rectifier circuit;
DC component removing means for removing a DC component from the output of the envelope detection means;
Amplifying means for amplifying the output of the envelope detecting means from which the direct current component has been removed by the direct current component removing means with a predetermined amplification;
Filter means for removing the first carrier component from the output of the amplification means;
Binarization means for binarizing the output of the amplification means from which the first carrier wave component has been removed by the filter means;
An information storage medium comprising:

In a battery-less information storage medium having a wireless communication function for transmitting data to the outside while receiving radio waves transmitted from the outside by one transmission / reception antenna,
One transmit / receive antenna coil for transmitting and receiving;
A tuning element connected to both ends of the transmission / reception antenna coil for tuning to the first carrier;
A full-wave rectifier circuit that is connected to both ends of the transmitting / receiving antenna coil and bridges four rectifier elements that rectifies the first carrier wave;
A power supply that is connected to the output of the full-wave rectifier circuit and generates a stabilized power supply for use in the information storage medium by clamping the output of the full-wave rectifier circuit to a predetermined voltage via a current-voltage converter. Generating means;
A third carrier generating means for receiving a first carrier by the transmission / reception antenna coil and generating a third carrier having a frequency of an integer of the first carrier;
Exclusive OR means for obtaining a phase modulation signal by taking an exclusive OR of the third carrier wave generated by the third carrier wave generating means and the transmission data;
A constant current circuit that converts each voltage of the phase modulation signal obtained by the exclusive OR means and the inverted phase modulation signal obtained by inverting the phase modulation signal to an inverter has a predetermined current value at each end of the transmission / reception antenna coil. Constant current driving means for connecting and performing transmission by push-pull driving both ends of the transmitting / receiving antenna coil with a predetermined current according to the phase modulation signal while receiving the first carrier wave;
An information storage medium comprising:

The third carrier wave generating means has binarizing means for binarizing the first carrier wave received by the transmission / reception antenna coil, and a binary signal of the first carrier wave obtained from the binarizing means 7. The information storage medium according to claim 6, wherein a third carrier wave having a frequency of 1 / integer of the first carrier wave is generated by dividing the frequency of.

For each of the phase modulation signal and the inverted phase modulation signal, a logical product is obtained by a transmission control signal for controlling transmission on / off, so that the constant current circuit for performing the respective voltage-current conversions other than at the time of transmission. 7. The information storage medium according to claim 6, wherein the output is turned off.

Filter means for removing the harmonic component of the third carrier from the phase modulation signal and the inverted phase modulation signal, respectively, and the output of each filter means is input to each constant current circuit. The information storage medium according to claim 6.

The impedance at the frequency of the third carrier wave of the transmitting / receiving antenna coil is configured to be smaller than the impedance of the current-voltage conversion means connected to the output of the full-wave rectifier circuit. The information storage medium described.