JP3937286B2 - System and method for low jamming signal transmission - Google Patents

Description

であって、これは次式に基ずく。
【００２１】
【式２】

〔式中、ｎ_{Ｆｒａｍｅ}はデータブロック中のビット数を示し、ｆ_Ｄａｔａはｆ_Ｍｉｎデータサイクル周波数を表わし、比較的低い周波数の限度を示す〕
【００２２】
これは低速周波数編移が１Ｇボー以下のデータ率では、どんな改良も供給しえないことを示している。
【００２３】
位相変調は制御電気遅延を搬送信号（もしくはクロック信号それぞれに）に挿入することで単純に達成される。位相変調の低周波数は受信機ＰＬＬによりタイミング良く自動的に制御できるが、それはスペクトルの著しい拡大をもたらさない。極めて高い周波数位相変調はスペクトルに好ましい効果を生成するが、その動作は受信器入力に与える付加的同期化妨害と比較し得る。
【００２４】
本発明のもう１つ別の好都合な実施例では、変調器装置が送信機の信号処理と変調段（ｓｔａｇｅ）の下流に配列されており、それが送信機の出力信号を直接変調できる。
【００２５】
本発明によれば、スペクトルも送信機出力信号（もしくはデータ流れのそれぞれ）を変調することで拡大できる。送信機出力信号（もしくはデータ流れのそれぞれ）変調もしくは状態修飾（ｍｏｄｉｆｉｃａｔｉｏｎ）はそれ自体送信機搬送信号（もしくは送信機データサイクル信号のそれぞれ）の状態修飾を上回わる大きい利点がある。送信機の状態修飾はそれ自体必要ではない。送信機出力信号（もしくはデータ流れのそれぞれ）が送信機回路のどこででも状態修飾できる。それ故に、本システムは、開発費の低減化と現存の設計に円滑な組込みを可能にし、送信機設計の状態修飾を全く必要としない。
【００２６】
本発明のさらなる好都合な実施例では、送信機が制御ジェネレータにより制御できる遅延回路から成り、それは孤立パルスもしくは出力信号端だけでも制御ジェネレータにより予め決められた低変調周波数に比例して遅らせる。本発明の意義では、用語「送信機」は、データ、信号もしくはサイクルの処理と組合せを表わし、かつそれらが伝送回路それ自体を経由して伝送できるような方法で行うすべての装置の組合せを表わすものと理解されるべきである。本発明のため、この遅延は、送信機のクロックジェネレータで、あるいは次の段階で、あるいは伝送回路のドライバ回路での同じ遅れでも達成できる。
【００２７】
既存のデータ流れをデータ送信機に僅かな影響も及ぼすことなく状態修飾する最上の方法は、それ故に制御遅延の採用にある。データ流れは遅延制御器手段に供給され、データ流れを分折し、また制御信号ＶＰを制御遅延回路のため発生させる。この回路はデータ流れをＶＰで規定された間隔に対し遅らせる。低周波数により変調された殆ど静的な遅延は位相変調に相当する。この形式の位相変調はスペクトルの幅に僅かな影響を及ぼすだけである。位相変調では、スペクトルの幅が変調周波数とは概ね無関係である。従って、変調角度はスペクトル拡大のため増やす必要がある。比較的高い変調は記憶素子を含む特定回路を必要とするし、これは平面遅延素子によってはもはや実施できない。ある種の周波数変調はここでは一層好都合である。周波数変調は位相変調の特殊な場合であって、時間に対して集積化した位相架角度を備えている。そのうえ、位相変換はクロック再生技術により好都合に実施できる。
【００２８】
変調器装置による変調に加え、擬以ランダムノイズによるデータコーディングが好都合に実施出来る。
【００２９】
本発明のもう１つ別の好都合の実施例に対応して、制御器装置が受信機に配設され、受信機のクロックジェネレータを送信機の変調と同期に制御する。この同期は送信機と受信機側に共同で利用できる信号たとえば通信網（ｎｅｔｗｏｒｋ）周波数を介して任意的に実施できる。
【００３０】
本発明のさらなる好都合の実施例では、制御器装置が受信機に設けられて、送信機のクロックジェネレータの周波数の変調の場合、受信機のクロックジェネレータをこの変調と同期に、受信信号が受信機で非変調形式でさらに処理できるように制御する。
【００３１】
本発明のもう１つの好都合の実施例では、付加的信号が送信機と受信機側の間の伝送回路を並行に、変調制御のため伝送される。ここではこの付加的信号のため、受信機で復調が行われ、送信機で変調と同期される。
【００３２】
【発明の実施の形態】
図１は伝送回路２を介して受信機３に接続される送信機１から成る発明のシステムを示す。前記送信機１は変調器装置４を備えて制御器装置５を介して制御される。この制御器によりここで送信機の信号またはクロックジェネレータの周波数をそれぞれ変調させる変調信号が前記データチャンネル２を介して伝送される出力信号のスペクトルが拡大されるような方法で生成される。先行技術に対応する受信機回路に対しては、特に送信機信号の周波数変調は問題でない。周波数特に低変調周波数の状態修飾はなんの問題もなく、前記受信機にデータと周期の再構築のため配設されたＰＬＬによりきめ細かく制御される。
【００３３】
図２は吸収器ホールで測定されたスペクトルを示し、先行技術に対応する送信機によりデータ回路２を介して放出される。
【００３４】
図３は発明のシステムのスペクトルを示し、そこでは制御ジェネレータが用いられて送信機の信号を２ＭＨｚだけ周波数変換して変調させる。その結果、スペクトル小数部もスペクトル線間のギャップとなる。それゆえ同一の出力信号振幅を用いて、個々の周波数中の電力密度が減少する。最大振幅の縮小はほぼ１６ｄＢの範囲で変動する。
【００３５】
デジタル信号の周波数スペクトルについては、ほとんどすべてのデジタルデータリンクで見られるのと同じように、データ流れはＰＣＭフォーマットにもあり、ただ２つのデジタルレベルすなわちゼロと１があることを意味する。情報は、被定義タイムウィンドウの中の複数のゼロと複数の１の共存する時含まれる。複数のゼロと複数の１の交互する信号には、波形は周波数がビット周期レートの半分に相当する周波数をもつ対称長方形波（図４）に相当する。このような信号は図５に示された一般に知られるスペクトルを呈する。
【００３６】
見えるものは線状に小さくなる振幅をもつ奇調波だけである。調波は信号が非対称の場合にだけまさに起こる。信号が複数のゼロと複数の１の比較的広い時限をもつ他のパターンを備える時、図６の信号のように、側波帯はこれらの比較的長い時限の周波数コンポーネントを倍数にしたオフセットをもつスペクトルに現れる。これはプレーンな針スペクトルから図７に示されたような逓倍多様化スペクトルに繋がる。
【００３７】
極めて多数の異なるパターンが在る時、たとえば異なる組合せである時、スペクトルは増加しつづける多様化を受ける。デジタル信号の大半にとっては、データの平均電力は一定である。かなり長時間に亘る測定では、複数のゼロと複数の１の数はほぼ等しい。たとえば、ランダム２進信号の平均電力Ｐ_Ｍｅａｎは次式の通り、ゼロＰ_０と１Ｐ_１の平均電力である。
【００３８】
【式３】

【００３９】
スペクトル線のすべての振幅Ａ_ｉの合計のスペクトル表現にすると、次式の通り、この合計は従ってこの値に等しい。
【００４０】
【式４】

【００４１】
スペクトル電力密度の低減については、パターン１０１０の本発明による第１の実施例（図４）では、高エネルギーレベルが信号とその調波の基準周波数で存在する。信号が付加周波数に拡大された場合、個々のスペクトル線のエネルギーは、合計エネルギーが一定であるので低減される必要がある。それ故に、帯域幅の無制限の拡大は理論的には、結果的に無限の低エネルギー密度をもたらす。しかしながら実際にはいくつかの制限がある。
【００４２】
帯域幅がたとえ左程高価につかなくても、無制限の帯域幅は高価につく。従ってデータ回路の優れた設計は情報の伝送に必要以上に多い帯域幅を用いない。しかし、スペクトル線間のギャップをうめることでもかなりの改良を与えることになる。データリンクの最適化には信号のコーディングと波形整形は、付加帯域幅が必要でなくなり、また個々のスペクトル線の代りに、周波数に依存しない電力密度をもつ定常電力スペクトルが共存するような方法で、行われる必要がある。図８は、１０１０信号で同一信号のスペクトルの第２のグラフを備える２ＭＨｚの周波数変調（ＦＭ）をもつ比較的広い帯域幅に状態修飾したスペクトルの第２グラフを備える典型的針スペクトルを示す。これら２つの信号間には著しい相異はない。
【００４３】
これはデジタルリンクのＥＭＣ特性が信号を僅かに状態修飾することによって著しく改良できる。以下にスペクトル拡大のいろいろな技術について説明する。
【００４４】
一般データコーディング図式について説明すると、データは通常ブロックにして付加ブロックとエラー（誤り）検孔ビットを含めて実装される。これらの付加ビットはデータ受信機と送信機を同期させる必要が同様にある。被定義コーディングたとえば８Ｂ／１０Ｂが、これらのタスクの実行にしばしば用いられる。この方法を複数のゼロと複数の１以外の何ものからも構成されない極めて長いデータ流れは決して起こらないであろう。同期化とエラー停正ビットを備える典型的ブロックはざっと１０乃至２０ビットのｎ_{Ｆｒａｍｅ}の大きさをもつ。これは、比較的低周波数制限とブロック繰返し数をもつスペクトル線の間隔を、たとえデータが複数のゼロと複数の１以外に何も含んでいなくても提供することになる。データ周期数ｆ_Ｄａｔａで比較的低い周波数限度ｆ_Ｍｉｎとスペクトル線の最小線間距離は次式に相当する。
【００４５】
【式５】

【００４６】
規定として、データは付加的に符号化されて、直流の自由を保証し、また平滑エラー検出の冗長度を増大させる。データ実装とコーディングの双方がスペクトルを拡大出来る。低実装密度は結果として比較的高い実装繰返し速度となり、従ってスペクトルの中程度の拡大をもたらす。たとえば、２００ＭＨｚのデータ周期信号速度で、１０ビットブロックは次のスペクトル線の線間距離をもたらす。
【００４７】
【式６】

【００４８】
これはスペクトル線が１００ＭＨｚ、３００ＭＨｚ、５００ＭＨｚなどで起こるばかりでなく、２０ＭＨｚの線間距離をとって付加のスペクトル線もスペクトルに起こる。これは電力の７ｄＢだけの平均リダクションで５倍ものスペクトル線を供給する。このようなコーデングだけでは有効なＥＭＣ改良には十分でない。
【００４９】
擬似ランダムパターンについて説明すると、複数のゼロと複数の１のランダムサクセションを含むデータ流れは結果として極めて均質のスペクトル分布をもたらす。理論上では、無限のランダムサクセションは結果として、一定のスペクトル電力密度を備える完全な拡大スペクトルをもたらす。このようなデータ流れが所望の情報を含み得ないことは不適当である。この問題解決の方法において、決定論的擬似ランダムパターンを用いることは可能である。これらのパターンは予め決められた一連の再生可能ビットから成る。規定として、これらのパターンの長さが決定される。これらのパターンは、それが決められたサクセションをたとえまた提出したとしても、また予期し得たとしても、一見してランダム連のように見えるため擬似パターンと言われる。
【００５０】
パターン長さのスペクトル密度に及ぼす影響について説明すると、実際の応用で用いられる擬似パターンは、制限されたパターンの長さをもつ。ｎ_Ｐビットの放出後、同一パターンが反復される。短いパターンの理由は、パターンの記憶と比較的単純な同期化のための限られた記憶装置である。長いパターンと、従って、低パターンペティション速度は、低周波数成分を信号に供給するので、スペクトル線の狭い線間距離に繁がる。隣接するスペクトル線の最小線間距離△ｆはランダムパターンの長さｎ_Ｐと相互に比例する。
【００５１】
【式７】

【００５２】
従って、長いパターン長さは、スペクトル線の小線間距離にとって好ましい。パターン長さの影響は図１０、１１と１２に示されている。
【００５３】
図１０では、スペクトル線が１．５６ＭＨｚだけ線間距離をとってあるのに対し、その振幅は−３６ｄＢｍになる。図１１に示されているように比較的長い符号ストリングが選ばれる場合、パターン長が２５６倍もの長さで、スペクトル線は６．１ＫＨｚだけ線間距離がある，これは分光分折器の分解能以下で直線を表示する。スペクトル線の振幅（これは線の振幅と同一である）は−６０９ｄＢｍになり、−３６ｄＢｍの先の振幅のまさに２５６分の１に相当する。図１２ではパターン長が用いられ、これは先の長さの４倍にもなり、信号振幅が４倍も小さい（−６ｄＢ）結果となる。
【００５４】
ここで先行技術の擬似ランダムパターンの応用について説明すると、極めて短い擬似ランダムストリングのプレーンの近似がコーディング図式であり共通して応用された４Ｂ／５Ｂもしくは８Ｂ／１０Ｂコーディングのようなものである。ここで８ビット２進数は１０の異なる１連のビットに符号化される。この方法でゼロビットの長いサクセッションはゼロからでも誘導しない。これらのパターンは僅かな拡大効果を生成するが、それはさらに均質の分光分布をもたらす。
【００５５】
そのうえ、擬似ランダムパターンの極めて普通の応用はビットエラーの速度試験で、その場合これらのパターンの広帯域は全伝達システムの完全なチェックを可能にする。
【００５６】
静的パターンについて説明すると、主として直列式の送信機は伝送されるべきデータがない場合、ブランクキャラクターで動作する。このブランクは不明瞭なパターンで識別を「ノーデータ」させ、そしてそのうえ、受信機の同期化を送信機クロック信号で可能にする。ただ１つの種類のブランクパターンが通常存在する。長時間にわたってデータが何も伝送されない場合、このパターンだけが回路を介して伝送される。それは、標準データ語と同一の長さを提示し、従って比較的高い低周波数と式７から誘導するスペクトルの線間距離とをもつ。このようなパターンは普通そのスペクトル線のストレート分布を通常呈しない。従って、高連データリンクはすぐれたＥＭＣ特性を実データが伝送された時表示することがある。しかし、伝送が終りブランクが伝送されるとすぐ、ＥＭＣ特性が強く害される。これらの静的パターンは電磁放出もしくは伝送それぞれの最も不適当な状態である。これらのパターンの伝送が長時間に亘って避けることができない場合、ＥＭＣ測定はこれらの条件下で行われる必要がある。
【００５７】
音響システムの規定では、このような静的パターンはあらゆる手段を用いて避ける必要がある。これは変受信機ブランクの伝送によるか、あるいはブランクキャラクターの伝送によるか、あるいはブランクキャラクター状態を信号化する擬似ランダムストリングの放出により達成できる。ゼロ符号の長いストリングでさえこのストリングが長いパターン長を備える擬似ノイズ信号で符号化する。
【００５８】
つぎに本発明の帯機幅拡大の方法について説明する。
前記した通り、スペクトルの拡大にはいろいろな方法がある。電磁放出に対する効果は少なくとも２つの互いを完成させる方法が用いられる。極めてすぐれた組合せは擬似ノイズデータのある種のデータ変分の変調との時宜得た符号化である。時宜を得たデータ変分はいろいろな方法で変調できる。１つの方法は元データ周期信号を送信機端で状態修飾することである。もう１つ別の方法はデータ流れそれ自体の時宜を得た変数の状態修飾である。
【００５９】
データコーディングについては前記の通り、データ流れはＥＭＣ特性の最適化のランダムストリングの外見を備える必要がある。実データはランダム特性を実にしばしば表示する。信号もしくはビデオ映像信号の測定では、特定のノイズが常に起こるが、これもランダム特性に効果を示す。別の場合では、ランダムストリングの備わるデータ流れのコーディングは好ましい結果をもたらす。このコーディングは実施するのは極めて容易である。データが大きいブロックで伝送されると、おのおののブロックは所定のランダムストリングで専用Ｏ−リング法（図１３）にかけることが出来る。ここで、伝送済み信号はランダム信号の外見を備える。複数のゼロもしくは複数の１のストリングの最悪の状態でさえも、信号はランダム信号のように見える。
【００６０】
受信機は元データを同一のランダムストリングを備えるブロックの専用Ｏ−リングにより元データブロックとして再構築できる。また別の方法で、信号はフィードバックのついた送りレジスタに基づくことができる伝統的な擬似ランダムジェネレータに送ることができる。
【００６１】
また特定の状況がある場合、それにも焦点を合わせるべきである。データ並行−直列式コンバータの大半が定義された「ノーデータ」信号を提示し、データを失った場合これらのコンバータデータを同期させることができる。並行−直列式コンバータにデータが供給されない場合、普通１０乃至２０ビットの連続から成るこの短いデータ語を連続的に伝送することになる。この信号は結果として極めて広い周波数線線間距離と、極めて不良のＥＭＣ特性とをもたらす。従って、静的パターンが伝送のため未決のままであることをなんとしてでも避けるべきである。この状況を防ぐには、データが並行−直列式コンバータに供給される必要がある。これは単純なソフトウェア状態修飾により実施することができる。データを伝送しない代りに、データに供用されるが複数のゼロもしくは「ノーデータ」として識別できるかなりの他のパターンで満たされる同一のブロックが、伝送できる。複数のゼロの流れは専用のランダムパターンの備わるＯＲ組合わせにかけられる時、これは完全なランダムパターンをデータリンクに、従って最上のＥＭＣ特性を供給する。ランダムパターンを備える専用ＯＲ組合せに続いて、複数のゼロの流れが受信機側に「ノーデータ」として容易に識別できる。
【００６２】
上述の通り、スペクトル線の線間距離は、擬似ランダムパターン長に反比例する。スペクトル線の最小線間距離は式５により計算できる。データコーディング作業は変数の時宜を得た変調の技術を用いることで完了すべきである。極めて長いコードストリングが用いられない時、データコーディング技術が粗拡大の供給に最適であるのに対し、変数の時宜を得た変調が優れた拡大をもたらす最適の方法である。
【００６３】
周波数変調の場合の比較的低いデータ速度の改良を達成するため、周期が最低許容１０^−４だけ移動される必要がある。これは送信機を受信機の周期の同期移動により達成できる。この移動の仕上げには、低周波数のメッセージ伝送が送信機と受信機の間に設けられる必要がある。このような情報は付加低周波数線を介するか、あるいは回転コネクタの場合、在来形のスリップ−リング回線を通して伝送できる。このような場合、騒音と帯域幅は決定的ではない。もう１つ別の方法は、送信機と受信機周期の間の同期性を変調させるＡＣエネルギー回路の場合のように、既に連帯して利用できるいくつかの信号を用いることである。それ故に付加信号は必要ではない。
【００６４】
よりよい成果は、時間に比例した極めて高い周波数をもつクロック信号の変調で達成できる。変調は極めて急速にして受信機ＰＬＬが周波数の変化について行けないようにする必要がある。全体の位相が大き過ぎると受信機はデータを失いかねない。このような場合、同様の技術たとえば序説で位相技術に関して述べたように適用出来る。この解決策は総体的にリンクならびにその実際のデータ周期速度と整合させる必要がある。
【００６５】
図１４は移相技術の回路構成の略図を示す。
【００６６】
図１５は１０ＫＨｚでの６．２８ラッド変調を備える位相変調された信号を示す。
【００６７】
図１６は１ＭＨｚの周波数変調をもつある種の周波数変調を示す。この周波数変調は時間に対し集積された位相角をもつ位相変調の特別の場合である。このような周波数変調された信号の単純実施例が図１７に示される。
【００６８】
入力信号は定常周期速度を提示する。これは間隔ｔ_ｎ−ｔ_ｎ−１が同一幅をもっていることを意味する。被制御遅延回路の場合、時間ｔ_０、ｔ_２、ｔ_４、ｔ_６、ｔ_８によるクロック信号変分がどんな遅延も提示しないのに対し、時間ｔ_３、ｔ_７による変分は小さい正遅延△と時間ｔ_１，とｔ_５の位置における変分が小さい負遅延−△ｔを表示する。その結果、第１のクロック信号周期Ｔ_１は第２のクロック信号周期Ｔ_２より大きい。その故にＴ_１は次式で表わされる。
【００６９】
【式８】

【００７０】
この目的のため、両クロック信号周期の基準周波数は等しい。
【００７１】
【式９】

【００７２】
【式１０】

【００７３】
ここでスペクトル線の数は２倍になった（図１８）。
【００７４】
スペクトル線のさらなる増加には、付加周波数ｆ_１とｆ_２の導入が可能である。これを達成させるには、遅延△ｔを式９と１０に対応して変化させることが必要なだけである。
【００７５】
このために、遅延制御手段が付加変調ジェネレータにより制御され、遅延制御手段を△ｔ_Ｍｉｎと△ｔ_Ｍａｘ間のすべての遅延を極めて低い周波数での通過を強いる。従って、ｆ_１とｆ_２間のスペクトル線が図１９に示されているようにうめられる。
【００７６】
極小付加遅延のため、信号は付加低同期化妨害（ジッタ）を備える信号と同様である（図２０参照）。この付加ジッタリングは考慮の要ある２つのスペクトル構成部分を与える。最初、高周波数変調は突ジッタのように作動する。それはリンク特性の影響を受ける。しかしながら、５％ジッタを与える無接触回転コネクタにとって５％の付加変調ジッタは受入れ可能である。デジタルリンク受信機の大半は２０％ジッタリングをなんの減損もなく受入れできる。変調ジェネレータの低周波構成部分は期間がＥＭＣ測定の集積の期間よりも僅かに短かくなるように選ばれる。ＣＩＳＰＲ１１に応じた測定には時間が１０ｍｓの間続く。それ故に変調周波数は１００Ｈｚより高い必要がある。この低周波数はすべての受信機により除去される。
【００７７】
周期リジェネレーション技術について説明すると、データ流れのスペクトル特性の状態修飾のもう１つの方法は完全な同期（リタイミング）回路の使用である。図２１は作業の基本的モード（Ｍｏｄｅ）を示す。データ流れはＰＬＬ回路に供給されてデータ周期の回復とリジェネレーションに回される。この再生クロック信号はデータ流れの同期（リタイミング）回路に供給される。付加変調ジェネレータ手段はＰＬＬ周波数を変化させてデータ流れを変調する。
【００７８】
この回路は前記の回路の特性と同様の動作を遅延させるが、同期化（リタイミング）と、従ってデータ流れのジッタリングのリダクション（低減）を付加的に行う。ＰＬＬ制御には利用できる２つの可能性がある。第１の機会はデジタルＰＬＬ出力信号の状態修飾と付加遅延の導入である。もう１つの可能性はＶＣＯアナログ信号による制御である。この概念の実施にはＶＣＯが当初その制御電圧に供給される小負パルスを供給、１期間もしくは数期間後、ＶＣＯに同一振幅をもつ小負パルスを供給出来る。これは結果として急速過渡周波数変化をもたらし、ＰＬＬが本質的に極めて急速となり、そのためＰＬＬがそれ自体それに対応できなくなる。
【００７９】
周期変調の場合と同様、付加ジッタリングはデータ流れに導入される。
【００８０】
さらに状態修飾されたデジタル信号についての測定について説明すると、いくつかの最終測定は拡大スペクトルを備えるＰＣＭ信号の利点を示す。図２２は１０１０信号の２００Ｍボーにおける最悪の状態を示す。ここでは振幅が１００ＭＨｚのピーク値が−１４．７ｄＢｍに等しい。正真正銘の８Ｂ／１０Ｂ符号化信号が用いられると、スペクトルは図２３に示された外観をもつ。この実施例では、ここで最大振幅は−２０．６ｄＢｍに相当する一方、スペクトル線の最小線間距離は２０ＭＨｚになる。短い長さのコーディングのため、このスペクトルは均質の拡がりを呈しない。それは望ましいことであろうが、定常電力密度を表示しないで、他方ではゼロが途中にあるいくつかのピーク値を示す。しかしながら、この配置でさえ１０１０信号の最悪の状態と比較してほぼ６ｄＢだけの改善をもたらす。また周波数変調が８Ｂ／１０Ｂ信号で行われる時、図２４によるスペクトルが得られる。ここでは最大振幅が−２５．３ｄＢｍに等しく、５ｄＢのさらなる改善がもたらされる。ここでは、周波数変調は８Ｂ／１０Ｂ信号スペクトル線間のギャップをうめるだけであるが、それはスペクトルの平滑化には適さない。パターン長が１２８ビットの長擬似ノイズストリングでのコーディングは、極めて均一のスペクトルをもたらし、図２５に図示したように最大振幅−３２．５ｄＢｍを呈する。この測定値は理論的研究で確認されている。いくつかの変化は理論的モデルの規定と単純化によってもたらされる。
【００８１】
【発明の効果】
以上説明したごとく、本発明に係る低妨害信号伝送のシステムおよび方法は、放出されたノイズレベルが、現行のＥＭＣ標準規格の意義の中で、伝送の品質特性の対応する減損なしに縮小することができるので、デジタル伝送回路、特に無接触回転伝送回路を形成することが可能となり、無接触高速データ回路、特に極めて大型の開放型装置たとえば計算機Ｘ線断層撮影機（ＣＴスキャナー手段）用に設計された装置の利用に不可欠である。
【図面の簡単な説明】
【図１】本発明の低妨害信号伝送のシステムの１つの実施例を示すブロック図である。
【図２】同上システムにおけるベースバンドで１９０Ｍボーを備える典型的伝送回路のノイズスペクトルを示す図である。
【図３】同上システムにおけるクロックジェネレータの周波数変調をさせた伝送回路のノイズスペクトルを示す図である。
【図４】同上システムにおける２００Ｍボー１０１０ＰＣＭ信号（上部グラフ）とビット周期信号（下部グラフ）を示す図である。
【図５】同上システムにおける２００Ｍボー１０１０−ＰＣＭ信号の９乃至１ＧＨｚのスペクトルを示す図である。
【図６】同上システムにおける１００００１００パターン（上部グラフ）をもつ２００ＭボーＰＣＭ信号と、ビット周期信号（下部グラフ）を示す図である。
【図７】同上システムにおける２００ＭボーＰＣＭ信号（１００００１００）の９乃至１ＧＨz のスペクトルを示す図である。
【図８】同上システムにおける標準ＭボーＰＣＭ信号（狭いグラフ）と、１００ＭＨｚの図示中心周波数で周波数変調済みビットクロック信号（幅広グラフ）と１０ＭＨｚだけ線間距離をあけた２００９ＭボーＰＣＭ信号を示す図である。
【図９】同上システムにおける周波数変調済みビットクロック信号（下部グラフ）を備える図８の２００Ｍボー信号（上部グラフ）の例証を示す図である。
【図１０】同上システムにおけるピーク振幅が−３６ｄＢｍと線間距離が１．５６ＭＨｚの２００ＭボーＰＣＭ−ＰＮ７スペクトル（ビットバターン長が１２８の擬似ノイズ）を示す図である。
【図１１】同上システムにおける振幅が−６０ｄＢｍそして線間距離が６．１ＫＨｚの２００ＭボーＰＣＭ−ＰＮ１５−スペクトル（ビットパターン長が３２７６８の擬似ノイズ）を示す図である。
【図１２】同上システムにおける振幅が−５４ｄＢｍそして線間距離が１．５ＫＨｚの２００ＭボーＰＣＭ−ＰＮ１７スペクトル（ビットパターン長が１３１０７２の擬似ノイズ）を示す図である。
【図１３】同上システムにおけるランダムコーディング（上部３つのグラフ）とデコーディング（下部３つのグラフ）をコーディングが擬似ノイズストリングの備わるデータの専用−ＯＲリンキングにより実現された状態を示す図である。
【図１４】同上システムにおける制御された位相移動手段を示す図である。
【図１５】同上システムにおける１００ＭＨｚでの２００ＭボーＰＣＭ基準周波数（狭いピーク）と１０ＫＨｚでの６．２８ラドの位相変調済み信号のスペクトル（幅広ピーク）を示す図である。
【図１６】同上システムにおける１００ＭＨｚでの２００ＭボーＰＣＭ基準周波数（狭いピーク）と１ＭＨｚでの周波数−変調済み信号（幅広ピーク）を示す図である。
【図１７】同上システムにおけるプレーン周波数変調済み信号を示す図である。
【図１８】同上システムにおける２重スペクトルを示す図である。
【図１９】同上システムにおける低周波数偏数でのＦＭ拡大スペクトルを示す図である。
【図２０】同上システムにおけるＦＭ−ＰＣＭ信号（上部クラフ）と低周波数偏移をもつビットクロック信号（下部グラフ）を示す図である。
【図２１】同上システムにおける周期リジェネレーションによる変調を示す図である。
【図２２】同上システムにおける９乃至１ＧＨｚの２００Ｍボー１０１０ＰＣＭ信号スペクトルを示す図である。
【図２３】同上システムにおける９乃至１ＧＨｚの８Ｂ／１０Ｂコーディングを備える２００Ｍボー１０１０−ＰＣＭ信号スペクトルを示す図である。
【図２４】同上システムにおける９乃至１ＧＨｚの８Ｂ／１０ＢコーディングとＦＭを備える２００Ｍボー１０１０−ＰＣＭ信号スペクトルを示す図である。
【図２５】同上システムにおける９乃至１ＧＨｚの擬似ランダムコーディングを備える２００Ｍボー１０１０−ＰＣＭ信号スペクトルを示す図である。
【符号の説明】
１ 送信機
２ 伝送回路（データチャンネル）
３ 受信機
４ 変調器装置
５ 制御器装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic field compatibility of a data line, and more particularly to an improvement of an electromagnetic field compatibility of a digital data line, and relates to a system and method for low interference signal transmission in digital signal transmission.
[0002]
[Prior art]
The use of digital data lines is constantly expanding. In most cases, digital signal transmission has shown significant advantages over analog transmission. The cost of high-speed data channels will be eliminated by the development of new transmission technologies. The width of individual channels becomes very cheap, and it is often the best economic solution to form a single high speed signal line and multiplex several low speed signal lines. This was particularly met by high speed rotating connectors.
[0003]
The traditional solution for transmitting large volumes of data from rotating parts to stationary parts has been the parallel application of multiple slip ring paths. This resulted in a monolithic structure that was very heavy and expensive. Even though mechanical slip rings are particularly suitable for energy transmission, the transmission of large amounts of data has several significant drawbacks such as bandwidth limitations, contact noise and failure.
[0004]
Due to the large number of circuits with data transmission capabilities close to the physical limits of the contact slip ring path, the useful life and maintenance are of primary concern. The new contactless high-speed circuit overcomes all of these problems and enables a service-free service life with the highest quality transmission and almost unlimited bandwidth.
[0005]
A very important aspect that can be applied not only to contactless high-speed lines but also to any electronic device is this electromagnetic field compatibility. Electromagnetic emissions are most important for both wire-based circuits and unshielded rotary connectors, but even transmitters, receivers and amplifiers in the circuit of optical fiber systems emit electromagnetic fields.
[0006]
[Problems to be solved by the invention]
Corresponding to the prior art, the optional signal, in particular the digital signal, is transmitted in the form of a signal string with a degree of variation, but mainly with sharp corners. These signal strings show a clear broad line spectrum as a function of their coding. This spectrum results in radiation interference already in closed or shielded systems, however, especially in open systems such as rotating transmitters that interfere with radiation, exceeding the limits specified in the common EMC standard. In this regard, contactless open transmission systems such as those used for line transmission or rotational transmission are particularly problematic. It is clear that the leak line system is also affected by this effect.
[0007]
Various measures for reducing the amount of noise have become known. For example, a low-pass filter or even a band filter is suitable for limiting the transmitted frequency range. However, this is possible, but only with difficulty, especially for transmission in broadband transmission systems such as 200 Mbaud (MBaud). For example, a minimum bandwidth of 140 MHz requires a 200M baud circuit. Another measure is to reduce the transmission signal level. However, such a measure results in a poor signal-to-noise ratio and therefore also a loss of bit error rate in the digital system. It may be difficult to improve the EMC characteristics of such a transmission circuit without deteriorating it by taking measures corresponding to the prior art.
From European Patent Publication No. 0163313A2, a spectral energy distribution device and its distribution method emitted by a digital system are known. This solution is built into the components that are deployed in every PC today. However, this method is not suitable for signal transmission between a transmitter and a receiver that move relative to each other. An apparatus which uses part of the solution described above in part is known from European Patent Publication No. 0505771 A1. According to this reference, since the output signal spectrum from the transmitter is expanded, the spectral power density of the output signal for transmission is lowered. In this method, the signal is shortened, so that the signal is phased along its length. That is, the signal bandwidth is also greatly changed. On the other hand, the solution of the present invention, which will be described in detail below, aims to provide a method and apparatus for transmitting a signal with low interference force that is very small even if the signal bandwidth changes.
[0008]
The object of the present invention is therefore to form a digital transmission circuit, in particular a contactless rotary transmission circuit, where the emitted noise level is within the meaning of the current EMC standard, corresponding loss of transmission quality characteristics. We propose a system and method for low jamming signal transmission that can be scaled down without.
[0009]
[Means for Solving the Problems]
The present invention shows how electromagnetic field compatibility (EMC) depends on emission signals, especially in high-speed data circuits, and how these signals can be changed by minimizing electromagnetic emission by such methods. The gist of the disclosure is that the gist may be via a line connection or in contact with the transmission circuit, especially in the case of a rotary transmitter via a contactless transmission circuit, preferably from a transmitter that can move relative to each other, A system for transmitting signals, particularly digital interference signals, to remote receivers,
Regardless of the modulation selected for signal transmission, the signal to be transmitted by the modulator device and the carrier signal of the transmission means in the transmitter or the transmitter output signal which may be located anywhere in the transmission circuit, A system for low jamming signal transmission is characterized in that the output signal spectrum of the transmitter is expanded and therefore modulated so that the spectral power density of the transmitter output signal is reduced.
[0010]
According to the present invention, modulation of the transmission period creates a gap between the individual spectral lines, thus reducing the average spectral frequency, but in this way the transmitted line spectrum of the signal is expanded. The system of the present invention comprises a transmitter corresponding to the prior art, which broadens the spectrum of the clock generator and further the transmitter output signal to each of the transmitter or each of its clock generators or anywhere in the transmission circuit. It consists of an additional modulator which is controlled in the same way. Such control is also phase or, for example, frequency modulation. Amplitude modulation or other modulation techniques are conceivable as well. In addition, a special controller is provided to provide a modulator device for supplying a modulation signal.
[0011]
The present invention relates to an integrated circuit known from prior art from a publication by the March 1997 USA entitled "Spread Spectrum Clock Generator", USA of San Jose, California, 3725 North Street Company of IC Works. Obviously, it is distinct from the modulation technique for improving EMC characteristics. This prior art reference relates to the improvement of the EMC characteristics present in the computer board, not in the transmission circuit.
[0012]
Here, the influence of spectrum broadening on EMC characteristics will be described.
The general term “magnetic field compatibility (EMC)” is difficult to define. Reference is now made to the very general CISPR11 standard. This defines the maximum emission limit for electromagnetic energy and specifies appropriate measurement techniques. This criterion determines the emitted emission capacity with a frequency of 30 MHz to 1 GHz. The emitted power is measured in 120 kHz steps with a 120 kHz bandwidth. Having a homogeneously distributed broadband spectrum is not necessary at all for spectrum broadening techniques, but the only thing that needs to be considered correctly is the fact that the same amount of energy is delivered to each 120 kHz range. . This can be achieved using a wideband signal or individual narrowband peaks in this range. In most applications, the expansion of the spectrum with a line-to-line distance from each other of 120 kHz or a safety line distance of 100 kHz is the most inappropriate solution. This further expansion of the spectrum requires the introduction of very small frequency variations in the data stream. In some applications, these modifications occur naturally, such as when "true data" is transmitted, for example a video signal. However, measures must be taken to ensure that in extreme situations, such as when the video signal is deactivated and only digital zeros are transmitted, the spectrum is widened to accommodate the EMC specification. There is.
[0013]
In the application of high-speed digital data circuits, considerable measures need to be taken to ensure that the essential conditions of international EMC regulations are met. At a data rate of hundreds to thousands of M baud, the reference frequency falls within the common transmission, broadcast and television bands. For general reduction of disturbances, it is better to transmit the information in a single wideband signal rather than information containing a few individual high power spectral lines in a low frequency spectrum with a homogeneous distribution of information.
[0014]
The present invention discloses how commonly applied digital data circuits can correct the spectral broadening in this way.
[0015]
There are two supplementary techniques that can be used to accomplish this problem. The first technique is to properly code the digital signal. A further technique is some kind of frequency modulation. This frequency modulation can be performed anywhere in the circuit without affecting the transmitter or receiver.
[0016]
According to the invention, conventional data coding is advantageously continued for optimization of EMC characteristics.
[0017]
Next, expansion of the carrier signal (data cycle signal) of the transmitter will be described.
In the transmitter, the timely development of the data flow can be controlled simply by controlling the carrier signal of the transmitter. This requires direct access to the transmitter carrier signal. One conventional solution is to replace the newly modulated oscillator with a standard quartz oscillator device in the same device.
[0018]
In a particularly advantageous embodiment of the invention, the modulator device is arranged to subject the cycle frequency of the oscillator clock generator to a frequency modulation corresponding to the modulation signal of the controller device. In this configuration, the implementation by placing a VCO on the frequency determining element of the clock generator that changes the frequency of the clock generator as a function of the control presence applied to it from an engineering point of view is particularly simple. The control voltage of this VCO is predetermined by the controller device. When the controller device now provides a low frequency signal, the frequency of the oscillator's clock generator changes with the cycle of this signal and therefore it is frequency modulated.
[0019]
Frequency modulation is a direct method of spectrum expansion. Serial standard transmission circuits such as TAXchip or Hot-Link allow static variation by ± 0.1% from the cycle frequency. For the limit friction set for the quartz oscillator tolerance, a variation of the maximum frequency is 10%. ^-4 It needs to be the following. As the spectral line expansion does not provide the advantage below 100 kHz as detailed above, the minimum data rate f of the low frequency shift _Dmin Is as follows:
[0020]
[Formula 1]

This is based on the following formula.
[0021]
[Formula 2]

[Where n _Frame Indicates the number of bits in the data block and f _Data Is f _Min (Represents the data cycle frequency and indicates the lower frequency limit)
[0022]
This shows that no improvement can be delivered at data rates of 1 Gbaud or less for low frequency transfer.
[0023]
Phase modulation is simply achieved by inserting a control electrical delay into the carrier signal (or each clock signal). The low frequency of phase modulation can be automatically controlled in a timely manner by the receiver PLL, but it does not result in a significant spread of the spectrum. Although very high frequency phase modulation produces a positive effect on the spectrum, its operation can be compared to additional synchronization disturbances applied to the receiver input.
[0024]
In another advantageous embodiment of the invention, a modulator device is arranged downstream of the transmitter signal processing and modulation stage, which can directly modulate the transmitter output signal.
[0025]
According to the present invention, the spectrum can also be expanded by modulating the transmitter output signal (or each of the data streams). The transmitter output signal (or data stream each) modulation or modification itself has a significant advantage over the state modification of the transmitter carrier signal (or each transmitter data cycle signal). Transmitter state modification is not necessary per se. The transmitter output signal (or each of the data streams) can be modified anywhere in the transmitter circuit. Therefore, the system allows for a reduction in development costs and smooth integration into existing designs and does not require any state modification of the transmitter design.
[0026]
In a further advantageous embodiment of the invention, the transmitter consists of a delay circuit which can be controlled by a control generator, which delays either the isolated pulse or the output signal alone in proportion to the low modulation frequency predetermined by the control generator. In the sense of the present invention, the term “transmitter” represents the combination of all devices that represent the processing and combination of data, signals or cycles, and that they can be transmitted via the transmission circuit itself. Should be understood. For the purposes of the present invention, this delay can be achieved with the same delay in the transmitter clock generator or in the next stage or in the driver circuit of the transmission circuit.
[0027]
The best way to state-modify an existing data stream without affecting the data transmitter is therefore to employ control delay. The data stream is supplied to the delay controller means to break up the data stream and generate a control signal VP for the control delay circuit. This circuit delays the data flow for an interval defined by VP. Almost static delay modulated by low frequency corresponds to phase modulation. This type of phase modulation has only a minor effect on the width of the spectrum. In phase modulation, the width of the spectrum is largely independent of the modulation frequency. Therefore, the modulation angle needs to be increased for spectrum expansion. The relatively high modulation requires specific circuitry including storage elements, which can no longer be implemented with planar delay elements. Certain types of frequency modulation are more convenient here. Frequency modulation is a special case of phase modulation and has a phase angle integrated with respect to time. Moreover, phase conversion can be conveniently performed by clock recovery techniques.
[0028]
In addition to modulation by the modulator device, data coding with pseudo-random noise can be conveniently performed.
[0029]
In accordance with another advantageous embodiment of the present invention, a controller device is provided in the receiver to control the receiver clock generator in synchronization with the modulation of the transmitter. This synchronization can optionally be implemented via a signal that can be used jointly by the transmitter and receiver, such as a network frequency.
[0030]
In a further advantageous embodiment of the invention, in the case of a modulation of the frequency of the clock generator of the transmitter when a controller device is provided in the receiver, the receiver clock generator is synchronized with this modulation and the received signal is received by the receiver. To allow further processing in unmodulated form.
[0031]
In another advantageous embodiment of the invention, additional signals are transmitted for modulation control in parallel through a transmission circuit between the transmitter and the receiver side. Here, for this additional signal, demodulation is performed at the receiver and synchronized with the modulation at the transmitter.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an inventive system consisting of a transmitter 1 connected to a receiver 3 via a transmission circuit 2. The transmitter 1 comprises a modulator device 4 and is controlled via a controller device 5. The controller generates a modulated signal which modulates the frequency of the transmitter signal or the clock generator, respectively, in such a way that the spectrum of the output signal transmitted via the data channel 2 is expanded. For receiver circuits corresponding to the prior art, in particular the frequency modulation of the transmitter signal is not a problem. The state modification of the frequency, especially the low modulation frequency, has no problem and is finely controlled by a PLL arranged in the receiver for data and period reconstruction.
[0033]
FIG. 2 shows the spectrum measured at the absorber hall and is emitted via the data circuit 2 by a transmitter corresponding to the prior art.
[0034]
FIG. 3 shows the spectrum of the inventive system in which a control generator is used to frequency convert and modulate the transmitter signal by 2 MHz. As a result, the fractional part of the spectrum also becomes a gap between the spectrum lines. Therefore, using the same output signal amplitude, the power density in each frequency is reduced. The maximum amplitude reduction varies in the range of approximately 16 dB.
[0035]
For the frequency spectrum of a digital signal, as seen in almost all digital data links, the data stream is also in PCM format, meaning that there are only two digital levels, zero and one. Information is included when multiple zeros and multiple ones coexist in a defined time window. For a plurality of alternating zeros and a plurality of ones, the waveform corresponds to a symmetric rectangular wave (FIG. 4) with a frequency corresponding to half the bit period rate. Such a signal exhibits the generally known spectrum shown in FIG.
[0036]
All that can be seen is an odd harmonic with a linearly decreasing amplitude. Harmonics only occur when the signal is asymmetric. When the signal has other patterns with a plurality of zeros and a plurality of ones with a relatively wide time period, as in the signal of FIG. 6, the sidebands have offsets that are multiples of these relatively long time period frequency components. Appear in the spectrum. This leads from a plain needle spectrum to a multiplied and diversified spectrum as shown in FIG.
[0037]
When there are a large number of different patterns, for example different combinations, the spectrum is subject to ever-increasing diversification. For most digital signals, the average power of the data is constant. In measurements over a fairly long time, the number of zeros and the number of 1s are approximately equal. For example, the average power P of a random binary signal _Mean Is zero P as ₀ And 1P ₁ Is the average power.
[0038]
[Formula 3]

[0039]
All amplitudes of spectral lines A _i In the spectral representation of the sum of, this sum is therefore equal to this value as follows:
[0040]
[Formula 4]

[0041]
For spectral power density reduction, in the first embodiment of the present invention of pattern 1010 (FIG. 4), a high energy level exists at the reference frequency of the signal and its harmonics. If the signal is expanded to an additional frequency, the energy of the individual spectral lines needs to be reduced because the total energy is constant. Therefore, unlimited bandwidth expansion theoretically results in infinitely low energy density. In practice, however, there are some limitations.
[0042]
Unlimited bandwidth is expensive, even if the bandwidth is not as expensive as the left. Thus, an excellent design of the data circuit does not use more bandwidth than necessary to transmit information. However, filling the gaps between the spectral lines can also provide significant improvements. For data link optimization, signal coding and waveform shaping do not require additional bandwidth, and instead of individual spectral lines, a stationary power spectrum with frequency-independent power density coexists. Need to be done. FIG. 8 shows a typical needle spectrum with a second graph of spectrum modified to a relatively wide bandwidth with a frequency modulation (FM) of 2 MHz with a second graph of the spectrum of the same signal at 1010 signals. There is no significant difference between these two signals.
[0043]
This can be significantly improved by the EMC characteristics of the digital link by slightly conditioning the signal. The following describes various techniques for spectrum expansion.
[0044]
The general data coding scheme will be described. The data is implemented as a normal block including an additional block and an error inspection bit. These additional bits are similarly required to synchronize the data receiver and transmitter. Defined coding, such as 8B / 10B, is often used to perform these tasks. An extremely long data stream in which this method is not composed of anything other than zeros and ones will never occur. A typical block with synchronization and error correction bits is roughly 10-20 bits n _Frame Has the size of This will provide spectral line spacing with a relatively low frequency limit and block repetition number, even if the data contains nothing other than multiple zeros and multiple ones. Number of data cycles f _Data Relatively low frequency limit f _Min And the minimum distance between spectral lines corresponds to the following equation.
[0045]
[Formula 5]

[0046]
By convention, the data is additionally encoded to ensure direct current freedom and increase the redundancy of smooth error detection. Both data implementation and coding can expand the spectrum. Low mounting density results in a relatively high mounting repetition rate, thus resulting in a moderate broadening of the spectrum. For example, at a data period signal rate of 200 MHz, a 10-bit block provides the line spacing of the next spectral line.
[0047]
[Formula 6]

[0048]
This occurs not only at spectral lines of 100 MHz, 300 MHz, 500 MHz, etc., but additional spectral lines also occur in the spectrum with a line spacing of 20 MHz. This provides five times as many spectral lines with an average reduction of only 7 dB of power. Such coding alone is not sufficient for effective EMC improvement.
[0049]
Describing a pseudo-random pattern, a data stream that includes multiple zeros and multiple 1 random successions results in a very homogeneous spectral distribution. In theory, infinite random succession results in a fully expanded spectrum with a constant spectral power density. It is inappropriate that such a data stream cannot contain the desired information. In this problem solving method, it is possible to use a deterministic pseudo-random pattern. These patterns consist of a predetermined series of reproducible bits. As a rule, the length of these patterns is determined. These patterns are said to be pseudo-patterns, even if they submit a predetermined succession, and even if they can be expected, it looks like a random series at first glance.
[0050]
Explaining the effect of the pattern length on the spectral density, the pseudo pattern used in the actual application has a limited pattern length. n _P After the bit is released, the same pattern is repeated. The reason for short patterns is limited storage for pattern storage and relatively simple synchronization. Long patterns, and therefore low pattern petition rates, crawl into narrow line distances of spectral lines as they provide low frequency components to the signal. The minimum distance Δf between adjacent spectral lines is the length n of the random pattern _P Are proportional to each other.
[0051]
[Formula 7]

[0052]
Therefore, a long pattern length is preferred for the distance between the spectral lines. The effect of pattern length is illustrated in FIGS.
[0053]
In FIG. 10, the spectral line has a line-to-line distance of 1.56 MHz, whereas its amplitude is −36 dBm. When a relatively long code string is selected as shown in FIG. 11, the pattern length is 256 times longer and the spectral line has a line-to-line distance of 6.1 KHz, which is the resolution of the spectral analyzer. Display a straight line below. The amplitude of the spectral line (which is the same as the line amplitude) will be -609 dBm, which is exactly 256 times the previous amplitude of -36 dBm. In FIG. 12, the pattern length is used, which is 4 times the previous length and the signal amplitude is 4 times smaller (−6 dB).
[0054]
The application of the prior art pseudo-random pattern will now be described. An approximation of a very short pseudo-random string plane is a coding scheme, such as 4B / 5B or 8B / 10B coding applied in common. Here, an 8-bit binary number is encoded into a series of 10 different bits. In this way, a long succession of zero bits is not derived from zero. These patterns produce a slight magnification effect, which results in a more homogeneous spectral distribution.
[0055]
Moreover, a very common application of pseudo-random patterns is bit error rate testing, where the wide bandwidth of these patterns allows a complete check of the entire transmission system.
[0056]
Describing static patterns, primarily serial transmitters operate with blank characters when there is no data to be transmitted. This blank makes the identification "no data" in an obscure pattern, and additionally allows receiver synchronization with the transmitter clock signal. There is usually only one type of blank pattern. If no data is transmitted for a long time, only this pattern is transmitted through the circuit. It presents the same length as a standard data word, and therefore has a relatively high low frequency and spectral line distance derived from Equation 7. Such a pattern usually does not normally exhibit a straight distribution of its spectral lines. Thus, high data links may display excellent EMC characteristics when actual data is transmitted. However, as soon as transmission is completed and a blank is transmitted, the EMC characteristics are strongly impaired. These static patterns are the most inappropriate states of electromagnetic emission or transmission, respectively. If transmission of these patterns is unavoidable over a long period of time, EMC measurements need to be performed under these conditions.
[0057]
In the definition of acoustic systems, such static patterns should be avoided by any means. This can be accomplished by transmission of a variable receiver blank, by transmission of a blank character, or by the release of a pseudo-random string that signals the blank character status. Even a long string of zero codes is encoded with a pseudo-noise signal that has a long pattern length.
[0058]
Next, the method for expanding the band width of the present invention will be described.
As described above, there are various methods for expanding the spectrum. For the effect on electromagnetic emission, at least two methods of completing each other are used. A very good combination is a timely encoding with modulation of some data variation of the pseudo-noise data. Timely data variation can be modulated in various ways. One way is to qualify the original data periodic signal at the transmitter end. Another method is timely modification of variables in the data stream itself.
[0059]
As described above for data coding, the data flow needs to have the appearance of a random string of EMC property optimization. Real data really displays random characteristics. In the measurement of a signal or video image signal, specific noise always occurs, which also has an effect on random characteristics. In other cases, coding data streams with random strings yields favorable results. This coding is very easy to implement. When data is transmitted in large blocks, each block can be subjected to a dedicated O-ring method (FIG. 13) with a predetermined random string. Here, the transmitted signal has the appearance of a random signal. Even in the worst case of multiple zeros or multiple strings of ones, the signal looks like a random signal.
[0060]
The receiver can reconstruct the original data as original data blocks by a dedicated O-ring of blocks with the same random string. Alternatively, the signal can be sent to a traditional pseudo-random generator that can be based on a feed register with feedback.
[0061]
You should also focus on specific situations, if any. Most of the data parallel-serial converters present a defined “no data” signal, and these data can be synchronized if data is lost. If no data is supplied to the parallel-to-serial converter, this short data word, usually consisting of a sequence of 10 to 20 bits, will be transmitted continuously. This signal results in a very wide frequency line spacing and very poor EMC characteristics. Therefore, it should be avoided in any way that the static pattern remains pending for transmission. To prevent this situation, data needs to be supplied to the parallel-serial converter. This can be done by simple software state modification. Instead of transmitting data, the same block that is used for data but filled with a number of other patterns that can be identified as multiple zeros or “no data” can be transmitted. When multiple zero streams are subjected to an OR combination with a dedicated random pattern, this provides the complete random pattern to the data link and thus the best EMC characteristics. Following a dedicated OR combination with a random pattern, multiple zero streams can be easily identified as “no data” on the receiver side.
[0062]
As described above, the distance between the spectral lines is inversely proportional to the pseudo-random pattern length. The minimum distance between spectral lines can be calculated by Equation 5. The data coding task should be completed using variable timely modulation techniques. When very long code strings are not used, data coding techniques are optimal for providing coarse expansion, whereas timely modulation of variables is the optimal method that provides excellent expansion.
[0063]
To achieve a relatively low data rate improvement in the case of frequency modulation, the period must be at least 10 ^-4 Need only be moved. This can be achieved by synchronizing the transmitter to the receiver's period. To complete this movement, a low frequency message transmission needs to be provided between the transmitter and the receiver. Such information can be transmitted over an additional low frequency line or, in the case of a rotary connector, over a conventional slip-ring line. In such cases, noise and bandwidth are not critical. Another method is to use several signals that are already available jointly, as in the case of an AC energy circuit that modulates the synchrony between the transmitter and receiver periods. Therefore, no additional signal is necessary.
[0064]
Better results can be achieved by modulating a clock signal with a very high frequency proportional to time. The modulation needs to be very rapid so that the receiver PLL cannot keep up with frequency changes. If the overall phase is too large, the receiver can lose data. In such a case, a similar technique can be applied, for example as described in the introduction to the phase technique. This solution needs to be consistent with the link as well as its actual data cycle rate.
[0065]
FIG. 14 shows a schematic diagram of the circuit configuration of the phase shift technique.
[0066]
FIG. 15 shows a phase modulated signal with 6.28 rad modulation at 10 KHz.
[0067]
FIG. 16 shows some kind of frequency modulation with 1 MHz frequency modulation. This frequency modulation is a special case of phase modulation with an integrated phase angle with respect to time. A simple example of such a frequency modulated signal is shown in FIG.
[0068]
The input signal presents a steady cycle speed. This is the interval t _n -T _n-1 Means that they have the same width. For a controlled delay circuit, time t ₀ , T ₂ , T ₄ , T ₆ , T ₈ The clock signal variation due to does not present any delay, whereas the time t ₃ , T ₇ The variation due to is a small positive delay Δ and time t ₁ , And t ₅ The negative delay −Δt with a small variation at the position of is displayed. As a result, the first clock signal period T ₁ Is the second clock signal period T ₂ Greater than. Therefore T ₁ Is expressed by the following equation.
[0069]
[Formula 8]

[0070]
For this purpose, the reference frequencies of both clock signal periods are equal.
[0071]
[Formula 9]

[0072]
[Formula 10]

[0073]
Here, the number of spectral lines doubled (FIG. 18).
[0074]
For further increases in spectral lines, the additional frequency f ₁ And f ₂ Can be introduced. To achieve this, it is only necessary to change the delay Δt corresponding to equations 9 and 10.
[0075]
For this purpose, the delay control means is controlled by the additional modulation generator, and the delay control means is _Min And △ t _Max Force all delays in between to pass at very low frequencies. Therefore, f ₁ And f ₂ The spectral lines in between are filled as shown in FIG.
[0076]
Due to the minimal additional delay, the signal is similar to a signal with additional de-synchronization interference (jitter) (see FIG. 20). This additional jittering provides two spectral components that need to be considered. Initially, high frequency modulation operates like a sudden jitter. It is affected by link characteristics. However, for contactless rotary connectors that give 5% jitter, 5% additional modulation jitter is acceptable. Most digital link receivers can accept 20% jittering without any impairment. The low frequency component of the modulation generator is chosen such that the duration is slightly shorter than the duration of the EMC measurement integration. The measurement according to CISPR11 lasts for 10 ms. Therefore, the modulation frequency needs to be higher than 100 Hz. This low frequency is eliminated by all receivers.
[0077]
Describing the periodic regeneration technique, another method of state modification of the spectral characteristics of the data stream is the use of a fully synchronized (retiming) circuit. FIG. 21 shows the basic mode of operation (Mode). The data stream is fed to the PLL circuit and routed to data period recovery and regeneration. This recovered clock signal is supplied to a data flow synchronization (retiming) circuit. The additional modulation generator means modulates the data stream by changing the PLL frequency.
[0078]
This circuit delays operations similar to the characteristics of the circuit described above, but additionally performs synchronization (retiming) and thus reduction (reduction) of jittering of the data stream. There are two possibilities available for PLL control. The first opportunity is the state modification of the digital PLL output signal and the introduction of additional delay. Another possibility is control by a VCO analog signal. To implement this concept, the VCO can initially supply a small negative pulse that is supplied to its control voltage, and after one or several periods, the VCO can be supplied with a small negative pulse having the same amplitude. This results in a rapid transient frequency change, which makes the PLL inherently very rapid, so that the PLL cannot cope with it itself.
[0079]
As with periodic modulation, additional jittering is introduced into the data stream.
[0080]
Further describing the measurements on the state-modified digital signal, some final measurements show the advantages of a PCM signal with an extended spectrum. FIG. 22 shows the worst case at 200M baud for 1010 signals. Here, the peak value with an amplitude of 100 MHz is equal to −14.7 dBm. When a genuine 8B / 10B encoded signal is used, the spectrum has the appearance shown in FIG. In this embodiment, the maximum amplitude here corresponds to −20.6 dBm, while the minimum distance between the spectral lines is 20 MHz. Due to the short length coding, this spectrum does not exhibit a homogeneous spread. Although it would be desirable, it does not display a steady power density, but on the other hand shows some peak values with zero in the middle. However, even this arrangement provides an improvement of almost 6 dB compared to the worst case of the 1010 signal. Also, when frequency modulation is performed with an 8B / 10B signal, the spectrum shown in FIG. 24 is obtained. Here the maximum amplitude is equal to −25.3 dBm, resulting in a further improvement of 5 dB. Here, frequency modulation only fills the gap between 8B / 10B signal spectral lines, but it is not suitable for spectral smoothing. Coding with a long pseudo-noise string with a pattern length of 128 bits results in a very uniform spectrum and exhibits a maximum amplitude of -32.5 dBm as illustrated in FIG. This measurement has been confirmed by theoretical studies. Some changes come from the definition and simplification of theoretical models.
[0081]
【The invention's effect】
As explained above, the system and method for low jamming signal transmission according to the present invention allows the noise level emitted to be reduced within the meaning of the current EMC standard without corresponding impairment of the quality characteristics of the transmission. Therefore, it is possible to form a digital transmission circuit, especially a contactless rotation transmission circuit, and it is designed for a contactless high-speed data circuit, particularly a very large open type device such as a computer X-ray tomography machine (CT scanner means). Indispensable for the use of the device.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating one embodiment of a low jamming signal transmission system of the present invention.
FIG. 2 is a diagram showing a noise spectrum of a typical transmission circuit having 190 Mbaud at baseband in the same system.
FIG. 3 is a diagram showing a noise spectrum of a transmission circuit that is frequency-modulated by a clock generator in the system;
FIG. 4 is a diagram showing a 200M baud 1010 PCM signal (upper graph) and a bit period signal (lower graph) in the system.
FIG. 5 is a diagram showing a spectrum of 9 to 1 GHz of a 200M baud 1010-PCM signal in the system.
FIG. 6 is a diagram showing a 200M baud PCM signal having a 10000100 pattern (upper graph) and a bit period signal (lower graph) in the system.
FIG. 7 is a diagram showing a 9 to 1 GHz spectrum of a 200M baud PCM signal (10000100) in the system.
FIG. 8 is a diagram showing a standard M baud PCM signal (narrow graph), a frequency-modulated bit clock signal (wide graph) at a center frequency of 100 MHz, and a 2009 M baud PCM signal with a line distance of 10 MHz in the same system as above. It is.
9 is a diagram showing an illustration of the 200M baud signal (upper graph) of FIG. 8 with a frequency-modulated bit clock signal (lower graph) in the system.
FIG. 10 is a diagram showing a 200M baud PCM-PN7 spectrum (pseudo noise with a bit pattern length of 128) having a peak amplitude of −36 dBm and a line-to-line distance of 1.56 MHz in the system;
FIG. 11 is a diagram showing a 200M baud PCM-PN15-spectrum (pseudo noise with a bit pattern length of 32768) having an amplitude of −60 dBm and a line-to-line distance of 6.1 KHz in the system;
FIG. 12 is a diagram showing a 200M baud PCM-PN17 spectrum (pseudo noise with a bit pattern length of 131072) having an amplitude of −54 dBm and a line-to-line distance of 1.5 KHz in the system;
FIG. 13 is a diagram showing a state in which random coding (upper three graphs) and decoding (lower three graphs) in the system are realized by exclusive-OR linking of data having a pseudo noise string.
FIG. 14 is a diagram showing controlled phase shift means in the system.
FIG. 15 is a diagram showing a spectrum (wide peak) of a 200 Mbaud PCM reference frequency (narrow peak) at 100 MHz and a phase-modulated signal of 6.28 rad at 10 KHz in the system;
FIG. 16 is a diagram showing a 200M baud PCM reference frequency (narrow peak) at 100 MHz and a frequency-modulated signal (wide peak) at 1 MHz in the system;
FIG. 17 is a diagram showing a plane frequency modulated signal in the system.
FIG. 18 is a diagram showing a double spectrum in the system.
FIG. 19 is a diagram showing an FM expanded spectrum at a low frequency deviation number in the system.
FIG. 20 is a diagram showing an FM-PCM signal (upper graph) and a bit clock signal (lower graph) having a low frequency shift in the system same as above.
FIG. 21 is a diagram showing modulation by periodic regeneration in the system;
FIG. 22 is a diagram showing a 9 to 1 GHz 200M baud 1010 PCM signal spectrum in the system;
FIG. 23 is a diagram showing a 200M baud 1010-PCM signal spectrum with 8B / 10B coding from 9 to 1 GHz in the system.
FIG. 24 is a diagram showing a 200M baud 1010-PCM signal spectrum including 9 to 1 GHz 8B / 10B coding and FM in the system;
FIG. 25 is a diagram showing a 200M baud 1010-PCM signal spectrum with pseudorandom coding of 9 to 1 GHz in the system.
[Explanation of symbols]
1 Transmitter
2 Transmission circuit (data channel)
3 receivers
4 Modulator device
5 Controller device

Claims (36)

Via a line connection or in contact with the transmission circuit, especially with a rotary transmitter via a contactless transmission circuit (2), preferably spaced apart from the transmitter (1) which can move relative to each other A system for transmitting a signal, in particular a digital low-interference signal, to a receiver (3),
The signal to be transmitted by the modulator device (4) and the carrier signal of the transmission means in the transmitter (1) or the transmitter output signal at any location in the transmission circuit (2) Regardless of the modulation chosen for transmission, the output signal spectrum of the transmitter (1) is expanded by the individual spectral functions, so that the spectral power density of the transmitter output signal does not increase the bandwidth of the signal. A system for low jamming signal transmission characterized by being modulated to be reduced. The line spectrum of the transmitter output signal is expanded regardless of the transmission period, where the signal to be transmitted or the carrier signal or transmitter output signal of the transmission means in the transmitter is at any arbitrary position in the transmission circuit. 2. The system of low jamming signal transmission according to claim 1, wherein the average spectral power density is modulated in such a way that it is reduced by filling the gaps between the individual signal lines. System according to claim 1 or 2, characterized in that a controller device (5) serves to control the modulator device (4). 4. The system for low interference signal transmission according to any one of claims 1 to 3, characterized in that the transmitter (1) comprises a clock generator. System according to claim 4, characterized in that the modulator device (4) substantially controls the clock generator to expand the line spectrum. 6. The system of low interference signal transmission according to claim 5, characterized in that the modulator device (4) applies frequency modulation to the periodic frequency of the clock generator. 7. The system for low interference signal transmission according to claim 6, wherein said clock generator is a frequency determining element from a VCO. The system for low jamming signal transmission according to claim 7, characterized in that the controller device (5) regulates the VCO. 9. A low jamming signal transmission according to claim 1, characterized in that the modulator device (4) applies a signal to be transmitted, in particular a digital signal, to frequency, phase or amplitude modulation. system. The modulator device (4) may be located at any location along the carrier signal or transmission circuit (2) of the transmission means in the transmitter (1) for frequency or phase modulation of the transmitter output signal. 10. A system for low jamming signal transmission according to any one of claims 1 to 9, characterized in that each is applied independently of the modulation technique selected for signal transmission. In the case of the pulse carrier signal or the pulse transmitter output signal of the transmitter (1), the modulator device (4) has a time proportional to the signal defined by the signal generator additionally provided with the individual signal ends. The system for low interference signal transmission according to any one of claims 1 to 10, wherein the system is moved or delayed toward an earlier or later time point, respectively. 12. Low interference according to claim 11, characterized in that the modulator device (4) comprises delay control means and analyzes the transmitter output signal or controls delay circuits which cause each of the movement or delay. Signal transmission system. 13. The system for low interference signal transmission according to claim 12, wherein said delay control means comprises PLL means, and said delay circuit comprises a flip flap circuit. 14. The system for low interference signal transmission according to any one of claims 1 to 13, wherein the transmitter comprises PLL means. 15. System for low interference signal transmission according to claim 14, characterized in that the modulation change of the modulator device (4) is converted by the control range of the PLL means of the transmitter (1). 16. The system for low interference signal transmission according to any one of claims 1 to 15, characterized in that data coding with pseudo-random noise (noise) is performed in addition to the modulation by the modulator device (4). A controller device (5) is disposed in the receiver (3) so that the receiver (3) is synchronized with the modulation by the modulator device (4) in any arbitrary location of the transmitter or transmission circuit. The signal received by the machine (3) can be processed in synchronism between the transmitter (1) or the transmission circuit (2) at least without this additional modulation, and the receiver can process the modulated signal or Control is provided so that each receiver (1) or transmission circuit (2) and the receiver can be adapted to any implementation via another signal that can be used jointly by the receiver. The system for low interference signal transmission according to any one of 1 to 16. An additional transmission circuit controls modulation of each of the transmitter (1) or the transmission circuit (2), each of the transmitter (1) or the transmission circuit (2), and the receiver (3). 18. The system for low interference signal transmission according to any one of claims 1 to 17, characterized in that it is arranged between the receiver (3) for transmission of a signal. Wires connected to a receiver (3), preferably spaced from each other, preferably in contact with each other, contacted and / or contactless transmission circuit (2), especially in a rotating transmitter A low-interference signal transmission method for a signal, particularly a digital signal, via a transmitter, wherein the carrier signal of the transmission means in the transmitter (1) is to be transmitted at any arbitrary location in the transmission circuit (2). Regardless of the modulation chosen for signal transmission, the transmitter output signal may be expanded by the modulator device so as to reduce the power density to the spectrum of the transmitter output signal and thus to the spectrum of the transmitter output signal. A method of low jamming signal transmission characterized by modulation performed. 20. The method of low interference signal transmission according to claim 19, wherein the average spectral power density is reduced by filling a gap between the individual signal lines. 21. The method of low disturbance signal transmission according to claim 19 or 20, characterized in that the modulator device (4) is controlled by a controller device (5).
[Contents of correction] 22. The method of low jamming signal transmission according to any one of claims 19 to 21, characterized in that the transmitter (2) comprises a clock generator. 23. The method of low jamming signal transmission according to claim 22, characterized by suitable control for line spectrum expansion by the modulator device (4) of the clock generator. 24. The method of low jamming signal transmission according to claim 23, characterized by frequency modulation by the modulator device (4) of the clock generator. 25. The method of claim 24, wherein the clock generator is a frequency determining element from a VCO. 26. The method of low jamming signal transmission according to claim 25, characterized in that the controller device (5) of the VCO is adjusted. 27. Low-interference signal transmission according to any one of claims 19 to 26, characterized in that the modulator device (4) applies a signal to be transmitted, in particular a digital signal, to frequency, phase or amplitude modulation. Method. The modulator device (4) can be in any location along the carrier signal or transmission circuit (2) of the transmission means of the transmitter (1), and the transmitter output signal can be frequency or phase modulated respectively. 28. The method of low interference signal transmission according to any one of claims 19 to 27, wherein a modulation selected for signal transmission is applied regardless of the signal. In the case of a pulse carrier signal or said transmitter (1) or pulse transmitter signal, each of the modulator devices (4) has its individual signal ends converted to signals envisaged by an additionally arranged modulation signal generator. 29. The method of low interference signal transmission according to any one of claims 19 to 28, wherein the signal is moved or delayed in proportion to an earlier or later point in time. 30. Low interference according to claim 29, characterized in that the modulator device (4) comprises delay control means for controlling the delay circuit which causes the splitting of the transmitter output signal and the respective movement and delay. The method of signal transmission. 31. The method of claim 30, wherein the delay control means comprises PLL means, and the delay circuit comprises a flip-flop circuit. 32. The method of low jamming signal transmission according to any one of claims 19 to 31, characterized in that the transmitter (1) comprises PLL means. 34. Low interference signal transmission according to any one of claims 19 to 33, characterized in that the modulation variation of the modulator device (4) is converted by the control range of the PLL means of the transmitter (1). the method of. 34. The method of low interference signal transmission according to any one of claims 19 to 33, characterized in that the data coding is performed by pseudo-random noise (noise) in addition to the modulation by the modulator device (4). . A controller device (5) is disposed in the receiver (3), and the modulator device (4) can be located anywhere in the transmitter (1) or transmission circuit (2). The signal received by the receiver (3) in synchronization with the modulation can be processed in synchronization between the transmitter (1) and the transmission circuit (2) at least without this additional modulation, The receiver (3) is controlled so that it can be adapted to any implementation via the modulated signal or each of the receiver or transmission circuit and another signal that can be used jointly with the receiver. 35. The method of low interference signal transmission according to any one of claims 19 to 34. Arranged between each of the transmitter (1) or transmitter circuit (2) and the receiver (3), an additional synchronization signal is transmitted through the transmitter (1) or transmission circuit. 36. The method of low jamming signal transmission according to any one of claims 19 to 35, characterized in that each of (2) and the receiver (3) are controlled.

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