JP3698962B2

JP3698962B2 - Repeater

Info

Publication number: JP3698962B2
Application number: JP2000180416A
Authority: JP
Inventors: 和也大谷
Original assignee: NEC Magnus Communications Ltd
Current assignee: NEC Magnus Communications Ltd
Priority date: 2000-06-15
Filing date: 2000-06-15
Publication date: 2005-09-21
Anticipated expiration: 2020-06-15
Also published as: JP2001359078A

Description

【０００１】
【発明の属する技術分野】
本発明は中継器に関し、特に双方向ＣＡＴＶ伝送路における上り分岐回線からの雑音を遮断させる中継器に関する。
【０００２】
【従来の技術】
この種の従来例について図面を参照して説明する。
【０００３】
図３は従来の双方向ＣＡＴＶ中継器の一例を示すブロック図である。
【０００４】
図３において、この従来例の双方向ＣＡＴＶ中継器は、特許第２８９１７５４号の開示内容を示し、増幅器１０３，１０６がセンターから各端末への下り方向信号（７０ＭＨｚ〜４５０ＭＨｚ帯域）および各端末装置などからの上り方向信号（１０ＭＨｚ〜５０ＭＨｚ帯域）を増幅する。また、方向性ろ波器１０８が幹線より各上り、下り信号を分岐する。一方、４分配器１０９の、使用されない分配端子には、通常、終端を施す（一般的に７５Ω）。
【０００５】
このように終端された分配端子において、分配端子１１１で使用しない分配端子に終端を施すことにより金属間の接触状態の不完全が生じ伝送信号による相互変調歪が発生する時がある。このようなとき、この一定周波数間隔で発生する歪（例えば、６ＭＨｚ間隔）を検知する歪周波数検知部１１２において検知する。そして、検知した場合、スイッチ回路制御部１１３は、分配系と幹線系とを切り分けるため、スイッチ回路部１０７を制御し開閉する。
【０００６】
また、従来の他の中継器においては、上り流合雑音による妨害が発生した場合、雑音による実害が出た時点（サービスが停止する等）で施設管理者が障害に気付き、ＣＡＴＶセンタからブリッジャ・ゲートスイッチ等の遠隔制御により当該中継器の切り分け作業を行っていた。
【０００７】
【発明が解決しようとする課題】
この従来例の双方向ＣＡＴＶ中継器においては、分配系の上り方向の信号を歪周波数検知部によって相互変調歪の有無を検知し、歪を検知するとスイッチ回路部で幹線等への入力を閉じる構成になっているので、歪を検知した場合に分配系の総ての端子からの上り方向の信号をスイッチ回路部で総て遮断してしまうという問題点がある。
【０００８】
また、従来の他の中継器においては、上り流合雑音による妨害が発生した場合、ＣＡＴＶセンタからブリッジャ・ゲートスイッチ等の遠隔制御により該当中継器の切り分け作業を行うため、復旧に時間が掛かるだけでなく、そのための人員が必要であるという問題点がある。
【０００９】
（発明の目的）
本発明の目的は、雑音発生が多い分岐系の入力端子のみの入力を遮断して、雑音発生源と直接関係のない伝送路への影響を無くすることのできる、中継器を提供することにある。
【００１０】
【課題を解決するための手段】
本発明の中継器は、光伝送路を介してＣＡＴＶセンタと接続するノードが複数の双方向の中継器が木状に上り及び下りの幹線を介して接続してなるＣＡＴＶ伝送システムに使用される前記中継器であって、
前記ＣＡＴＶセンタに対する幹線系の上り信号が入力され下り信号が出力される第１の入出力端子と、
前記ＣＡＴＶセンタに対する前記幹線系の下り信号が入力され上り信号が出力される第２の入出力端子と、
下位および上位にそれぞれ配置されると共に、分岐系信号線を介して分岐系の上り信号及び下り信号の入出力を行う複数の分岐端子と、
前記第１の入出力端子，前記第２の入出力端子，および前記複数の分岐端子にそれぞれ接続され、且つ前記幹線系からの上りの幹線系信号に、前記複数の分岐端子を介してそれぞれ入力される上りの分岐系雑音が流合することによる流合雑音を、予め設定されたしきい値と比較することによって検出し、前記流合雑音が前記しきい値を超えることを検出した場合に、前記しきい値を超える前記分岐端子からの雑音混入を阻止すべく前記分岐系信号線における下位の前記分岐端子と上位の前記分岐端子との線路の開閉を順次制御すると共に、
前記複数の下位の分岐端子から入力される総ての前記上りの分岐系雑音の混入を阻止しても検出した雑音が前記しきい値を超える場合には前記第１の入出力端子からの上りの幹線による信号の前記第２の入出力端子への送出を阻止すべく前記上りの幹線における前記第１の入出力端子と前記第２の入出力端子との線路の開閉を制御する流合雑音混入阻止制御手段と、
を備える
【００１１】
本発明の中継器は、光伝送器を介してＣＡＴＶセンタと接続するノードから複数の双方向の中継器が木状に上り及び下り幹線を介して接続してなるＣＡＴＶ伝送システムに使用される前記中継器であって、前記ＣＡＴＶセンタに対する幹線系の上り信号が入力され下り信号が出力される第１の入出力端子と、この入出力端子に接続し前記上り信号及び下り信号の方向を分離する第１の方向性ろ波器と、前記ＣＡＴＶセンタに対する前記幹線系の下り信号が入力され上り信号が出力される第２の入出力端子と、この第２の入出力端子に接続し前記下り信号及び上り信号の方向を分離する第２の方向性ろ波器と、前記第１の方向性ろ波器と前記第２の方向性ろ波器間の上り幹線に直列に接続する前記上り幹線の上り信号及び分岐系の上り信号を増幅する上り幹線増幅部と、この上り幹線増幅部の出力信号から上り信号全体に対する前記複数の分岐端子からの流合雑音の混入を検出する検出部と、この検出部の流合雑音の検出の結果に基づく開閉制御されて前記上り幹線及び分岐系の上り信号を前記第２の方向性ろ波器へ出力する第１のスイッチ部と、前記分岐系の上り信号及び下り信号の入出力の端子となる複数の分岐端子と、この複数の分岐端子のそれぞれに接続して前記分岐系の上り信号及び下り信号に分離させる複数の第３の方向性ろ波器と、この複数の第３の方向性ろ波器のそれぞれの前記分岐系の上り信号の進行を前記検出部の制御によって開閉が制御される複数の第２のスイッチ部と、この複数の第２のスィッチ部からの前記分岐系の上り信号を集合させて前記上り幹線増幅系へ入力させる上り用4スプリット部と、前記下り幹線のアラーム情報及び前記検出部からのアラーム情報を前記上り幹線側に出力して前記ＣＡＴＶのセンタヘ送出しまた前記ＣＡＴＶセンタからの前記検出部への制御信号を前記下り幹線から入力して前記検出部へ出力する中継器監視制御部とを有する。
【００１２】
【発明の実施の形態】
次に本発明について図面を参照して説明する。
【００１３】
図１は本発明の一実施の形態における中継器を示すブロック図、図２は本実施の形態における中継器内の検出部を示すブロック図である。
【００１４】
図１において、本実施の形態の中継器２０は、光伝送路を介してＣＡＴＶセンタ（図面省略）に接続するノードから複数の中継器が上り及び下りの幹線（同軸線）を介して接続してなるＣＡＴＶ伝送システム内で使用され、
ＣＡＴＶセンタに対する幹線系の上り信号が入力され下り信号が出力される入出力端子１５と、入出力端子１５に接続し上り信号および下り信号の方向を分離する方向性ろ波器（ＤＦ）８₁ と、ＣＡＴＶセンタからの下り信号が入力され上り信号が出力される入出力端子１４と、入出力端子１４に接続し下り信号および上り信号の方向を分離する方向性ろ波器（ＤＦ）８₂ と、ＤＦ８₂ とＤＦ８₁ 間の下り幹線２１に直列に接続して下り信号を増幅する下り幹線増幅部２３と、ＤＦ８₁ とＤＦ８₂ の間の上り幹線２２に直列に接続する上り幹線２２の上り信号および分岐系の上り信号を増幅する上り幹線増幅部７と、この上り幹線増幅部７の出力信号から上り信号全体に対する分岐端子１０〜１３からの流合雑音の混入を検出する検出部６と、検出部６の流合雑音の検出の結果に基づいて開閉制御されて上り幹線２２及び全分岐系の上り信号をＤＦ８₂ へ出力するスイッチ部５と、分岐系の上り信号及び下り信号の入出力の端子となる分岐端子１０〜１３と、この分岐端子１０〜１３のそれぞれに接続して分岐系の上り信号及び下り信号に分離されるＤＦ８₃ 〜ＤＦ８₆ と、ＤＦ８₃ 〜ＤＦ８₆ のそれぞれの分岐系の上り信号の進行を検出部６の制御によって開閉が制御されるスイッチ部１〜スイッチ部４と、スイッチ部１〜スイッチ部４からの分岐系の上り信号を集合させて上り幹線増幅部７へ入力させる上り用４スプリット部（上り用４ＳＰ）９と、下り幹線２１からの下り信号を分岐のために増幅する下り分岐増幅部２４と、下り分岐増幅部２４からの下り信号をＤＦ８₃ 〜ＤＦ８₆ へ分岐するための下り用４スプリット部（下り用４ＳＰ）２５と、下り幹線２１のアラーム情報及び検出部６からのアラーム情報を上り幹線側に出力してＣＡＴＶセンタへ送出しまた、ＣＡＴＶセンタからの検出部６への制御信号を下り幹線２１から入力して検出部６へ出力する中継器監視制御部（ＳＭＴ）１６とを有している。
【００１５】
図２において、本実施の形態における中継器２０の検出部６は、上り幹線増幅部７にインタフェースしてインピータレス整合する入力上り幹線インタフェース部６１と、入力上り幹線インタフェース部６１に介して入力された上り信号全体の電力を測定し測定結果をＣＰＵ６８へ通知するパワーメータ６２と、上り信号全体内に分岐系からの流合雑音の混入を判定するための予め定められた電力しきい値を記憶しているしきい値メモリ部６３と、流合雑音の混入の判定の基にスイッチ部１〜５を制御するスイッチ制御部６５と、スイッチ部５にインタフェースしてインピーダレス整合すると共に判定結果の上り信号をスイッチ部５へ送出する出力上り幹線インタフェース部６６と、ＳＭＴ１６にインタフェースしＳＭＴ１６を介してのＣＡＴＶセンタからの各種制御信号及び流合雑音の混入の判定結果によるアラーム情報をＳＭＴ１６へ送出するＳＭＴインタフェース部６７と、スイッチ部１〜４の開閉順序やスイッチ部１〜４の開閉によって流合雑音の混入の判定を行うための電力しきい値と判定した電力との差のデータを一時記憶し、また検出部６全体の制御プログラム及び自己の機器番号を格納している主メモリ６４と、主メモリ６４が格納している制御プログラムの基に検出部６全体を制御し、上り信号全体からの流合雑音の混入を判定し、流合雑音を上位の中継器に対し上り幹線に混入しないように制御し、混入している場合にはＳＭＴ１６へ通知するＣＰＵ６８とを有している。
【００１６】
次に、本実施の形態における検出部の動作とその第１、第２の流合雑音遮断方法について図１、図２を参照して説明する。
【００１７】
先ず、検出部６の動作とその第１の流合雑音遮断方法について以下に説明する。
【００１８】
ＣＡＴＶ伝送システム内の全中継器２０においては、ＣＡＴＶ伝送システムとして移動する前に、ＣＡＴＶセンタからＣＡＴＶ伝送システムの全中継器２０に共通の「共通機器番号」と共に書く中継器２０内検出部６のしきい値メモリ６３に記憶させて流合雑音混入を検出するための予め定められた「電力しきい値」及び「設定コマンド」等が、端子１４、ＤＦ８₂ 下り幹線増幅部２３及びＳＭＴ１６を経由して検出部６に入力される。検出部６のＣＰＵ６８はＳＭＴインタフェース部６７を介して入力されたＣＡＴＶセンタからの情報を主メモリ６７を参照して解析し、全中継器２０に対する「電力しきい値の設定」だと判断するとしきい値メモリ６３に「電力しきい値」を記憶させる。
【００１９】
次に、ＣＡＴＶ伝送システムの稼働中において、通常、スイッチ部１〜５は閉じた状態になっているため、分岐端子１０〜１３のそれぞれに混入した雑音は、ＤＦ８₃ 〜８₆ にて下り信号成分と分離し、分岐系の雑音はスイッチ部１、スイッチ部２、スイッチ部３、スイッチ部４を経由して、さらに上り用４ＳＰ９を経由し、入出力端子１５からの幹線系の上りの雑音と結合される。幹線系と分岐系との上り流合雑音は、上り幹線増幅部７により増幅され、検出部６に入力される。
【００２０】
検出部６は入力上り幹線インタフェース部６１を介して入力された上り信号の電力をパワーメータ６２で測定してＣＰＵ６８に通知され、ＣＰＵ６８はしきい値メモリ６３に記憶されている予め定められた電力のしきい値と比較して流合雑音混入の有無を検出する。
【００２１】
ＣＰＵ６８は流合雑音混入を検出した場合、スイッチ部１〜スイッチ部４に対してスイッチ制御部６５によって開制御を順に実行し、各スイッチ１〜４を開閉したときの電力の変化をパワーメータ６２で測定し、電力がしきい値以下になった時点で開制御されている分岐端子のスイッチ部は、開状態を保持し、それ以外の分岐端子のスイッチ部は閉状態を保持する。
【００２２】
また、複数のスイッチ部を同時に順に開制御することも可能とすることにより、複数の分岐端子から同時に上り流合雑音が混入しても、ＣＡＴＶセンタ方向への混入を阻止することもできる。
【００２３】
尚、スイッチ部１〜４を全て開制御してもパワーメータ６２で測定される電力が電力しきい値以下とならない場合は、幹線系からの雑音混入または機器内部でのトラブルであると想定されるため、ＣＰＵ６８はスイッチ制御部６５によってスイッチ部５のスイッチを開とする。
【００２４】
先ず、検出部６の動作とその第２の流合雑音遮断方法について以下に説明する。
【００２５】
この第２の流合雑音遮断方法においては、上記で説明した第１の流合雑音遮断方法における「電力しきい値」の設定方法、及び各分岐端子１０〜１３からの分岐系の雑音が入出力端子１５からの幹線系の雑音と流合されて上り幹線増幅部７で増幅された後に検出部６へ入力までの動作は同じなので省略する。
【００２６】
検出部６は入力上り幹線インタフェース部６１を介して入力された上り信号の電力をパワーメータ６２で測定してＣＰＵ６８に通知され、ＣＰＵ６８はしきい値メモリ６３に記憶されている予め定められた電力のしきい値と比較して流合雑音混入の有無を検出する。
【００２７】
ＣＰＵ６８は流合雑音を検出した場合、スイッチ部１〜スイッチ部４に対してスイッチ制御部６５によって開閉制御を順に実行し、各スイッチ部１〜４の開したときの電力をパワーメータ６２が測定し、測定電力としきい値との差の値をＣＰＵ６８に通知する。
【００２８】
ＣＰＵ６８はパワーメータ６２からの差の値を測定したスイッチ部と対応付けて一旦主メモリ６４に記憶し、次にスイッチ部１〜スイッチ部４に対する開閉制御が終ると、主メモリ６４を参照して、測定電力としきい値との差の値が一番大きいスイッチ部をスイッチ制御部６５を介して開状態に実行し、そのスイッチ部は開状態に保持する。
【００２９】
他に、しきい値との差の値の一番大きいスイッチ部が複数ある場合にはその複数のスイッチ部を開状態に実行し、残りのスイッチ部は閉状態に保持する。
【００３０】
尚、第２の流合雑音遮断方法においても、第１の流合雑音遮断方法の場合と、同様に、スイッチ部１〜４を全て開制御してもパワーメータ６２で測定される電力がしきい値以下とならない場合は、幹線系からの雑音混入または機器内部でのトラブルであると想定されるため、ＣＰＵ６８はスイッチ制御部６によってスイッチ部５のスイッチを開とする。
【００３１】
次に、中継器２０とＣＡＴＶセンタとのアラーム情報及び制御情報の送受信動作について以下に説明する。
【００３２】
中継器２０において、検出部６が上記で説明した第１又は第２の流合雑音遮断方法によって流合雑音を検出した場合、ＣＰＵ６８は主メモリ６４を参照して自己の機器番号及び、開状態にしたスイッチ部の番号と共に流合雑音混入したことを示すアラーム情報をＳＭＴインタフェース部６７を介してＳＭＴ１６へ送出する。
【００３３】
ＳＭＴ１６は上り幹線２２を介してＤＦ８₂ を経由し入出力する端子１４から検出部６からのアラーム情報をＣＡＴＶセンタへ送出する。
【００３４】
尚、ＳＭＴ１６は下り幹線系のアラーム情報についても同様方法でＣＡＴＶセンタへ送出することができる。
【００３５】
中継器２０の流合雑音混入等の障害が復旧し、ＣＡＴＶセンタから中継器２０の目的のスイッチ部の開閉を遠隔制御する場合、ＣＡＴＶセンタは中継器の機器番号と制御する目的のスイッチ部の番号と共に開制御、又は閉制御のコマンドを含んだ制御情報を送出する。
【００３６】
中継器２０は入出力端子１４、ＤＦ８₂ 及び下り幹線増幅部２３を経由したＣＡＴＶセンタからの制御情報をＳＭＴ１６が受信して検出部６へ送出し、下り分岐増幅部２４に対しては制御情報の出力を禁止する。検出部６のＣＰＵ６８はＳＭＴインタフェース部６７を介して制御情報を受信すると、主メモリ６４を参照して自己の機器のスイッチ部への制御であることを認識すると、制御情報の中のコマンドに従って目的のスイッチ部を開閉すべくスイッチ制御部６５へ通知する。
【００３７】
以上に示した本実施の形態における中継器２０は、検出部６が上り流合雑音成分を検出した時点でＳＭＴ１６にアラーム情報を出力して、ＣＡＴＶセンタに設置される監視制御装置により、中継器２０で流合雑音を検出したことを確認することができ、また、ＣＡＴＶセンタの監視制御装置からスイッチ部１〜スイッチ部５を遠隔制御することも可能である。
【００３８】
また本実施の形態の中継器２０は、ＣＡＴＶ伝送システムを利用した通信サービスにおいて、上り流合雑音発生時にサービス停止がサービスエリア全域に及ぶことを防止するとともに、サービス停止から復旧までの一連の作業を簡素化することに着目したもので、ＣＡＴＶ伝送システムを構成する中継器２０に上り流合雑音成分を検出する検出部６と幹線及び分岐系の上り信号を阻止するスイッチ部１〜５を搭載し、雑音成分を検出すると同時にスイッチ部１〜５を搭載し、雑音成分を検出すると同時にスイッチ部１〜５の開閉を行い、上り流合雑音が発生した箇所のみＣＡＴＶ伝送路網から切り離すことで、通信サービスの停止範囲を小規模に限定するとともに、上り流合雑音発生箇所の特定作業を速やかに行えるようにすることができる。
【００３９】
【発明の効果】
以上説明したように本発明は、以下に示す結果が得られる。
【００４０】
第１の効果は、上り流合雑音が発生した場合、作業員がブリッジャ、ゲートスイッチを利用した切り分けによる仮復旧を行う等の必要が無く、自動的に障害箇所直近の中継器のみが上り雑音をカットするため、夜間等、人員が不在の時でも仮復旧が可能であり、これにより、施設管理者の工数を削減することができる。
【００４１】
第２の効果は、突然の流合雑音増加に対しても数秒で仮復旧することが可能なため、作業員が切り分けを行う場合に比較し、極めて短時間であり、これにより、利用者へのサービスが向上させることができる。
【図面の簡単な説明】
【図１】本発明の一実施の形態における中継器を示すブロック図である。
【図２】本実施の形態における中継器内の検出部を示すブロック図である。
【図３】従来の双方向ＣＡＴＶ中継器の一例を示すブロック図である。
【符号の説明】
１〜５スイッチ部
６検出部
７上り幹線増幅部
８₁ 〜８₆ 方向性ろ波器（ＤＦ）
９上り用４スプリット部（上り用４ＳＰ）
１０〜１３分岐端子
１４，１５入出力端子
１６中継器監視制御部（ＳＭＴ）
２０中継器
２１下り幹線
２２上り幹線
２３下り幹線増幅部
２４下り分岐増幅部
２５下り用４スプリット部（下り用４ＳＰ）
６１入力上り幹線インタフェース部
６２パワーメータ
６３しきい値メモリ
６４主メモリ
６５スイッチ制御部
６６出力上り幹線インタフェース部
６７ＳＭＴインタフェース部
６８ＣＰＵ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a repeater, and more particularly to a repeater that blocks noise from an upstream branch line in a bidirectional CATV transmission line .
[0002]
[Prior art]
This type of conventional example will be described with reference to the drawings.
[0003]
FIG. 3 is a block diagram showing an example of a conventional bidirectional CATV repeater.
[0004]
In FIG. 3, the bidirectional CATV repeater of this conventional example shows the disclosure of Japanese Patent No. 2891754, where the amplifiers 103 and 106 are downstream signals (70 MHz to 450 MHz band) from the center to each terminal, each terminal device, etc. The upstream signal from (10 MHz to 50 MHz band) is amplified. Further, the directional filter 108 branches the upstream and downstream signals from the main line. On the other hand, the unused distribution terminals of the 4-distributor 109 are usually terminated (generally 75Ω).
[0005]
In the distribution terminal terminated in this way, when the distribution terminal not used in the distribution terminal 111 is terminated, the contact state between the metals may be incomplete and intermodulation distortion due to the transmission signal may occur. In such a case, the distortion frequency detection unit 112 that detects distortion (for example, 6 MHz interval) generated at a constant frequency interval detects the distortion. When detected, the switch circuit control unit 113 controls the switch circuit unit 107 to open and close to separate the distribution system and the main line system.
[0006]
Also, in the other conventional repeaters, when the disturbance due to the upstream inflow noise occurs, the facility manager notices the failure at the time when the actual damage is caused by the noise (service is stopped, etc.). The repeater was separated by remote control such as a gate switch.
[0007]
[Problems to be solved by the invention]
In the conventional bidirectional CATV repeater, the upstream signal of the distribution system is detected by the distortion frequency detection unit for the presence of intermodulation distortion, and when the distortion is detected, the switch circuit unit closes the input to the trunk line or the like Therefore, there is a problem that when the distortion is detected, all the upstream signals from all terminals of the distribution system are blocked by the switch circuit unit.
[0008]
In addition, in the other conventional repeater, when the interference due to the upstream inflow noise occurs, the operation is separated from the CATV center by remote control such as a bridger / gate switch, so that it takes time to recover. However, there is a problem that personnel are required for that purpose.
[0009]
(Object of invention)
An object of the present invention is to provide a repeater that can cut off the input of only a branch system input terminal that generates a lot of noise, and eliminate the influence on a transmission line that is not directly related to the noise generation source. is there.
[0010]
[Means for Solving the Problems]
The repeater according to the present invention is used in a CATV transmission system in which a plurality of bidirectional repeaters are connected to a CATV center via an optical transmission line via a tree-like upstream and downstream trunk line. Said repeater, comprising:
A first input / output terminal from which a trunk line upstream signal to the CATV center is input and a downstream signal is output ;
A second input / output terminal from which a downstream signal of the trunk system to the CATV center is input and an upstream signal is output ;
A plurality of branch terminals that are arranged at the lower and upper levels, respectively, and perform input / output of the upstream and downstream signals of the branch system via the branch system signal line,
Said first input-output terminal, said second input terminal, and respectively connected to said plurality of branch terminals, and the uplink trunk system signal from the trunk line, respectively inputted through the plurality of branch terminals the ingress noise due to the upstream branch system noise is ingress is, detected by comparison with a preset threshold value, when the flow ingress noise is detected that exceeds the threshold And sequentially controlling the opening and closing of the line between the lower branch terminal and the upper branch terminal in the branch signal line in order to prevent noise mixing from the branch terminal exceeding the threshold,
If the detected noise exceeds the threshold value even if blocking of all the upstream branching system noises input from the plurality of lower branch terminals is prevented, the upstream from the first input / output terminal Inflow noise for controlling the opening and closing of the line between the first input / output terminal and the second input / output terminal in the upstream trunk line in order to prevent the transmission of the signal by the main line to the second input / output terminal Mixing prevention control means;
[0011]
The repeater of the present invention is used in the CATV transmission system in which a plurality of bidirectional repeaters are connected in a tree shape via upstream and downstream trunk lines from a node connected to the CATV center via an optical transmitter. A repeater, a first input / output terminal to which a trunk line upstream signal for the CATV center is input and a downstream signal is output; and a connection to the input / output terminal to separate the directions of the upstream signal and the downstream signal A first directional filter; a second input / output terminal to which the trunk system downstream signal for the CATV center is input and an upstream signal is output; and the downstream signal connected to the second input / output terminal And a second directional filter for separating the direction of the upstream signal, and the upstream trunk line connected in series to the upstream trunk line between the first directional filter and the second directional filter. Increase the upstream signal and the upstream upstream signal An upstream trunk amplifying unit, a detection unit for detecting mixing noise from the plurality of branch terminals with respect to the entire upstream signal from an output signal of the upstream trunk amplifying unit, and a result of detection of the joint noise by the detection unit A first switch unit that is controlled to open and close based on the output and outputs the upstream signal of the upstream trunk line and the branch system to the second directional filter; and an input / output terminal for the upstream signal and the downstream signal of the branch system; A plurality of branch terminals, a plurality of third directional filters connected to each of the plurality of branch terminals and separated into the upstream and downstream signals of the branch system, and the plurality of third directional filters A plurality of second switch units whose opening / closing is controlled by the control of the detection unit, and the upstream of the branch system from the plurality of second switch units. Increase the upstream trunk line by collecting signals Uplink 4 split section to be input to the system, alarm information from the down trunk line and alarm information from the detection section are output to the upstream trunk side and sent to the center of the CATV, and to the detection section from the CATV center And a repeater monitoring control unit that inputs the control signal from the down trunk line and outputs the control signal to the detection unit.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a block diagram showing a repeater according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a detector in the repeater according to the present embodiment.
[0014]
In FIG. 1, a repeater 20 according to the present embodiment has a plurality of repeaters connected from a node connected to a CATV center (not shown) via an optical transmission line via upstream and downstream trunk lines (coaxial lines). Used in the CATV transmission system
An input / output terminal 15 that receives an upstream signal from the trunk line and outputs a downstream signal to the CATV center, and a directional filter (DF) 8 ₁ that is connected to the input / output terminal 15 and separates the direction of the upstream signal and the downstream signal. An input / output terminal 14 that receives a downstream signal from the CATV center and outputs an upstream signal, and a directional filter (DF) 8 ₂ that is connected to the input / output terminal 14 and separates the direction of the downstream signal and the upstream signal. When a downlink trunk amplifier 23 for amplifying a connection to a downstream signal in series downstream trunk 21 between DF8 ₂ and DF8 _1, uplink trunk 22 connected in series to the upstream main line 22 between DF8 ₁ and DF8 ₂ An upstream trunk amplifying unit 7 that amplifies the upstream signal and the branched upstream signal, and a detection unit 6 that detects mixing noise from the branch terminals 10 to 13 with respect to the entire upstream signal from the output signal of the upstream trunk amplifying unit 7. And A switch unit 5 to output the upstream signal of the uplink trunk 22 and the entire branch system to DF8 ₂ are opened and closed controlled based on the ingress noise of the detection result of the part 6, the input and output of the upstream signal and the downstream signal branching system the branch terminal 10-13 as a terminal, and DF8 ₃ ~DF8 ₆ which connect separated into uplink signal and downlink signal branch system to each of the branch terminals 10 to 13, each branch of DF8 ₃ ~DF8 ₆ The switch unit 1 to the switch unit 4 whose opening / closing is controlled by the control of the detection unit 6 and the branch system upstream signals from the switch unit 1 to the switch unit 4 are assembled to collect the upstream signal amplification unit 7. ascending 4 split portion for input to the (ascending 4SP) 9, a downstream branch amplifier 24 for amplifying a downlink signal from the downlink trunk 21 for branching, DF8 ₃ ~ a downlink signal from the downlink branch amplifier 24 DF8 ₆ 4 split section for downlink (4SP for downlink) 25 for branching to the center, and alarm information of the downlink trunk line 21 and alarm information from the detection section 6 are output to the uplink trunk line side and sent to the CATV center. And a repeater monitoring control unit (SMT) 16 that inputs a control signal to the detection unit 6 from the down trunk 21 and outputs the control signal to the detection unit 6.
[0015]
In FIG. 2, the detection unit 6 of the repeater 20 according to the present embodiment is input via the input upstream trunk interface unit 61 and the input upstream trunk interface unit 61 that interface with the upstream trunk amplification unit 7 and perform impedanceless matching. A power meter 62 that measures the power of the entire upstream signal and notifies the CPU 68 of the measurement result, and stores a predetermined power threshold value for determining the presence of infusion noise from the branch system in the entire upstream signal. Threshold memory unit 63, switch control unit 65 for controlling switch units 1-5 based on determination of mixing noise, interface with switch unit 5 and impederless matching, and increase in determination result An output upstream trunk line interface unit 66 for sending a signal to the switch unit 5; and a CAT interfaced with the SMT 16 via the SMT 16 Various control signals from the center and alarm information based on the result of determination of mixing noise are sent to the SMT 16, and the switching order of the switches 1 to 4 and the switching of the switching sections 1 to 4 are used to reduce the noise. A main memory 64 that temporarily stores data on the difference between the power threshold value for determining mixing and the determined power, and stores a control program for the entire detection unit 6 and its own device number; 64 controls the entire detection unit 6 based on the control program stored therein, determines the mixing noise from the entire upstream signal, and prevents the upstream noise from being mixed into the upstream trunk line with the upstream relay. It has a CPU 68 that controls and notifies the SMT 16 when it is mixed.
[0016]
Next, the operation of the detection unit and the first and second infusion noise blocking methods in the present embodiment will be described with reference to FIGS.
[0017]
First, the operation of the detection unit 6 and the first infusion noise blocking method will be described below.
[0018]
In all repeaters 20 in the CATV transmission system, before moving as a CATV transmission system, the repeater 20 detection unit 6 writes together with a “common device number” common to all repeaters 20 in the CATV transmission system from the CATV center. predetermined "power threshold" and "setting command" or the like for detecting the ingress noise mixed and stored in the threshold memory 63, via the terminal 14, DF8 ₂ downstream trunk amplifier 23 and SMT16 And input to the detection unit 6. The CPU 68 of the detection unit 6 analyzes the information from the CATV center input via the SMT interface unit 67 with reference to the main memory 67 and determines that it is “setting of power threshold value” for all repeaters 20. The “power threshold value” is stored in the threshold memory 63.
[0019]
Then, during the operation of the CATV transmission system, usually, since the switching unit 1-5 is in the closed state, the noise mixed in the respective branch terminals 10-13, the downstream signal at DF8 ₃ to 8 ₆ The noise of the branching system is separated from the component, passes through the switch unit 1, the switch unit 2, the switch unit 3, and the switch unit 4 and further through the upstream 4SP9, and then the upstream noise of the trunk line from the input / output terminal 15 Combined with. Upstream inflow noise between the trunk line system and the branch system is amplified by the upstream trunk line amplification unit 7 and input to the detection unit 6.
[0020]
The detection unit 6 measures the power of the upstream signal input via the input upstream trunk interface unit 61 by the power meter 62 and notifies the CPU 68 of the power, and the CPU 68 determines a predetermined power stored in the threshold memory 63. The presence or absence of mixed noise is detected in comparison with the threshold value.
[0021]
When the CPU 68 detects mixing noise mixing, the switch control unit 65 sequentially performs opening control on the switch unit 1 to the switch unit 4, and changes in power when the switches 1 to 4 are opened and closed are indicated by the power meter 62. The switch part of the branch terminal that is controlled to open when the power becomes equal to or lower than the threshold value holds the open state, and the switch parts of the other branch terminals hold the closed state.
[0022]
In addition, since the plurality of switch units can be simultaneously controlled to be opened simultaneously, even if upstream inflow noise is mixed from a plurality of branch terminals, mixing in the CATV center direction can be prevented.
[0023]
If the power measured by the power meter 62 does not fall below the power threshold even when all the switches 1 to 4 are controlled to open, it is assumed that there is noise from the trunk line or a trouble inside the equipment. Therefore, the CPU 68 opens the switch of the switch unit 5 by the switch control unit 65.
[0024]
First, the operation of the detection unit 6 and the second infusion noise blocking method will be described below.
[0025]
In this second infusion noise cutoff method, the “power threshold” setting method in the first ingress noise cutoff method described above and the branch system noise from each of the branch terminals 10 to 13 are input. Since the operation up to the input to the detection unit 6 after being combined with the noise of the trunk line system from the output terminal 15 and amplified by the upstream trunk line amplification unit 7 is the same, the description is omitted.
[0026]
The detection unit 6 measures the power of the upstream signal input via the input upstream trunk interface unit 61 by the power meter 62 and notifies the CPU 68 of the power, and the CPU 68 determines a predetermined power stored in the threshold memory 63. The presence or absence of mixed noise is detected in comparison with the threshold value .
[0027]
When the CPU 68 detects inflow noise, the switch unit 65 sequentially performs opening / closing control on the switch unit 1 to the switch unit 4, and the power meter 62 measures the power when each of the switch units 1 to 4 is opened. The CPU 68 is notified of the difference between the measured power and the threshold value.
[0028]
The CPU 68 temporarily stores the difference value from the power meter 62 in association with the measured switch unit in the main memory 64, and then refers to the main memory 64 when the switching control for the switch unit 1 to the switch unit 4 is finished. The switch unit having the largest difference between the measured power and the threshold value is executed in the open state via the switch control unit 65, and the switch unit is held in the open state.
[0029]
In addition, when there are a plurality of switch parts having the largest difference value from the threshold value, the plurality of switch parts are executed in the open state, and the remaining switch parts are held in the closed state.
[0030]
In the second infusion noise cutoff method, as in the first infusion noise cutoff method, the power measured by the power meter 62 is reduced even if all the switches 1 to 4 are controlled to open. If it is not less than the threshold value, it is assumed that there is noise from the trunk line system or a trouble inside the equipment, so the CPU 68 opens the switch of the switch unit 5 by the switch control unit 6.
[0031]
Next, alarm information and control information transmission / reception operations between the repeater 20 and the CATV center will be described below.
[0032]
In the repeater 20, when the detection unit 6 detects the joint noise by the first or second joint noise blocking method described above, the CPU 68 refers to the main memory 64 and determines its own device number and the open state. Alarm information indicating that mixed noise is mixed is sent to the SMT 16 via the SMT interface unit 67 together with the number of the switch unit.
[0033]
SMT16 sends the alarm information from the detector 6 from the terminal 14 to input and output via the DF8 ₂ via the uplink trunk 22 to the CATV center.
[0034]
Note that the SMT 16 can also send down the trunk line alarm information to the CATV center in the same manner.
[0035]
When a failure such as intrusion noise mixing in the repeater 20 is recovered and the opening / closing of the target switch unit of the repeater 20 is remotely controlled from the CATV center, the CATV center determines the device number of the repeater and the target switch unit to be controlled. Control information including an open control or close control command is sent together with the number.
[0036]
The repeater 20 receives the control information from the CATV center via the input / output terminal 14, the DF 8 ₂ and the down trunk amplifier 23 and sends it to the detector 6, and sends control information to the down branch amplifier 24. Prohibit output. When the CPU 68 of the detection unit 6 receives the control information via the SMT interface unit 67 and recognizes the control to the switch unit of its own device with reference to the main memory 64, the CPU 68 in accordance with the command in the control information The switch control unit 65 is notified to open and close the switch unit.
[0037]
The repeater 20 in the present embodiment described above outputs the alarm information to the SMT 16 when the detecting unit 6 detects the upstream inflow noise component, and the repeater 20 is installed by the monitoring control device installed in the CATV center. It is possible to confirm that the inflow noise has been detected at 20, and it is also possible to remotely control the switch unit 1 to the switch unit 5 from the monitoring control device of the CATV center.
[0038]
The repeater 20 of the present embodiment prevents a service stop from extending over the entire service area when an upstream inflow noise occurs in a communication service using a CATV transmission system, and a series of operations from service stop to recovery. The repeater 20 constituting the CATV transmission system is equipped with a detection unit 6 that detects upstream inflow noise components and switch units 1 to 5 that block upstream signals in the trunk and branch systems. In addition, the switch units 1 to 5 are mounted simultaneously with the detection of the noise component, and the switch units 1 to 5 are opened and closed simultaneously with the detection of the noise component, and only the portion where the upstream inflow noise is generated is separated from the CATV transmission line network. In addition to limiting the stoppage range of communication services to a small scale, it is possible to quickly identify the location where upstream inflow noise occurs.
[0039]
【The invention's effect】
As described above, the present invention provides the following results.
[0040]
The first effect is that when upstream inflow noise occurs, there is no need for the operator to perform temporary restoration by separation using a bridger or a gate switch, and only the repeater nearest to the fault location automatically becomes upstream noise. Therefore, provisional restoration is possible even when there are no personnel, such as at night, thereby reducing the man-hours for the facility manager.
[0041]
The second effect is that it is possible to recover temporarily even in a few seconds even if there is a sudden increase in inflow noise, so it is extremely short compared with the case where the worker performs carving. Service can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a repeater in an embodiment of the present invention.
FIG. 2 is a block diagram showing a detection unit in the repeater in the present embodiment.
FIG. 3 is a block diagram showing an example of a conventional bidirectional CATV repeater.
[Explanation of symbols]
1 to 5 Switch unit 6 Detection unit 7 Upstream trunk amplification unit 8 ₁ to 8 _6- directional filter (DF)
9 Up 4 split sections (up 4SP)
10 to 13 Branch terminals 14 and 15 Input / output terminal 16 Repeater monitoring controller (SMT)
20 repeater 21 downstream trunk line 22 upstream trunk line 23 downstream trunk line amplification section 24 downstream branch amplification section 25 downstream 4 split section (downstream 4SP)
61 Input Upstream Trunk Line Interface Unit 62 Power Meter 63 Threshold Memory 64 Main Memory 65 Switch Control Unit 66 Output Upstream Trunk Line Interface Unit 67 SMT Interface Unit 68 CPU

Claims

A node connected to a CATV center via an optical transmission line is a repeater used in a CATV transmission system in which a plurality of bidirectional repeaters are connected in a tree shape via upstream and downstream trunk lines,
A first input / output terminal from which a trunk line upstream signal to the CATV center is input and a downstream signal is output ;
A second input / output terminal from which the downstream signal of the trunk system to the CATV center is input and an upstream signal is output ;
A plurality of branch terminals that are arranged at the lower and upper levels, respectively, and perform input / output of the uplink and downlink signals of the branch system via the branch signal line,
Said first input-output terminal, said second input terminal, and respectively connected to said plurality of branch terminals, and the uplink trunk system signal from the trunk line, respectively inputted through the plurality of branch terminals the ingress noise due to the upstream branch system noise is ingress is, detected by comparison with a preset threshold value, when the flow ingress noise is detected that exceeds the threshold And sequentially controlling the opening and closing of the line between the lower branch terminal and the upper branch terminal in the branch signal line in order to prevent noise mixing from the branch terminal exceeding the threshold,
If the detected noise exceeds the threshold value even if blocking of all the upstream branching system noises input from the plurality of lower branch terminals is prevented, the upstream from the first input / output terminal Inflow noise for controlling the opening and closing of the line between the first input / output terminal and the second input / output terminal in the upstream trunk line in order to prevent the transmission of the signal by the main line to the second input / output terminal Mixing prevention control means;
A repeater comprising:

A repeater used in a CATV transmission system in which a plurality of bidirectional repeaters are connected in a tree shape via upstream and downstream trunk lines from a node connected to a CATV center via an optical transmitter, A first input / output terminal that receives a trunk line upstream signal to the CATV center and outputs a downstream signal, and a first directional filter that is connected to the input / output terminal and separates the directions of the upstream signal and the downstream signal. And a second input / output terminal to which the trunk line system downstream signal is input to the CATV center and the upstream signal is output, and the direction of the downstream signal and the upstream signal is separated by being connected to the second input / output terminal. The second directional filter, and the upstream signal of the upstream trunk line connected in series to the upstream trunk line between the first directional filter and the second directional filter and the upstream of the branch system Upstream trunk amplification for signal amplification And a detection unit that detects mixing noise from the plurality of branch terminals with respect to the entire upstream signal from the output signal of the upstream trunk amplification unit, and open / close control based on the detection result of the coupling noise of the detection unit A first switch unit that outputs the upstream signal of the upstream trunk line and the branch system to the second directional filter, and a plurality of branch terminals serving as input / output terminals for the upstream signal and the downstream signal of the branch system A plurality of third directional filters connected to each of the plurality of branch terminals and separated into the upstream signal and the downstream signal of the branch system, and each of the plurality of third directional filters. A plurality of second switch units whose opening / closing is controlled by the control of the detection unit, and the branch system upstream signals from the plurality of second switch units are assembled together In addition to input to the upstream trunk line amplification system 4 split section, alarm information from the downstream trunk line and alarm information from the detection section are output to the upstream trunk line and sent to the center of the CATV, and a control signal from the CATV center to the detection section A repeater having a repeater monitoring control unit that inputs from a down trunk line and outputs to the detection unit.

The detection unit includes a power measurement unit that measures the power of mixing noise from the plurality of branch terminals with respect to the entire upstream signal, and a threshold value that determines whether the mixing noise is mixed or not. 3. The repeater according to claim 2, further comprising a threshold memory for storing the threshold used for detection by comparison.

The detection unit measures a change in input power when the plurality of second switch units are opened from a closed state according to a predetermined order by the power measurement unit, and the measured power is the threshold value. discontinue the opening control when it becomes below claims, characterized in that it comprises a switch control means for the second switch portion other than the second switch unit for controlling to hold the closed state of the open control Item 3. The repeater according to item 3 .

The detecting unit measures a change in input power when the whole of the plurality of second switch units is controlled to open from a closed state according to a predetermined order, and stores the measured power by the power measuring unit. Then, for the whole of the plurality of second switch units, only the second switch unit having a large difference from the threshold value after the end of the open control unit is opened, and the other second switch units are opened. 4. The repeater according to claim 3, further comprising switch control means for controlling the switch appropriately.

Even when the first switch unit is provided in series on the output side of the detection unit to the main line, and the plurality of second switch units are entirely opened by the switch control unit, the flow to the detection unit is performed. 6. The repeater according to claim 2, 4 or 5 , wherein the switch control means opens the first switch unit when the detection unit detects that the noise is not less than the threshold value. .

The plurality of second switch units and the first switch unit detect and receive a control signal via the repeater monitoring control unit via a down trunk from the CATV center, 7. The repeater according to claim 2, wherein the switch is controlled by the switch control means based on the control signal when it is recognized that the control signal is to itself.

In the threshold memory, the detection unit detects and receives threshold data from the CATV center through the repeater monitoring control unit via the down trunk line, and threshold data to itself is received. 4. The repeater according to claim 3 , wherein the threshold data is stored in the threshold memory when the threshold data is recognized.