JP3616978B2

JP3616978B2 - Highly reliable wireless receiver

Info

Publication number: JP3616978B2
Application number: JP02683797A
Authority: JP
Inventors: 祥一楢橋; 哲也三村; 俊雄野島
Original assignee: NTT Docomo Inc
Current assignee: NTT Docomo Inc
Priority date: 1997-02-10
Filing date: 1997-02-10
Publication date: 2005-02-02
Anticipated expiration: 2017-02-10
Also published as: JPH10224269A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えば移動通信や衛星通信等の基地局受信装置に適用され、高周波受信部を冷却して、所望の信号を受信する高信頼無線受信機に関する。
【０００２】
【従来の技術】
従来の高信頼無線受信機の基本構成を図１０に示す。この従来の高信頼無線受信機は、アンテナ１と、アンテナ１で受信された信号を伝送するためのアンテナフィーダ２と、アンテナ２の出力を切り替える第１切替手段（ＳＷ）３と、第１ＳＷ３の一方に接続された、所望の帯域の信号を選択する第１受信帯域フィルタ（ＲＸＦ）４と、第１ＲＸＦ４の出力を所望のレベルまで低雑音で増幅する第１受信低雑音増幅器（ＲＡ）５と、第１ＲＡ５の出力信号が一方の入力端に入力される第２切替手段（ＳＷ）６と、第２ＳＷ６により出力される信号を出力するための出力端子７とを備えている。第２ＳＷ６の端子のうち、出力端子７と接続されていない端子は終端器８及び９で終端されている。
【０００３】
第１ＲＸＦ４及び第１ＲＡ５は、熱遮蔽函１０に封入され、外部と断熱されるとともに、冷却手段１１により冷却される。さらに、第１ＲＡ５に電力を供給するための第１の電源端子１２と冷却手段１１に電力を供給するための第２の電源端子１３がそれぞれ設けられる。ここで図示していないが、第１ＲＸＦ４と第１ＲＡ５との間で整合をとるために、両者の間にアイソレータを設ける場合もある。
【０００４】
また、第１ＳＷ３のもう一方の端子に接続された、第２受信帯域フィルタ（ＲＸＦ）１４と、第２ＲＸＦ１４の出力信号を所望のレベルまで増幅する第２受信低雑音増幅器（ＲＡ）１５が設けられ、第２ＲＡ１５の出力信号は第２ＳＷ６のもう一方の入力端子に入力される。ここで、第２ＲＸＦ１４及び第２ＲＡ１５の周波数帯域は、第１ＲＸＦ４及び第１ＲＡ５のそれらと同一である。第２ＲＡ１５には第３電源端子１６を通して電力が供給され、第１ＳＷ３及び第２ＳＷ６は制御端子１７を通して入力される制御信号により実線または点線の位置に同時に切り替えられる。通常は第１ＳＷ３及び第２ＳＷ６とも実線のように接続される。また、上記の第１ＳＷ３，熱遮蔽函１０，冷却手段１１，第２ＳＷ６，第２ＲＸＦ１４及び第２ＲＡ１５は筐体１８に収納される。
【０００５】
第１ＲＸＦ４及び第１ＲＡ５は、例えばデュワー瓶等の熱遮蔽函１０に封入され、冷却手段１１の冷却部材１１ａにより、例えば数１０Ｋ程度といった極めて低い温度に長時間安定して冷却される。ここで冷却手段１１は、例えばヘリウムガスの圧縮・膨張による熱交換サイクルを利用する極低温冷凍機で構成され、これらは市販の製品を利用することができる。
【０００６】
このように、第１ＲＸＦ４及び第１ＲＡ５を長時間安定して極限的に冷却することにより、第１ＲＸＦ４及び第１ＲＡ５で発生する熱雑音を極限的に低減するとともに、第１ＲＸＦ４を構成する段数を増やしても低温のため損失分が少なくてすむので減衰特性を急峻にすることができる。その結果、図１０に示した構成を用いることにより、低いレベルの受信信号に対しても、例えば規定されたＣ／Ｎ比（搬送波電力／雑音電力）の受信出力を得ることができる。また、規定されたＣ／Ｎ比受信出力を得るのに必要な送信側の送信電力が小さくて済む。
【０００７】
次に、この高信頼無線受信機の動作について説明する。第１ＲＡ５で動作異常が発生すると、出力端子７から伝送される受信信号が著しく劣化するか、或いは受信不能という状態に陥る。そこで、例えば出力端子７よりの受信信号を屋内装置（図示せず）で監視し、受信信号が著しく劣化しているか、または、受信不能であると判断される場合、屋内装置から制御端子１７を通じて制御信号を送出し、第１ＳＷ３及び第２ＳＷ６が共に点線の状態となるように切り替える。このとき、アンテナ１よりの信号は第２ＲＸＦ１４及び第２ＲＡ１５を通じて出力端子７に供給される。つまり、第１ＲＸＦ４及び第１ＲＡ５の予備系である第２ＲＸＦ１４及び第２ＲＡ１５を通して信号が受信されることになる。第２ＲＸＦ１４及び第２ＲＡ１５は冷却されない構成となっており、第１ＲＸＦ４及び第１ＲＡ５の場合と比較すると冷却による雑音指数の改善効果はないものの、安価で簡素に構成でき、かつ受信不能という状態を回避することが可能となる。
【０００８】
【発明が解決しようとする課題】
従来の高信頼無線受信機において、第１ＲＡ５に障害が発生した場合の動作異常検出方法として、出力端子７よりの受信信号のレベルを観測し、そのレベルの低下をもって動作異常と判断する方法がある。しかし、このような受信信号のレベルに依存する動作異常検出機能は、例えば送受信設備が移動しない固定回線では、受信信号のレベルが一定であることから受信信号のレベルの低下により第１ＲＡ５の動作異常を検出することができるが、携帯・自動車電話等の移動通信方式用基地局装置では、通信相手が常に移動しているために受信信号レベルが大きく変化するので、第１ＲＡ５の動作異常を受信信号のレベルの低下により検出することはできないという問題があった。
【０００９】
また、従来の高信頼無線受信機においては、冷却手段１１で発生する障害を直接検出することができないだけでなく、第１ＲＡ５に障害が発生した場合に予備系として動作する第２ＲＡ１５に関して、それが正常であるかどうか、すなわち予備系として正しく機能するかどうかを確認する手段がないという問題があった。
【００１０】
本発明の目的は、高信頼無線受信機の第１ＲＡ５または冷却手段１１に障害が発生した場合に、確実に予備系統に切り替えることにより受信不能となる状態を回避することができるとともに、予備系である第２ＲＡ１５の動作を監視することのできる高信頼無線受信機を提供することにある。
【００１１】
【課題を解決するための手段】
（１）請求項１の発明は、アンテナと、アンテナフィーダと、そのアンテナフィーダからの信号が入力され、制御信号により切り替えられる第１信号切替手段と、その第１信号切替手段の一方に接続された第１受信帯域フィルタと、その第１受信帯域フィルタに接続された第１受信低雑音増幅器と、その第１受信低雑音増幅器の出力側に設けられ、制御信号により切り替えられる第２信号切替手段と、その第２信号切替手段よりの出力信号を出力する出力端子と、第１信号切替手段のもう一方の接続端子に接続された第２受信帯域フィルタと、その第２受信帯域フィルタに接続され、第２信号切替手段のもう一方の接続端子に接続された第２受信低雑音増幅器とを有し、第１受信帯域フィルタ及び第１受信低雑音増幅器は熱遮蔽函に封入されて冷却手段により冷却され、第１受信低雑音増幅器、冷却手段及び第２受信低雑音増幅器にそれぞれ第１，第２及び第３電源端子を通して動作電力が供給される高信頼無線受信機に関する。
【００１２】
請求項１では、第１及び第２受信帯域フィルタの減衰帯域内の周波数を有するパイロット信号を発生するパイロット信号発生手段と、第１受信帯域フィルタ及び第１受信低雑音増幅器の間の経路に挿入された第１パイロット信号注入手段と、第２受信帯域フィルタ及び上記第２受信低雑音増幅器の間の経路に挿入された第２パイロット信号注入手段と、第１受信低雑音増幅器の出力側と第２信号切替手段の間であって、熱遮蔽函の外側に挿入された第１分配手段と、第２受信低雑音増幅器の出力側と第２信号切替手段の間に挿入された第２分配手段とが設けられる。
【００１３】
また、第１分配手段より分配された信号よりパイロット信号のレベルを検出する第１レベル検出手段と、第２分配手段より分配された信号よりパイロット信号のレベルを検出する第２レベル検出手段と、第１レベル検出手段により検出されたパイロット信号のレベルとあらかじめ設定されたしきい値とを比較し、パイロット信号のレベルがしきい値よりも低い場合に、第１及び第２信号切替手段を切り替えるとともに第１警報信号を送出し、第２レベル検出手段により検出されたパイロット信号のレベルとしきい値とを比較し、パイロット信号のレベルがしきい値よりも低い場合に、第２警報信号を送出する制御手段と、上記制御手段内において第１及び第２信号切替手段を手動で切り替える手動切替手段とが設けられる。
【００１４】
第１受信帯域フィルタは超電導材料で構成され、冷却手段により超電導状態とされている。
（２）請求項２の発明では、上記（１）において、第１及び第３電源端子の代わりに共通の電源端子を設け、その共通の電源端子から供給される電力を電源分配手段により分配して、第１及び第２受信低雑音増幅器に供給する。
【００１５】
（３）請求項３の発明では、上記（２）の第２電源端子を削除し、上記電力分配手段から冷却手段にも動作電力を供給する。
（４）請求項４の発明では、上記（１）において、第１及び第３電源端子が削除され、第２信号切替手段と出力端子との間に挿入され、出力端子を介して供給された動作電力を高周波の受信信号より分離する電力分離フィルタと、その電力分離フィルタにより分離された電力を安定化して第１及び第２受信低雑音増幅器へ供給する電力安定化手段が設けられる。
【００１６】
（５）請求項５の発明では、上記（４）において、第２電源端子が削除され、電力安定化手段から冷却手段にも動作電力を供給する。
（６）請求項６の発明では、上記（１）乃至（５）の何れかにおいて、熱遮蔽函内の温度を検出する温度検出手段を設け、制御手段は、温度検出手段より熱遮蔽函内の温度情報を得、その温度情報があらかじめ定められた温度以上のとき、第１及び第２信号切替手段を切り替えるとともに、第３警報信号を送出する。
【００１７】
（７）請求項７の発明では、上記（６）において、温度検出手段は熱遮蔽函内の第１受信帯域フィルタ、第１受信低雑音増幅器または冷却手段の冷却部材の温度を検出する。
（８）請求項８の発明では、上記（１）乃至（７）の何れかにおいて、第１及び第２レベル検出手段の代わりに共通のレベル検出手段を設けるとともに、第１及び第２分配手段よりの信号を切り替えて共通のレベル検出手段に供給する第３信号切替手段が設けられる。
【００１８】
（９）請求項９の発明では、上記（１）乃至（７）の何れかにおいて、超電導材料は高温超電導体で構成される。
（１０）請求項１０の発明では、上記（１）乃至（７）の何れかにおいて、アンテナフィーダが省略されて、アンテナが装置筐体に直結される。
【００１９】
【発明の実施の形態】
請求項１の発明の実施例を図１に、図１０と対応する部分に同一の符号を付けて示す。この実施例では、第１ＲＸＦ４及び第２ＲＸＦ１４の減衰帯域の範囲内のパイロット信号を発生するパイロット信号発生手段２１が熱遮蔽函１０の外側に設けられ、パイロット信号発生手段２１で発生されたパイロット信号を第１ＲＸＦ４と第１ＲＡ５の間及び第１ＲＸＦ１４と第２ＲＡ１５の間にそれぞれ注入する第１パイロット信号注入手段２２及び第２パイロット信号注入手段２３が設けられる。また、第１ＲＡ５と第２ＳＷ６の間に第１分配手段２４が設けられ、第２ＲＡ１５と第２ＳＷ６の間に第２分配手段２５が設けられる。さらに、第１分配手段２４及び第２分配手段２５で分配された信号からパイロット信号のレベルをそれぞれ検出する第１レベル検出手段２６及び第２レベル検出手段２７が設けられる。
【００２０】
第１レベル検出手段２６及び第２レベル検出手段２７の出力信号が制御手段２８に入力される。さらにこの制御手段２８には、手動にて第１ＳＷ３及び第２ＳＷ６を切り替える手動切替手段２９が設けられる。パイロット信号発生手段２１，第１分配手段２４，第２分配手段２５，第１レベル検出手段２６，第２レベル検出手段２７及び制御手段２８は１つの筐体１８に収納される。
【００２１】
第１ＲＸＦ４は超電導材料で構成され、冷却手段１１による冷却により超電導材料は超電導状態とされている点が図１０とは異なる。
第１レベル検出手段２６及び第２レベル検出手段２７は選択レベルメータ等が利用できる。
制御手段２８は、あらかじめ設定されたしきい値電圧を発生する基準電圧発生手段とコンパレータ等で構成されるか、あるいは基本回路としてのマイクロプロセッサ、Ａ／Ｄ変換器、ＲＯＭ，ＲＡＭ，Ｄ／Ａ変換器等により構成され、いずれの構成においても、第１レベル検出手段２６及び第２レベル検出手段２７よりの信号を監視しつつ、あらかじめ設定されたしきい値と比較し、しきい値よりも低い場合には第１ＳＷ３及び第２ＳＷ６を切り替える、又は／及び、所定の警報信号を送出する機能を有する。
【００２２】
第１ＲＸＦ４は、例えばマイクロストリップラインで構成され、そのマイクロストリップラインを構成するグランド層と信号線とがともに超電導材料で構成され、これらが冷却手段１１による冷却により超電導状態とされているため、第１ＲＸＦ４にて発生する熱雑音が著しく小さく、従って受信機の雑音指数が改善される。
【００２３】
次に、本実施例の動作について説明する。パイロット信号発生手段２１で発生されたパイロット信号は第１パイロット信号注入手段２２により注入される。このとき、パイロット信号の周波数は第１ＲＸＦ４の減衰帯域になるように設定されているから、注入されたパイロット信号は第１ＲＸＦ４で反射され、第１ＲＡ５に入力されるのでパイロット信号がアンテナ１から放射されることはなく、他のシステムに妨害を与える心配はない。パイロット信号が付加された受信信号は第１ＲＡ５で増幅された後、第１分配手段２４で分配され、第１レベル検出手段２６において、注入されたパイロット信号のレベルが検出される。この検出されたパイロット信号のレベルが制御手段２８で監視され、あらかじめ設定されたしきい値よりも低い場合には、第１ＳＷ３及び第２ＳＷ６がそれぞれ実線の位置から点線の位置に切り替えられるとともに、第１ＲＡ５の系統に障害が発生したことを表す第１警報信号が端子３０を通して出力される。
【００２４】
一方、パイロット信号は第１パイロット信号注入手段と同様に第２パイロット信号注入手段２３によって注入され、第２ＲＡ１５で増幅された後、第２分配手段２５で分配され、第２レベル検出手段２７においても、注入されたパイロット信号のレベルが検出される。この検出されたパイロット信号のレベルが制御手段２８で監視され、あらかじめ設定されたしきい値よりも低い場合には第２ＲＡ１５の系統に障害が発生したことを表す第２警報信号が端子３０を通して出力される。
【００２５】
また、手動にて第１ＳＷ３及び第２ＳＷ６を切り替えることができるように手動切替手段２９が制御手段２８に併せて設けられており、保守・点検時には、保守者がこの手動切替手段２９を操作することにより、手動で予備系である第２ＲＸＦ１４及び第２ＲＡ１５の経路に切り替えられる構成にもなっている。
以上のように、受信信号とは独立したパイロット信号を用い、かつ、パイロット信号のレベルをあらかじめ設定されたしきい値と比較することで、第１ＲＡ５及び第２ＲＡ１５の動作異常を確実に検出できるとともに障害発生を表す警報信号を送出することができる。その結果、制御手段２８により、または保守者が手動切替手段２９を操作することにより予備系に切り替わるので第１ＲＡ５の動作異常時にも、また保守・点検時にも受信不能という状態を回避することができる。
【００２６】
なお、図１おいては、第１パイロット信号注入手段２２を冷却手段１１で冷却しない例を記載しているが、第１パイロット信号注入手段２２を冷却手段１１により冷却する構成としてもよい。
図２に示すように、共通の電源端子１２’及び電源分配手段３１を通して第１ＲＡ５及び第２ＲＡ１５のそれぞれに動作電力を供給するようにしてもよく（請求項２）、この場合、電源端子を節減することができる。
【００２７】
図３に示すように、共通の電源端子１２’及び電源分配手段３１を通して第１ＲＡ５及び第２ＲＡ１５の他にさらに冷却手段１１のそれぞれに動作電力を供給するようにしてもよく（請求項３）、この場合、さらに電源端子を節減することができる。
図４に示すように、アンテナ１をアンテナフィーダ２を介さずに筐体１８に直結してもよい（請求項１０）。このようにアンテナフィーダ２を除去することでアンテナフィーダ２の損失分を低減することができ、結果として受信機全体の雑音指数を改善できるので、さらに受信感度が改善される。図４は図１の実施例を基にしているが、勿論図２、図３の実施例にも適用できる。
【００２８】
図５は、請求項４の発明による高信頼無線受信機の実施例を示す。この発明では、図１の実施例と比較して、第１電源端子１２及び第３電源端子１６に代えて、第２ＳＷ６と出力端子７の間であって筐体１８の内部に電力分離フィルタ４１が設けられていること、また電力分離フィルタ４１の出力電力を安定化する電力安定化手段４２が熱遮蔽函１０の外側に設けられている点が異なる。
【００２９】
第１ＲＡ５及び第２ＲＡ１５に電力を供給する方法として、受信信号に直流または低周波電流を重畳して屋内から送出する方法、すなわち、ファントム給電方法も利用できる。この実施例は、第１ＲＡ５及び第２ＲＡ１５への給電方法として、ファントム給電がなされた場合で、出力端子７に接続された伝送線（図示せず）を通じて屋内の受信信号復調手段などが設けられているところから、直流電流または低周波電流が前記伝送線を通し、出力端子７から電力分離フィルタ４１へ供給されている。電力分離フィルタ４１は、受信信号と直流または低周波電流を分離する簡単な分波器で構成される。また、電力安定化手段４２は電力分離フィルタ４１で分離された直流または低周波電流を安定化させるとともに所定の電圧の直流を安定に出力する手段であり、ＤＣ−ＤＣコンバータやスイッチング電源等により構成可能である。このようにすることで、屋内からの電源ケーブルを低減しつつ、かつ高信頼無線受信機を構成することができるという利点がある。なお、本実施例を図４に示したようにアンテナフィーダ２を除去し、アンテナ１を筐体１８に直結した構成に適用してもよい。
【００３０】
図６に示すように、電力安定化手段４２を通してさらに冷却手段１１に動作電力を供給するようにしてもよく（請求項５）、この場合、さらに電源端子を節減することができる。勿論、本実施例を図４に示したようにアンテナフィーダ２を除去し、アンテナ１を筐体１８に直結した構成に適用してもよい。
図７は請求項６による発明の高信頼無線受信機の実施例を示す。この実施例は図１の実施例と比較して熱遮蔽函１０の内部の温度を測定する温度検出手段５１が熱遮蔽函１０の内部に設けられている点が異なる。
【００３１】
制御手段２８は、第１レベル検出手段２６及び第２レベル検出手段２７よりの検出レベルだけでなく、温度検出手段５１で検出された熱遮蔽函１０の内部の温度も監視しつつ、温度検出手段よりの信号があらかじめ設定されたしきい値よりも高くなる場合にも、第１ＳＷ及び第２ＳＷ６を共に実線から点線の位置に切り替えるとともに、冷却障害が発生したことを表す第３警報信号が端子３０を通して送出されるような構成となっている。
【００３２】
以上のような構成をとることにより、熱遮蔽函１０内の温度情報を得、これが所定値以上になる場合にも、予備の受信系統に切り替わるので受信不能という状態を回避することができるとともに、障害発生を表す警報信号を送出することができる。
なお、図７では図１の構成例を基にしているが、図２乃至図６に示す構成例を基にしても同様の効果が得られる。
【００３３】
図８は請求項７による発明の高信頼無線受信機の実施例を示す。この実施例では、図７の実施例と比較して、図８（Ａ）は第１ＲＸＦ４の、図８（Ｂ）は第１ＲＡ５の、図８（Ｃ）は冷却部材１１ａの温度をそれぞれ直接検出する点が異なる。このような構成をとることにより冷却対象である第１ＲＸＦ４，第１ＲＡ５または冷却部材１１ａで発生する温度障害をより正確に検出することができる。
【００３４】
図９に示すように、制御手段２８によって切り替えられる第３信号切替手段（ＳＷ）６１を設け、共通のレベル検出手段２６’によりパイロット信号のレベルを検出してもよく（請求項８）。この場合、さらにレベル検出手段を節減することができる。
なお、図９では図１の実施例を基にしているが、図２乃至図８に示す構成例においても同様の効果が得られる。
【００３５】
また、図示していないが、第１ＲＸＦ４を構成する際、超電導材料として高温超電導体を成分に含む材料を用いることができる（請求項９）。高温超電導体としては、例えば銅酸化物を成分に含む超電導体がある。高温超電導体の中には超電導状態が達成される臨界温度が１００Ｋを超えるものもあり、このような超電導体では、例えば液体窒素の沸点７７．４Ｋ程度に冷却するだけで超電導状態が得られるため、冷却手段１１の冷却能力を緩和できるとともに、より小形で、かつ安価な極低温冷凍機が使用可能となる。その結果、高信頼無線受信機を小形かつ安価に構成することができる。
【００３６】
【発明の効果】
▲１▼ 以上述べたように、この発明では常時パイロット信号を第１ＲＡ５に入力し、その出力レベルを監視することによって、第１ＲＡ５の障害を検出し、予備系に切り替えることができる。
▲２▼ また、温度検出手段１５を熱遮蔽函内に設けて、温度監視することによって冷却手段１１の障害を検出し、予備系に切り替えることができる。
【００３７】
▲３▼ パイロット信号を予備系の第２ＲＡ１５に入力し、その出力レベルを常時監視して正常か否かを検知することにより、信頼性の高い保守を行うことができる。
【図面の簡単な説明】
【図１】請求項１の発明の実施例を示すブロック図。
【図２】請求項２の発明の実施例を示すブロック図。
【図３】請求項３の発明の実施例を示すブロック図。
【図４】請求項１０の発明の実施例を示すブロック図。
【図５】請求項４の発明の実施例を示すブロック図。
【図６】請求項５の発明の実施例を示すブロック図。
【図７】請求項６の発明の実施例を示すブロック図。
【図８】請求項７の発明の実施例を示すブロック図。
【図９】請求項８の発明の実施例を示すブロック図。
【図１０】従来の高感度無線受信機を示すブロック図。
【符号の説明】
１アンテナ
１ａアンテナ結合部材
２アンテナフィーダ
３第１信号切替手段（ＳＷ）
４第１受信帯域フィルタ（ＲＸＦ）
５第１受信低雑音増幅器（ＲＡ）
６第２信号切替手段（ＳＷ）
７出力端子
８，９終端器
１０熱遮蔽函
１１冷却手段
１２第１電源端子
１２’ 共通の電源端子
１３第２電源端子
１４第２受信帯域フィルタ（ＲＸＦ）
１５第２受信低雑音増幅器（ＲＡ）
１６第３電源端子
１７制御端子
１８筐体
２１パイロット信号発生手段
２２第１パイロット信号注入手段
２３第２パイロット信号注入手段
２４第１分配手段
２５第２分配手段
２６第１レベル検出手段
２６’ 共通のレベル検出手段
２７第２レベル検出手段
２８制御手段
２９手動切替手段
３０（警報）端子
３１電源分配手段
４１電力分離フィルタ
４２電力安定化手段
５１温度検出手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-reliability wireless receiver that is applied to a base station receiver such as mobile communication or satellite communication and receives a desired signal by cooling a high-frequency receiver.
[0002]
[Prior art]
FIG. 10 shows a basic configuration of a conventional highly reliable radio receiver. This conventional high-reliability wireless receiver includes an antenna 1, an antenna feeder 2 for transmitting a signal received by the antenna 1, a first switching means (SW) 3 for switching the output of the antenna 2, and a first SW 3 A first reception band filter (RXF) 4 for selecting a signal in a desired band, connected to one side, and a first reception low noise amplifier (RA) 5 for amplifying the output of the first RXF 4 to a desired level with low noise, The second switching means (SW) 6 to which the output signal of the first RA 5 is input to one input terminal, and the output terminal 7 for outputting the signal output from the second SW 6 are provided. Of the terminals of the second SW 6, terminals not connected to the output terminal 7 are terminated by terminators 8 and 9.
[0003]
The first RXF 4 and the first RA 5 are enclosed in the heat shielding box 10, insulated from the outside, and cooled by the cooling means 11. Further, a first power supply terminal 12 for supplying power to the first RA 5 and a second power supply terminal 13 for supplying power to the cooling means 11 are provided. Although not shown here, an isolator may be provided between the first RXF 4 and the first RA 5 in order to achieve matching.
[0004]
A second reception band filter (RXF) 14 connected to the other terminal of the first SW 3 and a second reception low noise amplifier (RA) 15 for amplifying the output signal of the second RXF 14 to a desired level are provided. The output signal of the second RA 15 is input to the other input terminal of the second SW 6. Here, the frequency bands of the second RXF 14 and the second RA 15 are the same as those of the first RXF 4 and the first RA 5. Electric power is supplied to the second RA 15 through the third power supply terminal 16, and the first SW 3 and the second SW 6 are simultaneously switched to the position of the solid line or the dotted line by the control signal input through the control terminal 17. Normally, the first SW 3 and the second SW 6 are also connected as indicated by a solid line. Further, the first SW 3, the heat shielding box 10, the cooling means 11, the second SW 6, the second RXF 14, and the second RA 15 are accommodated in a housing 18.
[0005]
The first RXF 4 and the first RA 5 are sealed in a heat shielding box 10 such as a Dewar bottle, and are stably cooled for a long time to an extremely low temperature of, for example, about several tens K by the cooling member 11a of the cooling means 11. Here, the cooling means 11 is composed of, for example, a cryogenic refrigerator that uses a heat exchange cycle by compression and expansion of helium gas, and these can use commercially available products.
[0006]
As described above, the first RXF 4 and the first RA 5 are stably cooled for a long time, and the thermal noise generated in the first RXF 4 and the first RA 5 is extremely reduced, and the number of stages constituting the first RXF 4 is increased. However, since the loss is small because of the low temperature, the attenuation characteristic can be made steep. As a result, by using the configuration shown in FIG. 10, it is possible to obtain, for example, a reception output having a prescribed C / N ratio (carrier power / noise power) even for a low level reception signal. Further, the transmission power on the transmission side required to obtain the prescribed C / N ratio reception output can be reduced.
[0007]
Next, the operation of this highly reliable radio receiver will be described. When an operation abnormality occurs in the first RA 5, the reception signal transmitted from the output terminal 7 is significantly deteriorated or falls into a state where reception is impossible. Therefore, for example, the received signal from the output terminal 7 is monitored by an indoor device (not shown), and when it is determined that the received signal is significantly degraded or cannot be received, the indoor device passes through the control terminal 17. A control signal is sent, and the first SW 3 and the second SW 6 are switched so as to be in a dotted line state. At this time, the signal from the antenna 1 is supplied to the output terminal 7 through the second RXF 14 and the second RA 15. That is, a signal is received through the second RXF 14 and the second RA 15 that are backup systems of the first RXF 4 and the first RA 5. The second RXF 14 and the second RA 15 are configured not to be cooled, and compared with the first RXF 4 and the first RA 5, there is no noise figure improvement effect due to the cooling, but the configuration can be simplified and inexpensive, and a state where reception is not possible is avoided. It becomes possible.
[0008]
[Problems to be solved by the invention]
In a conventional highly reliable radio receiver, there is a method of detecting an operation abnormality when a failure occurs in the first RA 5 by observing the level of a received signal from the output terminal 7 and determining that the operation is abnormal when the level is lowered. . However, such an operation abnormality detection function depending on the level of the received signal is, for example, in a fixed line where the transmission / reception equipment does not move, because the level of the received signal is constant. However, in mobile communication system base station devices such as mobile phones and mobile phones, the reception signal level changes greatly because the communication partner is constantly moving. There was a problem that it could not be detected due to a decrease in the level of.
[0009]
Further, in the conventional highly reliable radio receiver, not only the failure that occurs in the cooling means 11 cannot be directly detected, but also the second RA 15 that operates as a standby system when a failure occurs in the first RA 5 There is a problem that there is no means for confirming whether it is normal, that is, whether it functions correctly as a standby system.
[0010]
An object of the present invention is to avoid a state in which reception becomes impossible by reliably switching to a standby system when a failure occurs in the first RA 5 or the cooling means 11 of the highly reliable radio receiver, and in the standby system. An object of the present invention is to provide a highly reliable radio receiver capable of monitoring the operation of a second RA 15.
[0011]
[Means for Solving the Problems]
(1) The invention of claim 1 is connected to one of an antenna, an antenna feeder, a first signal switching means to which a signal from the antenna feeder is inputted and switched by a control signal, and the first signal switching means. The first reception band filter, the first reception low noise amplifier connected to the first reception band filter, and the second signal switching means provided on the output side of the first reception low noise amplifier and switched by the control signal And an output terminal for outputting an output signal from the second signal switching means, a second reception band filter connected to the other connection terminal of the first signal switching means, and a second reception band filter. And a second reception low noise amplifier connected to the other connection terminal of the second signal switching means, wherein the first reception band filter and the first reception low noise amplifier are enclosed in a heat shielding box. It is cooled by the cooling means, first receiving a low-noise amplifier, the first respectively the cooling means and the second reception low noise amplifier, to a high radio receiver operating power through the second and third power terminal is supplied.
[0012]
The pilot signal generating means for generating a pilot signal having a frequency within the attenuation band of the first and second reception band filters and a path between the first reception band filter and the first reception low noise amplifier according to claim 1 First pilot signal injection means, second pilot signal injection means inserted in a path between the second reception bandpass filter and the second reception low noise amplifier, the output side of the first reception low noise amplifier, and the second First distribution means inserted between the two signal switching means and outside the heat shielding box; and second distribution means inserted between the output side of the second receiving low noise amplifier and the second signal switching means. And are provided.
[0013]
A first level detecting means for detecting the level of the pilot signal from the signal distributed by the first distributing means; a second level detecting means for detecting the level of the pilot signal from the signal distributed by the second distributing means; The pilot signal level detected by the first level detection means is compared with a preset threshold value, and the first and second signal switching means are switched when the pilot signal level is lower than the threshold value. And a first warning signal is sent, the level of the pilot signal detected by the second level detecting means is compared with a threshold value, and if the pilot signal level is lower than the threshold value, the second warning signal is sent. And a manual switching means for manually switching the first and second signal switching means within the control means.
[0014]
The first reception band filter is made of a superconducting material and is in a superconducting state by a cooling means.
(2) In the invention of claim 2, in (1) above, a common power supply terminal is provided in place of the first and third power supply terminals, and the power supplied from the common power supply terminal is distributed by the power distribution means. To the first and second receiving low noise amplifiers.
[0015]
(3) In the invention of claim 3, the second power supply terminal of (2) is deleted, and operating power is supplied from the power distribution means to the cooling means.
(4) In the invention of claim 4, in the above (1), the first and third power supply terminals are deleted, inserted between the second signal switching means and the output terminal, and supplied via the output terminal. A power separation filter that separates the operating power from the high-frequency received signal and a power stabilization unit that stabilizes the power separated by the power separation filter and supplies the power to the first and second reception low noise amplifiers are provided.
[0016]
(5) In the invention of claim 5, in the above (4), the second power supply terminal is deleted, and the operating power is supplied from the power stabilizing means to the cooling means.
(6) In the invention of claim 6, in any one of the above (1) to (5), a temperature detecting means for detecting the temperature in the heat shielding box is provided, and the control means is controlled by the temperature detecting means. When the temperature information is equal to or higher than a predetermined temperature, the first and second signal switching means are switched and a third alarm signal is transmitted.
[0017]
(7) In the invention of claim 7, in the above (6), the temperature detecting means detects the temperature of the cooling member of the first receiving band filter, the first receiving low noise amplifier or the cooling means in the heat shielding box.
(8) In the invention of claim 8, in any of the above (1) to (7), a common level detecting means is provided instead of the first and second level detecting means, and the first and second distributing means are provided. There is provided third signal switching means for switching the above signals and supplying them to the common level detection means.
[0018]
(9) In the invention of claim 9, in any of the above (1) to (7), the superconducting material is composed of a high-temperature superconductor.
(10) In the invention of claim 10, in any of the above (1) to (7), the antenna feeder is omitted, and the antenna is directly connected to the apparatus housing.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the invention of claim 1 is shown in FIG. 1 with the same reference numerals given to the portions corresponding to FIG. In this embodiment, a pilot signal generating means 21 for generating a pilot signal within the range of the attenuation band of the first RXF 4 and the second RXF 14 is provided outside the heat shielding box 10, and the pilot signal generated by the pilot signal generating means 21 is First pilot signal injection means 22 and second pilot signal injection means 23 for injection between the first RXF 4 and the first RA 5 and between the first RXF 14 and the second RA 15 are provided. A first distribution unit 24 is provided between the first RA 5 and the second SW 6, and a second distribution unit 25 is provided between the second RA 15 and the second SW 6. Furthermore, a first level detection means 26 and a second level detection means 27 are provided for detecting the pilot signal level from the signals distributed by the first distribution means 24 and the second distribution means 25, respectively.
[0020]
Output signals from the first level detection means 26 and the second level detection means 27 are input to the control means 28. Further, the control means 28 is provided with a manual switching means 29 for manually switching the first SW 3 and the second SW 6. The pilot signal generating means 21, the first distributing means 24, the second distributing means 25, the first level detecting means 26, the second level detecting means 27 and the control means 28 are accommodated in one housing 18.
[0021]
The first RXF 4 is composed of a superconducting material, and is different from FIG. 10 in that the superconducting material is brought into a superconducting state by cooling by the cooling means 11.
As the first level detection means 26 and the second level detection means 27, a selection level meter or the like can be used.
The control means 28 is composed of a reference voltage generating means for generating a preset threshold voltage and a comparator or the like, or a microprocessor, A / D converter, ROM, RAM, D / A as a basic circuit. It is composed of a converter or the like, and in any configuration, the signals from the first level detection means 26 and the second level detection means 27 are monitored and compared with a preset threshold value. When it is low, it has a function of switching the first SW 3 and the second SW 6 and / or sending a predetermined alarm signal.
[0022]
The first RXF 4 is constituted by, for example, a microstrip line, and both the ground layer and the signal line constituting the microstrip line are constituted by a superconducting material, and these are brought into a superconducting state by cooling by the cooling unit 11, The thermal noise generated in 1RXF4 is significantly less, thus improving the noise figure of the receiver.
[0023]
Next, the operation of this embodiment will be described. The pilot signal generated by the pilot signal generation means 21 is injected by the first pilot signal injection means 22. At this time, since the frequency of the pilot signal is set to be within the attenuation band of the first RXF 4, the injected pilot signal is reflected by the first RXF 4 and input to the first RA 5, so that the pilot signal is radiated from the antenna 1. Never worry about disturbing other systems. The received signal to which the pilot signal is added is amplified by the first RA 5 and then distributed by the first distribution means 24, and the level of the injected pilot signal is detected by the first level detection means 26. When the level of the detected pilot signal is monitored by the control means 28 and is lower than a preset threshold value, the first SW 3 and the second SW 6 are switched from the solid line position to the dotted line position, respectively. A first alarm signal indicating that a failure has occurred in the 1RA5 system is output through the terminal 30.
[0024]
On the other hand, the pilot signal is injected by the second pilot signal injection means 23 in the same manner as the first pilot signal injection means, amplified by the second RA 15, then distributed by the second distribution means 25, and also by the second level detection means 27. The level of the injected pilot signal is detected. The level of the detected pilot signal is monitored by the control means 28, and when the level is lower than a preset threshold value, a second alarm signal indicating that a failure has occurred in the system of the second RA 15 is output through the terminal 30. Is done.
[0025]
Further, a manual switching means 29 is provided together with the control means 28 so that the first SW 3 and the second SW 6 can be manually switched, and the maintenance person operates the manual switching means 29 during maintenance / inspection. Thus, the second RXF 14 and the second RA 15 which are standby systems can be manually switched.
As described above, by using a pilot signal independent of the received signal and comparing the pilot signal level with a preset threshold value, it is possible to reliably detect an abnormal operation of the first RA5 and the second RA15. An alarm signal indicating the occurrence of a failure can be transmitted. As a result, the control unit 28 or the maintenance person operates the manual switching unit 29 to switch to the standby system, so that it is possible to avoid a state in which reception is not possible even when the operation of the first RA 5 is abnormal or during maintenance / inspection. .
[0026]
In FIG. 1, an example in which the first pilot signal injection unit 22 is not cooled by the cooling unit 11 is described, but the first pilot signal injection unit 22 may be cooled by the cooling unit 11.
As shown in FIG. 2, the operating power may be supplied to each of the first RA 5 and the second RA 15 through the common power terminal 12 ′ and the power distribution means 31. In this case, the power terminal is saved. can do.
[0027]
As shown in FIG. 3, operating power may be supplied to each of the cooling means 11 in addition to the first RA 5 and the second RA 15 through the common power terminal 12 ′ and the power distribution means 31 (Claim 3). In this case, power supply terminals can be further saved.
As shown in FIG. 4, the antenna 1 may be directly connected to the housing 18 without the antenna feeder 2 (Claim 10). By removing the antenna feeder 2 in this way, the loss of the antenna feeder 2 can be reduced. As a result, the noise figure of the entire receiver can be improved, so that the reception sensitivity is further improved. FIG. 4 is based on the embodiment of FIG. 1, but of course can also be applied to the embodiments of FIGS.
[0028]
FIG. 5 shows an embodiment of a highly reliable radio receiver according to the invention of claim 4. In the present invention, in place of the first power supply terminal 12 and the third power supply terminal 16, the power separation filter 41 is provided between the second SW 6 and the output terminal 7 and inside the housing 18 as compared with the embodiment of FIG. And a power stabilizing means 42 for stabilizing the output power of the power separation filter 41 is provided outside the heat shielding box 10.
[0029]
As a method for supplying power to the first RA 5 and the second RA 15, a method of superimposing a direct current or a low frequency current on a received signal and transmitting the signal from the indoor, that is, a phantom power feeding method can also be used. In this embodiment, as a method of feeding power to the first RA 5 and the second RA 15, when phantom power feeding is performed, an indoor received signal demodulating means is provided through a transmission line (not shown) connected to the output terminal 7. Therefore, a direct current or a low frequency current is supplied from the output terminal 7 to the power separation filter 41 through the transmission line. The power separation filter 41 is configured by a simple duplexer that separates a received signal from a direct current or low frequency current. The power stabilizing means 42 is means for stabilizing the direct current or low frequency current separated by the power separation filter 41 and stably outputting a direct current of a predetermined voltage, and is constituted by a DC-DC converter, a switching power supply, or the like. Is possible. By doing in this way, there exists an advantage that a highly reliable radio | wireless receiver can be comprised, reducing the power cable from an indoor. The present embodiment may be applied to a configuration in which the antenna feeder 2 is removed and the antenna 1 is directly connected to the housing 18 as shown in FIG.
[0030]
As shown in FIG. 6, operating power may be further supplied to the cooling means 11 through the power stabilizing means 42 (Claim 5), and in this case, the power supply terminal can be further reduced. Of course, this embodiment may be applied to a configuration in which the antenna feeder 2 is removed and the antenna 1 is directly connected to the housing 18 as shown in FIG.
FIG. 7 shows an embodiment of the highly reliable radio receiver of the invention according to claim 6. This embodiment is different from the embodiment of FIG. 1 in that temperature detecting means 51 for measuring the temperature inside the heat shielding box 10 is provided inside the heat shielding box 10.
[0031]
The control means 28 monitors not only the detection levels from the first level detection means 26 and the second level detection means 27 but also the temperature inside the heat shielding box 10 detected by the temperature detection means 51, while detecting the temperature. Even when the above signal becomes higher than a preset threshold value, both the first SW and the second SW 6 are switched from the solid line to the dotted line position, and a third alarm signal indicating that a cooling failure has occurred is displayed on the terminal 30. It is configured to be sent through.
[0032]
By taking the configuration as described above, temperature information in the heat shielding box 10 is obtained, and even when this is a predetermined value or more, it is possible to avoid a state where reception is not possible because it is switched to a spare reception system, An alarm signal indicating the occurrence of a failure can be transmitted.
Although FIG. 7 is based on the configuration example of FIG. 1, similar effects can be obtained based on the configuration examples shown in FIGS.
[0033]
FIG. 8 shows an embodiment of the highly reliable radio receiver according to the invention. In this embodiment, compared with the embodiment of FIG. 7, FIG. 8A directly detects the temperature of the first RXF 4, FIG. 8B directly detects the temperature of the first RA 5, and FIG. 8C directly detects the temperature of the cooling member 11a. The point to do is different. By adopting such a configuration, it is possible to more accurately detect a temperature failure that occurs in the first RXF4, the first RA5, or the cooling member 11a that is a cooling target.
[0034]
As shown in FIG. 9, third signal switching means (SW) 61 that is switched by the control means 28 may be provided, and the level of the pilot signal may be detected by the common level detecting means 26 ′. In this case, the level detection means can be further saved.
Although FIG. 9 is based on the embodiment of FIG. 1, similar effects can be obtained in the configuration examples shown in FIGS.
[0035]
Although not shown, when the first RXF 4 is configured, a material containing a high-temperature superconductor as a component can be used as a superconducting material (claim 9). An example of the high-temperature superconductor is a superconductor containing copper oxide as a component. Some high-temperature superconductors have a critical temperature exceeding 100 K at which a superconducting state is achieved, and in such a superconductor, a superconducting state can be obtained simply by cooling to a boiling point of about 77.4 K of liquid nitrogen, for example. The cooling capacity of the cooling means 11 can be reduced, and a smaller and cheaper cryogenic refrigerator can be used. As a result, a highly reliable wireless receiver can be configured in a small size and at low cost.
[0036]
【The invention's effect】
(1) As described above, according to the present invention, by constantly inputting a pilot signal to the first RA 5 and monitoring its output level, the failure of the first RA 5 can be detected and switched to the standby system.
{Circle around (2)} The temperature detecting means 15 is provided in the heat shielding box, and the temperature of the cooling means 11 can be detected by monitoring the temperature, and the system can be switched to the standby system.
[0037]
(3) Highly reliable maintenance can be performed by inputting a pilot signal to the second RA 15 of the standby system and constantly monitoring its output level to detect whether it is normal or not.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of the invention of claim 1;
FIG. 2 is a block diagram showing an embodiment of the invention of claim 2;
FIG. 3 is a block diagram showing an embodiment of the invention of claim 3;
FIG. 4 is a block diagram showing an embodiment of the invention of claim 10;
FIG. 5 is a block diagram showing an embodiment of the invention of claim 4;
6 is a block diagram showing an embodiment of the invention of claim 5. FIG.
FIG. 7 is a block diagram showing an embodiment of the invention of claim 6;
FIG. 8 is a block diagram showing an embodiment of the invention of claim 7;
FIG. 9 is a block diagram showing an embodiment of the invention of claim 8;
FIG. 10 is a block diagram showing a conventional high sensitivity wireless receiver.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Antenna 1a Antenna coupling member 2 Antenna feeder 3 1st signal switching means (SW)
4 First reception band filter (RXF)
5 First receiver low noise amplifier (RA)
6 Second signal switching means (SW)
7 Output terminals 8 and 9 Terminator 10 Heat shielding box 11 Cooling means 12 First power terminal 12 ′ Common power terminal 13 Second power terminal 14 Second reception band filter (RXF)
15 Second receiving low noise amplifier (RA)
16 Third power supply terminal 17 Control terminal 18 Housing 21 Pilot signal generating means 22 First pilot signal injecting means 23 Second pilot signal injecting means 24 First distributing means 25 Second distributing means 26 First level detecting means 26 'Common Level detection means 27 Second level detection means 28 Control means 29 Manual switching means 30 (alarm) terminal 31 Power distribution means 41 Power separation filter 42 Power stabilization means 51 Temperature detection means

Claims

An antenna, an antenna feeder, a first signal switching means that receives a signal from the antenna feeder and is switched by a control signal, a first reception band filter connected to one of the first signal switching means, and a first A first reception low noise amplifier connected to one reception band filter, a second signal switching means provided on the output side of the first reception low noise amplifier and switched by a control signal, and a second signal switching means An output terminal for outputting an output signal; a second reception band filter connected to the other connection terminal of the first signal switching means; and a second reception band filter connected to the second reception band filter. A second reception low noise amplifier connected to one of the connection terminals, and the first reception band filter and the first reception low noise amplifier are enclosed in a heat shielding box and cooled. Is cooled by said first receiver low noise amplifier, the cooling means and the second receiving low noise amplifier to the first, respectively, high radio receiver operating power through the second and third power terminal is supplied,
Pilot signal generating means for generating a pilot signal having a frequency within the attenuation band of the first and second reception band filters;
First pilot signal injection means inserted in a path between the first reception bandpass filter and the first reception low noise amplifier;
Second pilot signal injection means inserted in a path between the second reception band filter and the second reception low noise amplifier;
First distribution means inserted between the output side of the first reception low noise amplifier and the second signal switching means and outside the heat shielding box;
Second distribution means inserted between the output side of the second reception low noise amplifier and the second signal switching means;
First level detection means for detecting the level of the pilot signal from the signal distributed by the first distribution means;
Second level detection means for detecting the level of the pilot signal from the signal distributed by the second distribution means;
The pilot signal level detected by the first level detection means is compared with a preset threshold value. When the pilot signal level is lower than the threshold value, the first and second levels are detected. The signal switching means is switched and the first alarm signal is sent, and the pilot signal level detected by the second level detection means is compared with the threshold value, and the pilot signal level is set to the threshold value. Control means for sending a second alarm signal when lower than the value;
Manual switching means for manually switching the first and second signal switching means provided in the control means,
The high-reliability wireless receiver, wherein the first reception band filter is made of a superconducting material and is in a superconducting state by the cooling means.

2. A common power supply terminal is provided in place of the first and third power supply terminals, and power supplied from the common power supply terminal is supplied to the first and second reception low noise amplifiers by power distribution means. A highly reliable wireless receiver.

3. The highly reliable wireless receiver according to claim 2, wherein the second power supply terminal is deleted, and operating power is supplied from the power distribution means to the cooling means.

In claim 1, the first and third power supply terminals are deleted,
A power separation filter that is inserted between the second signal switching means and the output terminal and separates operating power supplied via the output terminal from a high-frequency received signal;
A highly reliable radio receiver comprising power stabilizing means for stabilizing the power separated by the power separation filter and supplying the power to the first and second reception low noise amplifiers.

5. The highly reliable radio receiver according to claim 4, wherein the second power supply terminal is deleted and operating power is supplied from the power stabilizing means to the cooling means.

In any one of Claims 1 thru | or 5, the temperature detection means to detect the temperature in the said heat shielding box is provided,
The control means obtains temperature information in the heat shield box by the temperature detection means, and switches the first and second signal switching means when the temperature information is equal to or higher than a predetermined temperature, and a third alarm. A highly reliable wireless receiver characterized by transmitting a signal.

7. A highly reliable radio receiver according to claim 6, wherein said temperature detecting means detects a temperature of a cooling member of said first reception band filter, first reception low noise amplifier or cooling means in said heat shielding box. .

8. The highly reliable wireless receiver according to claim 1, wherein a common level detecting means is provided in place of the first and second level detecting means, and signals from the first and second distributing means are switched. And a third signal switching means for supplying to the common level detecting means.

8. The highly reliable radio receiver according to claim 1, wherein the superconducting material is composed of a high temperature superconductor.

8. The high-reliability wireless receiver according to claim 1, wherein the antenna feeder is omitted and the antenna is directly connected to a device housing.