JPH11331177A - Spatial optical transmission equipment - Google Patents
Spatial optical transmission equipmentInfo
- Publication number
- JPH11331177A JPH11331177A JP12792898A JP12792898A JPH11331177A JP H11331177 A JPH11331177 A JP H11331177A JP 12792898 A JP12792898 A JP 12792898A JP 12792898 A JP12792898 A JP 12792898A JP H11331177 A JPH11331177 A JP H11331177A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- collision
- master station
- station
- transmission
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Small-Scale Networks (AREA)
- Mobile Radio Communication Systems (AREA)
- Optical Communication System (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、空間に放射した光
によりデータを伝送するＬＡＮ（local area network）
等に好適な空間光伝送装置に関し、特に、複数局間にお
ける送信信号の衝突の検知（Collision Detection ）
と、その後の回避処理を適正に行なうことができる空間
光伝送装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a LAN (local area network) for transmitting data by light emitted to a space.
The present invention relates to a spatial light transmission device suitable for, for example, collision detection of transmission signals between a plurality of stations (Collision Detection).
And a spatial light transmission device capable of appropriately performing the subsequent avoidance processing.
【０００２】[0002]
【従来の技術】従来、オフィスや工場内でＬＡＮを構築
する場合、空間に放射された光によりデータを伝送する
空間光伝送装置を使用して、各端末装置を結び、伝送ケ
ーブルの使用を最小限にしてＬＡＮ等を構築する技術
が、特開平６−１３２９０２号公報等で提案されてい
る。2. Description of the Related Art Conventionally, when a LAN is constructed in an office or a factory, a spatial light transmission device for transmitting data by light radiated into the space is used to connect each terminal device, and the use of a transmission cable is minimized. A technique for constructing a LAN or the like with a minimum is proposed in JP-A-6-132902 or the like.
【０００３】この種のＬＡＮ等に使用される空間光伝送
装置は、１台の親局に対し複数の子局との間でデータの
送信を行なう場合があり、このようなシステムにおいて
は、複数の子局から親局に向けて同時に送信動作を行な
った場合、それらの送信信号に衝突（Collision ）が発
生し、送信データが破壊されてしまう。A spatial light transmission device used for such a LAN or the like sometimes transmits data to a plurality of slave stations with respect to one master station. If the transmission operation is performed simultaneously from the slave station to the master station, a collision occurs in those transmission signals, and the transmission data is destroyed.
【０００４】このために、図６（ａ）に示すように、親
局３０は、子局３１からの送信信号ＴＤＡを受信する
と、その信号をリピート信号ＲＤＡとして、同様に、子
局３２からの送信信号ＴＤＢを受信すると、その信号を
リピート信号ＲＤＢとして、全子局３１、３２に送り返
す。このとき、各々の子局３１、３２は、リピート信号
ＲＤＡと送信信号ＴＤＡまたはリピート信号ＲＤＢと送
信信号ＴＤＢとを比較し、不一致の場合、信号の衝突が
発生したとして、データの送信を一時中止する。[0006] To this end, as shown in FIG. 6 (a), when the master station 30 receives the transmission signal TDA from the slave station 31, the master station 30 uses the signal as a repeat signal RDA and similarly sends the signal from the slave station 32. When receiving the transmission signal TDB, the transmission signal TDB is sent back to all the slave stations 31 and 32 as a repeat signal RDB. At this time, each of the slave stations 31 and 32 compares the repeat signal RDA with the transmission signal TDA or the repeat signal RDB and the transmission signal TDB. I do.
【０００５】例えば、子局３１と子局３２から親局３０
に向けて同時に光信号ＰＡ、ＰＢが送信された場合、親
局３０の受信信号は、図７（ａ）に示すように、それら
を加算した合成信号波形となり、信号の衝突が発生し、
その信号から得られる論理値データは、両光信号ＰＡ、
ＰＢに対応したデータとは相違したものとなるから、親
局３０から送られる各々のリピート信号は両光信号Ｐ
Ａ、ＰＢに対応した信号とは異なる。[0005] For example, a slave station 31 and a slave station 32
When the optical signals PA and PB are transmitted at the same time, the received signal of the master station 30 has a combined signal waveform obtained by adding them as shown in FIG.
The logical value data obtained from the signal is the two optical signals PA,
Since the data is different from the data corresponding to PB, each repeat signal sent from the master station 30 is
Different from signals corresponding to A and PB.
【０００６】このため、リピート信号を受信しその信号
と送信信号を比較した子局３１、３２は、信号の衝突と
判断して、データの送信を一時中止し、再び送信動作を
繰り返すように動作する。これによって、子局３１と子
局３２は、時間をずらしてデータ送信を行なうように
し、信号の衝突（Collision ）を回避し、送信データを
安全に送信するようにしている。For this reason, the slave stations 31 and 32, which have received the repeat signal and compared the signal with the transmission signal, determine that there is a signal collision, suspend the data transmission, and repeat the transmission operation again. I do. As a result, the slave station 31 and the slave station 32 transmit data at staggered times, avoid collision of signals, and transmit the transmission data safely.
【０００７】[0007]
【発明が解決しようとする課題】しかし、図６（ｂ）に
示すように、親局３０と子局３１間の距離と親局３０と
子局３３間の距離が大きく相違している場合、近い距離
にある親局３０と子局３１の伝送は、光信号の強度が十
分に高いため、遠い距離にあり光信号の強度の低い親局
３０と子局３３間の伝送の影響を受けない。このため
に、近い距離にある子局３１は、信号の衝突処理を行な
わずに送信データを送り続ける。これに対し、遠い距離
にある子局３３は、子局３１と同時に送信動作を行なっ
た場合、子局３１が信号の衝突を検知せずに送信データ
を送り続けるため、子局３３は信号の衝突を回避でき
ず、上記のような信号の衝突処理を繰り返すことにな
る。However, as shown in FIG. 6 (b), when the distance between the master station 30 and the slave station 31 and the distance between the master station 30 and the slave station 33 are greatly different, The transmission between the master station 30 and the slave station 31 located at a short distance is not affected by the transmission between the master station 30 and the slave station 33 located at a far distance and having a low optical signal strength because the optical signal strength is sufficiently high. . For this reason, the slave station 31 located at a short distance keeps sending the transmission data without performing the signal collision processing. On the other hand, if the slave station 33 at a long distance performs a transmission operation simultaneously with the slave station 31, the slave station 31 continues to send transmission data without detecting a signal collision. The collision cannot be avoided, and the above-described signal collision processing is repeated.
【０００８】即ち、図６（ｂ）に示すように、子局３１
と子局３３から親局３０に向けて各々送信信号ＴＤＡ、
ＴＤＢが送信された場合、子局３３の距離がより離れて
いるため、親局３０に届く光信号ＰＢの強度は、図７
（ｂ）のように低下し、距離の短い子局３１から親局３
０に届く光信号ＰＡの強度はそれ程低下しない。That is, as shown in FIG.
And the transmission signal TDA from the slave station 33 to the master station 30,
When the TDB is transmitted, the strength of the optical signal PB reaching the master station 30 is smaller than that of the slave station 33 because the distance of the slave station 33 is farther.
As shown in (b), the distance from the slave station 31 to the master station 3 is short.
The intensity of the optical signal PA reaching 0 does not decrease so much.
【０００９】また、親局３０の受信信号は、図７（ｂ）
のように、両光信号ＰＡ、ＰＢを加算した合成信号とな
るが、その受信信号から論理入力信号を取り出す際のコ
ンパレータの閾値は、通常、中間部に設定され、ヒステ
リシスを持ってコンパレートされるため、その受信信号
から得られる論理入力信号は、強度の低い光信号ＰＢと
は相違するが、強度の高い光信号ＰＡと同じになってし
まう。The received signal of the master station 30 is shown in FIG.
As shown in the above, the combined signal is obtained by adding the two optical signals PA and PB, but the threshold value of the comparator when extracting the logical input signal from the received signal is usually set to the middle part, and is compared with the hysteresis. Therefore, the logic input signal obtained from the received signal is different from the low-intensity optical signal PB, but becomes the same as the high-intensity optical signal PA.
【００１０】このため、親局３０から子局３１に送られ
るリピート信号は送信信号ＴＤＡと同じものとなり、親
局３０から子局３３に送られるリピート信号は送信信号
ＴＤＢと相違したものとなる。つまり子局３３は信号の
衝突を検知するが、子局３１は信号の衝突を検知できな
いために、信号の衝突処理を行なわずに送信データを送
り続ける。Therefore, the repeat signal sent from the master station 30 to the slave station 31 is the same as the transmission signal TDA, and the repeat signal sent from the master station 30 to the slave station 33 is different from the transmission signal TDB. That is, although the slave station 33 detects the collision of the signal, the slave station 31 cannot detect the collision of the signal, and therefore continuously transmits the transmission data without performing the collision processing of the signal.
【００１１】従って、子局３３は、子局３１と同時に送
信動作を行なった場合、子局３１が信号の衝突を検知せ
ずに送信データを送り続けるため、子局３３は信号の衝
突を回避できず、信号の衝突処理を繰り返す、つまり、
送信を一時停止し、ランダムな時間経過後、再度送信動
作を行なうように、信号の衝突処理を繰り返すことか
ら、子局３３の親局３０へのデータ伝送速度が、子局３
１に比べ、大幅に低下する問題があった。Therefore, when the slave station 33 performs a transmission operation simultaneously with the slave station 31, the slave station 31 keeps transmitting data without detecting a signal collision. I can't do that and repeat the signal collision process,
The transmission of the signal is temporarily stopped, and after a random time elapses, the signal collision processing is repeated so that the transmission operation is performed again.
There was a problem that it was greatly reduced as compared with 1.
【００１２】本発明は、上記の点に鑑みてなされたもの
で、親局と複数の子局間で空間光伝送により信号を伝送
する場合、各子局と親局間の各距離が相違している時で
も、各子局が同時伝送時の信号の衝突を確実に認識し、
信号の衝突回避処理を実施して、各子局が信号を効率よ
く送信することができる空間光伝送装置を提供すること
を目的とする。The present invention has been made in view of the above points, and when signals are transmitted by spatial light transmission between a master station and a plurality of slave stations, the distances between the slave stations and the master station are different. Even when the slave station, each station securely recognizes signal collision at the time of simultaneous transmission,
It is an object of the present invention to provide a spatial light transmission device capable of performing signal collision avoidance processing and enabling each slave station to transmit a signal efficiently.
【００１３】[0013]
【課題を解決するための手段】上記目的を達成するため
に、本発明の空間光伝送装置は、図１に示すように、親
局１と複数の子局２、３間で空間に放射した光により信
号を伝送する空間光伝送装置において、親局１には、子
局２、３から信号が送られた時、その信号を認識しリピ
ート信号として子局２、３に送信するリピート信号送信
手段Ｋ１が設けられ、子局２、３には、親局１に送った
信号とリピート信号とを比較して相違する時、信号の衝
突と判断する衝突判定手段Ｋ２と、衝突判定手段Ｋ２に
よって信号の衝突が検知された時、信号の送信を中止
し、通常より強い強度の光信号を衝突検知信号として親
局１に送信する衝突検知信号送信手段Ｋ３と、が設けら
れたことを特徴とする。In order to achieve the above object, a spatial light transmission apparatus according to the present invention radiates a space between a master station 1 and a plurality of slave stations 2 and 3 as shown in FIG. In a spatial light transmission device for transmitting a signal by light, when a signal is sent from a slave station 2 or 3 to a master station 1, a repeat signal transmission for recognizing the signal and transmitting the signal as a repeat signal to the slave stations 2 and 3 is performed. Means K1 are provided. The slave stations 2 and 3 compare the signal sent to the master station 1 with the repeat signal, and when they differ from each other, a collision determining means K2 for determining a signal collision and a collision determining means K2. And a collision detection signal transmission unit K3 for stopping transmission of the signal when a collision of the signal is detected and transmitting an optical signal having a stronger intensity than normal to the master station 1 as a collision detection signal. I do.
【００１４】[0014]
【発明の作用・効果】上記空間光伝送装置では、子局２
または子局３から親局１に対し空間光を用いて信号を送
信すると、親局１は、リピート信号送信手段Ｋ１が、そ
の信号を認識しリピート信号として子局２、３に送信す
るが、子局２と子局３の送信が同時に行なわれた場合、
親局の受信時において信号の衝突が発生する。In the above spatial light transmission device, the slave station 2
Alternatively, when a signal is transmitted from the slave station 3 to the master station 1 using spatial light, the master station 1 recognizes the signal and transmits the signal to the slave stations 2 and 3 as a repeat signal. When the transmissions of the slave stations 2 and 3 are performed simultaneously,
Signal collision occurs at the time of reception at the master station.
【００１５】このとき、例えば子局３と親局１間の距離
が子局２と親局１間の距離より大きく離れている場合、
親局１から子局３には衝突によって破壊したリピート信
号が送信され、子局３の衝突判定手段Ｋ２は、送信信号
とリピート信号とを比較し、両信号が相違するため、信
号の衝突と判断するが、親局１から子局２には送信信号
と一致したリピート信号が送られるため、子局２は信号
の衝突を検知することができず、信号を送り続ける。At this time, for example, when the distance between the slave station 3 and the master station 1 is larger than the distance between the slave station 2 and the master station 1,
The repeat signal destroyed by the collision is transmitted from the master station 1 to the slave station 3, and the collision determination means K2 of the slave station 3 compares the transmission signal and the repeat signal. It is determined that the repeat signal matching the transmission signal is sent from the master station 1 to the slave station 2, so that the slave station 2 cannot detect the collision of the signal and continues to send the signal.
【００１６】しかし、子局３では衝突検知信号送信手段
Ｋ３が、信号の衝突を検知した際、通常より強い強度の
光信号を衝突検知信号として親局１に送信する。このた
め、親局１では、この衝突検知信号によって子局２から
の送信信号が破壊され、親局１から子局２に送信される
リピート信号が送信信号とは相違した信号となり、或は
リピート信号の送信が停止される。これにより子局２の
衝突判定手段Ｋ２は信号の衝突を確実に検知し、子局２
は信号の送信を一時中止して、信号衝突時の処理を行な
うから、子局２、３双方が信号の衝突を回避しながら、
遅滞なくデータ送信を実行することができる。However, in the slave station 3, when the collision detection signal transmitting means K3 detects a signal collision, it transmits an optical signal having a stronger intensity than normal to the master station 1 as a collision detection signal. Therefore, in the master station 1, the transmission signal from the slave station 2 is destroyed by the collision detection signal, and the repeat signal transmitted from the master station 1 to the slave station 2 becomes a signal different from the transmission signal, or The transmission of the signal is stopped. As a result, the collision determination means K2 of the slave station 2 reliably detects the signal collision, and
Suspends signal transmission and performs signal collision processing, so that both the slave stations 2 and 3 avoid signal collisions,
Data transmission can be performed without delay.
【００１７】[0017]
【発明の実施の形態】以下、本発明の実施の形態を図面
に基づいて説明する。図２は空間光伝送装置のシステム
接続図を示し、図３は空間光伝送装置の子局２、３のブ
ロック図を示している。Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a system connection diagram of the spatial light transmission device, and FIG. 3 is a block diagram of slave stations 2 and 3 of the spatial light transmission device.
【００１８】このシステムは、有線（幹線）ＬＡＮと接
続される親局１と、有線ＬＡＮを介して端末装置４、５
に接続される子局２、３とからなり、親局１と各子局
２、３間で空間光を用いた双方向通信により信号を伝送
するように構成される。空間光伝送装置の親局１と子局
２、３は、例えば薄型のケース内に、投光部、受光部を
配設すると共に、その前面の開口部に板状の近赤外線透
過フィルタを配設し、送信回路、受信回路、デジタル処
理回路等を内蔵して構成される。投光部は複数の発光ダ
イオード等からなる投光素子を有し、受光部にはフォト
ダイオード等からなる受光素子が配設される。また、親
局１には、子局２又は子局３からデータ信号が送られた
時、データ信号を認識し、そのデータ信号をリピート信
号として子局２又は３に送信するリピート信号送信回路
が設けられる。This system comprises a master station 1 connected to a wired (trunk) LAN, and terminal devices 4 and 5 connected via a wired LAN.
, And is configured to transmit a signal between the master station 1 and each of the slave stations 2 and 3 by bidirectional communication using spatial light. The master station 1 and the slave stations 2 and 3 of the spatial light transmission device are provided with, for example, a light projecting unit and a light receiving unit in a thin case, and a plate-like near-infrared transmitting filter is arranged in an opening on the front surface thereof. And a transmission circuit, a reception circuit, a digital processing circuit, and the like. The light projecting unit has a light projecting element composed of a plurality of light emitting diodes and the like, and the light receiving unit is provided with a light receiving element composed of a photodiode and the like. When a data signal is sent from the slave station 2 or the slave station 3, the master station 1 has a repeat signal transmitting circuit that recognizes the data signal and transmits the data signal to the slave station 2 or 3 as a repeat signal. Provided.
【００１９】空間光伝送装置の子局は、図３のブロック
図に示すように、例えばベースバンド方式の送信回路と
受信回路を備えて構成され、送信信号と親局１側から戻
されたリピート信号とを比較し、両信号が相違していた
場合、信号の衝突が発生したとして衝突検知信号を発生
する回路等を有している。デジタル処理回路１０は、イ
ンターフェイス９を介して端末装置４、５に送出する信
号のデジタル処理、端末装置から取り込まれる信号のデ
ジタル処理などを行う。As shown in the block diagram of FIG. 3, the slave station of the free-space optical transmission apparatus is provided with, for example, a transmission circuit and a reception circuit of a baseband system, and transmits a transmission signal and a repeat returned from the master station 1 side. There is provided a circuit for comparing the signals with each other and, when the two signals are different from each other, generating a collision detection signal assuming that a signal collision has occurred. The digital processing circuit 10 performs digital processing of signals transmitted to the terminal devices 4 and 5 via the interface 9, digital processing of signals fetched from the terminal devices, and the like.
【００２０】具体的には、デジタル処理回路１０は、イ
ンターフェイス９入力したＬＡＮ用の符号化データ信号
を復号化し、デジタル信号の１、０に対応した符号化信
号、つまり一つの符号の中間点で電圧反転部を設けるよ
うに符号化された光通信用のマンチェスタ符号化信号に
変換し、その信号を投光駆動部１２に送り、投光駆動部
１２がその信号に基づき投光素子６を駆動する。More specifically, the digital processing circuit 10 decodes the LAN encoded data signal input to the interface 9 and encodes the encoded signal corresponding to the digital signal 1 or 0, that is, the intermediate point of one code. The signal is converted into an encoded Manchester encoded signal for optical communication so as to provide a voltage inverting unit, and the signal is sent to the light emitting drive unit 12, which drives the light emitting element 6 based on the signal. I do.
【００２１】受信回路は、受光素子７から出力された受
光電流を電圧に変換する受光回路１４、その電圧信号を
増幅する増幅器１５、増幅された受光信号をコンパレー
タに通し信号の中間部を閾値として２値化する２値化回
路１６を備え、２値化された受信信号はデジタル処理回
路１０と共に比較部１７に出力される。デジタル処理回
路１０は、入力した光通信用の符号化データ信号を復号
化し、それをＬＡＮ用の符号化データ信号に変換し、加
えて、衝突発生時、所定のＪＡＭ信号を発生し、インタ
ーフェイス９を介して端末装置４、５にＪＡＭ信号を出
力するように構成される。The receiving circuit includes a light receiving circuit 14 for converting a light receiving current output from the light receiving element 7 to a voltage, an amplifier 15 for amplifying the voltage signal, and passing the amplified light receiving signal through a comparator to set an intermediate portion of the signal as a threshold. A binarization circuit 16 for binarization is provided, and the binarized reception signal is output to the comparison unit 17 together with the digital processing circuit 10. The digital processing circuit 10 decodes the input coded data signal for optical communication and converts it into a coded data signal for LAN. In addition, when a collision occurs, a predetermined JAM signal is generated. Is configured to output a JAM signal to the terminal devices 4 and 5 via the.
【００２２】比較部１７は、親局１へのデータ送信時
に、２値化回路１６から入力した受信信号（親局１から
戻されたリピート信号）と、データ記憶部１８から入力
したデータ信号（親局１に向けて送信したデータ信号）
を比較し、両信号が相違していた場合、親局１で信号の
衝突が発生しデータが破壊されたとして、信号を衝突検
知信号発生部１９と切換回路２１に出力する。衝突検知
信号発生部１９は、例えば２００ｎｓのパルス幅を有す
るパルス信号を衝突検知信号として電圧変換部２０に出
力し、電圧変換部２０は、その衝突検知信号を例えばデ
ータ信号の２倍のレベルに増幅して切換回路２１に出力
する。When transmitting data to master station 1, comparison section 17 receives a received signal (repeated signal returned from master station 1) input from binarization circuit 16 and a data signal (repeated signal returned from master station 1). Data signal transmitted to master station 1)
And if the two signals are different, it is determined that a signal collision has occurred in the master station 1 and the data has been destroyed, and the signal is output to the collision detection signal generator 19 and the switching circuit 21. The collision detection signal generator 19 outputs a pulse signal having a pulse width of, for example, 200 ns to the voltage converter 20 as a collision detection signal, and the voltage converter 20 converts the collision detection signal to, for example, a level twice as high as the data signal. The signal is amplified and output to the switching circuit 21.
【００２３】この種の空間光伝送装置は、電源をオンし
た状態の通常時、データ伝送を行わないときには、相互
にリンクパルス信号を相手側に常時伝送するが、このリ
ンクパルス信号には、通常、２００ｎｓのパルス幅のパ
ルス信号が使用されるため、このリンクパルス信号を上
記衝突検知信号として使用することもできる。This type of spatial light transmission apparatus always transmits link pulse signals to each other at normal times when the power is on and when data transmission is not performed. , 200 ns pulse signal, the link pulse signal can be used as the collision detection signal.
【００２４】なお、この空間光伝送装置が採用するISO/
IEC8802-3 内の10BASE-Tの規格では、データ信号のパル
ス幅は５０ｎｓ〜１００ｎｓであり、１５０ｎｓ以上の
パルス幅のハイレベルパルス信号はデータ終了を示すか
ら、信号の衝突時に子局から親局に送る衝突検知信号に
この２００ｎｓのパルス幅のパルス信号を使用した場
合、親局１にはデータ終了時を示す信号が受信されたと
してリピート信号の送信停止を行なわせることができ
る。It should be noted that this spatial optical transmission apparatus employs ISO /
According to the 10BASE-T standard in IEC8802-3, the pulse width of a data signal is 50 ns to 100 ns, and a high-level pulse signal with a pulse width of 150 ns or more indicates the end of data. When a pulse signal having a pulse width of 200 ns is used as the collision detection signal to be sent to the master station, the master station 1 can stop the transmission of the repeat signal assuming that the signal indicating the end of the data has been received.
【００２５】切換回路２１の入力側は、デジタル処理回
路１０からの信号ラインと上記の電圧変換部２０からの
信号ラインが接続され、切換信号として上記比較部１７
からの出力信号が入力されるように接続される。切換回
路２１の出力側は、投光駆動部１２に接続され、投光駆
動部１２の出力側が投光素子６に接続される。デジタル
処理回路１０にはコネクタ１１を設けたインターフェイ
ス９が接続され、コネクタ１１に端末装置４または５が
接続される。The input side of the switching circuit 21 is connected to a signal line from the digital processing circuit 10 and a signal line from the above-mentioned voltage conversion unit 20.
Are connected so that the output signal from the input is input. The output side of the switching circuit 21 is connected to the light emitting drive unit 12, and the output side of the light emitting drive unit 12 is connected to the light emitting element 6. An interface 9 provided with a connector 11 is connected to the digital processing circuit 10, and the terminal device 4 or 5 is connected to the connector 11.
【００２６】図２に示すようなシステムにおいて、親局
１は有線ＬＡＮに接続され、上記構成を有する子局２、
３は、各々コネクタ１１を有線ＬＡＮに接続することに
より端末装置４、５に接続される。親局１と子局２、３
は各々その受光部と・投光部を対向させ光軸を合わせた
状態にセットされ、且つ親局１と子局２間の距離はより
短く、親局１と子局３間の距離はより長く配置される。In a system as shown in FIG. 2, a master station 1 is connected to a wired LAN, and
3 are connected to the terminal devices 4 and 5 by connecting the connector 11 to a wired LAN. Master station 1 and child stations 2, 3
Are set so that the light receiving unit and the light projecting unit face each other and the optical axes are aligned, and the distance between the master station 1 and the slave station 2 is shorter, and the distance between the master station 1 and the slave station 3 is longer. It is arranged long.
【００２７】端末装置４又は５から親局１に接続する有
線ＬＡＮにデータを送出した場合、伝送データは有線Ｌ
ＡＮを通して子局２又は３のデジタル処理回路１０に送
られ、ここで、マンチェスター符号変換方式によりデジ
タル値に対応した電圧信号に変換され、その信号が切換
回路２１を経て投光駆動部１２に送られ、投光駆動部１
２は投光素子６を駆動し、これにより投光部からデータ
信号をのせた近赤外線が親局１に向けて投光される。When data is sent from the terminal device 4 or 5 to the wired LAN connected to the master station 1, the transmission data is
The signal is sent to the digital processing circuit 10 of the slave station 2 or 3 through the AN, where it is converted into a voltage signal corresponding to a digital value by the Manchester code conversion method, and the signal is sent to the light emitting drive unit 12 via the switching circuit 21. And the light emitting drive 1
2 drives the light projecting element 6, whereby the near infrared ray carrying the data signal from the light projecting section is projected toward the master station 1.
【００２８】親局１は、その受光素子が投光された近赤
外線を受光し、受光素子から出力される受光電流が受光
回路で電圧信号に変換され、増幅回路でその信号が増幅
され、更に、２値化回路で２値化された後、信号はデジ
タル処理回路でデジタル値に復号化され、復号化された
データ信号はインターフェイスを通して有線ＬＡＮに送
出される。The master station 1 receives the near-infrared light projected by the light-receiving element, converts a light-receiving current output from the light-receiving element into a voltage signal by a light-receiving circuit, amplifies the signal by an amplifier circuit, and further After being binarized by the binarization circuit, the signal is decoded into a digital value by the digital processing circuit, and the decoded data signal is transmitted to the wired LAN through the interface.
【００２９】またこのとき、親局１は、受信したデータ
信号をそのままリピート信号として、送信元の子局２又
は子局３に、投光駆動部、投光素子を動作させて戻すよ
うに送信する。子局２又は子局３は、このリピート信号
を受光素子７、受光回路１４等を介して受信すると、送
信した元のデータ信号とこのリピート信号を比較部１７
で比較し、両信号が一致すれば、信号衝突と判断せず、
通常の送信動作を継続して行なう。送信元以外の子局
は、比較動作を行なわずに、リピート信号をデータ信号
として有線ＬＡＮに出力する。At this time, the master station 1 transmits the received data signal as a repeat signal as it is to the slave station 2 or the slave station 3 of the transmission source so that the light emitting drive unit and the light emitting element are operated and returned. I do. When the slave station 2 or the slave station 3 receives the repeat signal via the light receiving element 7, the light receiving circuit 14, and the like, the slave station 2 or the slave station 3 compares the transmitted original data signal with the repeat signal.
And if the two signals match, it is not determined that there is a signal collision,
Normal transmission operation is continued. The slave stations other than the transmission source output the repeat signal as a data signal to the wired LAN without performing the comparison operation.
【００３０】子局２と子局３から同時にデータ信号が親
局１に送信された場合、受信先の親局１において信号の
衝突が発生する。この場合、子局３と親局１間は子局２
と親局１間に比べ距離が遠く離れているため、図７
（ｂ）の如く、子局３から親局１に送られ受光される光
信号ＰＢのレベルは、子局２から親局１に送られ受光さ
れる光信号ＰＡのレベルに比べ、低くなる。When data signals are transmitted from the slave stations 2 and 3 to the master station 1 at the same time, signal collision occurs in the master station 1 at the destination. In this case, the slave station 2 is located between the slave station 3 and the master station 1.
7 is farther than the distance between
As shown in (b), the level of the optical signal PB sent from the slave station 3 to the master station 1 and received is lower than the level of the optical signal PA sent from the slave station 2 to the master station 1 and received.
【００３１】このため、親局１で受信される２つの受信
信号は、光信号ＰＡの上部と下部に光信号ＰＢを重畳さ
せた合成信号となり、この受信信号はコンパレータを通
して２値化されるが、その閾値は信号の中間値に設定さ
れるため、親局１に入力される論理入力信号（図７ｂ）
は、子局２からの送信信号と同じ信号となるが、子局３
からの送信信号とは相違した信号となり、この論理入力
信号がリピート信号として子局２と子局３にそのまま戻
される。Therefore, the two received signals received by the master station 1 are combined signals in which the optical signal PB is superimposed on the upper and lower portions of the optical signal PA, and the received signal is binarized through the comparator. , Its threshold value is set to the intermediate value of the signal, so that the logical input signal input to the master station 1 (FIG. 7B)
Is the same signal as the transmission signal from the slave station 2,
The logical input signal is returned to the slave stations 2 and 3 as it is as a repeat signal.
【００３２】このとき、子局２は、送信した送信信号と
戻されたリピート信号とを比較部１７で比較するが、送
信信号とリピート信号は一致するため、子局２は信号の
衝突とは判断しない。At this time, the slave station 2 compares the transmitted transmission signal with the returned repeat signal in the comparing section 17, but since the transmission signal and the repeat signal match, the slave station 2 is not aware of the signal collision. Do not judge.
【００３３】一方、子局３は、送信した送信信号と戻さ
れたリピート信号とを比較部１７で比較するが、送信し
た送信信号と戻されたリピート信号が不一致であるた
め、信号の衝突と判断し、親局１に対し衝突検知信号を
送信し、端末装置５に対してＪＡＭ信号を出力し、端末
装置５はデータの送信を中止する。On the other hand, the slave station 3 compares the transmitted transmission signal with the returned repeat signal by the comparing unit 17, but since the transmitted transmission signal and the returned repeat signal are inconsistent, a collision of the signals may occur. Judgment is made, a collision detection signal is transmitted to the master station 1, a JAM signal is output to the terminal device 5, and the terminal device 5 stops transmitting data.
【００３４】即ち、子局３は、比較部１７において送信
した送信信号と戻されたリピート信号を比較し、不一致
と判断して、比較部１７から不一致信号が衝突検知信号
発生部１９に送られ、衝突検知信号発生部１９から衝突
検知信号が出力される。この衝突検知信号は、例えば２
００ｎｓのパルス幅を持つリンクパルス信号で、電圧変
換部２０に送られて電圧値がデータ信号の２倍に増幅さ
れ、切換回路２１を通して、投光駆動部１２に送られ、
投光駆動部１２によって投光素子６が駆動され、この衝
突検知信号が近赤外線にのせて親局１に送信される。That is, the slave station 3 compares the transmitted signal transmitted by the comparing section 17 with the returned repeat signal, determines that they do not match, and sends the mismatch signal from the comparing section 17 to the collision detection signal generating section 19. The collision detection signal is output from the collision detection signal generator 19. This collision detection signal is, for example, 2
A link pulse signal having a pulse width of 00 ns, which is sent to the voltage converter 20 where the voltage value is amplified to twice the data signal, and sent to the light emitting drive unit 12 through the switching circuit 21;
The light emitting element 6 is driven by the light emitting drive unit 12, and the collision detection signal is transmitted to the master station 1 on near infrared rays.
【００３５】親局１は、子局３からの衝突検知信号を受
信するが、子局２からも継続してデータ信号が送られて
いるから、親局２には図４に示すように、子局２からの
光信号ＰＡと共に子局３からの光信号ＰＢ（衝突検知信
号）が受信される。両信号は合成されて図４に示すよう
な受信信号となり、この受信信号は親局１において中間
部を閾値とするコンパレータを通して２値化され、親局
１の論理入力信号は、図４のように変形し、またマンチ
ェスター符号化信号の形式からも外れたものとなる。The master station 1 receives the collision detection signal from the slave station 3, but since the data signal is continuously transmitted from the slave station 2, the master station 2 receives the collision detection signal as shown in FIG. An optical signal PB (collision detection signal) from the slave station 3 is received together with the optical signal PA from the slave station 2. The two signals are combined into a received signal as shown in FIG. 4. This received signal is binarized through a comparator having a threshold value at the intermediate portion in the master station 1. The logical input signal of the master station 1 is as shown in FIG. , And deviates from the format of the Manchester coded signal.
【００３６】このため、親局１はこれをデータ品質の低
下と判断し、子局２から信号が送信されてきても、子局
２へのリピート信号の送信を中止する。或は、親局１は
子局３から送られた衝突検知信号をデータ終了信号と判
断し、リピート信号の送出を一定時間中止する。For this reason, the master station 1 determines that this is a deterioration in data quality, and stops transmitting a repeat signal to the slave station 2 even if a signal is transmitted from the slave station 2. Alternatively, the master station 1 determines that the collision detection signal sent from the slave station 3 is a data end signal, and suspends the transmission of the repeat signal for a certain period of time.
【００３７】これにより、子局２は、親局１からのリピ
ート信号が受信されないことを理由として、信号の衝突
があったと判断し、端末装置４にＪＡＭ信号を送って、
送信信号の衝突を知らせ、端末装置４はデータの送信を
中止する。次に、子局２は端末装置４からのデータ送信
がなくなったことを確認すると、ＪＡＭ信号の送信を停
止する。そして、端末装置４はこのＪＡＭ信号の消失に
伴い、信号衝突後の再送信の処理を引き続き行なう。Thus, the slave station 2 determines that there has been a signal collision because the repeat signal from the master station 1 is not received, and sends a JAM signal to the terminal device 4,
Notifying the collision of the transmission signal, the terminal device 4 stops the data transmission. Next, upon confirming that data transmission from the terminal device 4 has ceased, the slave station 2 stops transmitting the JAM signal. Then, with the loss of the JAM signal, the terminal device 4 continues to perform the retransmission processing after the signal collision.
【００３８】一方、子局３は、親局１からのリピート信
号の中断によって、子局２へ衝突の通知がなされたこと
を確認し、衝突検知信号の親局１への送信とＪＡＭ信号
の端末装置５への送信を停止する。そして、端末装置５
はこのＪＡＭ信号の消失に伴い、信号衝突後の再送信の
処理を引き続き行なう。On the other hand, the slave station 3 confirms that the collision has been notified to the slave station 2 due to the interruption of the repeat signal from the master station 1, and transmits the collision detection signal to the master station 1 and the JAM signal. The transmission to the terminal device 5 is stopped. And the terminal device 5
With the loss of the JAM signal, the retransmission processing after the signal collision is continuously performed.
【００３９】図５は他の実施例のブロック図を示してい
る。この例では、衝突検知信号を送信する際、通常の投
光素子６と共に補助投光素子２３を動作させることによ
り、通常の光信号レベルより高い、つまり照度の高い光
信号を衝突検知信号として送信するように構成する。FIG. 5 shows a block diagram of another embodiment. In this example, when transmitting the collision detection signal, the auxiliary light emitting element 23 is operated together with the normal light emitting element 6 to transmit an optical signal higher than the normal light signal level, that is, a light signal with high illuminance as the collision detection signal. It is constituted so that.
【００４０】即ち、投光駆動部１２の出力側にスイッチ
回路２２を介して補助投光素子２３が接続され、スイッ
チ回路２２は比較部１７の出力信号でオンするように接
続される。この図５に示すブロック図の伝送装置は、子
局３として使用され、比較部１７において送信した送信
信号と戻されたリピート信号が比較され、両信号が不一
致と判断すると、比較部１７から出力信号が、衝突検知
信号発生部１９、切換回路２１、及びスイッチ回路２２
に送られ、切換回路２１は、衝突検知信号発生部１９の
出力側を投光駆動部１２側に接続するように切換、スイ
ッチ回路２２は補助投光素子２３側の線路をオンする。That is, the auxiliary light emitting element 23 is connected to the output side of the light emitting drive section 12 via the switch circuit 22, and the switch circuit 22 is connected so as to be turned on by the output signal of the comparing section 17. The transmission device of the block diagram shown in FIG. 5 is used as the slave station 3, and the transmission signal transmitted by the comparison unit 17 is compared with the returned repeat signal. The signal is output from the collision detection signal generator 19, the switching circuit 21, and the switch circuit 22.
The switching circuit 21 switches so that the output side of the collision detection signal generating unit 19 is connected to the light emitting drive unit 12 side, and the switch circuit 22 turns on the line on the auxiliary light emitting element 23 side.
【００４１】そして、衝突検知信号発生部１９から衝突
検知信号が切換回路２１を通して投光駆動部１２に出力
され、投光駆動部１２は、投光素子６と共に補助投光素
子２３を投光駆動し、通常の光信号レベルより高い照度
の光信号が衝突検知信号として親局１に送信される。上
記実施例と同様に、子局３は、この高レベルの衝突検知
信号を親局１へ送信することにより、他方の子局２に信
号の衝突を認識させ、双方でデータ送信の時間をずらし
ながら信号の衝突を回避し、データ送信を行なう。Then, a collision detection signal is output from the collision detection signal generating section 19 to the light projecting drive section 12 through the switching circuit 21, and the light projecting drive section 12 drives the auxiliary light projecting element 23 together with the light projecting element 6 to project light. Then, an optical signal having an illuminance higher than the normal optical signal level is transmitted to the master station 1 as a collision detection signal. Similarly to the above embodiment, the slave station 3 transmits this high-level collision detection signal to the master station 1 to cause the other slave station 2 to recognize the signal collision and shift the data transmission time between the two. While avoiding signal collision, data transmission is performed.
【００４２】以上のように、親局１と子局２間の距離と
親局１と子局３間の距離が大きく相違している場合であ
っても、遠い距離にある子局３から衝突検知信号を親局
１に送り、近い距離の子局２に対する親局１からのリピ
ート信号の送信を停止して、子局２に信号の衝突を確実
に検知させ、子局２は信号の送信を一時中止して、信号
衝突時の処理を行なうから、子局２、３双方が信号の衝
突を回避しながら、遅滞なくデータ送信を実行すること
ができる。As described above, even when the distance between the master station 1 and the slave station 2 and the distance between the master station 1 and the slave station 3 are greatly different, a collision from the slave station 3 located at a long distance. The detection signal is sent to the master station 1, the transmission of the repeat signal from the master station 1 to the slave station 2 in a short distance is stopped, and the slave station 2 reliably detects the collision of the signal, and the slave station 2 transmits the signal. Is temporarily stopped and the processing at the time of signal collision is performed, so that both the slave stations 2 and 3 can execute data transmission without delay while avoiding signal collision.
【００４３】なお、本発明の空間光伝送装置は、上記の
実施形態に限定されるものではなく、以下のような態様
でも実施することができる。The spatial light transmission device of the present invention is not limited to the above embodiment, but can be implemented in the following modes.
【００４４】上記実施例では、１台の親局と２台の子
局間のデータ送信の例を説明したが、子局が３台以上の
場合にも適用することができる。In the above embodiment, an example of data transmission between one master station and two slave stations has been described. However, the present invention can be applied to a case where there are three or more slave stations.
【００４５】空間光伝送の信号変調方式は、上記のベ
ースバンド方式の他、ＡＳＫ、ＦＳＫ、ＰＳＫなどの変
調を行うブロードバンド方式を用いることもできる。As a signal modulation method for spatial light transmission, a broadband method for performing modulation such as ASK, FSK, and PSK can be used in addition to the above-described baseband method.
【図１】本発明の請求項１の全体構成図である。FIG. 1 is an overall configuration diagram according to claim 1 of the present invention.
【図２】本発明の一実施形態を示す空間光伝送装置のシ
ステム接続図である。FIG. 2 is a system connection diagram of the spatial light transmission device according to the embodiment of the present invention.
【図３】空間光伝送装置の子局のブロック図である。FIG. 3 is a block diagram of a slave station of the spatial light transmission device.
【図４】親局における受信信号などの波形図である。FIG. 4 is a waveform diagram of a received signal and the like in a master station.
【図５】他の実施例の子局のブロック図である。FIG. 5 is a block diagram of a slave station according to another embodiment.
【図６】従来の空間光伝送装置のシステム接続図であ
る。FIG. 6 is a system connection diagram of a conventional spatial light transmission device.
【図７】従来の空間光伝送装置の親局の受信信号などの
波形図である。FIG. 7 is a waveform diagram of a received signal and the like of a master station of a conventional spatial light transmission device.
１−親局 ２、３−子局 ４、５−端末装置 １７−比較部 １８−データ記憶部 １９−衝突検知信号発生部 1-Master station 2, 3-Slave station 4,5-Terminal device 17-Comparison unit 18-Data storage unit 19-Collision detection signal generation unit
Claims (3)
により信号を伝送する空間光伝送装置において、 該親局には、該子局から信号が送られた時、該信号を認
識しリピート信号として子局に送信するリピート信号送
信手段が設けられ、 該子局には、該親局に送った信号と該リピート信号とを
比較して相違する時、信号の衝突と判断する衝突判定手
段と、該衝突判定手段によって信号の衝突が検知された
時、信号の送信を中止し、通常より強い強度の光信号を
衝突検知信号として該親局に送信する衝突検知信号送信
手段と、が設けられたことを特徴とする空間光伝送装
置。1. A spatial light transmission device for transmitting a signal by light radiated into space between a master station and a plurality of slave stations, comprising: transmitting a signal to the master station when a signal is sent from the slave station; A repeat signal transmitting means for recognizing and transmitting to the slave station as a repeat signal is provided. The slave station compares the signal sent to the master station with the repeat signal and determines that there is a signal collision when they differ. Collision determination means, and collision detection signal transmission means for stopping transmission of a signal when a collision of a signal is detected by the collision determination means, and transmitting an optical signal having a stronger intensity than normal as a collision detection signal to the master station; And a spatial light transmission device.
を高めた駆動信号を投光駆動部に送り、投光素子の駆動
電流を増すことにより送信されることを特徴とする請求
項１記載の空間光伝送装置。2. An optical signal having an intensity higher than normal intensity is transmitted by sending a drive signal with an increased voltage to a light emitting drive unit and increasing a drive current of the light emitting element. The spatial light transmission device as described in the above.
投光素子を通常の投光素子と合わせて動作させることに
より送信されることを特徴とする請求項１記載の空間光
伝送装置。3. The spatial light transmission apparatus according to claim 1, wherein the optical signal having an intensity higher than normal is transmitted by operating an auxiliary light projecting element together with a normal light projecting element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12792898A JPH11331177A (en) | 1998-05-11 | 1998-05-11 | Spatial optical transmission equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12792898A JPH11331177A (en) | 1998-05-11 | 1998-05-11 | Spatial optical transmission equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11331177A true JPH11331177A (en) | 1999-11-30 |
Family
ID=14972110
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12792898A Pending JPH11331177A (en) | 1998-05-11 | 1998-05-11 | Spatial optical transmission equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11331177A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006077968A1 (en) * | 2005-01-21 | 2006-07-27 | Nakagawa Laboratories, Inc. | Optical communication system |
-
1998
- 1998-05-11 JP JP12792898A patent/JPH11331177A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006077968A1 (en) * | 2005-01-21 | 2006-07-27 | Nakagawa Laboratories, Inc. | Optical communication system |
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