JPS59236A - Signal collision detecting system - Google Patents

Signal collision detecting system

Info

Publication number
JPS59236A
JPS59236A JP57109557A JP10955782A JPS59236A JP S59236 A JPS59236 A JP S59236A JP 57109557 A JP57109557 A JP 57109557A JP 10955782 A JP10955782 A JP 10955782A JP S59236 A JPS59236 A JP S59236A
Authority
JP
Japan
Prior art keywords
signal
star coupler
station
collision
output
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.)
Pending
Application number
JP57109557A
Other languages
Japanese (ja)
Inventor
Kazuyoshi Oshima
一能 大島
Tadayoshi Kitayama
北山 忠義
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP57109557A priority Critical patent/JPS59236A/en
Publication of JPS59236A publication Critical patent/JPS59236A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/27Arrangements for networking

Landscapes

  • Engineering & Computer Science (AREA)
  • Computing Systems (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Small-Scale Networks (AREA)
  • Optical Communication System (AREA)
  • Testing Or Measuring Of Semiconductors Or The Like (AREA)

Abstract

PURPOSE:To detect a collision at a low cost and with high reliability, by monitoring a receiving optical level by a collision detecting device installed adjacently to a star coupler. CONSTITUTION:When a transmitting signal is sent out from a transmitter 2, the signal is sent to all connected stations through a star coupler 4, also is received by an amplifier 20 of a collision detecting device 25 connected to a pair of short ports of the star coupler 4, and an output of the amplifier 20 is inputted to an integration circuit 21. In case when the transmitting signal is sent out from only one station, an output of the integration circuit 21 is smaller than a decided threshold level 24 of a discriminator 22, and no alarm signal is sent out from an alarm signal transmitter 23. On the other hand, in case when optical signals are sent simultaneously to the star coupler 4 from two or more stations, and a collision of the opticals occurs, the output of the amplifier 20 increases, the output of the circuit 21 also exceeds the threshold level 24, and an alarm signal is sent out from the transmitter 23. When the station which transmits the optical signal detects this alarm signal, it detects a collision with the optical signal of other station.

Description

【発明の詳細な説明】 この発明は受動型の星状光分岐回路を用いて多数の局が
接続された星状光フアイバ通信網において、相異なる任
意の2つ以上の局が送出した信号が衝突したことを検出
する信号衝突検出方式に関するものである。
DETAILED DESCRIPTION OF THE INVENTION The present invention uses a passive star-like optical branch circuit to connect signals transmitted by two or more different stations in a star-like optical fiber communication network in which a large number of stations are connected. This invention relates to a signal collision detection method for detecting a collision.

従来のこの種方式として、第1図に示すものがあった。A conventional system of this type is shown in FIG.

図において、(1)は送信信号線、(2)は送信器、(
31は発光素子、(4)はスターカプラ、(5a) 、
 (5b) 、 (5c) 、 (6a) 、 (6b
) 、 (6c)はそれぞれスターカプラに接続された
光ファイバ、(71は受光素子、(8)はアンプ、(9
)は波形整形回路、 (11は受信信号線、 (Ill
は積分回路、(I3は識別器、 (IJは閾値設定用端
子、(I4は衝突信号線である。第2図は、伝送系各部
の信号の時間変化を示す波形図である。(1a)は送信
信号、  (15a)は上記(1)の送信信号がスター
カプラを経由してアンプ(8)に受信された受信信号、
  (16a)は(15a)を受信した場合の積分回路
出力信号、  (15b)は衝突が生じた場合の受信信
号、  (16b)は(15b)を受信した場合の積分
回路出力、(lηは衝突検出時刻である。
In the figure, (1) is the transmission signal line, (2) is the transmitter, (
31 is a light emitting element, (4) is a star coupler, (5a),
(5b), (5c), (6a), (6b
), (6c) are the optical fibers connected to the star coupler, (71 is the light receiving element, (8) is the amplifier, (9
) is a waveform shaping circuit, (11 is a receiving signal line, (Ill
is an integrator circuit, (I3 is a discriminator, (IJ is a threshold setting terminal, and (I4 is a collision signal line.) Figure 2 is a waveform diagram showing time changes of signals in each part of the transmission system. (1a) is a transmitted signal, (15a) is a received signal in which the transmitted signal in (1) above is received by the amplifier (8) via a star coupler,
(16a) is the output signal of the integrating circuit when receiving (15a), (15b) is the received signal when a collision occurs, (16b) is the output of the integrating circuit when receiving (15b), (lη is the collision This is the detection time.

次に動作について説明する。伝送路で自局信号光と他局
信号光の衝突がない場合、自局の送信信号(1)に対す
るアンプ(8)の出力信号(15a)は、積分回路Iに
入力される。積分回路Iはこの入力に対し、積分値出力
(16a)を比較器収■−\出力する。判定閾値も騰は
自局信号光に対する積分値出力<16a)よりも大きい
値に設定され、比較器(13から有意信号は出力されず
、正常な送信が行なわれていることを示す。
Next, the operation will be explained. When there is no collision between the local station signal light and the other station signal light on the transmission path, the output signal (15a) of the amplifier (8) for the local station transmission signal (1) is input to the integrating circuit I. In response to this input, the integrating circuit I outputs an integral value output (16a) to the comparator. The determination threshold value is set to a value larger than the integral value output for the signal light of the own station (<16a), and no significant signal is output from the comparator (13), indicating that normal transmission is being performed.

伝送路で自局信号光と他局信号光の衝突が生じた場合、
アンプ(8)の出力信号(16b)は衝突の発生したと
ころから大きい振幅となる。この信号に対し積分回路I
から出力される積分値出力(16b)は時刻0ηにおい
て判定しきい値a簿を越え、比較器a邊から有意信号が
出力される。判定しきい値0は自局信号に対する積分値
出力(16a)から、自局信号に対する積分値出力(1
6a)と他局信号のうち最少レベルの信号の積分値出力
との和で与えられる値の間に設定することによシ、自局
が送信中に他のどの局の信号と衝突しても検出できるこ
とになる。
When a collision occurs between the local station signal light and the other station signal light on the transmission path,
The output signal (16b) of the amplifier (8) has a large amplitude from the point where the collision occurs. Integrating circuit I for this signal
The integral value output (16b) output from the comparator exceeds the determination threshold value a at time 0η, and a significant signal is output from the comparator a. The determination threshold value 0 is calculated from the integral value output (16a) for the own station signal to the integral value output (16a) for the own station signal.
By setting the value between 6a) and the sum of the integral value output of the signal with the lowest level among the signals of other stations, even if the own station collides with the signal of any other station during transmission, This means that it can be detected.

従来の方式は以上のように構成されているので、伝送路
長が各局ごとに異ったり、スターカプラ(4)の分岐特
性にばらつきがある場合には。
Since the conventional system is configured as described above, if the transmission path length differs from station to station or if the branching characteristics of the star coupler (4) vary.

1つの局に受信される光レベルが1発信局ごとに異なっ
た値をもつため、上記識別器←2の判定しきい値の設定
が困難になるとともに1判定許容誤差が小さくなり、衝
突検出の信頼性が低下する等の欠点があった。
Since the light level received by one station has a different value for each transmitting station, it becomes difficult to set the judgment threshold for the above discriminator ← 2, and the 1 judgment tolerance becomes small, making it difficult to detect collisions. There were drawbacks such as reduced reliability.

この発明は、これらの欠点を除去するためにスターカプ
ラのボートの1対を利用して、スターカプラ内での2つ
以上の信号光の衝突をモニタし、衝突が発生した場合に
は、接続されているすべての局へ衝突が発生したことを
知らせる警報信号を送出し、各局はこの警報信号の受信
によって衝突を検知するようにしたもので。
In order to eliminate these drawbacks, this invention utilizes a pair of boats in a star coupler to monitor collisions of two or more signal lights within the star coupler, and if a collision occurs, connects A warning signal is sent to all stations that are connected to the station to notify them that a collision has occurred, and each station detects a collision by receiving this warning signal.

以下図面について詳細に説明する。The drawings will be explained in detail below.

第8図はこの発明の一実施例であって、衝突検出回路の
ブロック図を示す。
FIG. 8 is an embodiment of the present invention, and shows a block diagram of a collision detection circuit.

第8図において、(1)〜Iは第1図と同一あるいは相
当部分であり、Qlは信号の衝突が発生した場合に送ら
れる警報信号を識別して有意信号を生じる警報信号識別
回路、  (19a) (19b)はスターカプラ(4
)の短い一対のボート、(イ)はアンプ、 C19は積
分回路、(至)は識別器、(2)は衝突が発生した場合
に送出する警報信号送信器、(ハ)は閾値設定用端子、
@はスターカプラに隣接して置かれる衝突検知装置の全
体である。
In FIG. 8, (1) to I are the same or equivalent parts as in FIG. 19a) (19b) is a star coupler (4
) A pair of short boats, (A) is an amplifier, C19 is an integrating circuit, (To) is a discriminator, (2) is an alarm signal transmitter that sends out in the event of a collision, (C) is a terminal for setting a threshold value. ,
@ is the entire collision detection device placed adjacent to the star coupler.

今、送信器(2)から送信信号が送出されると。Now, when a transmission signal is sent out from the transmitter (2).

スターカプラ(4)を経由して、接続されている局のす
べてに信号が送られるとともに、スターカプラの短い一
対のボートに接続された衝突検知装[@のアンプ翰にも
受信され、アンプ翰の出力が積分回路QBに入力される
。送信信号が1つの局からのみ送出された場合には、積
分回路01)の出力は、識別器翰の判定閾値@よりも小
さく、警報信号送信器(ハ)から警報信号は送出されな
い。
The signal is sent to all connected stations via the star coupler (4), and is also received by the amplifier of the collision detection device [@] connected to the star coupler's short pair of boats. The output of is input to the integrating circuit QB. If the transmission signal is sent out from only one station, the output of the integrating circuit 01) is smaller than the determination threshold @ of the discriminator 1, and no alarm signal is sent out from the alarm signal transmitter (c).

一方、スターカプラ内に2つ以上の局から同時に光信号
が送られ、光信号の衝突が発生した場合には、衝突検知
装置(至)のアンプ■の出力は増大1−7.積分回路c
lpの出力も増加して識別器@の判定閾値Q4を越え、
警報信号送信器(ハ)から一定時間だけ警報信号が送出
される。光信号を送信していた局は、この警報信号を検
知することによシ、他局の光信号と衝突したことを検出
することができる。
On the other hand, when optical signals are simultaneously sent from two or more stations into the star coupler and a collision of optical signals occurs, the output of the amplifier (2) of the collision detection device (to) increases 1-7. Integral circuit c
The output of lp also increases and exceeds the judgment threshold Q4 of the discriminator @,
An alarm signal is sent from the alarm signal transmitter (c) for a certain period of time. By detecting this alarm signal, the station that was transmitting the optical signal can detect that it has collided with the optical signal of another station.

この方式では、衝突検知装置(至)のアンプ■へ到達す
る光レベルを0発信局によらずほぼ一是になるよう設計
できるため、識別器(2)の判定閾値の設定が容易とな
り1判定許容誤差を大きくとれるため、衝突検出の信頼
性が著しく増大する。
With this method, the light level reaching the amplifier ■ of the collision detection device (to) can be designed to be almost the same regardless of the source station, making it easy to set the judgment threshold of the discriminator (2) and making a 1 judgment. The reliability of collision detection is significantly increased due to the large tolerance.

衝突検知装置(至)のアンプ翰に受信される光レベルを
そろえる方法として社、光ファイノく長とスターカプラ
の光パワーの結合率のばらつきによる伝送損失の差を補
正するように減衰器を挿入するかあるいは送信光レベル
を調節するなどの方法が考えられる。
As a way to equalize the light level received by the amplifier of the collision detection device (toward), an attenuator was inserted to compensate for the difference in transmission loss due to variations in the coupling rate of the optical power between the optical fiber length and the star coupler. Possible methods include adjusting the transmitting light level or adjusting the level of the transmitted light.

また、警報信号は、衝突の発生を伝達できるものであれ
ばどのようなものでもよいが1例えば送信信号のスペク
トラムとの重なりの少い周期信号が利用できる。−例と
して送信信号が10M b/sのバイフェーズ符号化さ
れた信号であるとすると、2.5MHz程度よりも低い
周波数の正弦波信号であれば、送信信号と重畳して送ら
れてもフィルタによって容易に分離することが可能であ
る。
Further, the warning signal may be of any type as long as it can convey the occurrence of a collision; for example, a periodic signal with little overlap with the spectrum of the transmitted signal can be used. - For example, if the transmitted signal is a 10 Mb/s bi-phase encoded signal, if it is a sine wave signal with a frequency lower than about 2.5 MHz, the filter will not pass even if it is sent superimposed with the transmitted signal. can be easily separated by

なお9以上は入力側光ファイバと出力側光ファイバが独
立した形のいわゆる透過形のスターカプラに適用した場
合について述べたが1反射形のスターカプラはもちろん
多数接続された光ネットワークにおいて、いずれの局が
送出した光信号も共通に通追するような位置がある場合
には、その位置に上記の衝突検知装置を置き。
Note that above 9 describes the case where the input side optical fiber and the output side optical fiber are applied to a so-called transmission type star coupler where the input side optical fiber and the output side optical fiber are independent. If there is a position where the optical signals sent out by the station can also be tracked in common, place the above-mentioned collision detection device at that position.

各局にはこの衝突検知装置からの警報信号を受信する装
置を持たせることによって、光信号衝突検出系を構成す
ることができる。また、電気系の伝送路にこの方式を適
用しても同様の効果が得られる。
By providing each station with a device for receiving the alarm signal from this collision detection device, an optical signal collision detection system can be constructed. Further, similar effects can be obtained even if this method is applied to an electrical transmission line.

以上のように、この発明に係る衝突検出方式では、スタ
ーカプラに隣接して設置された衝突検知専用の装置で受
信光レベルを監視し、衝突が発生した場合には、接続さ
れた一全局に警報信号を送出して衝突の発生を知らせる
方式により、安価で信頼度の高い衝突検出装置が得られ
る効果がある。
As described above, in the collision detection method according to the present invention, the level of received light is monitored by a device dedicated to collision detection installed adjacent to the star coupler, and when a collision occurs, all connected stations are By sending out a warning signal to notify the occurrence of a collision, an inexpensive and highly reliable collision detection device can be obtained.

【図面の簡単な説明】[Brief explanation of drawings]

第1図は、従来の衝突検出方式を説明する九めのブロッ
ク図、第2図は従来の衝突検出装置における各部の波形
図、第8図はこの発明による衝突検出方式を説明するた
めのブロック図である。 図中、+71.(至)は受光素子、(81,■はアンプ
。 (楊は警報信号識別回路、  (19a)は短尺のスタ
ーカプラ入力端子、  (19b)は短尺のスターカプ
ラ出力端子、Qυは積分回路、(23は識別器、(至)
は警報信号送信器、6!4は判定閾値設定端子、(至)
は衝突検知装置、@は発光素子である。 なお1図中、同一あるいは相当部分には同一符号を付し
て示しである。 代理人  葛 野 信 − 第1図 第2図 第3図
FIG. 1 is a ninth block diagram for explaining a conventional collision detection method, FIG. 2 is a waveform diagram of each part in a conventional collision detection device, and FIG. 8 is a block diagram for explaining a collision detection method according to the present invention. It is a diagram. In the figure, +71. (to) is the light receiving element, (81, ■ is the amplifier. (Yang is the alarm signal identification circuit, (19a) is the short star coupler input terminal, (19b) is the short star coupler output terminal, Qυ is the integrating circuit, ( 23 is a discriminator, (to)
is the alarm signal transmitter, 6!4 is the judgment threshold setting terminal, (to)
is a collision detection device, and @ is a light emitting element. In FIG. 1, the same or corresponding parts are designated by the same reference numerals. Agent Shin Kuzuno - Figure 1 Figure 2 Figure 3

Claims (1)

【特許請求の範囲】 受動型の星状光分岐結合回路であるスターカプラと、上
記スターカプラの各入出力端子に長尺の光ファイバによ
って接続された複数の光送受信局と、上記スターカプラ
のうちの一対の入出力端子に短尺の光ファイバによって
接続された信号衝突検知装置より成る星状光フアイバ通
信網において、1つの局のみが光信号を送出中には信号
衝突検知装置は有意信号を発生せず。 二つ以上の局が同時に光信号を送出した場合には、上記
信号衝突検知装置がこれを検知して。 接続されているすべての局に対してスターカプラを介し
て警報信号を送出し、光信号を送出中の局はこの警報信
号を受信すること罠よって自
[Claims] A star coupler that is a passive star-shaped optical branching/coupling circuit, a plurality of optical transmitting/receiving stations connected to each input/output terminal of the star coupler by a long optical fiber, and a star coupler of the star coupler. In a star-shaped optical fiber communication network consisting of a signal collision detection device connected to a pair of input/output terminals by a short optical fiber, the signal collision detection device does not generate a significant signal while only one station is transmitting an optical signal. Did not occur. If two or more stations send out optical signals at the same time, the signal collision detection device detects this. An alarm signal is sent to all connected stations via the star coupler, and the station that is sending out the optical signal is automatically triggered by a trap when it receives this alarm signal.
JP57109557A 1982-06-25 1982-06-25 Signal collision detecting system Pending JPS59236A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP57109557A JPS59236A (en) 1982-06-25 1982-06-25 Signal collision detecting system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP57109557A JPS59236A (en) 1982-06-25 1982-06-25 Signal collision detecting system

Publications (1)

Publication Number Publication Date
JPS59236A true JPS59236A (en) 1984-01-05

Family

ID=14513250

Family Applications (1)

Application Number Title Priority Date Filing Date
JP57109557A Pending JPS59236A (en) 1982-06-25 1982-06-25 Signal collision detecting system

Country Status (1)

Country Link
JP (1) JPS59236A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60172840A (en) * 1984-02-10 1985-09-06 Nippon Telegr & Teleph Corp <Ntt> Optical star coupler with collision detection
JPS6230441A (en) * 1985-08-01 1987-02-09 Japanese National Railways<Jnr> Train radio communication system
EP0216214A2 (en) * 1985-09-25 1987-04-01 Siemens Aktiengesellschaft Method for the automatic level adjustment in a local area network, in particular for a multiprocessor arrangement with a bus system of optical fibres, for the purpose of collision detection

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5896436A (en) * 1981-12-03 1983-06-08 Ricoh Co Ltd Optical data communication system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5896436A (en) * 1981-12-03 1983-06-08 Ricoh Co Ltd Optical data communication system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60172840A (en) * 1984-02-10 1985-09-06 Nippon Telegr & Teleph Corp <Ntt> Optical star coupler with collision detection
JPH0323030B2 (en) * 1984-02-10 1991-03-28 Nippon Telegraph & Telephone
JPS6230441A (en) * 1985-08-01 1987-02-09 Japanese National Railways<Jnr> Train radio communication system
EP0216214A2 (en) * 1985-09-25 1987-04-01 Siemens Aktiengesellschaft Method for the automatic level adjustment in a local area network, in particular for a multiprocessor arrangement with a bus system of optical fibres, for the purpose of collision detection

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