JPS6112146A - Signal transmission system from terminal equipment - Google Patents
Signal transmission system from terminal equipmentInfo
- Publication number
- JPS6112146A JPS6112146A JP59132633A JP13263384A JPS6112146A JP S6112146 A JPS6112146 A JP S6112146A JP 59132633 A JP59132633 A JP 59132633A JP 13263384 A JP13263384 A JP 13263384A JP S6112146 A JPS6112146 A JP S6112146A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- level
- bus
- terminal device
- 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.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Small-Scale Networks (AREA)
Abstract
Description
【発明の詳細な説明】
(発明の技術分野)
本発明はバス終端装置と複数の端末装置との間を時分割
多重デジタルバスで結合し、双方との間で情報の授受を
行う方式の時分割多重デジタル信号伝送システムに於い
て、特にバス終端装置から端末装置に向けて送出される
情報(下り信号)と端末装置からバス終端装置に向けて
送出される情報(上り信号)とが上記時分割多重デジタ
ルバス上を同一方向に伝送されるようにしたシステムの
端末装置に於ける送出信号の送出レベル設定方式に関す
る。Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a method in which a bus terminal device and a plurality of terminal devices are connected by a time division multiplex digital bus, and information is exchanged between the two. In a division multiplexing digital signal transmission system, especially when the information sent from the bus terminal device to the terminal device (downlink signal) and the information sent from the terminal device toward the bus terminal device (uplink signal) are The present invention relates to a method for setting the output level of output signals in a terminal device of a system in which transmission is performed in the same direction on a division multiplex digital bus.
(本発明の技術背景と従来技術)
本発明が実施されるシステムの時分割多重デジタルバス
の構成は第3図に示すように、下り信号が伝送される下
りバス線13と上り信号が伝送される上りバス線14と
が別封で構成され、いずれか一方のバス線、例えば下り
ノくス線13が折返しバス線12によって折返し往復経
路となるようにして下り信号及び上り信号のノくス11
上の伝播方向が同一となるようにし、これによって信号
の伝播遅延時間が下り信号、」二り信号とも端末装置T
1〜Tnが接続されている地点呼でのバス線路長に見合
った長さとなるようにして異った端末装置からの信号の
ビットの重なりがないように構成されている。(Technical Background and Prior Art of the Present Invention) As shown in FIG. 3, the configuration of a time division multiplex digital bus in a system in which the present invention is implemented is as shown in FIG. The upstream bus line 14 and the upstream bus line 14 are separately packaged, and one of the bus lines, for example, the downstream bus line 13, is routed back and forth by the return bus line 12, so that the downstream signal and the upstream signal are routed separately. 11
The upper propagation direction is the same, so that the signal propagation delay time is the lower signal, and both the terminal equipment T
The bus line length is made to match the length of the bus line in the point call to which terminals 1 to Tn are connected, so that bits of signals from different terminal devices do not overlap.
ところで、端末装置Tl−Tnが上りバス線14に送出
した信号は当該端末装置T1〜Tnの接続点で順方向(
バス終端装置MEO受端に向う方向)と逆方向(終端抵
抗15に向う方向)の両側に等しく分割されて伝播し、
順方向の信号はバス終端装置MEで受信され、逆方向の
信号は終端抵抗15に吸収される。By the way, the signals sent from the terminal devices Tl to Tn to the upstream bus line 14 are transmitted in the forward direction (
It propagates equally in both directions (direction towards the receiving end of the bus terminating device MEO) and in the opposite direction (direction towards the terminating resistor 15),
The forward direction signal is received by the bus termination device ME, and the reverse direction signal is absorbed by the termination resistor 15.
一般にバス11に端末装置T1〜Tnを接続すると、そ
の接続点に於けるバス11の電気的特性が他の部分とは
異った特性に変化し、例えば上記のようにして端末装置
T1〜Tnから送出された信号はバス11を伝播する際
、上記電気的特性の変化点(各端末装置T1〜Tnの接
続点)で当該変化の程朋に応じた強度で反射を起し、反
射波は信号の伝播方向とは逆の方向に伝播する。例えば
上りバスN14への接続点がバス終端装置MEiO受端
に最も近い端末装置Tn (以下、端末装置について遠
い又は近いという場合は上ねバス線14への接続に於い
ていうものとする。)について考乏−ると、当該端末装
置tTnから上りバス雌14に送出された信号は接続点
で順、逆双方向に伝播し、順方向の信号は上ねバス線1
4上を距離tnに相当する時間ののちバス終端装置MP
O受端に達し、逆方向の信号は端末装置Tn−1〜T1
の各接続点で反射して、例えば端末装置Tn−1の接続
点で反射した成分は距離” 2C1n−+ IJ ”
ののち、すなわち順方向の信号がバス終端装置MEO受
端に達した時から、信号送出端末装置i’rnの接続点
と反射点との間の距離u tn−、、tn、、を往復す
る時間ののち、バス終端装置MEO受端に達する。端末
装置Tnからの信号送出レベルが太きいと、上記反射波
のレベルもそれに従って大きくなり、当該反射波は正規
の信号(順方向に伝播する信号)の後続のタイムスロッ
トに現われ、当該後続のタイムスロットのデータを破壊
する反射障害が引き起される。Generally, when the terminal devices T1 to Tn are connected to the bus 11, the electrical characteristics of the bus 11 at that connection point change to characteristics different from those of other parts. When the signal transmitted from the bus 11 propagates through the bus 11, it is reflected at the change point of the electrical characteristics (connection point of each terminal device T1 to Tn) with an intensity corresponding to the degree of the change, and the reflected wave is It propagates in the opposite direction to the signal propagation direction. For example, the terminal device Tn whose connection point to the upstream bus line N14 is closest to the receiving end of the bus terminal device MEiO (hereinafter, when a terminal device is referred to as far or near, it refers to the connection to the upstream bus line 14). Considering this, the signal sent from the terminal device tTn to the upstream bus 14 propagates in both forward and reverse directions at the connection point, and the signal in the forward direction is transmitted to the upstream bus 14 at the connection point.
4 after a time corresponding to the distance tn, the bus terminal device MP
The signal in the opposite direction reaches the O receiving end and is sent to the terminal equipment Tn-1 to T1.
For example, the component reflected at each connection point of the terminal device Tn-1 has a distance of "2C1n-+IJ"
Later, from the time when the forward signal reaches the receiving end of the bus termination device MEO, the signal travels back and forth over the distance u tn-,,tn, between the connection point of the signal sending terminal device i'rn and the reflection point. After some time, the bus terminator MEO receiver is reached. When the signal transmission level from the terminal device Tn is thick, the level of the reflected wave increases accordingly, and the reflected wave appears in the subsequent time slot of the regular signal (signal propagating in the forward direction) and A reflection failure is caused which destroys the data of the time slot.
以上のことを図面により具体的に説明すると、下りバス
線13の各点に於ける下シ信号のレベルは、第4図の直
線21に示すごとく、バス終端装置MEに近づくにつれ
て減衰量が直線的に増大する。又、各端末装置T1〜T
nからの上り信号の出力レベルが一定であるとすると、
第4図の直線22に示すごとく、バス端末装置MEの上
りバス線14の受端に於ける上り信号のレベルは、端末
装置T1〜Tnがバス終端装置MEO受端に近づくにつ
れて直線的に増加する。この様な状態に於いて、上りバ
ス線14の受端に於ける受信波形をモデル化して示すと
第5図のようになる。この第5図で、31はバス終端装
置ME K最も近い端末装ftTnの出力信号のバス終
端装置MEO受端での波形(エンベロープで示す。他の
信号についても同じ)を、32は端末装置Tnの出力信
号が端末′装置’rn−tと上りバス線14との分岐点
で反射してパス終端装置MEO受端に現われた反射波の
波形を、33はバス終端装置MPに最も遠い端末装置T
1の出力信号のバス終端装置MEO受端での波形を、3
4は上記31〜33に示した信号が合成されバス終端装
置MFiO受端で実際に観測される波形をそれぞれ示す
。上記33の信号波形で示すようにバス終端装置MEか
ら離れた位置の端末装置から送出される上り信号は上り
バス線14での伝送損失によって大きく減衰している。To explain the above in detail with reference to the drawings, the level of the down signal at each point on the down bus line 13 is attenuated linearly as it approaches the bus termination device ME, as shown by the straight line 21 in FIG. increase. In addition, each terminal device T1 to T
Assuming that the output level of the upstream signal from n is constant,
As shown by a straight line 22 in FIG. 4, the level of the upstream signal at the receiving end of the upstream bus line 14 of the bus terminal ME increases linearly as the terminals T1 to Tn approach the receiving end of the bus terminal MEO. do. In such a state, the received waveform at the receiving end of the upstream bus line 14 is modeled and shown as shown in FIG. In FIG. 5, 31 represents the waveform (indicated by an envelope; the same applies to other signals) of the output signal from the terminal ftTn closest to the bus terminating device MEK at the receiving end of the bus terminating device MEO; 33 is the waveform of the reflected wave that is reflected at the branch point between the terminal device 'rn-t and the upstream bus line 14 and appears at the receiving end of the path termination device MEO. T
The waveform of the output signal of 1 at the bus termination device MEO receiving end is expressed as 3
4 shows the waveforms actually observed at the bus terminal device MFiO receiving end by combining the signals shown in 31 to 33 above. As shown in the signal waveform 33 above, the upstream signal sent from the terminal device located away from the bus termination device ME is greatly attenuated due to the transmission loss in the upstream bus line 14.
又、上記34の信号波形に於いて、341と344は反
射障害のない部分であり、342.343は反射波32
により障害を受けている部分でそれぞれの振幅が反射波
32の分だけ大きくなっている。上記に於いて、342
部分では上り信号の受信レベルaに対して反射波32に
よる振幅増加分すの割合が小さいので反射障害による実
害は発生しないが、343部分では上り信号の受信レベ
ルCに対して反射波32による振幅増加分すの割合が大
きくなるため反射障害が生じ、上り信号の正常な受信は
不可能となる。In addition, in the signal waveform 34 above, 341 and 344 are parts without reflection failure, and 342 and 343 are parts of the reflected wave 32.
The amplitude of each wave is increased by the amount of the reflected wave 32 in the area affected by the interference. In the above, 342
In the part 343, the ratio of the amplitude increase due to the reflected wave 32 to the reception level a of the upstream signal is small, so no actual damage will occur due to reflection failure, but in the part 343, the amplitude increase due to the reflected wave 32 to the reception level C of the upstream signal Since the rate of increase increases, reflection failure occurs and normal reception of upstream signals becomes impossible.
以上のような逆方向信号の反射は各端末装置’rn、
−TIの接続点の全てで生ずるため、上りバス線14の
受端では第7図の波形写真(中央より右側)に示すよう
に、信号が幾重にも重なって受信されるのでバス終端装
置MEで当該信号から正しいデータを再現することがで
きなくなる。この反射障害は一般にバス11の長さ、端
末装置T1〜Tnの設置台数、信号の伝送速度及びチャ
ンネル数の増大に伴って、その程度が増大する傾向にあ
シ、またバス11への接続点がバス終端装置MEから遠
くてバス上の信号の伝送損失が大きい端末装置からの送
出信号はど、上記反射障害を受ける度合いが大きい。The reflection of the reverse direction signal as described above is reflected by each terminal device'rn,
- This occurs at all connection points of the TI, so at the receiving end of the upstream bus line 14, signals are received in multiple layers, as shown in the waveform photograph in Figure 7 (right side of the center). This makes it impossible to reproduce correct data from the signal. Generally, the degree of this reflection interference tends to increase as the length of the bus 11, the number of installed terminal devices T1 to Tn, the signal transmission speed, and the number of channels increase. A signal transmitted from a terminal device that is far from the bus termination device ME and has a large signal transmission loss on the bus is more susceptible to the above-mentioned reflection disturbance.
上記反射障害を除去するために、従来はバス11と端末
装置T1〜Tnとの間にバッファアンプを挿入し、バス
11側からみた端末装置’rl−Tnの出力インピーダ
ンスを高くすることによって当該端末装置T1〜Tnの
バス11への接続点に於ける逆方向信号の反射を極力抑
えるように構成しているが、この構成のために使用され
る分岐用装置は送受2系統のフソファアンプと、これを
作動させるだめの安定化電源を内蔵し、形状が大きくか
つ高価なものとなる。しかも当該分岐用装置はケーブル
の端末T1〜Tn個々への分岐点に必要となり、ケーブ
ルの布設が容易でなく、また端末装置の設置変更も簡単
には行なえない等、システムの価格低減と設置コストの
低減化に対する大きな障害となっている。In order to eliminate the above-mentioned reflection disturbance, conventionally, a buffer amplifier is inserted between the bus 11 and the terminal devices T1 to Tn, and the output impedance of the terminal device 'rl-Tn as seen from the bus 11 side is increased. The configuration is such that reflection of reverse direction signals at the connection point of devices T1 to Tn to bus 11 is suppressed as much as possible, and the branching device used for this configuration is a two-system transmitting/receiving fusso amplifier. , it has a built-in stabilized power supply to operate it, making it large and expensive. Moreover, the branching device is required at the branching point for each of the cable terminals T1 to Tn, which makes it difficult to lay the cable and change the installation of the terminal device, which reduces system price and installation costs. This is a major obstacle to the reduction of
(本発明の目的)
本発明は以上に述べた従来の問題点を解決し、バッファ
アンプを含む分岐用装置等、特別な回路手段を用いるこ
となく信号の反射障害を防止できる信号送出方式の提供
を目的とする。(Objective of the present invention) The present invention solves the above-mentioned conventional problems and provides a signal transmission method that can prevent signal reflection failure without using special circuit means such as a branching device including a buffer amplifier. With the goal.
(本発明の概要)
反射障害に関し、反射点が信号の受信点(バス終端装置
の受端)に近く反射波の時間遅れが受信符号の10分の
1以下のとき、又は反射波の強度が当該反射波が重畳す
る符号の強度に比べて十分に低いレベルのときは前記反
射障害は生じない。本発明はこの特性のうち特に後者を
利用するものである。(Summary of the present invention) Regarding reflection failure, when the reflection point is close to the signal reception point (reception end of the bus terminal device) and the time delay of the reflected wave is less than 1/10 of the received code, or the intensity of the reflected wave is When the level of the reflected wave is sufficiently lower than the intensity of the superimposed code, the reflection failure does not occur. The present invention particularly utilizes the latter of these characteristics.
すなわち、バス終端装置からの端末装置向は送出信号(
下り信号)と、端末装置からのバス終端装置向は送出信
号(上り信号)とがバス上を同一方向に伝送されるよう
にしたシステムでは、バス伝送中に下り信・号が受ける
減衰量と上り信号が受ける減衰量との合計がどの端末装
置についてもほぼ同じである。In other words, from the bus terminal device to the terminal device, the sending signal (
In a system where the downlink signal (downlink signal) and the outgoing signal (uplink signal) from the terminal device to the bus termination device are transmitted in the same direction on the bus, the amount of attenuation that the downlink signal/signal receives during bus transmission is The total amount of attenuation received by uplink signals is approximately the same for all terminal devices.
従って、各端末装置に於いて、下り信号の受信レベルを
検出し、当該受信レベルに対して一定比率のレベルで上
り信号を送出すればそれぞれの端末装置からの上り信号
は、それぞれの端末装置とバス終端装置との間のバス長
に対応した減衰を受け、バス終端装置で受信されるとき
はいずれの端末装置からの上り信号もほぼ同じレベルと
なっている。また、上記のように構成すれば上りバス線
との接続に於いてバス終端装置に近い端末装置からの上
り信号はど低いレベルで送出されるので、上り信号の反
射波がバス終端装置に達するときのレベルは、いずれの
端末装置の分岐点からのものであっても常に一定レベル
以下に抑制することができる。Therefore, if each terminal device detects the received level of the downlink signal and sends out the uplink signal at a level that is a certain ratio to the received level, the uplink signal from each terminal device will be transmitted to the respective terminal device. The upstream signals from all terminal devices are attenuated in accordance with the length of the bus between the bus terminal device and the bus terminal device, so that the upstream signals from all terminal devices are at approximately the same level when received by the bus terminal device. In addition, with the above configuration, the upstream signal from the terminal device close to the bus termination device when connected to the upstream bus line is sent out at a low level, so the reflected wave of the upstream signal reaches the bus termination device. The current level can always be suppressed to a certain level or below, regardless of the branch point of any terminal device.
本発明は以上の事項を利用することによって新たな反射
障害除去手法を得たものであり、具体的には端末装置内
に受信信号(下シ信号)のレベルと送出信号(上り信号
)のレベルとの比−較手段を設け、該比較手段の出力に
基いて上シ信号の送出レベルを自動的又は人為的に設定
するようにしたものである。The present invention has obtained a new reflection interference removal method by utilizing the above-mentioned matters. Specifically, the level of the received signal (lower signal) and the level of the transmitted signal (upstream signal) are determined in the terminal device. A comparison means is provided, and the output level of the upper signal is automatically or artificially set based on the output of the comparison means.
(本発明の実施例)
第1図及び第2図は本発明の第1及び第2の実施例を示
すブロック図であり、Tは端末装置(第3図のT1〜T
nに相当する。)、1は受信回路、2は受信レベル検出
器、3は送信回路、4は比較器、5は送出レベル自動調
整器、6は中央処理装置(所謂、CPU)、7は表示器
、8は送出レベル設定器をそれぞれ示し、9及び10は
それぞれ下りバス線13及び上りバス線14の信号レベ
ル測定点を示す。面、下りバス線及び上りバス線の記号
は前記第3図と同じ記号″13”及び゛】4″を使用し
ている。 ′まず、第1図に示す第1の実楕
例の動作を説明する。(Embodiments of the present invention) FIGS. 1 and 2 are block diagrams showing first and second embodiments of the present invention, and T is a terminal device (T1 to T in FIG. 3).
Corresponds to n. ), 1 is a receiving circuit, 2 is a receiving level detector, 3 is a transmitting circuit, 4 is a comparator, 5 is an automatic transmission level adjuster, 6 is a central processing unit (so-called CPU), 7 is a display, and 8 is a The transmission level setters are respectively shown, and 9 and 10 are signal level measurement points of the down bus line 13 and the up bus line 14, respectively. The same symbols ``13'' and ``4'' as in Figure 3 are used for the bus lines, down bus lines, and up bus lines.'First, let us explain the operation of the first real ellipse shown in Figure 1. explain.
バス終端装置MI!!(第3図)から出力される端末装
置T向けの下り信号は下りバス線13により伝送され、
下りバス線13の端末装置Tまでのバス長に対応した量
の減衰を受けて当該端末装置Tの受信回路1で受信され
、中央処理装置6に送付されて分析される。Bus termination device MI! ! The downlink signal for the terminal device T outputted from (FIG. 3) is transmitted by the downlink bus line 13,
The signal is attenuated by an amount corresponding to the bus length of the downlink bus line 13 to the terminal device T, is received by the receiving circuit 1 of the terminal device T, and is sent to the central processing unit 6 for analysis.
上記下り信号は受信レベル検出器2にも入力され、これ
を受けて当該受信レベル検出器2は下り信号の端末装置
Tでの受信レベルを検出しこれを直流電圧等に変換して
比較器4に出力する。一方送倍回路3は上りバス線13
に上り信号を送出すべく間欠的に動作しており、当該動
作時の送出レベルに相当する信号を上記比較器4に出力
する。The downlink signal is also input to the reception level detector 2, and in response to this, the reception level detector 2 detects the reception level of the downlink signal at the terminal device T, converts it into a DC voltage, etc., and converts it into a comparator 4. Output to. On the other hand, the multiplication circuit 3 is connected to the upstream bus line 13.
It operates intermittently to send out an upstream signal to the comparator 4, and outputs a signal corresponding to the sending level at the time of the operation to the comparator 4.
比較器4は上記2つの信号のレベル比較結果に基ずく信
号を送出レベル自動調整器5に送付し、送出レベル自動
調整器5は上記比較器4の出力信号を受けて比較器4に
入力されている前記上り信号の送出レベルに相当する信
号のレベルと下り信号のレベルとが一致する様に送信回
路3からの送出レベルを自動設定する。この比較器4及
び送出レベル自動調整器5での動作機構を更に具体的に
説明すると、比較器4の出力信号で送信回路3の送信部
電源電圧を制御して当該電源電圧を下り信号の受信レベ
ルに合致させるようにする方法(このように制御された
電源電圧が上記上す信号の送出レベルに相当する信号“
に対応する。)、又は実際に上り信号が送出されたとき
の当該上り信号のレベルを検出して保持し、この保持し
た信号レベルを比較器4に入力して下り信号のレベルと
比較し、比較器4からの比較結果出力信号によって送信
回路3の送信部電源電圧を設定する方法(保持した信号
レベルが上記止り信号の送出レベルに相当する信号”に
対応する。)等が考えられる。The comparator 4 sends a signal based on the level comparison result of the two signals to the automatic output level adjuster 5, and the automatic output level adjuster 5 receives the output signal of the comparator 4 and inputs the signal to the comparator 4. The output level from the transmitting circuit 3 is automatically set so that the level of the signal corresponding to the output level of the upstream signal and the level of the downstream signal match. To explain the operating mechanism of the comparator 4 and the automatic transmission level adjuster 5 in more detail, the output signal of the comparator 4 controls the transmitter power supply voltage of the transmitter circuit 3, and lowers the power supply voltage to receive the signal. (The power supply voltage controlled in this way matches the output level of the above-mentioned signal.)
corresponds to ), or detect and hold the level of the uplink signal when it is actually sent out, input this held signal level to the comparator 4 and compare it with the level of the downlink signal, and output the signal from the comparator 4. A possible method is to set the transmitter power supply voltage of the transmitter circuit 3 using the comparison result output signal (the held signal level corresponds to the signal corresponding to the sending level of the stop signal).
以上の状態で中央処理装置6が上り信号を送信回路3を
通して上りバス線14に送出すると、下りバス線13の
測定点9と上りノくス線14の測定点10の信号レベル
は一致し、本発明の目的が達成される。When the central processing unit 6 sends an upstream signal to the upstream bus line 14 through the transmission circuit 3 in the above state, the signal level at the measurement point 9 on the downstream bus line 13 and the measurement point 10 on the upstream bus line 14 match, The objectives of the invention are achieved.
次に第2図によって本発明の第2の実施例の動作を説明
する。Next, the operation of the second embodiment of the present invention will be explained with reference to FIG.
前記第1の実施例との相異点は上り信号の送出レベルを
自動的に調整せず、表示器7に比較器4での前記2つの
信号の比較結果を表示1〜、その結果を見なから送出レ
ベル設定器8で上り信号の出力レベルを手動設定する点
にある。表示器7が受信信号(下り信号)レベルと送出
信号(上り信号)レベルの一致を表示するまで送出レベ
ル設定器8を調整すると、上り下り各バス線の測定点9
及び10での信号レベルは一致し、本発明の目的が達成
される。The difference from the first embodiment is that the sending level of the upstream signal is not automatically adjusted, and the comparison results of the two signals from the comparator 4 are displayed on the display 7. The key point is that the output level of the upstream signal is manually set using the output level setter 8. When the output level setter 8 is adjusted until the display 7 shows that the received signal (downstream signal) level and the output signal (upstream signal) level match, the measurement points 9 of each upstream and downstream bus line are adjusted.
The signal levels at and 10 match and the object of the invention is achieved.
壕だ本発明は、端末向けの下り信号とノくス終端装置向
けの」二り信号が同一伝送方向であるようなバス方式で
あれば、いずれのシステムにも実施できる。更に各端末
装置に於ける出力信号レベルの設定は、当該出力信号レ
ベルを入力信号レベルに一致さぜるように設定するので
はなく、双方のレベルを一定の関係に維持させるべく出
力信号のレベルを制御するようにl〜でもよい。The present invention can be implemented in any bus system in which the downlink signal for the terminal and the two signals for the terminal device are transmitted in the same direction. Furthermore, the output signal level of each terminal device is not set so that the output signal level matches the input signal level, but the output signal level is set to maintain a constant relationship between both levels. l~ may be used to control.
以上のように構成した端末装置Tを第3図に示すように
バス11に結合したときの上り・くス線14の信号重畳
状態を第6図によって説明する。尚、第6図は前記第5
図と同様の方法で示しである。すなわち、41は/くス
終端装置MEに最も近い端末装置Tnの出力信号の/く
ス終端装置MEO受端での波形(エンベロープで示す。The signal superimposition state of the upstream/downstream line 14 when the terminal device T configured as described above is connected to the bus 11 as shown in FIG. 3 will be explained with reference to FIG. In addition, Fig. 6 shows the above-mentioned 5th
Shown in a similar manner to the figure. That is, 41 represents the waveform (indicated by an envelope) at the receiving end of the /x terminal device MEO of the output signal of the terminal device Tn closest to the /x terminal device ME.
他の記号についても同じ)を、42は端末装置Tnの出
力信号が端末装fttTn−iと上りノくス線14との
分岐点で反射してバス終端装置MEO受端に現われた反
射波の波形を、43はノくス終端装置MFiに最も遠い
端末装置T1の出力信号のバス終端装置MEO受端での
波形を、44は上記41〜43に示した信号が合成され
パス終端装置MFiO受端で実際に観測される波形をそ
れぞれモデル的に示しており、44の波形で441 、
442 、443.444はそれぞれ前記第5図の34
の波形に於ける341.342 、343及び344に
対応する。42 is the reflected wave that appears at the receiving end of the bus terminal device MEO after the output signal of the terminal device Tn is reflected at the branch point between the terminal device fttTn-i and the upstream line 14. 43 is the waveform at the bus termination device MEO receiving end of the output signal of the terminal device T1 which is farthest from the path termination device MFi, and 44 is the waveform at the bus termination device MEO receiving end where the signals shown in 41 to 43 above are combined and sent to the path termination device MFiO reception end. The waveforms actually observed at the edges are shown as models, and the 44 waveforms are 441, 441,
442, 443.444 are respectively 34 in the above figure 5.
This corresponds to 341, 342, 343, and 344 in the waveform.
第3図に於いて、バス終端装置MPから最も遠い端末装
置T1の受信レベル検出器2で検出される下り信号のレ
ベルは、バス終端装置MEに最も近い端末装置Tnの受
信レベル検出器2で検出される下り信号のレベルよりバ
ス11の線路長II t1tn++での伝送損失分に相
当するレベルだけ高い。送信回路3から出力される上り
信号のレベルは前記17だように比較器4及び送出レベ
ル自動調整器5又は送出レベル設定器8の作用で上記下
り信号のレベルに基いて設定されるので、端末装置T1
から送出される上り信号のレベルは上記線路長″t、
tnII での伝送損失分に相当するレベルだけ端
末装置Tnから送出される上り信号のレベルより高く設
定される。すなわち、バス終端装置MEから遠い端末装
置はどその間のバス110線路長に対応して高いレベル
で上り信号を出力することとなる。In FIG. 3, the level of the downlink signal detected by the reception level detector 2 of the terminal device T1 farthest from the bus termination device MP is the level of the downlink signal detected by the reception level detector 2 of the terminal device Tn closest to the bus termination device ME. The level is higher than the level of the detected downlink signal by a level corresponding to the transmission loss in the line length II t1tn++ of the bus 11. The level of the upstream signal output from the transmitting circuit 3 is set based on the level of the downstream signal by the action of the comparator 4 and the automatic transmission level adjuster 5 or the transmission level setter 8 as shown in 17 above, so that the terminal Device T1
The level of the upstream signal sent from the above line length "t,
The level corresponding to the transmission loss at tnII is set higher than the level of the upstream signal sent from the terminal device Tn. That is, terminal devices far from the bus termination device ME output uplink signals at a high level corresponding to the line length of the bus 110 between them.
従って第6図で41.43に示すように端末装置Tn及
び端末装置T□が出力するおのおのの上り信号がバス終
端装置MEO受端に達するときには双方ともほぼ同じレ
ベル(すなわち、44の波形に於いてa ’Hb )に
なっている。Therefore, as shown at 41.43 in FIG. 6, when the respective upstream signals output from the terminal device Tn and the terminal device T□ reach the receiving end of the bus terminal device MEO, they both have approximately the same level (that is, the waveform of 44). and a'Hb).
すなわち、第4図゛23”の直線に示すように、バス終
端装置MEの上りバス線14の受端に於ける各端末装置
T1〜Tnからの信号の着信レベルは全てはtぽ均一と
なる。That is, as shown by the straight line ``23'' in FIG. 4, the incoming levels of the signals from each of the terminal devices T1 to Tn at the receiving end of the upstream bus line 14 of the bus termination device ME are all equal to t. .
従って端末装置T1からの上り信号43が反射波42に
よって受ける影響は第6図で443及び444の関係で
示すように前記従来例に於ける場合に比べて極めて小さ
く (b/cが第5図の場合に比べて小さい。)、バス
終端装置MEでデータの誤検出が生ずることはない。Therefore, the influence of the reflected wave 42 on the upstream signal 43 from the terminal device T1 is extremely small compared to the case of the conventional example, as shown by the relationship between 443 and 444 in FIG. ), erroneous data detection does not occur at the bus termination device ME.
(本発明の効果)
第7図及び第8図は本発明の効果を示す波形写真であり
、それぞれ従来例(端末装fftTの送信回路部にレベ
ル調整手段を有しないもの)及び本発明の実施例(端末
装置Tの送信回路部にレベル調整手段を有するもの)の
バス終端装置ME受端に於ける実際の波形をオシロスコ
ープで観測した波形である。(Effects of the present invention) FIGS. 7 and 8 are waveform photographs showing the effects of the present invention, and are respectively a conventional example (one that does not have a level adjustment means in the transmitting circuit section of the terminal equipment fftT) and an example of the implementation of the present invention. This is an actual waveform observed with an oscilloscope at the receiving end of the bus terminating device ME in an example (the transmitting circuit section of the terminal device T has level adjustment means).
第7図及び第8図で、中央から左側はバス終端装置MF
jに最も近い端末装置′rnからの送信信号をバス終端
装置MEO受端で観測した波形を、中央から右側はバス
終端装置MEに最も遠い端末装置T1からの送信信号を
パス終端装置MEO受端で観測した波形をそれぞれ示し
ている。In Figures 7 and 8, the left side from the center is the bus termination device MF.
The waveform of the transmission signal from the terminal device 'rn closest to j is observed at the bus termination device MEO receiving end. The waveforms observed in each are shown.
この第7図及び第8図で理解できるように、従来ではバ
ス終端装置MEから離れた端末装置力・らの信号波形は
、従来の場合、信号の反射によって幾重にも重なった波
形が観測されるが、本発明実施例の場合、信号の反射に
よる影響は殆んどないため波形の重なりは観測されない
。As can be understood from FIGS. 7 and 8, conventionally, the signal waveform of the terminal device remote from the bus termination device ME is observed to have a waveform that overlaps many times due to signal reflection. However, in the case of the embodiment of the present invention, there is almost no influence due to signal reflection, so no overlap of waveforms is observed.
また第8図の中央から右側と左側との対比で明らかなよ
うに端末装置T、バス終端装置MB間の距離が異ってい
ても端末装置Tからの送信信号はほぼ同一レベルでバス
終端装置MEに受信される。Furthermore, as is clear from the comparison between the right side and the left side from the center of Fig. 8, even if the distance between the terminal device T and the bus termination device MB is different, the transmission signal from the terminal device T is at almost the same level. Received by ME.
以上のことから、本発明によれば、バスの端末装置への
分岐点に設備する分岐装置にバッファアンプ及び当該バ
ッファアンプを作動させる電源等を必要とせず、例えば
簡単なコネクタだけで分岐装置を構成でき、本発明はシ
ステムの小形、低コスト化及び運用コストの低減等に極
めて大きな効果を奏するものである。From the above, according to the present invention, the branch device installed at the branch point to the bus terminal device does not require a buffer amplifier and a power source to operate the buffer amplifier, and for example, the branch device can be installed with only a simple connector. The present invention is extremely effective in reducing system size, cost reduction, and operation cost.
第1図及び第2図はそれぞれ本発明の実施例のブロック
図、第3図は本発明を実施する時分割多重デジタル信号
伝送システムのブロック図、第4図′はバスの信号レベ
ルを説明するグラフ、第5図及び第6図はそれぞれ従来
例及び本発明の実施例に係るバス終端装置での受信信号
レベルを説明する図、第7図及び第8図はそれぞれ従来
例及び本発明の実施例に係るバス終端装置MEでの受信
信号波形のオシロスコープ写真である。
(主な記号)
MID・・・バス終端装置t T(Tt〜’rn)
・・・端末装置1・・・受信回路 2・・・受
信レベル検出器3・:・送信回路 4・・・比
較器5・・・送出レベル自動調整器
6・・・中央処理装ft7・・・表示器8・・・送出レ
ベル設定i11・・・バス13・・・下りバス線
14・・・上りバス線。
第1図
第2図
第4図
TIT2−−−−−−−−7yI ME −□4P請
イfl 置
第5図
第6図
第7図
手続補正書
昭和2θ年7月//日
1、事件の表示
昭和ケア手持 許願第7326.j3号事件との関係
出 願 人
4、代理人
(f所 東京都千代田区丸の内2丁目6番2号丸の内
へ屯洲ビル33〇8、補正の内容 別紙のとおり
補 正 書
本願明細書及び図面中下記事項を補正いたします。
記
1、第8頁6行目に
「フツファアンプ」とあるを
「バッファアンプ」と訂正する。
2、図面中「第3図」を本日提出の図面に訂正する。
、−)
代理人 谷 山 輝 雄:□ [
ヒ」Figures 1 and 2 are block diagrams of embodiments of the present invention, Figure 3 is a block diagram of a time division multiplex digital signal transmission system implementing the present invention, and Figure 4' explains bus signal levels. Graphs, FIGS. 5 and 6 are diagrams illustrating received signal levels in the bus termination devices according to the conventional example and the embodiment of the present invention, respectively, and FIGS. 7 and 8 are graphs illustrating the conventional example and the implementation of the present invention, respectively. It is an oscilloscope photograph of the received signal waveform in the bus termination device ME according to an example. (Main symbols) MID...Bus terminal device t T (Tt~'rn)
...Terminal device 1...Receiving circuit 2...Reception level detector 3...Transmission circuit 4...Comparator 5...Sending level automatic adjuster 6...Central processing unit ft7...・Display 8...Output level setting i11...Bus 13...Down bus line
14...Inbound bus line. Figure 1 Figure 2 Figure 4 TIT2---------7yI ME -□4P request
Ifl Figure 5 Figure 6 Figure 7 Procedural amendment document Showa 2θ July//Date 1, Incident display Showa Care in hand Permission No. 7326. Relationship with the j3 incident
Applicant 4, Agent (f: 3308 Marunouchi Hetonzu Building, 2-6-2 Marunouchi, Chiyoda-ku, Tokyo) Contents of the amendments The following matters have been amended in the specification and drawings of the application as shown in the attached document. Note 1. On page 8, line 6, the word "futufa amplifier" is corrected to "buffer amplifier." 2. "Figure 3" in the drawing is corrected to the drawing submitted today. ,-) Agent Tani Teruo Yama: □ [hi]
Claims (1)
信号の伝送方向と端末装置から送出されてバス終端装置
で受信される信号の伝送方向とが時分割多重デジタルバ
ス上で同一となるようにしてある時分割多重デジタル信
号送出システムの端末装置に於いて、端末装置ごとに受
信信号レベルと送出信号レベルとを比較し、このレベル
比較結果に基いて端末装置毎に設定した送出レベルによ
つて信号を上記時分割多重デジタルバスに送出するよう
にした端末装置からの信号送出方式。 2 レベル比較結果を信号送出回路に入力して送出信号
レベルを自動的に設定するようにした特許請求の範囲第
1項に記載の端末装置からの信号送出方式。 3 レベル比較結果を表示し、この表示に基いて送出信
号レベルを人為的に設定するようにした特許請求の範囲
第1項に記載の端末装置からの信号送出方式。[Claims] 1. The transmission direction of the signal sent from the bus termination device and received by the terminal device and the transmission direction of the signal sent out from the terminal device and received by the bus termination device are on a time division multiplexed digital bus. In the terminal equipment of the time division multiplex digital signal transmission system, which is set to be the same at the terminal equipment, the received signal level and the transmitted signal level are compared for each terminal equipment, and the settings are made for each terminal equipment based on the result of this level comparison. A signal transmission method from a terminal device that transmits a signal to the time division multiplex digital bus according to a transmission level. 2. A signal transmission system from a terminal device according to claim 1, wherein the level comparison result is input to a signal transmission circuit to automatically set a transmission signal level. 3. The signal transmission method from the terminal device according to claim 1, wherein the level comparison result is displayed and the transmission signal level is artificially set based on this display.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59132633A JPS6112146A (en) | 1984-06-27 | 1984-06-27 | Signal transmission system from terminal equipment |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59132633A JPS6112146A (en) | 1984-06-27 | 1984-06-27 | Signal transmission system from terminal equipment |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS6112146A true JPS6112146A (en) | 1986-01-20 |
Family
ID=15085888
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP59132633A Pending JPS6112146A (en) | 1984-06-27 | 1984-06-27 | Signal transmission system from terminal equipment |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6112146A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0225766U (en) * | 1988-08-05 | 1990-02-20 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS54115011A (en) * | 1978-02-28 | 1979-09-07 | Fujitsu Ltd | Signal compensation system |
JPS5917753A (en) * | 1982-07-20 | 1984-01-30 | Nippon Telegr & Teleph Corp <Ntt> | Connecting system of bus cable |
-
1984
- 1984-06-27 JP JP59132633A patent/JPS6112146A/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS54115011A (en) * | 1978-02-28 | 1979-09-07 | Fujitsu Ltd | Signal compensation system |
JPS5917753A (en) * | 1982-07-20 | 1984-01-30 | Nippon Telegr & Teleph Corp <Ntt> | Connecting system of bus cable |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0225766U (en) * | 1988-08-05 | 1990-02-20 |
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