JPH05315998A - Method for reducing distortion on transmission line - Google Patents
Method for reducing distortion on transmission lineInfo
- Publication number
- JPH05315998A JPH05315998A JP12090392A JP12090392A JPH05315998A JP H05315998 A JPH05315998 A JP H05315998A JP 12090392 A JP12090392 A JP 12090392A JP 12090392 A JP12090392 A JP 12090392A JP H05315998 A JPH05315998 A JP H05315998A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- transmission
- transmission line
- circuit
- low frequency
- 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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明はパルス符号通信（ベー
スバンド伝送）あるいは変復調を使用したデータ通信に
おいて、伝送路歪を低減することにより正しい受信を行
う伝送路歪の低減方法に関するものである。なお以下各
図において同一の符号は同一もしくは相当部分を示す。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission line distortion reducing method for performing correct reception by reducing transmission line distortion in pulse code communication (baseband transmission) or data communication using modulation / demodulation. In the following figures, the same reference numerals indicate the same or corresponding parts.
【０００２】[0002]
【従来の技術】従来、伝送路歪を低減して正しくデータ
通信するための技術としては大きく分けて２種類ある。
１つの方法は図６のように受信側で歪を低減する方法で
ある。なお同図において０１は送信回路、０２は受信回
路、１は送信回路０１と受信回路０２とを結ぶ伝送路、
２は受信回路０２内に設けられた等化器、３は同じく復
調器である。2. Description of the Related Art Conventionally, there are roughly two types of techniques for reducing transmission line distortion and performing correct data communication.
One method is to reduce distortion on the receiving side as shown in FIG. In the figure, 01 is a transmitting circuit, 02 is a receiving circuit, 1 is a transmission line connecting the transmitting circuit 01 and the receiving circuit 02,
Reference numeral 2 is an equalizer provided in the receiving circuit 02, and 3 is a demodulator.
【０００３】即ち受信回路０２側に、信号が伝達される
伝送路１の特性と逆特性のフィルタとしての等化器２を
設け、伝送路からの受信信号をそのフィルタ２を通すこ
とにより、伝送路歪を除去し復調器３を介し正しく復調
しようとする方法である。もう１つの方法は、送信側に
てあらかじめ送信波形を変化させておくことにより歪を
低減する方法である。１０ＢＡＳＥ−Ｔでのプリディス
トーション技術がこれに当たる。That is, the receiving circuit 02 side is provided with an equalizer 2 as a filter having characteristics opposite to those of the transmission line 1 through which a signal is transmitted, and a received signal from the transmission line is transmitted by passing through the filter 2. This is a method of removing the path distortion and trying to demodulate correctly through the demodulator 3. The other method is to reduce distortion by changing the transmission waveform in advance on the transmission side. This is the pre-distortion technology with 10BASE-T.
【０００４】図７はこのプリディストーション技術を説
明するための波形図であり、同図において点線の波形が
プリディストーションしない場合の送受信波形で、実線
がプリディストーションを行なった場合の送受信波形で
ある。即ちプリディストーションを行なった実線の波形
では送信波形と受信波形のゼロクス時点が互いに一致し
ている。FIG. 7 is a waveform diagram for explaining this predistortion technique. In FIG. 7, the dotted line waveform is the transmission / reception waveform when no predistortion is performed, and the solid line is the transmission / reception waveform when predistortion is performed. That is, in the predistorted solid line waveform, the zerox time points of the transmission waveform and the reception waveform coincide with each other.
【０００５】[0005]
【発明が解決しようとする課題】しかし、これらの方式
には問題点がある。即ち前者の方式の場合、まず伝送路
と完全に逆特性の等化器を作り出すことは不可能であ
り、また等化器の入力インピーダンスを高く保ち、等化
器で信号が減衰しないためには、受信装置の初段にバッ
ファを設けるか、アクティブ素子を使用した等化器を構
成しなければならず、いずれにしろ回路構成が複雑にな
るという欠点がある。However, these methods have problems. That is, in the case of the former method, it is impossible to first create an equalizer whose characteristics are completely opposite to those of the transmission line.Moreover, the input impedance of the equalizer is kept high and the signal is not attenuated by the equalizer. However, it is necessary to provide a buffer at the first stage of the receiving device or to configure an equalizer using active elements, which has a drawback that the circuit configuration becomes complicated in any case.
【０００６】また後者の方式の場合、送信波形に段差
（中間レベル）を作り出すことが必要である。そのため
には送信ドライバへの供給電圧を２種類用意して段差を
設ける方法や、あるいは通常の方法として、抵抗分圧を
使用して段差を設けるという方法があるが、これには送
信損失を伴うという問題がある。そこでこの発明は上述
の欠点を除去し、簡単な回路方式で、送信損失が少な
く、伝送路歪を正確に除去できる伝送路歪の低減方法を
提供することを課題とする。In the latter method, it is necessary to create a step (intermediate level) in the transmission waveform. For that purpose, there are a method of preparing two kinds of voltage to be supplied to the transmission driver to form the step, or a method of forming the step using resistance voltage division as a usual method, but this involves transmission loss. There is a problem. Therefore, it is an object of the present invention to provide a method for reducing transmission line distortion, which eliminates the above-mentioned drawbacks, has a simple circuit system, has a small transmission loss, and can accurately remove transmission line distortion.
【０００７】[0007]
【課題を解決するための手段】前記の課題を解決するた
めに、本発明の伝送路歪の低減方法は、デジタルデータ
（送信データ４などの）送信の際、信号が伝達される伝
送路（１などの）上で生じる、信号中の低い周波数成分
の群遅延時間から高い周波数成分の群遅延時間を差し引
いた群遅延時間差だけ、送信装置（０１などの）側にて
（プリディストーション回路５，プリディストーション
付変調回路１５などを介し）送信信号（１Ｓなどの）中
の低い周波数信号成分を、高い周波数成分に比べ、より
早く送信するようにする。In order to solve the above-mentioned problems, a transmission line distortion reducing method according to the present invention uses a transmission line (a transmission line through which a signal is transmitted when transmitting digital data (such as transmission data 4)). 1)) and the group delay time difference obtained by subtracting the group delay time of the high frequency component from the group delay time of the low frequency component in the signal (predistortion circuit 5, The low frequency signal component in the transmission signal (such as 1S) is transmitted earlier than the high frequency component (via the modulation circuit with predistortion 15 or the like).
【０００８】[0008]
【作用】送信側にて、送信信号中の低い周波数成分を高
い周波数成分より伝送路によるジッタ分（群遅延時間差
＝低い周波数の群遅延時間−高い周波数の群遅延時間）
だけ早く出力するようにし、その伝送路を経由した受信
側の伝送路歪が零となるようにする。On the transmitting side, the low frequency component in the transmission signal is compared with the high frequency component by the amount of jitter due to the transmission path (group delay time difference = low frequency group delay time−high frequency group delay time).
The output is performed as early as possible so that the transmission line distortion on the receiving side via the transmission line becomes zero.
【０００９】[0009]
【実施例】以下図１ないし図５に基づいて本発明の実施
例を説明する。図１は本発明の第１の実施例としての要
部構成を示すブロック図、図２は図１における各部の波
形図、図３は図１において本発明を適用しない場合の各
部の波形図である。図２，図３では実際には送信信号１
Ｓより受信信号１Ｒが遅れているはずであるが、判り易
くするため受信信号１Ｒの位置を前にずらして表現して
いる。Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a main part as a first embodiment of the present invention, FIG. 2 is a waveform diagram of each part in FIG. 1, and FIG. 3 is a waveform diagram of each part when the present invention is not applied in FIG. is there. 2 and 3, the transmission signal 1 is actually
Although the received signal 1R should be delayed from S, the position of the received signal 1R is shifted to the front for easy understanding.
【００１０】図１はマンチェスタ符号でベースバンド伝
送する場合に本発明を実施した例である。同図において
５は送信装置０１に新設された本発明の主体となるプリ
ディストーション回路である。なお６は送信装置０１内
にあって伝送路１に送信信号１Ｒを入力するドライバ、
８は受信装置０２内にあって伝送路１から受信信号１Ｒ
を取出し検出信号９とするレシーバである。FIG. 1 shows an example in which the present invention is implemented in the case of baseband transmission with Manchester code. In the figure, reference numeral 5 denotes a predistortion circuit which is the main subject of the present invention and which is newly installed in the transmitter 01. In addition, 6 is a driver for inputting the transmission signal 1R to the transmission line 1 in the transmission device 01,
Reference numeral 8 denotes a reception signal 1R from the transmission line 1 in the reception device 02.
It is a receiver that takes out and outputs the detection signal 9.
【００１１】次に図２を参照しつつ図１の動作を説明す
ると、送信装置０１では図２に示す波形の送信データ４
をプリディストーション回路５を通し、図２に示す波形
のプリディストーションされた信号（プリディストーシ
ョン信号）５ａとして送信ドライバ６に送る。そして送
信ドライバ６は図２に示す波形の送信信号１Ｓを伝送路
１に送出する。この送信信号１Ｓは伝送路１を経由して
図２に示すような波形の受信信号１Ｒとなり、この受信
信号１Ｒは受信装置０２のレシーバ８に入力されてレシ
ーバ８からは図２に示す波形の検出信号９が出力され
る。この検出信号９はさらに図外の手段で復調されて受
信データが得られる。Next, the operation of FIG. 1 will be described with reference to FIG. 2. In the transmitter 01, the transmission data 4 having the waveform shown in FIG.
Through the predistortion circuit 5 and sent to the transmission driver 6 as a predistorted signal (predistortion signal) 5a having the waveform shown in FIG. Then, the transmission driver 6 sends out the transmission signal 1S having the waveform shown in FIG. This transmission signal 1S becomes a reception signal 1R having a waveform as shown in FIG. 2 via the transmission line 1, and this reception signal 1R is input to the receiver 8 of the receiving apparatus 02 and the reception signal 1R has the waveform shown in FIG. The detection signal 9 is output. This detection signal 9 is further demodulated by means not shown to obtain received data.
【００１２】次に図１のプリディストーション回路５の
説明を行なう。図３は図１において図２と同じ送信デー
タ４をプリディストーション回路５を通さず（つまりジ
ッタ抑制を行わず）送信した場合における送信信号１
Ｓ，受信信号１Ｒおよび検出信号９の夫々の波形を示す
もので、受信信号１Ｒの波形に歪が生じ、そのため検出
信号９にジッタＴｊを生じている。これに対し図２は本
発明によるプリディストーション回路５を通した場合の
プリディストーション信号５ａ，送信信号１Ｓ，受信信
号１Ｒと検出信号９の関係を示す図である。つまりプリ
ディストーション回路５では入力された送信データ４を
基にして、伝送路１の予測されたジッタ分Ｔｊだけ、低
い周波数成分を高い周波数成分より早く出力するように
動作する。そのようにして作られた信号が図２のプリデ
ィストーション信号５ａである。このように動作するた
め、伝送路１を経由した受信信号１Ｒ、そしてレシーバ
８を介して検出した検出信号９は歪が除去された正しい
目的の信号波形となる。Next, the predistortion circuit 5 of FIG. 1 will be described. 3 is a transmission signal 1 in the case where the same transmission data 4 as in FIG. 2 is transmitted without passing through the predistortion circuit 5 (that is, without suppressing jitter) in FIG.
The waveforms of S, the received signal 1R, and the detection signal 9 are shown, and the waveform of the received signal 1R is distorted, so that the detection signal 9 has a jitter Tj. On the other hand, FIG. 2 is a diagram showing the relationship between the predistortion signal 5a, the transmission signal 1S, the reception signal 1R and the detection signal 9 when passing through the predistortion circuit 5 according to the present invention. That is, the predistortion circuit 5 operates so that the low frequency component is output earlier than the high frequency component by the predicted jitter amount Tj of the transmission line 1 based on the input transmission data 4. The signal thus produced is the predistortion signal 5a in FIG. Since it operates in this way, the received signal 1R passing through the transmission line 1 and the detection signal 9 detected through the receiver 8 become a correct target signal waveform with distortion removed.
【００１３】プリディストーション信号５ａから判るよ
うに、高い周波数信号の次に低い周波数信号が来る場
合、その低い周波数信号の最初の半周期は低い周波数信
号の正規の周波数より少し周波数が高くなる。逆に低い
周波数信号の次に高い周波数信号が来る場合、その高い
周波数信号の最初の半周期は高い周波数信号の正規の周
波数より少し周波数が低くなる。As can be seen from the pre-distortion signal 5a, when the next low frequency signal comes after the high frequency signal, the first half cycle of the low frequency signal becomes slightly higher in frequency than the normal frequency of the low frequency signal. On the contrary, when the next high frequency signal comes after the low frequency signal, the first half cycle of the high frequency signal is slightly lower in frequency than the normal frequency of the high frequency signal.
【００１４】図４は本発明の第２の実施例としての要部
構成を示すブロック図で、１５は送信装置０１内に設け
られた、この発明の主体となるプリディストーション付
変調回路、１８は受信装置０２内に設けられた復調回路
である。また図５は図４の動作説明用の各部の波形図で
ある。図５では実際には送信信号１Ｓより受信信号１Ｒ
が遅れているはずであり、また減衰のため受信信号１Ｒ
の波高値は低くなるはずであるが、判り易くするため位
置関係をずらし、波高値を同一にしている。FIG. 4 is a block diagram showing the configuration of the essential parts of the second embodiment of the present invention. Reference numeral 15 is a modulation circuit with predistortion, which is the main subject of the present invention, provided in the transmitter 01. This is a demodulation circuit provided in the receiving device 02. FIG. 5 is a waveform diagram of each part for explaining the operation of FIG. In FIG. 5, the received signal 1R is actually changed from the transmitted signal 1S.
Should be delayed, and the received signal 1R due to attenuation
The crest value should be low, but in order to make it easier to understand, the positional relationship is shifted and the crest value is made the same.
【００１５】図４は変調（位相連続ＦＳＫ）を使用して
データ伝送する場合に本発明を実施した例である。送信
装置０１では図５に示す波形の送信データ４を、本発明
によるプリディストーションが付いた変調回路１５を通
して図５に示す波形の送信信号１Ｓとして伝送路１に送
出する。そして送信信号１Ｓは伝送路１を経由して受信
装置０２に入り、復調回路１８を介して検出信号９を得
る。FIG. 4 shows an example in which the present invention is carried out when data is transmitted using modulation (phase continuous FSK). In the transmission device 01, the transmission data 4 having the waveform shown in FIG. 5 is transmitted to the transmission line 1 as the transmission signal 1S having the waveform shown in FIG. 5 through the modulation circuit 15 with predistortion according to the present invention. Then, the transmission signal 1S enters the receiving device 02 via the transmission path 1 and obtains the detection signal 9 via the demodulation circuit 18.
【００１６】次にこの第２の実施例の場合のプリディス
トーション方法について説明を行なう。図５はプリディ
ストーションが付いた変調回路１５を通した場合の送信
信号１Ｓ，受信信号１Ｒの各波形の関係を示している。
プリディストーションが付いた変調回路１５では入力さ
れた送信データ４を基にして、伝送路の予測されたジッ
タ分Ｔｊだけ、低い周波数成分を高い周波数成分より早
く出力するように動作する。そのように動作するため、
伝送路１を経由した受信信号１Ｒは歪が除去された正し
い目的の変調波形となる。送信信号１Ｒの波形から判る
ように、高い周波数信号の次に低い周波数信号が来る場
合、その低い周波数信号の最初の半周期（ｆＬ２）は低
い周波数信号の正規の周波数（ｆＬ１）より少し周波数
が高くなる。逆に低い周波数信号の次に高い周波数信号
が来る場合、その高い周波数信号の最初の半周期（ｆＨ
２）は高い周波数信号の正規の周波数（ｆＨ１）より少
し周波数が低くなる。つまり ｆＨ１＞ｆＨ２ ｆＬ２＞ｆＬ１ ─────────── （１） のような関係がある。Next, the predistortion method in the case of the second embodiment will be described. FIG. 5 shows the relationship between the waveforms of the transmission signal 1S and the reception signal 1R when passing through the modulation circuit 15 with predistortion.
The modulation circuit 15 with predistortion operates so as to output the low frequency component earlier than the high frequency component by the predicted jitter amount Tj of the transmission line based on the input transmission data 4. Because it works that way,
The received signal 1R passing through the transmission line 1 has a correct target modulation waveform with distortion removed. As can be seen from the waveform of the transmission signal 1R, when the low frequency signal comes next to the high frequency signal, the first half cycle (fL2) of the low frequency signal has a frequency slightly smaller than the normal frequency (fL1) of the low frequency signal. Get higher On the contrary, when the next high frequency signal comes after the low frequency signal, the first half period (fH
In 2), the frequency is slightly lower than the normal frequency (fH1) of the high frequency signal. In other words, there is a relationship such as fH1> fH2 fL2> fL1 ─────────── (1).
【００１７】[0017]
【発明の効果】本発明によれば、伝送路中で発生する高
い周波数成分と低い周波数成分の群遅延差（ジッタ）が
伝送路長あるいは伝送路の材質、形状から予測できるの
で、あらかじめ送信信号にその伝送路上で生じる予測群
遅延差を逆に上乗せするようにしたので、その伝送路を
経由した受信信号は正確に伝送路歪を除去され、目的と
する正しい信号デューティとすることができ、より正し
い受信が行い易くなる。According to the present invention, the group delay difference (jitter) between the high frequency component and the low frequency component generated in the transmission line can be predicted from the transmission line length or the material and shape of the transmission line. Since the predicted group delay difference occurring on the transmission path is added in reverse, the reception signal passing through the transmission path is accurately removed of the transmission path distortion, and the target correct signal duty can be obtained. It becomes easier to perform correct reception.
【図１】本発明の第１の実施例としての要部構成を示す
ブロック図FIG. 1 is a block diagram showing a main part configuration as a first embodiment of the present invention.
【図２】図１の各部の信号の波形図FIG. 2 is a waveform diagram of signals at various parts in FIG.
【図３】本発明を適用しない場合の図１の各部の信号の
波形図FIG. 3 is a waveform diagram of signals at various parts in FIG. 1 when the present invention is not applied.
【図４】本発明の第２の実施例としての要部構成を示す
ブロック図FIG. 4 is a block diagram showing a main configuration of a second embodiment of the present invention.
【図５】図４の各部の信号の波形図FIG. 5 is a waveform diagram of signals at various parts in FIG.
【図６】従来の伝送歪低減方法の１例を説明するための
ブロック図FIG. 6 is a block diagram for explaining an example of a conventional transmission distortion reduction method.
【図７】従来の伝送歪低減方法の他の例を説明するため
の波形図FIG. 7 is a waveform diagram for explaining another example of the conventional transmission distortion reduction method.
０１ 送信装置 ０２ 受信装置 １ 伝送路 １Ｓ 送信信号 １Ｒ 受信信号 ４ 送信データ ５ プリディストーション回路 ５ａ プリディストーション信号 ６ ドライバ ８ レシーバ ９ 検出信号 １５ プリディストーション付変調回路 １８ 復調回路 01 transmitter 02 receiver 1 transmission path 1S transmission signal 1R reception signal 4 transmission data 5 predistortion circuit 5a predistortion signal 6 driver 8 receiver 9 detection signal 15 modulation circuit with predistortion 18 demodulation circuit
Claims (1)
る伝送路上で生じる、信号中の低い周波数成分の群遅延
時間から高い周波数成分の群遅延時間を差し引いた群遅
延時間差だけ、送信装置側にて送信信号中の低い周波数
信号成分を、高い周波数成分に比べ、より早く送信する
ことを特徴とする伝送路歪の低減方法。1. At the time of digital data transmission, the transmitter side is equal to a group delay time difference which is generated on a transmission path through which a signal is transmitted and which is obtained by subtracting a group delay time of a high frequency component from a group delay time of a low frequency component in the signal. In the method of reducing transmission line distortion, the low frequency signal component in the transmission signal is transmitted earlier than the high frequency component.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12090392A JPH05315998A (en) | 1992-05-14 | 1992-05-14 | Method for reducing distortion on transmission line |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12090392A JPH05315998A (en) | 1992-05-14 | 1992-05-14 | Method for reducing distortion on transmission line |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05315998A true JPH05315998A (en) | 1993-11-26 |
Family
ID=14797853
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12090392A Pending JPH05315998A (en) | 1992-05-14 | 1992-05-14 | Method for reducing distortion on transmission line |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05315998A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002037785A1 (en) * | 2000-10-30 | 2002-05-10 | Daikin Industries, Ltd. | Data transmission method and data transmission device |
| JP2005168031A (en) * | 2003-12-04 | 2005-06-23 | Lucent Technol Inc | Electrical backplane transmission using duobinary signal transmission |
| US7184479B2 (en) | 2000-10-30 | 2007-02-27 | Daikin Industries, Ltd. | Data transmission method and data transmission device |
| JP2012165253A (en) * | 2011-02-08 | 2012-08-30 | Mitsubishi Electric Corp | Transmission distance extension device and communication device |
| US8923433B2 (en) | 1997-06-20 | 2014-12-30 | Massachusetts Institute Of Technology | Digital transmitter |
| WO2015140976A1 (en) * | 2014-03-20 | 2015-09-24 | 三菱電機株式会社 | Processing circuit and signal correction method |
-
1992
- 1992-05-14 JP JP12090392A patent/JPH05315998A/en active Pending
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| US8923433B2 (en) | 1997-06-20 | 2014-12-30 | Massachusetts Institute Of Technology | Digital transmitter |
| US8989303B2 (en) | 1997-06-20 | 2015-03-24 | Massachusetts Institute Of Technology | Digital transmitter |
| US9419824B2 (en) | 1997-06-20 | 2016-08-16 | Massachusetts Institute Of Technology | Digital transmitter |
| US9647857B2 (en) | 1997-06-20 | 2017-05-09 | Massachusetts Institute Of Technology | Digital transmitter |
| WO2002037785A1 (en) * | 2000-10-30 | 2002-05-10 | Daikin Industries, Ltd. | Data transmission method and data transmission device |
| AU759254B2 (en) * | 2000-10-30 | 2003-04-10 | Daikin Industries, Ltd. | Data transmission method and data transmission device |
| US7184479B2 (en) | 2000-10-30 | 2007-02-27 | Daikin Industries, Ltd. | Data transmission method and data transmission device |
| JP2005168031A (en) * | 2003-12-04 | 2005-06-23 | Lucent Technol Inc | Electrical backplane transmission using duobinary signal transmission |
| JP2012165253A (en) * | 2011-02-08 | 2012-08-30 | Mitsubishi Electric Corp | Transmission distance extension device and communication device |
| WO2015140976A1 (en) * | 2014-03-20 | 2015-09-24 | 三菱電機株式会社 | Processing circuit and signal correction method |
| US10084618B2 (en) | 2014-03-20 | 2018-09-25 | Mitsubishi Electric Corporation | Processing circuit and signal correction method |
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