JPH04372213A - Transmission interface circuit for lan - Google Patents
Transmission interface circuit for lanInfo
- Publication number
- JPH04372213A JPH04372213A JP17618391A JP17618391A JPH04372213A JP H04372213 A JPH04372213 A JP H04372213A JP 17618391 A JP17618391 A JP 17618391A JP 17618391 A JP17618391 A JP 17618391A JP H04372213 A JPH04372213 A JP H04372213A
- Authority
- JP
- Japan
- Prior art keywords
- filter circuit
- unbalanced
- filter
- pulse transformer
- balanced
- 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.)
- Granted
Links
- 230000005540 biological transmission Effects 0.000 title claims abstract description 39
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 239000003990 capacitor Substances 0.000 abstract description 12
- 238000004806 packaging method and process Methods 0.000 abstract 1
- 238000004804 winding Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000005674 electromagnetic induction Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
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Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、ＬＡＮ用伝送インター
フェース回路に関するものである。更に詳しく述べると
、送受信側の各フィルタ回路と伝送路間にパルストラン
スを配置して両者を分離絶縁し、ツイストペア電線によ
り平衡型伝送を行うＬＡＮ用伝送インターフェース回路
、特にそのフィルタ回路に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission interface circuit for LAN. More specifically, the present invention relates to a transmission interface circuit for a LAN, in which a pulse transformer is placed between each filter circuit on the transmitting/receiving side and the transmission line to isolate and insulate the two, and balanced transmission is performed using twisted pair electric wires, and in particular to the filter circuit. .
【０００２】0002
【従来の技術】ＬＡＮとはローカル・エリア・ネットワ
ークの略で、同一の建物内や敷地内など比較的限られた
地域内に設置されたコンピュータ、端末、大容量記憶装
置、プリンタ等を結ぶネットワーク・システムのことで
あり、情報交換の能率を向上する手段として使用されて
いる。このＬＡＮの伝送路の媒体には、同軸ケーブル、
光ファイバ等種々のものがあるが、最近はイーサーネッ
ト系の１０ＢａｓｅＴ規格の出現により、ツイストペア
電線を媒体に使用する方式が注目を浴びており、比較的
安価にＬＡＮシステムを構築できるようになった。[Background Art] LAN is an abbreviation for local area network, which is a network that connects computers, terminals, mass storage devices, printers, etc. installed within a relatively limited area such as within the same building or site. - A system used as a means to improve the efficiency of information exchange. The medium of this LAN transmission path is a coaxial cable,
There are various types such as optical fibers, but recently, with the advent of the Ethernet-based 10BaseT standard, methods that use twisted pair electric wires as a medium have been attracting attention, and it has become possible to construct LAN systems at a relatively low cost. .
【０００３】ツイストペア電線を伝送媒体に使用する場
合、電線をより合わせているため電磁誘導によるノイズ
電圧は２本の電線に等しく且つ相殺する方向に発生し、
結果として互いに打ち消し合ってノイズが除去されるは
ずである。しかし、電磁誘導による磁界変化は常に電線
に均一作用せず電線に誘起するノイズ電圧が等しくなる
とは限らないため、ノイズが完全に除去されるわけでは
ない。同軸ケーブル等のようにシールドされているわけ
ではないので当然ノイズの影響を避けることはできず、
その対策としてパルストランスや各種フィルタ回路を使
用しなければならない。When twisted pair electric wires are used as a transmission medium, since the electric wires are twisted together, noise voltage due to electromagnetic induction is generated in the two electric wires equally and in a direction that cancels each other out.
As a result, noise should be removed by canceling each other out. However, since changes in the magnetic field due to electromagnetic induction do not always act uniformly on the wires and the noise voltages induced on the wires are not always equal, noise cannot be completely removed. Since it is not shielded like a coaxial cable, it is naturally impossible to avoid the effects of noise.
As a countermeasure, pulse transformers and various filter circuits must be used.
【０００４】図２にツイストペア電線を伝送路とするＬ
ＡＮで用いられている従来の典型的なフィルタ回路の例
を示す。Ａは送信側、Ｂは受信側である。Ａの送信側に
おいては、ドライバＩＣ１ とフィルタ回路３０を組み
合わせ、パルストランスＴ１ を介して伝送路であるツ
イストペア電線１２に接続する構成である。点線で囲ま
れたフィルタ回路３０は、コイルとコンデンサで構成さ
れる４組のＬＣフィルタ部をグランドと両信号線間に各
二段配置した平衡型である。この平衡型のフィルタ回路
３０は４個のコイル（Ｌ３１〜Ｌ３４）と１０個のコン
デンサ（Ｃ３１〜Ｃ４０）からなり、各ＬＣフィルタ部
が特性インピーダンス５０Ωに設定され、所望の周波数
帯域の信号を通過させノイズを抑えるフィルタ特性を有
する。そして、パルストランスＴ１ を介して特性イン
ピーダンス１００Ωのツイストペア電線１２が接続され
、平衡信号が送出される。パルストランスＴ１ は直流
レベルの接続を断ち切ることにより良好なサージ対策と
なり、またアースから切り離すことにより伝送路側にグ
ランドループが発生することを防止している。FIG. 2 shows an L using twisted pair electric wires as a transmission path.
An example of a conventional typical filter circuit used in an AN is shown. A is the sending side and B is the receiving side. On the transmission side of A, a driver IC1 and a filter circuit 30 are combined and connected to a twisted pair electric wire 12, which is a transmission path, via a pulse transformer T1. The filter circuit 30 surrounded by dotted lines is a balanced type in which four sets of LC filter sections each consisting of a coil and a capacitor are arranged in two stages between the ground and both signal lines. This balanced filter circuit 30 consists of four coils (L31 to L34) and ten capacitors (C31 to C40), each LC filter section is set to a characteristic impedance of 50Ω, and passes signals in a desired frequency band. It has filter characteristics that suppress noise. Then, a twisted pair electric wire 12 having a characteristic impedance of 100Ω is connected via a pulse transformer T1, and a balanced signal is sent out. The pulse transformer T1 serves as a good measure against surges by cutting off the DC level connection, and also prevents ground loops from occurring on the transmission line side by separating it from the ground.
【０００５】同様にＢの受信側においては、レシーバＩ
Ｃ２ と平衡型フィルタ回路４０を組み合わせパルスト
ランスＴ２ を介して伝送路であるツイストペア電線１
２に接続する構成である。送出されてきた平衡信号はパ
ルストランスＴ２ を介してフィルタ回路４０に入力す
る。上記送信側と同様の平衡型フィルタ回路４０は、所
望の信号を通過させ、外来ノイズを抑える。この平衡型
フィルタ回路４０も、４個のコイル（Ｌ４１〜Ｌ４４）
と１０個のコンデンサ（Ｃ４１〜Ｃ５０）からなる。Similarly, on the receiving side of B, receiver I
C2 and a balanced filter circuit 40 are combined and a twisted pair electric wire 1 serving as a transmission path is connected via a pulse transformer T2.
This configuration connects to 2. The sent balanced signal is input to the filter circuit 40 via the pulse transformer T2. A balanced filter circuit 40 similar to that on the transmitting side passes the desired signal and suppresses external noise. This balanced filter circuit 40 also has four coils (L41 to L44).
and 10 capacitors (C41 to C50).
【０００６】なお上記の構成で、フィルタ部を二段縦続
接続しているのは、フィルタ部が一段のみでは所望のフ
ィルタ特性（特に減衰特性）が得られないからである。[0006] In the above configuration, the filter sections are connected in two stages in cascade because the desired filter characteristics (particularly attenuation characteristics) cannot be obtained with only one stage of filter sections.
【０００７】[0007]
【発明が解決しようとする課題】最近のパーソナル・コ
ンピュータ等の小型化と合わせＬＡＮ伝送装置の小型化
も要請されているが、平衡型フィルタ回路を使用してい
るため部品点数が多く小型化が困難である。またツイス
トペア電線などの安価な伝送媒体を使用しながらフィル
タ回路が高価となるため装置全体の価格の低減に支障を
きたしている。[Problem to be solved by the invention] Along with the recent miniaturization of personal computers, there is a demand for miniaturization of LAN transmission equipment, but since a balanced filter circuit is used, there are many parts, making it difficult to miniaturize. Have difficulty. Furthermore, although an inexpensive transmission medium such as a twisted pair electric wire is used, the filter circuit becomes expensive, which poses an obstacle to reducing the price of the entire device.
【０００８】ところでパルストランスには本来、平衡−
不平衡変換機能がある。従って、フィルタ回路が不平衡
であってもパルストランスの出力側は平衡（差動）信号
にできる。そこでこのことを利用し、ドライバ又はレシ
ーバとパルストランスとの間に不平衡型フィルタ回路を
組み込むことで、部品点数の低減を図ることが考えられ
る。しかし、通常の不平衡型フィルタ回路を組み込んだ
構成で実験した結果、所望のフィルタ特性は得られるが
、伝送路での信号波形のバランスが崩れ、実用には供し
えないことが判明した。By the way, a pulse transformer originally has a balanced -
It has an unbalanced conversion function. Therefore, even if the filter circuit is unbalanced, the output side of the pulse transformer can be a balanced (differential) signal. Therefore, it is conceivable to utilize this fact to reduce the number of parts by incorporating an unbalanced filter circuit between the driver or receiver and the pulse transformer. However, as a result of experimenting with a configuration incorporating a normal unbalanced filter circuit, it was found that although the desired filter characteristics could be obtained, the balance of the signal waveform in the transmission path was lost, making it impractical.
【０００９】本発明の目的は、上記のような技術的課題
を解決し、伝送特性を損なうことなしに、部品点数を半
減しうるＬＡＮ用伝送インターフェース回路を提供する
ことである。SUMMARY OF THE INVENTION An object of the present invention is to provide a LAN transmission interface circuit that solves the above technical problems and can reduce the number of components by half without impairing transmission characteristics.
【００１０】0010
【課題を解決するための手段】本発明はフィルタ回路と
伝送路間にパルストランスを配置して送信側又は受信側
回路と伝送路との間を分離絶縁し、ツイストペア電線に
よって平衡型伝送を行うＬＡＮ用伝送インターフェース
回路である。フィルタ回路は二段の不平衡型フィルタ部
からなり、両フィルタ部を両信号線にそれぞれ挿入し、
パルストランスで平衡−不平衡変換を行わせるように構
成してある。[Means for Solving the Problems] The present invention places a pulse transformer between a filter circuit and a transmission line to isolate and insulate the transmitting or receiving side circuit from the transmission line, and performs balanced transmission using twisted pair electric wires. This is a transmission interface circuit for LAN. The filter circuit consists of a two-stage unbalanced filter section, and both filter sections are inserted into both signal lines, respectively.
It is configured to perform balanced-unbalanced conversion using a pulse transformer.
【００１１】[0011]
【作用】フィルタ回路は所定の周波数帯域の信号のみ通
過させ、それ以外は減衰させることにより、ノイズを抑
える。パルストランスは伝送路の平衡信号とフィルタ回
路の不平衡信号との間で平衡−不平衡変換を行う。二段
の不平衡型フィルタ部を一方の信号線に集中配置したと
き伝送路を通る信号波形にアンバランスが生じ実用化し
えない原因は、パルストランスの一次巻線と二次巻線間
に形成される分布容量のためである。この分布容量が大
きいと平衡−不平衡変換に影響を及ぼす。つまりフィル
タ回路を通る信号の一部が前記分布容量を通って（信号
の一部がスルーする）ツイストペア電線の一方により多
く伝達され、信号波形にアンバランスが生じるのである
。[Operation] The filter circuit suppresses noise by passing only signals in a predetermined frequency band and attenuating other signals. The pulse transformer performs balanced-unbalanced conversion between the balanced signal of the transmission line and the unbalanced signal of the filter circuit. When a two-stage unbalanced filter section is concentrated on one signal line, the signal waveform passing through the transmission line becomes unbalanced, making it impossible to put it into practical use.The reason is that the formation between the primary and secondary windings of a pulse transformer This is because of the distributed capacity. If this distributed capacitance is large, it will affect balanced-unbalanced conversion. In other words, a portion of the signal passing through the filter circuit passes through the distributed capacitance and is transmitted to one side of the twisted pair wire (through which a portion of the signal passes), causing an imbalance in the signal waveform.
【００１２】上記分布容量は巻線数にほぼ比例するから
、巻線数を必要程度内に抑えても、一次巻線と二次巻線
との分布容量の影響が無視できない場合が多くなる。
ところが本発明のように両信号線にそれぞれ不平衡型フ
ィルタ部を挿入すると、パルストランスに対してフィル
タ回路の両信号線は対称的な、ほぼ同等の関係となる。
そのため各フィルタ部が不平衡であっても、パルストラ
ンスでは波形バランスの良好な平衡（差動）信号に変換
される。Since the above-mentioned distributed capacitance is approximately proportional to the number of windings, even if the number of windings is kept within a necessary range, the influence of the distributed capacitance between the primary winding and the secondary winding cannot be ignored in many cases. However, when unbalanced filter sections are inserted into both signal lines as in the present invention, both signal lines of the filter circuit have a symmetrical and substantially equal relationship with respect to the pulse transformer. Therefore, even if each filter section is unbalanced, the pulse transformer converts it into a balanced (differential) signal with good waveform balance.
【００１３】[0013]
【実施例】図１は本発明によるＬＡＮ用フィルタ回路の
一実施例を示す回路図である。Ａは送信側、Ｂは受信側
である。フィルタ回路の構成を除けば、基本的には図２
に示すものと同様であってよい。本発明ではフィルタ回
路として二段の不平衡型フィルタ部を使用し、両フィル
タ部を両信号線にそれぞれ挿入しており、この点に特徴
がある。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram showing an embodiment of a LAN filter circuit according to the present invention. A is the sending side and B is the receiving side. Basically, except for the configuration of the filter circuit, Figure 2
It may be similar to that shown in . The present invention is characterized in that a two-stage unbalanced filter section is used as a filter circuit, and both filter sections are inserted into both signal lines, respectively.
【００１４】まず送信側ではドライバＩＣ１ と不平衡
型フィルタ回路１０とを組み合わせ、パルストランスＴ
１ を介してツイストペア電線１２に接続するように構
成する。点線で囲んだ不平衡型フィルタ回路１０は、コ
イルとコンデンサで構成される２段のＬＣフィルタ部１
４，１５からなり、それらを両信号線１６，１７に一段
ずつ挿入する。従って不平衡型フィルタ回路１０は２個
のコイル（Ｌ１１，Ｌ１２）と５個のコンデンサ（Ｃ１
１〜Ｃ１５）からなり、コイルＬ１２とコンデンサＣ１
２との並列接続を一方の信号線１６に挿入し、コイルＬ
１１とコンデンサＣ１２との並列接続を他方の信号線１
７に挿入する。更にそれらの接続点の前後及び中間位置
でコンデンサＣ１５，Ｃ１３，Ｃ１１を両信号線１６，
１７間に接続している。従来のフィルタ回路に置き換え
るには、フィルタとしての周波数特性はそのままでイン
ピーダンスは２倍（５０Ωを１００Ωに）する必要があ
る。そのため上記構成でＬの値は約２倍に、Ｃの値は約
１／２の定数に設定する。そしてパルストランスＴ１
の出力側の送信端子（＋Ｄ，−Ｄ）に特性インピーダン
ス１００Ωのツイストペア電線１２を接続する。First, on the transmitting side, a driver IC 1 and an unbalanced filter circuit 10 are combined, and a pulse transformer T
1 to the twisted pair electric wire 12. An unbalanced filter circuit 10 surrounded by a dotted line has a two-stage LC filter section 1 composed of a coil and a capacitor.
4 and 15, and they are inserted into both signal lines 16 and 17 one stage at a time. Therefore, the unbalanced filter circuit 10 has two coils (L11, L12) and five capacitors (C1
1 to C15), including a coil L12 and a capacitor C1.
Insert the parallel connection with 2 into one signal line 16, and connect the coil L
11 and capacitor C12 are connected in parallel to the other signal line 1.
Insert into 7. Furthermore, capacitors C15, C13, and C11 are connected to both signal lines 16,
It is connected between 17. To replace the conventional filter circuit, it is necessary to double the impedance (from 50Ω to 100Ω) while keeping the frequency characteristics of the filter unchanged. Therefore, in the above configuration, the value of L is set to approximately double, and the value of C is set to a constant of approximately 1/2. and pulse transformer T1
A twisted pair electric wire 12 with a characteristic impedance of 100Ω is connected to the output side transmission terminals (+D, -D) of the .
【００１５】次に受信側ではレシーバＩＣ２ と不平衡
型フィルタ回路２０とを組み合わせ、パルストランスＴ
２ を介してツイストペア電線１２に接続する。点線で
囲んだ不平衡型フィルタ回路２０は、上記送信側の不平
衡型フィルタ回路１０と同様の構成である。コイルとコ
ンデンサで構成される２段のＬＣフィルタ部２４，２５
からなり、それらを両信号線２６，２７に一段ずつ挿入
してある。従って不平衡型フィルタ回路２０は２個のコ
イル（Ｌ２１，Ｌ２２）と５個のコンデンサ（Ｃ２１〜
Ｃ２５）からなる。各コイル及び各コンデンサの定数の
選定も上記送信側と同様にして行う。そしてパルストラ
ンスＴ２ の受信端子（＋ＲＤ，−ＲＤ）にツイストペ
ア電線１２を接続する。Next, on the receiving side, the receiver IC 2 and the unbalanced filter circuit 20 are combined, and the pulse transformer T
2 to the twisted pair electric wire 12. The unbalanced filter circuit 20 surrounded by the dotted line has the same configuration as the unbalanced filter circuit 10 on the transmission side. Two-stage LC filter section 24, 25 consisting of a coil and a capacitor
They are inserted into both signal lines 26 and 27 one stage at a time. Therefore, the unbalanced filter circuit 20 includes two coils (L21, L22) and five capacitors (C21 to
C25). The constants of each coil and each capacitor are also selected in the same manner as on the transmitting side. Then, the twisted pair electric wire 12 is connected to the receiving terminals (+RD, -RD) of the pulse transformer T2.
【００１６】なお上記実施例で使用しているレシーバＩ
Ｃ２ は平衡信号が必要なタイプであるため、レシーバ
ＩＣ２ の入力に抵抗Ｒ４１，Ｒ４２を配置し、その中
点を等価グランドに落とすことにより、平衡信号がレシ
ーバに入力するようにしている。Note that the receiver I used in the above embodiment
Since C2 is of a type that requires a balanced signal, resistors R41 and R42 are placed at the input of the receiver IC2, and the midpoint thereof is grounded to the equivalent ground, so that a balanced signal is input to the receiver.
【００１７】送信側において、不平衡型フィルタ回路１
０は送信側回路からの輻射ノイズを抑える機能を有し、
所望周波数帯域の信号を通過させ、それ以外のノイズを
減衰させる。不平衡型フィルタ回路１０と伝送路である
ツイストペア電線１２の間に配置してあるパルストラン
スＴ１ は、両者を分離絶縁し且つ信号の平衡−不平衡
の変換を行っている。パルストランスＴ１ の絶縁機能
は直流レベルの接続を断ち切ることにより良好なサージ
対策となり、またアースから切り離すことにより伝送路
でのグランドループが発生することを防止している。し
かし、パルストランスＴ１ は一次巻線と二次巻線間に
分布容量を有し、該容量が大きいと平衡−不平衡の変換
に影響を及ぼす。即ち、パルストランスによる相互誘導
を介さずにフィルタ回路側から伝送路側へ伝達される信
号がでてくる。本発明ではフィルタ部を両信号線に一段
ずつ配置することにより、不平衡信号であっても波形バ
ランスの良い信号が得られるため、平衡−不平衡の変換
が不完全であっても、その影響は極く僅かに抑えること
ができる。On the transmitting side, an unbalanced filter circuit 1
0 has the function of suppressing radiation noise from the transmitting circuit,
Passes signals in a desired frequency band and attenuates other noises. A pulse transformer T1 disposed between the unbalanced filter circuit 10 and the twisted pair electric wire 12 serving as a transmission line separates and insulates the two and converts the signal from balanced to unbalanced. The insulating function of the pulse transformer T1 serves as a good measure against surges by cutting off the DC level connection, and also prevents ground loops from occurring in the transmission line by separating it from the ground. However, the pulse transformer T1 has a distributed capacitance between the primary winding and the secondary winding, and if the capacitance is large, it will affect the balanced-unbalanced conversion. That is, a signal is transmitted from the filter circuit side to the transmission line side without going through mutual induction by the pulse transformer. In the present invention, by arranging one filter section for each signal line, a signal with good waveform balance can be obtained even if it is an unbalanced signal, so even if the balanced-unbalanced conversion is incomplete, the effects of can be suppressed to a very small amount.
【００１８】次に受信側において、ツイストペア電線１
２は本来ノイズの同相成分を除去する機能を有するが、
シールドされていないのでノイズに影響されやすく、す
べてのノイズを完全に除去するには至らない。送信側と
同様、フィルタ回路２０でノイズを除去し、所望の信号
のみレシーバＩＣ２ へ導く。この場合も、フィルタ部
を両信号線に一段ずつ配置することにより、平衡−不平
衡の変換に悪影響がでにくい。Next, on the receiving side, the twisted pair electric wire 1
2 originally has the function of removing the in-phase component of noise, but
Since it is not shielded, it is susceptible to noise and cannot completely eliminate all noise. Similar to the transmitting side, the filter circuit 20 removes noise and guides only desired signals to the receiver IC2. In this case as well, by arranging one filter section for each signal line, the balanced-unbalanced conversion is less likely to be adversely affected.
【００１９】[0019]
【発明の効果】本発明は上記のようにフィルタ回路を不
平衡型としたため、部品点数を半分に減少させることが
でき、そのためフィルタ回路分の実装面積を小さくでき
、しかも価格も低減できる。また本発明では両信号線に
それぞれフィルタ部を配置したので、不平衡型のフィル
タ部を使用しても波形バランスのよい信号が得られ、何
ら伝送特性が損なわれることもない。According to the present invention, since the filter circuit is of an unbalanced type as described above, the number of parts can be reduced by half, and therefore the mounting area for the filter circuit can be reduced, and the cost can also be reduced. Furthermore, in the present invention, since filter sections are arranged on both signal lines, a signal with good waveform balance can be obtained even if an unbalanced filter section is used, and the transmission characteristics are not impaired in any way.
【図１】本発明によるＬＡＮ用伝送インターフェース回
路の一実施例を示す回路図。FIG. 1 is a circuit diagram showing an embodiment of a LAN transmission interface circuit according to the present invention.
【図２】従来のＬＡＮ用伝送インターフェース回路の回
路図。FIG. 2 is a circuit diagram of a conventional LAN transmission interface circuit.
１０ 不平衡フィルタ回路 １２ ツイストペア電線 ２０ 不平衡フィルタ回路 10 Unbalanced filter circuit 12 Twisted pair electric wire 20 Unbalanced filter circuit
Claims (1)
ンスを配置して送信側又は受信側回路と伝送路との間を
分離絶縁し、ツイストペア電線により平衡型伝送を行う
ＬＡＮ用伝送インターフェース回路において、フィルタ
回路は二段の不平衡型フィルタ部からなり、両フィルタ
部を両信号線にそれぞれ挿入し、パルストランスで平衡
−不平衡変換を行うことを特徴とするＬＡＮ用伝送イン
ターフェース回路。Claim 1. A transmission interface circuit for a LAN in which a pulse transformer is disposed between a filter circuit and a transmission line to isolate and insulate a transmitting side or receiving side circuit and the transmission line, and balanced transmission is performed using twisted pair electric wires, comprising: 1. A transmission interface circuit for LAN, characterized in that the filter circuit comprises two stages of unbalanced filter sections, both filter sections are inserted into both signal lines, and balanced-unbalanced conversion is performed by a pulse transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3176183A JP3021098B2 (en) | 1991-06-20 | 1991-06-20 | Transmission interface circuit for LAN |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3176183A JP3021098B2 (en) | 1991-06-20 | 1991-06-20 | Transmission interface circuit for LAN |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04372213A true JPH04372213A (en) | 1992-12-25 |
| JP3021098B2 JP3021098B2 (en) | 2000-03-15 |
Family
ID=16009106
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3176183A Expired - Fee Related JP3021098B2 (en) | 1991-06-20 | 1991-06-20 | Transmission interface circuit for LAN |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3021098B2 (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0539026U (en) * | 1991-10-22 | 1993-05-25 | 日本電信電話株式会社 | Coaxial cable / balanced cable converter string |
| EP0647020A2 (en) * | 1993-09-01 | 1995-04-05 | WERKSTÄTTE FÜR STUDIO-TECHNIK Dipl.-Ing. Hellmut Haufe | Amplifier circuit comprising an asymmetrical input and a symmetrical output |
| US5475346A (en) * | 1991-08-15 | 1995-12-12 | Amulet Electronics Limited | Impedance matching balum arrangement using a low pass filter |
| US7079644B1 (en) | 1998-01-14 | 2006-07-18 | Murata Manufacturing Co., Ltd. | Input-output balanced filter |
| WO2012014547A1 (en) * | 2010-07-30 | 2012-02-02 | オリンパスメディカルシステムズ株式会社 | Endoscope system |
| WO2013027349A1 (en) | 2011-08-19 | 2013-02-28 | Canon Kabushiki Kaisha | Differential transmission circuit and printed circuit board |
| WO2013038634A1 (en) | 2011-09-14 | 2013-03-21 | Canon Kabushiki Kaisha | Differential transmission circuit |
| US9538634B2 (en) | 2012-08-16 | 2017-01-03 | Canon Kabushiki Kaisha | Printed circuit board |
| US11181635B2 (en) | 2019-02-12 | 2021-11-23 | Denso Corporation | Ultrasonic distance detector |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106208999B (en) * | 2015-04-29 | 2018-12-11 | 富士康(昆山)电脑接插件有限公司 | Network filtering mould group and its manufacturing method |
-
1991
- 1991-06-20 JP JP3176183A patent/JP3021098B2/en not_active Expired - Fee Related
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5475346A (en) * | 1991-08-15 | 1995-12-12 | Amulet Electronics Limited | Impedance matching balum arrangement using a low pass filter |
| JPH0539026U (en) * | 1991-10-22 | 1993-05-25 | 日本電信電話株式会社 | Coaxial cable / balanced cable converter string |
| EP0647020A2 (en) * | 1993-09-01 | 1995-04-05 | WERKSTÄTTE FÜR STUDIO-TECHNIK Dipl.-Ing. Hellmut Haufe | Amplifier circuit comprising an asymmetrical input and a symmetrical output |
| EP0647020A3 (en) * | 1993-09-01 | 1996-01-17 | Werkstaette Fuer Studio Techni | Amplifier circuit comprising an asymmetrical input and a symmetrical output. |
| US7079644B1 (en) | 1998-01-14 | 2006-07-18 | Murata Manufacturing Co., Ltd. | Input-output balanced filter |
| US7113588B2 (en) | 1998-01-14 | 2006-09-26 | Murata Manufacturing Co., Ltd. | Input-output balanced filter |
| CN102791181A (en) * | 2010-07-30 | 2012-11-21 | 奥林巴斯医疗株式会社 | Endoscope system |
| JP5009452B2 (en) * | 2010-07-30 | 2012-08-22 | オリンパスメディカルシステムズ株式会社 | Endoscope system |
| WO2012014547A1 (en) * | 2010-07-30 | 2012-02-02 | オリンパスメディカルシステムズ株式会社 | Endoscope system |
| US8480567B2 (en) | 2010-07-30 | 2013-07-09 | Olympus Medical Systems Corp. | Endoscope system with differential signal transmission |
| WO2013027349A1 (en) | 2011-08-19 | 2013-02-28 | Canon Kabushiki Kaisha | Differential transmission circuit and printed circuit board |
| US9190978B2 (en) | 2011-08-19 | 2015-11-17 | Canon Kabushiki Kaisha | Differential transmission circuit and printed circuit board |
| WO2013038634A1 (en) | 2011-09-14 | 2013-03-21 | Canon Kabushiki Kaisha | Differential transmission circuit |
| US9374888B2 (en) | 2011-09-14 | 2016-06-21 | Canon Kabushiki Kaisha | Differential transmission circuit having an inductor unit and capacitor units configured to attenuate a common-mode digital signal component |
| US9538634B2 (en) | 2012-08-16 | 2017-01-03 | Canon Kabushiki Kaisha | Printed circuit board |
| US11181635B2 (en) | 2019-02-12 | 2021-11-23 | Denso Corporation | Ultrasonic distance detector |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3021098B2 (en) | 2000-03-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |