JP3232797B2 - Receiver circuit with carrier sense - Google Patents
Receiver circuit with carrier senseInfo
- Publication number
- JP3232797B2 JP3232797B2 JP20173693A JP20173693A JP3232797B2 JP 3232797 B2 JP3232797 B2 JP 3232797B2 JP 20173693 A JP20173693 A JP 20173693A JP 20173693 A JP20173693 A JP 20173693A JP 3232797 B2 JP3232797 B2 JP 3232797B2
- Authority
- JP
- Japan
- Prior art keywords
- signal
- circuit
- transmission line
- carrier sense
- 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.)
- Expired - Lifetime
Links
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- Dc Digital Transmission (AREA)
- Noise Elimination (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ベースバンド伝送のパ
ルス符号通信あるいは変復調技術を用いたデータ通信な
どにおいて、回線の休止状態時の、比較的インピーダン
スが高く、ノイズが伝送線路に重畳され易い期間も、ノ
イズに影響され難くするディジタル信号の送受信回路に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse code communication for baseband transmission or a data communication using a modulation / demodulation technique. The present invention also relates to a digital signal transmission / reception circuit whose period is hardly affected by noise.
【０００２】[0002]
【従来の技術】従来、ディジタル通信を行う場合、特
に、伝送距離が長いとか、ノイズ環境があまり良くない
場合などでは、耐ノイズ性を向上し伝送誤りを防ぐ方法
として、差動出力形のドライバと差動入力形のレシーバ
と平衡伝送路とを用いた平衡型伝送方式が使用されてい
る。データ伝送時は、必要な大きさの振幅を有した伝送
信号が受信端に伝送され、必要とする信号対雑音比(S/N
比) を確保し、ノイズの影響を受け難い様に構成してい
る。しかし、この方式でも回線が使用されている期間
は、伝送線路はドライバ出力インピーダンスによって短
絡され、伝送線路インピーダンスは非常に低い状態にあ
り、伝送線路に誘導されるノイズも低く抑えられるが、
しかし、これに対して、回線が使用されていない休止状
態時（以下無信号時という。）には、ドライバ出力はOF
F 状態にあり、伝送線路インピーダンスは伝送線路の特
性インピーダンス、あるいは終端抵抗分しかなく、比較
的インピーダンスが高くなり、ノイズを受け易い状態に
ある。2. Description of the Related Art Conventionally, when digital communication is performed, especially when the transmission distance is long or the noise environment is not very good, a differential output type driver is used as a method of improving noise resistance and preventing transmission errors. A balanced transmission system using a differential input type receiver and a balanced transmission line is used. At the time of data transmission, a transmission signal having a required amplitude is transmitted to the receiving end, and a required signal-to-noise ratio (S / N
Ratio) and is configured to be less susceptible to noise. However, even in this method, while the line is used, the transmission line is short-circuited by the driver output impedance, the transmission line impedance is in a very low state, and the noise induced in the transmission line can be kept low.
However, on the other hand, when the line is not in use (hereinafter, referred to as “no signal”), the driver output is turned off.
In the F state, the transmission line impedance is only the characteristic impedance of the transmission line or the terminating resistance, the impedance is relatively high, and the transmission line is susceptible to noise.
【０００３】[0003]
【発明が解決しようとする課題】伝送線路に接続される
伝送装置の入力インピーダンスは、伝送線路に与える影
響を少なくする、あるいは逆に、接続される伝送装置の
加入者数を増加するためにも、高入力インピーダンス回
路であることが望まれる。また、レシーバ回路用のLSI
は、比較的ノイズレベルの低い伝送線路で長距離伝送の
信号も受信できるように、比較的高感度に構成されてい
る。このため、一般的な伝送線路でノイズ環境が悪い所
で使用したとき、無信号時に伝送線路に誘起される比較
的微弱なノイズを受信して、レシーバ回路はそのノイズ
を検出して出力することがある。もし、今このノイズ信
号が正規の伝送信号に近いパルス波形（ベースバンド伝
送のとき）の誤信号であるとすると、伝送装置は受信動
作を開始する。しかし、この誤信号はノイズ信号であ
り、伝送手順の規約（例えば、スタートビット、ストッ
プビット、ビット長、パリティビットなど）に従ってい
ないので、伝送装置はこのノイズ信号をエラーとして除
去処理をする。このエラー処理は伝送装置に内蔵された
中央処理装置によって処理されるため、このエラー処理
が始まった後しばらくは回線上の信号を受信することが
できない状態となるのが普通であり、結局、回線利用効
率が落ちてしまう問題点がある。The input impedance of a transmission device connected to a transmission line is used to reduce the influence on the transmission line or, conversely, to increase the number of subscribers of the transmission device connected. , A high input impedance circuit is desired. LSI for receiver circuit
Are configured with relatively high sensitivity so that signals of long distance transmission can be received on a transmission line having a relatively low noise level. Therefore, when used in a place where the noise environment is poor in a general transmission line, the receiver circuit receives relatively weak noise induced in the transmission line when there is no signal, and the receiver circuit detects and outputs the noise. There is. If the noise signal is an erroneous signal having a pulse waveform (at the time of baseband transmission) close to a normal transmission signal, the transmission apparatus starts a receiving operation. However, since the erroneous signal is a noise signal and does not conform to the rules of the transmission procedure (for example, start bit, stop bit, bit length, parity bit, etc.), the transmission device performs a removal process on the noise signal as an error. Since this error processing is processed by the central processing unit built in the transmission device, it is normal that the signal on the line cannot be received for a while after this error processing starts. There is a problem that utilization efficiency is reduced.
【０００４】本発明は上記の点にかんがみてなされたも
のであり、その目的は前記した課題を解決して、簡単な
回路方式で、高入力インピーダンス回路を維持しなが
ら、無信号時のノイズ閾値レベルを増やし、ノイズの影
響を受け難くする伝送装置のキャリアセンス付き受信回
路を提供することにある。SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to solve the above-mentioned problems and to maintain a high input impedance circuit with a simple circuit method while maintaining a noise threshold when there is no signal. It is an object of the present invention to provide a receiving circuit with a carrier sense of a transmission device that increases the level and is less affected by noise.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に、伝送線路に接続され、受信端からの入力信号により
伝送線路上に送信される伝送信号を検出するレシーバ回
路と、伝送線路に接続され、予め設定された閾値を有し
この閾値を越える受信端からの入力信号を検出するキャ
リアセンス回路とを備え、レシーバ回路の出力とキャリ
アセンス回路の出力との論理積から、伝送線路上に伝送
信号が送信されているときのみ、レシーバ回路の出力を
有効検出信号として出力する構成とする。In order to achieve the above object, a receiver circuit connected to a transmission line for detecting a transmission signal transmitted on the transmission line by an input signal from a receiving end, and connected to the transmission line. A carrier sense circuit having a preset threshold value and detecting an input signal from the receiving end exceeding the threshold value, and a logical product of an output of the receiver circuit and an output of the carrier sense circuit is provided on the transmission line. Only when a transmission signal is being transmitted, the output of the receiver circuit is output as an effective detection signal.
【０００６】また、上記構成のキャリアセンス付き受信
回路において、伝送線路に接続され、受信端からの入力
信号により伝送線路上に送信される伝送信号を検出する
イネーブル端子機能を有するレシーバ回路と、伝送線路
に接続され、予め設定された閾値を有しこの閾値を越え
る受信端からの入力信号を検出するキャリアセンス回路
とを備え、キャリアセンス回路の出力でレシーバ回路の
イネーブル端子機能を制御し、伝送線路上に伝送信号が
送信されているときのみ、レシーバ回路の出力を有効検
出信号として出力する構成とする。Further, in the receiving circuit with carrier sense having the above-mentioned configuration, a receiver circuit connected to the transmission line and having an enable terminal function for detecting a transmission signal transmitted on the transmission line in response to an input signal from the receiving end; A carrier sense circuit connected to the line and having a preset threshold value and detecting an input signal from a receiving end exceeding the threshold value, controlling an enable terminal function of the receiver circuit with an output of the carrier sense circuit, and transmitting Only when a transmission signal is transmitted on the line, the output of the receiver circuit is output as an effective detection signal.
【０００７】[0007]
【作用】上記構成により、伝送線路に接続され、予め設
定された閾値を有し、この閾値を越える受信端からの入
力信号を検出するキャリアセンス回路を備えるキャリア
センス受信回路において、レシーバ回路の出力とキャリ
アセンス回路の出力との論理積から、伝送線路上に伝送
信号が送信されているときのみ、レシーバ回路の出力を
有効検出信号とする。キャリアセンス回路が伝送線路か
らの受信端入力信号を検出する閾値は、レシーバ回路が
伝送線路上の伝送信号を検出するレベルに較べて、数倍
から十数倍高い。従って、無信号時、レシーバ回路が伝
送線路上に重畳した比較的微弱なノイズを受信して誤信
号を検出しても、キャリアセンス回路の閾値が高いの
で、このキャリアセンス回路は作動せず、その出力は
(H) レベルを維持し、レシーバ回路が検出出力する誤信
号を除去する。次に、伝送線路上に伝送信号が信号有の
状態で、かつ、受信端の入力信号がキャリアセンス回路
の閾値以上のレベルを有するとき、キャリアセンス回路
は作動し、その出力は(L)に切り替わり、レシーバ回路
が検出した出力信号を有効信号として出力する。即ち、
伝送線路と接続される伝送装置のキャリアセンス付き受
信回路では、伝送装置側の入力インピーダンスは高イン
ピーダンスをそのまま保持し、かつ、無信号時の耐ノイ
ズレベルの大きい伝送装置が構成できる。According to the above construction, in a carrier sense receiving circuit which is connected to a transmission line, has a predetermined threshold value, and has a carrier sense circuit for detecting an input signal from a receiving end exceeding the threshold value, an output of the receiver circuit is provided. The output of the receiver circuit is used as the effective detection signal only when the transmission signal is being transmitted on the transmission line from the logical product of the output of the carrier sense circuit and the output of the carrier sense circuit. The threshold at which the carrier sense circuit detects the input signal at the receiving end from the transmission line is several times to several tens times higher than the level at which the receiver circuit detects the transmission signal on the transmission line. Therefore, when there is no signal, even if the receiver circuit receives relatively weak noise superimposed on the transmission line and detects an erroneous signal, the threshold value of the carrier sense circuit is high, so this carrier sense circuit does not operate, The output is
(H) Maintain the level and remove erroneous signals detected and output by the receiver circuit. Next, when the transmission signal on the transmission line has a signal and the input signal at the receiving end has a level equal to or higher than the threshold value of the carrier sense circuit, the carrier sense circuit operates, and the output thereof changes to (L). The signal is switched, and the output signal detected by the receiver circuit is output as a valid signal. That is,
In a receiving circuit with carrier sensing of a transmission device connected to a transmission line, a transmission device having a high level of noise immunity when no signal is input while maintaining a high input impedance on the transmission device side can be configured.
【０００８】また、イネーブル端子機能を有するレシー
バ回路と、伝送線路に接続され予め設定された閾値を有
しこの閾値を越える受信端からの入力信号を検出するキ
ャリアセンス回路とを備え、キャリアセンス回路の出力
でレシーバ回路のイネーブル端子機能を制御し、無信号
時は伝送線路上の検出信号（誤信号）を除去し、伝送線
路上に伝送信号が送信されている有信号時のみ、伝送線
路上の検出信号を有効検出信号として出力することによ
り、高入力インピーダンスを保持し、かつ、耐ノイズレ
ベルの大きい伝送装置が構成できる。In addition, the carrier sensing circuit includes a receiver circuit having an enable terminal function, and a carrier sensing circuit connected to the transmission line and having a preset threshold value and detecting an input signal from a receiving end exceeding the threshold value. The output of controls the enable terminal function of the receiver circuit, removes the detection signal (erroneous signal) on the transmission line when there is no signal, and only on the transmission line when there is a transmission signal transmitted on the transmission line. By outputting the above detection signal as an effective detection signal, a transmission device having a high input impedance and a high noise resistance level can be configured.
【０００９】[0009]
【実施例】図１は本発明による一実施例のキャリアセン
ス付き受信回路を説明するブロック回路図、図２は図１
の実施例の回路動作を説明する各部の波形図、図３は他
の実施例のキャリアセンス付き受信回路を説明するブロ
ック回路図である。図１において、キャリアセンス付き
受信回路は、平衡型伝送方式を採用し、平衡型伝送線路
１に差動入力形のレシーバ回路３および差動入力形のキ
ャリアセンス回路２が接続される。伝送装置が送受信機
能を有するキャリアセンス付きトランシーバ回路のとき
は、さらに図１に図示される様に、差動出力形のドライ
バ４が伝送線路１に接続され送信機能が付与される。こ
の伝送線路１には、回線が休止状態で無信号時は理想的
には何ら電圧・電流信号が無い状態であり、有信号時は
この伝送線路１上に±の極性をもったパルス波形で伝送
信号が伝送される。FIG. 1 is a block circuit diagram for explaining a receiving circuit with carrier sense according to an embodiment of the present invention, and FIG.
FIG. 3 is a block diagram illustrating a receiver circuit with a carrier sense according to another embodiment. In FIG. 1, the receiving circuit with carrier sense adopts a balanced transmission system, and a differential input type receiver circuit 3 and a differential input type carrier sense circuit 2 are connected to a balanced type transmission line 1. When the transmission apparatus is a transceiver circuit with a carrier sense having a transmission / reception function, as shown in FIG. 1, a differential output type driver 4 is connected to the transmission line 1 to provide a transmission function. The transmission line 1 is ideally free of any voltage or current signal when the line is inactive and there is no signal. When there is a signal, the transmission line 1 has a pulse waveform having a polarity of ± on the transmission line 1. A transmission signal is transmitted.
【００１０】伝送線路１に接続され、受信端からの入力
信号1Aにより伝送線路１上に送信される伝送信号を検出
するレシーバ回路３と、伝送線路１に接続され予め設定
された閾値2B,2C を有し、この閾値2B,2C を越える受信
端からの入力信号1Aから、伝送信号有りを検出するキャ
リアセンス回路２とを備え、レシーバ回路３の出力3Aと
キャリアセンス回路２の出力2Aとの論理積を論理回路５
にてとり、伝送線路１上に伝送信号が送信されていると
きのみ、レシーバ回路３の出力3Aを有効出力とし、検出
出力5Aとする。[0010] A receiver circuit 3 connected to the transmission line 1 for detecting a transmission signal transmitted on the transmission line 1 in response to an input signal 1A from the receiving end, and a predetermined threshold value 2B, 2C connected to the transmission line 1 And a carrier sense circuit 2 for detecting the presence of a transmission signal from an input signal 1A from the receiving end exceeding the thresholds 2B and 2C, and an output 3A of the receiver circuit 3 and an output 2A of the carrier sense circuit 2 Logical product to logical circuit 5
Therefore, only when a transmission signal is transmitted on the transmission line 1, the output 3A of the receiver circuit 3 is set as an effective output and the detection output 5A.
【００１１】キャリアセンス回路２が伝送線路１からの
受信端入力信号1Aを検出する閾値2B,2C は、レシーバ回
路３が受信端入力信号1Aを検出するレベルに較べて、数
倍から十数倍大きい。従って、無信号時、レシーバ回路
３が伝送線路１に重畳した比較的微弱なノイズを受信し
て、誤信号を検出しても、キャリアセンス回路２の閾値
2B,2C が高いので、このキャリアセンス回路２は作動せ
ず、その出力は(H) レベルを維持し、レシーバ回路３が
検出する誤信号を除去する。次に、伝送線路１に伝送信
号が信号有の状態で、かつ、受信端の入力信号1Aがキャ
リアセンス回路２の閾値2B,2C 以上のレベルを有すると
き、キャリアセンス回路２は作動し、その出力は(L) に
切り替わり、レシーバ回路３が検出した出力3Aを有効検
出信号5Aとして検出する。即ち、伝送線路１と接続され
る伝送装置のキャリアセンス付き受信回路では、伝送装
置側の入力インピーダンスは高インピーダンスをそのま
ま保持し、かつ、無信号時の耐ノイズレベルの大きい伝
送装置が構成できる。The thresholds 2B and 2C at which the carrier sense circuit 2 detects the receiving end input signal 1A from the transmission line 1 are several times to several tens times higher than the level at which the receiver circuit 3 detects the receiving end input signal 1A. large. Therefore, even when the receiver circuit 3 receives relatively weak noise superimposed on the transmission line 1 and detects an erroneous signal when there is no signal, the threshold value of the carrier sense circuit 2 is not changed.
Since 2B and 2C are high, the carrier sense circuit 2 does not operate, its output is maintained at the (H) level, and an erroneous signal detected by the receiver circuit 3 is removed. Next, when a transmission signal is present on the transmission line 1 and the input signal 1A at the receiving end has a level equal to or higher than the thresholds 2B and 2C of the carrier sense circuit 2, the carrier sense circuit 2 is activated. The output switches to (L), and the output 3A detected by the receiver circuit 3 is detected as a valid detection signal 5A. That is, in the receiving circuit with carrier sense of the transmission device connected to the transmission line 1, the transmission device having the high input impedance at the transmission device side and having a high noise resistance level when there is no signal can be configured.
【００１２】上記構成において、このキャリアセンス付
き受信回路の回路動作を図２を併用して説明する。図２
において、横軸に時間軸をとり、縦方向に上から順に、
受信端入力信号1A、レシーバ回路出力3A、キャリアセン
ス出力2A、そして本発明のキャリアセンス付き受信回路
の検出信号5Aの波形を図示する。受信端入力信号1Aは、
伝送線路１が無信号のとき、理想的には中心線として細
線で示される零の状態にあるが、実際には、伝送線路１
に比較的微弱なノイズ（三角形の波形で示す）が誘導・
重畳される。また、伝送線路１が有信号のときは、中心
線に対して、±の極性のパルス信号が伝送線路１に送信
され、伝送装置の受信端にて、入力信号1Aとして受信さ
れる。この入力信号1Aは、上記の無信号時の比較的微弱
なノイズよりも大きく、必要な信号対雑音比(S/N比) は
確保される。キャリアセンス回路２の閾値は、点線2B,2
C で示され、伝送装置の受信端の入力信号1Aは、このキ
ャリアセンス回路２の閾値2B,2C よりも大きく、また、
無信号時の比較的微弱なノイズは、このキャリアセンス
回路２の閾値2B,2C よりも小さい。In the above configuration, the circuit operation of the receiving circuit with carrier sense will be described with reference to FIG. FIG.
, The time axis is taken on the horizontal axis, and from the top in the vertical direction,
The waveforms of the receiving end input signal 1A, the receiver circuit output 3A, the carrier sense output 2A, and the detection signal 5A of the receiving circuit with carrier sense of the present invention are illustrated. The receiving end input signal 1A is
When the transmission line 1 has no signal, it is ideally in a zero state indicated by a thin line as a center line.
Relatively weak noise (indicated by a triangular waveform)
Superimposed. When the transmission line 1 has a signal, a pulse signal having a polarity of ± with respect to the center line is transmitted to the transmission line 1 and received as an input signal 1A at the receiving end of the transmission device. This input signal 1A is larger than the relatively weak noise when there is no signal, and a required signal-to-noise ratio (S / N ratio) is secured. The threshold value of the carrier sense circuit 2 is represented by dotted lines 2B and 2
C, the input signal 1A at the receiving end of the transmission device is larger than the thresholds 2B and 2C of the carrier sense circuit 2, and
The relatively weak noise when there is no signal is smaller than the thresholds 2B and 2C of the carrier sense circuit 2.
【００１３】レシーバ回路用のLSI は、比較的ノイズレ
ベルの低い伝送線路で長距離伝送の信号も受信できるよ
うに、比較的高感度に構成されている。このため、レシ
ーバ回路３は無信号時の比較的微弱なノイズも検知し、
誤信号3Bを検出する。有信号時は伝送されてきた入力信
号1Aを検出し、正規の伝送波形3Cを検出する。勿論、入
力信号1Aには誘導ノイズが重畳されているが、パルスの
切り替わり時点のノイズは時定数の小さいフィルタで除
去され、＋または−の信号に重畳した誘導ノイズはレシ
ーバ回路３の検出閾値を越えた所にあるノイズのため、
パルス出力には影響を与えない。The LSI for the receiver circuit has a relatively high sensitivity so that a signal of a long distance transmission can be received on a transmission line having a relatively low noise level. For this reason, the receiver circuit 3 also detects relatively weak noise when there is no signal,
The erroneous signal 3B is detected. When a signal is present, the transmitted input signal 1A is detected, and a normal transmission waveform 3C is detected. Of course, the induction noise is superimposed on the input signal 1A, but the noise at the time of the pulse switching is removed by a filter having a small time constant. Because of the noise that is beyond
It does not affect the pulse output.
【００１４】キャリアセンス回路２は、例えば、正の閾
値2Bを有し、この閾値2Bを越える正の入力信号1Aで作動
するコンパレータと、負の閾値2Cを有し、この閾値2Cを
越える負の入力信号1Aで作動するコンパレータと、両コ
ンパレータ出力のNOR で構成される。この様な構成で
は、閾値2B,2C より小さい範囲では両コンパレータ出力
はＬであり、この出力のNOR により、キャリアセンス回
路２のキャリアセンス出力2AはＨを出力する。有信号時
で、伝送線路１から伝送されてきた入力信号1Aが閾値2
B,2C より大きい範囲では、両コンパレータは各々正お
よび負のパルスで交互にＨを出力し、両コンパレータ出
力のNOR をとることにより、有信号時の期間キャリアセ
ンス回路２のキャリアセンス出力2AはＬを出力する。The carrier sense circuit 2 has, for example, a comparator having a positive threshold value 2B and operating with a positive input signal 1A exceeding the threshold value 2B, and a negative threshold value 2C having a negative threshold value 2C exceeding the threshold value 2C. It consists of a comparator that operates with input signal 1A and NOR of both comparator outputs. In such a configuration, both comparator outputs are L in a range smaller than the thresholds 2B and 2C, and the carrier sense output 2A of the carrier sense circuit 2 outputs H due to the NOR of these outputs. When there is a signal, the input signal 1A transmitted from the transmission line 1
In the range larger than B and 2C, both comparators output H alternately with positive and negative pulses, and by taking the NOR of the outputs of both comparators, the carrier sense output 2A of the carrier sense circuit 2 during the signal presence period becomes L is output.
【００１５】図１の回路に戻り、キャリアセンス回路２
からのキャリアセンス出力2Aは論理回路５の否定入力端
子に接続され、またレシーバ回路３の出力3Aは論理回路
５の肯定入力端子に接続されておるので、論理回路５の
検出信号5Aは、無信号時はＨレベルの出力を出し、有信
号時は伝送線路１に送信されてきた正規の伝送信号3Cを
出力する。Returning to the circuit of FIG.
Is connected to the negative input terminal of the logic circuit 5 and the output 3A of the receiver circuit 3 is connected to the positive input terminal of the logic circuit 5, so that the detection signal 5A of the logic circuit 5 is At the time of a signal, an H-level output is output. At the time of a signal, a normal transmission signal 3C transmitted to the transmission line 1 is output.
【００１６】図３は本発明の他の実施例のキャリアセン
ス付き受信回路を説明するブロック回路図であり、伝送
線路１に接続され、受信端からの入力信号1Aにより、伝
送線路１上に送信される伝送信号を検出するイネーブル
端子機能を有するレシーバ回路６と、伝送線路１に接続
され、予め設定された閾値2B,2C を有し、この閾値2B,2
C を越える受信端からの入力信号1Aを検出するキャリア
センス回路2Aとを備えている。キャリアセンス回路２の
出力2Aでレシーバ回路６のイネーブル端子機能を制御
し、無信号時は、例えば、レシーバ回路６の増幅度を低
下させるとか、出力を遮断状態にし、レシーバ回路６を
非能動的にし、伝送線路１からの検出信号（誤信号3B）
を除去する。伝送線路１に伝送信号が送信されている有
信号時のみ、レシーバ回路６を能動的にし、受信端から
の入力信号1Aを検出し、有効検出出力6Aとして出力する
ことにより、高入力インピーダンスを保持し、かつ、耐
ノイズレベルの大きい伝送装置が構成できる。FIG. 3 is a block circuit diagram for explaining a receiving circuit with carrier sense according to another embodiment of the present invention. The receiving circuit is connected to the transmission line 1 and transmitted on the transmission line 1 by an input signal 1A from the receiving end. A receiver circuit 6 having an enable terminal function for detecting a transmission signal to be transmitted, and a threshold 2B, 2C connected to the transmission line 1 and having preset thresholds 2B, 2C.
And a carrier sense circuit 2A for detecting an input signal 1A from the receiving end exceeding C. The enable terminal function of the receiver circuit 6 is controlled by the output 2A of the carrier sense circuit 2, and when there is no signal, for example, the amplification degree of the receiver circuit 6 is reduced or the output is cut off, and the receiver circuit 6 is deactivated. And the detection signal from transmission line 1 (error signal 3B)
Is removed. Only when there is a transmission signal being transmitted to the transmission line 1, the receiver circuit 6 is activated, the input signal 1A from the receiving end is detected and output as an effective detection output 6A, thereby maintaining a high input impedance. In addition, a transmission device having a high noise resistance level can be configured.
【００１７】本発明では、伝送回線が休止状態時に誘導
されるノイズの低減手段を与えるものである。従って、
キャリアセンス付き受信回路の受信回路を中心に説明し
たが、伝送装置として送受信機能を有するキャリアセン
ス付きトランシーバ回路として構成しても、同様に、伝
送回線が休止状態時に誘導されるノイズの低減手段を与
えることができる。また、伝送線路１を平衡型伝送線
路、例えば、ツイストペア線で説明したが、同軸ケーブ
ル（非平衡型伝送線路）でも、無信号時は同軸ケーブル
上の信号が零とし、有信号時は±の極性のパルス信号が
受信できるレシーバ回路およびキャリアセンス回路、即
ち、平衡形入力のレシーバ回路およびキャリアセンス回
路の一方の信号端子（同軸ケーブルの外皮側）を接地し
て、非平衡型伝送線路としても使用することができる。The present invention provides a means for reducing noise induced when the transmission line is in an idle state. Therefore,
The receiver circuit with carrier sense has been mainly described. However, even if the transmission device is configured as a transceiver circuit with carrier sense having a transmission / reception function, similarly, a means for reducing noise induced when the transmission line is in an idle state is similarly provided. Can be given. Also, the transmission line 1 has been described as a balanced transmission line, for example, a twisted pair line. However, even with a coaxial cable (unbalanced transmission line), the signal on the coaxial cable is zero when there is no signal, and ± when there is a signal. A receiver circuit and a carrier sense circuit capable of receiving a pulse signal of a polarity, that is, one of the signal terminals (outer side of the coaxial cable) of the receiver circuit and the carrier sense circuit of the balanced input is grounded to form an unbalanced transmission line. Can be used.
【００１８】[0018]
【発明の効果】以上述べたように本発明の構成によれ
ば、キャリアセンス付き受信回路は、通常の受信を行う
高感度のレシーバ回路と、比較的大きい閾値を有するキ
ャリアセンス回路とを並列に設置し、伝送線路への送信
がない無信号時に、伝送線路に誘起される比較的微弱な
ノイズを受信して、レシーバ回路がそのノイズを検出し
ても、キャリアセンス回路の出力でこのノイズに基づく
誤信号の除去処理を行い、伝送線路へ送信される有信号
時のみ、正規の伝送信号を検出する。本発明によれば、
標準的なICでもって、簡単な回路方式で、高入力インピ
ーダンス回路を維持しながら、無信号時のノイズ閾値レ
ベルを増やし、ノイズの影響を受け難くする伝送装置の
キャリアセンス付き受信回路を構成することができる。As described above, according to the configuration of the present invention, the receiver circuit with carrier sense has a high sensitivity receiver circuit for normal reception and a carrier sense circuit having a relatively large threshold value in parallel. When the receiver is installed and there is no signal transmitted to the transmission line, it receives relatively weak noise induced in the transmission line and the receiver circuit detects the noise. A genuine transmission signal is detected only when there is a signal transmitted to the transmission line. According to the present invention,
Using a standard IC, a simple circuit method increases the noise threshold level when there is no signal while maintaining a high input impedance circuit, and configures a receiver circuit with carrier sense for transmission equipment that is less susceptible to noise. be able to.
【図１】本発明による一実施例のキャリアセンス付き受
信回路のブロック回路図FIG. 1 is a block circuit diagram of a receiving circuit with carrier sense according to one embodiment of the present invention.
【図２】図１の実施例の回路動作を説明する各部の波形
図FIG. 2 is a waveform chart of each part for explaining the circuit operation of the embodiment of FIG. 1;
【図３】他の実施例のキャリアセンス付き受信回路のブ
ロック回路図FIG. 3 is a block circuit diagram of a receiving circuit with carrier sense according to another embodiment.
１ 伝送線路 1A 受信端入力信号 ２ キャリアセンス回路 2A キャリアセンス出力 2B,2C キャリアセンス回路の閾値 ３、６ レシーバ回路 3A レシーバ回路出力 3B 誤信号 3C 正規伝送信号 ４ ドライバ回路 ５ 論理回路 5A、6A 検出信号 DESCRIPTION OF SYMBOLS 1 Transmission line 1A Receiver end input signal 2 Carrier sense circuit 2A Carrier sense output 2B, 2C Threshold of carrier sense circuit 3, 6 Receiver circuit 3A Receiver circuit output 3B False signal 3C Regular transmission signal 4 Driver circuit 5 Logic circuit 5A, 6A detection signal
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H04B 15/00 H04L 25/02 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. 7 , DB name) H04B 15/00 H04L 25/02
Claims (2)
号により、前記伝送線路上に送信される伝送信号を検出
するレシーバ回路と、 前記伝送線路に接続され、予め設定された閾値を有し、
この閾値を越える前記受信端からの入力信号を検出する
キャリアセンス回路と、を備え、 前記レシーバ回路の出力と前記キャリアセンス回路の出
力との論理積から、前記伝送線路上に伝送信号が送信さ
れているときのみ、前記レシーバ回路の出力を有効検出
信号として出力する、 ことを特徴とするキャリアセンス付き受信回路。1. A receiver circuit connected to a transmission line and detecting a transmission signal transmitted on the transmission line in response to an input signal from a receiving end, and a receiver circuit connected to the transmission line and having a preset threshold value. And
A carrier sense circuit for detecting an input signal from the receiving end exceeding the threshold, wherein a transmission signal is transmitted on the transmission line from a logical product of an output of the receiver circuit and an output of the carrier sense circuit. And outputting the output of the receiver circuit as an effective detection signal only when the receiving circuit is in the receiving state.
号により、前記伝送線路上に送信される伝送信号を検出
するイネーブル端子機能を有するレシーバ回路と、 前記伝送線路に接続され、予め設定された閾値を有し、
この閾値を越える前記受信端からの入力信号を検出する
キャリアセンス回路と、を備え、 前記キャリアセンス回路の出力で前記レシーバ回路のイ
ネーブル端子機能を制御し、前記伝送線路上に伝送信号
が送信されているときのみ、前記レシーバ回路の出力を
有効検出信号として出力する、 ことを特徴とするキャリアセンス付き受信回路。2. A receiver circuit connected to the transmission line and having an enable terminal function for detecting a transmission signal transmitted on the transmission line in response to an input signal from a receiving end, and connected to the transmission line and preset. Has a threshold value,
A carrier sense circuit for detecting an input signal from the receiving end exceeding the threshold, wherein an output terminal of the carrier sense circuit controls an enable terminal function of the receiver circuit, and a transmission signal is transmitted on the transmission line. And outputting the output of the receiver circuit as an effective detection signal only when the receiving circuit is in the receiving state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20173693A JP3232797B2 (en) | 1993-08-16 | 1993-08-16 | Receiver circuit with carrier sense |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20173693A JP3232797B2 (en) | 1993-08-16 | 1993-08-16 | Receiver circuit with carrier sense |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0758712A JPH0758712A (en) | 1995-03-03 |
| JP3232797B2 true JP3232797B2 (en) | 2001-11-26 |
Family
ID=16446088
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20173693A Expired - Lifetime JP3232797B2 (en) | 1993-08-16 | 1993-08-16 | Receiver circuit with carrier sense |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3232797B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102015222334A1 (en) * | 2015-11-12 | 2017-05-18 | Robert Bosch Gmbh | Device and method for selective hiding of bus vibrations during data reception via a bus system |
-
1993
- 1993-08-16 JP JP20173693A patent/JP3232797B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0758712A (en) | 1995-03-03 |
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