JP2003224930A

JP2003224930A - Protector

Info

Publication number: JP2003224930A
Application number: JP2002017558A
Authority: JP
Inventors: Hiroshi Matsubara; 寛至松原
Original assignee: Maspro Denkoh Corp
Current assignee: Maspro Denkoh Corp
Priority date: 2002-01-25
Filing date: 2002-01-25
Publication date: 2003-08-08

Abstract

<P>PROBLEM TO BE SOLVED: To suppress that transmission of a downward signal be obstructed by leaking out of an incoming signal, which the information terminal transmits to a receive terminal side through a junction distribution means in a safety device, which switches unilateral and bidirection sides according to a terminal type which is connected with an output terminal, and has junction distribution means 31, 32 which form at least two output terminals. <P>SOLUTION: A switching means 42, which selectively switches the unilateral and bidirection sides, is installed in a transmission line which the junction distribution means forms. The transmission line which switched the switching means 42 to the unilateral side is constituted by a high pass filter 36, which passes the downward signal to the receiver terminals, a low-pass filter 38 of which one end is connected with the transmission line in between the junction distribution means 31 or 32 and the high-pass filter 36, and a termination resistor 39 connected with the other end of the low-pass filter 38 in order to absorb the incoming signal. <P>COPYRIGHT: (C)2003,JPO

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は，センタ装置と端末
との間で双方向に信号が伝送される双方向ＣＡＴＶシス
テムに最適な保安器に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protector suitable for a bidirectional CATV system in which signals are bidirectionally transmitted between a center device and a terminal.

【０００２】[0002]

【従来の技術】一般的に双方向ＣＡＴＶシステムは，セ
ンタ装置からの下り信号が７０〜７７０ＭＨｚであり，
端末側に接続された情報端末，例えばケーブルモデム等
からは１０〜５５ＭＨｚの周波数の信号にデータ信号を
のせた上り信号がセンタ装置に送出されている。この
時，建物内の受信端末や情報端末は，保安器を介して双
方向ＣＡＴＶシステムと同軸ケーブルで接続されてい
る。2. Description of the Related Art Generally, in a bidirectional CATV system, a downlink signal from a center device is 70 to 770 MHz,
From an information terminal connected to the terminal side, for example, a cable modem or the like, an upstream signal in which a data signal is added to a signal having a frequency of 10 to 55 MHz is sent to the center device. At this time, the receiving terminal and the information terminal in the building are connected to the bidirectional CATV system by a coaxial cable through a protector.

【０００３】このような双方向ＣＡＴＶシステムに用い
る保安器には，受信端末及び情報端末とを夫々接続する
２系統の伝送経路を形成する分岐または分配回路からな
る分岐分配手段を有した２出力型の保安器があり，受信
端末もしくは情報端末を接続する１出力型の保安器があ
る。これらの保安器は、双方向ＣＡＴＶシステムから分
岐増幅器，タップオフ等から分岐された引込線と、テレ
ビ（ＴＶ）信号などの下り信号を受信するテレビ受像機
（以下，単に「テレビ（ＴＶ）」と表現する。）等の受
信端末や，センタ装置にデータ信号をのせた上り信号を
送信するケーブルモデム等の情報端末と接続された屋内
引込線とを中継している。A protector used in such a bidirectional CATV system is a two-output type having a branching / distributing means formed of a branching or distributing circuit which forms two transmission paths for connecting a receiving terminal and an information terminal, respectively. There is a one-output protector for connecting a receiving terminal or an information terminal. These protectors are a drop line branched from a bidirectional CATV system from a branch amplifier, tap-off, etc., and a television receiver (hereinafter, simply referred to as “TV (TV)”) that receives a downlink signal such as a television (TV) signal. , Etc., and an information service terminal such as a cable modem for transmitting an upstream signal carrying a data signal to the center device and an indoor service line connected thereto.

【０００４】そして，これにより，例えば１出力型の保
安器の出力端子に接続された屋内用引込線にテレビを接
続すれば，センタより送られてくるＴＶ番組が視聴でき
るし，２出力型のデータ端子に接続された屋内用引込線
にケーブルモデムを接続すれば，パーソナルコンピュー
タ（以下，パソコン）を用いて，インターネットへのア
クセス等ができるようになる。Thus, for example, if a television is connected to the indoor service line connected to the output terminal of the one-output type protector, the TV program sent from the center can be viewed and the two-output type data can be viewed. If you connect a cable modem to the indoor service wire connected to the terminal, you will be able to access the Internet, etc. using a personal computer (hereinafter, personal computer).

【０００５】[0005]

【発明が解決しようとする課題】しかし，上述のような
保安器を使用して双方向ＣＡＴＶシステムに接続する方
法には，以下に示すような問題点があった。However, the method of connecting to the bidirectional CATV system using the protector as described above has the following problems.

【０００６】まず、１出力型の保安器において、テレビ
等の受信端末だけを接続する場合，例えば１０〜７７０
ＭＨｚ帯対応の双方向型の保安器でも良いが、この場
合、流合雑音が受信端末側よりセンタ装置へ流れ込んで
妨害を与える場合が考えられる。この流合雑音を防止す
るためには、通過帯域が７０〜７７０ＭＨｚの下り信号
用で、１０〜５５ＭＨｚの上り信号の通過を遮断する、
上り信号カットフィルター内蔵の保安器の使用が望まし
い。ところが、前記上り信号カットフィルター内蔵の保
安器の保安器を使用すると、パソコンとケーブルモデム
を使ったインターネット等へのアクセスを始めようとす
ると、保安器を変更する必要が生じる。First, in a one-output type security device, when only receiving terminals such as a television are connected, for example, 10 to 770.
A two-way type protector compatible with the MHz band may be used, but in this case, inflow noise may flow from the receiving terminal side to the center device to cause interference. In order to prevent this ingress noise, the pass band is for downlink signals of 70 to 770 MHz and the passage of uplink signals of 10 to 55 MHz is blocked.
It is desirable to use a protector with a built-in upstream signal cut filter. However, when the protector of the protector with the built-in upstream signal cut filter is used, it becomes necessary to change the protector when trying to start accessing the Internet or the like using a personal computer and a cable modem.

【０００７】また、２出力型の場合、以下に示すような
問題があった。つまり、分岐または分配回路からなる分
岐分配手段を用いているため，情報端末側から送信され
た信号レベルの高い上り信号が，分岐分配手段を介して
受信端末側に漏れ信号として伝送されてしまう。この漏
れ信号が発生する現象は，分岐分配手段がもつ特性から
来るものであり，例えば２分配器では入力端子から入力
された信号は，二つの出力端子のそれぞれから入力信号
から概３ｄＢ（入力信号の半分の信号レベル）少ないレ
ベルで出力されるだけでなく，一方の出力端子から信号
を入力すると，その信号は，概２０ｄＢ程度の端子間結
合損失によって，他方の出力端子から出力される。Further, the two-output type has the following problems. That is, since the branching / distributing means composed of a branching or distributing circuit is used, an upstream signal having a high signal level transmitted from the information terminal side is transmitted as a leak signal to the receiving terminal side via the branching / distributing means. The phenomenon in which this leak signal occurs is due to the characteristic of the branching / distributing means. For example, in a 2-divider, the signal input from the input terminal is approximately 3 dB (input signal) from each of the two output terminals. (Half of the signal level), the signal is output at a small level, and when a signal is input from one output terminal, the signal is output from the other output terminal due to inter-terminal coupling loss of about 20 dB.

【０００８】上述のごとく，一方の出力端子に情報端末
からの上り信号が入力されると，端子間結合損失によ
り，上り信号レベルが概２０ｄＢ抑えられ，他方の出力
端子である，受信端末側に漏れ信号として上り信号が伝
送され，この受信端末側に漏れ出た上り信号は，雑音と
して下り信号に影響を与える。特に，双方向ＣＡＴＶシ
ステムのように，情報端末から送信される上り信号をセ
ンタ装置に確実に伝送させるために，ケーブルモデム等
の情報端末付近において，上り信号が，その伝送線にお
ける下り信号より高い信号レベルで伝送されているの
で，漏れ信号としての上り信号の信号レベルのほうが下
り信号より高くなって，該上り信号が下り信号に大きい
影響を及ぼし，例えば，ＴＶ信号の場合には，ＴＶ画面
にちらつきが発生したりする原因となっていた。As described above, when the upstream signal from the information terminal is input to one output terminal, the upstream signal level is suppressed by about 20 dB due to the coupling loss between the terminals, and the other output terminal, that is, the receiving terminal side. An upstream signal is transmitted as a leakage signal, and the upstream signal leaked to the receiving terminal side affects the downstream signal as noise. In particular, in order to reliably transmit the upstream signal transmitted from the information terminal to the center device as in the bidirectional CATV system, the upstream signal is higher than the downstream signal on the transmission line near the information terminal such as a cable modem. Since the signal is transmitted at the signal level, the signal level of the upstream signal as the leakage signal is higher than that of the downstream signal, and the upstream signal has a great influence on the downstream signal. For example, in the case of a TV signal, the TV screen is displayed. This caused flicker.

【０００９】また、将来を考えて、この２出力型の保安
器を取付けたが、当面の間，テレビ等の受信端末しか接
続しない場合は、受信端末側から流合雑音がセンタ装置
へ流れ込んで妨害を与える場合が考えられる。In consideration of the future, the two-output type protector is attached. However, if only the receiving terminal such as a television is connected for the time being, ingress noise flows into the center apparatus from the receiving terminal side. It may cause interference.

【００１０】本発明は，こうした問題に鑑みなされたも
のであり，単方向もしくは双方向を選択的に切換可能な
切換手段を有し、必要に応じて単方向もしくは双方向の
切換が可能な保安器であり、さらに、２出力型の保安器
においては、情報端末から送信される上り信号が前記分
岐分配手段を介して受信端末側に漏れ出して下り信号の
伝送を妨害するのを抑制することを目的とする。The present invention has been made in view of these problems, and has a switching means capable of selectively switching between unidirectional or bidirectional, and a security system capable of unidirectional or bidirectional switching as required. Furthermore, in a two-output type security device, it is possible to prevent an upstream signal transmitted from an information terminal from leaking to the receiving terminal side through the branching / distributing means and interfering with the transmission of the downstream signal. With the goal.

【００１１】[0011]

【課題を解決するための手段】上記課題を解決するため
に，請求項１の発明は，センタ装置から端末側に伝送線
を介して所定周波数帯域の下り信号が伝送されるととも
に，端末からセンタ装置側に該伝送線を介して該下り信
号とは異なる所定周波数帯域の上り信号が伝送される双
方向ＣＡＴＶシステムにおいて，前記伝送線の端末側に
設けられ，前記伝送線と屋内引込線とを接続する保安器
であり，前記保安器は，入力端子と出力端子と共通線と
を備え，外部導体が共通線と直接接続された前記入力端
子と，外部導体と共通線とがコンデンサーを介して接続
され，高周波的に接地された前記出力端子と，前記入力
端子と前記出力端子との間の伝送経路に直列に接続され
た，前記所定周波数帯域を選択的に切換える切換手段
と，前記入力端子と前記切換手段との間の伝送経路に直
列に接続された，高周波信号を通過させ電流の通過は遮
断する入力側のコンデンサーと，前記入力端子と前記入
力側のコンデンサーとの間の伝送経路に一端が接続され
他端が共通線と接続されたアレスター又はチョークコイ
ルと，前記切換手段と前記出力端子との間の伝送回路に
直列に接続された，高周波信号を通過させ電流の通過は
遮断する出力側のコンデンサーと，からなり，前記切換
手段は，前記上り信号及び下り信号を通過させる双方向
の伝送経路と，前記下り信号を通過させ，前記上り信号
の通過を遮断する単方向の伝送経路を切換えるよう構成
され，前記単方向の伝送経路には，前記上り信号の通過
を遮断し，前記下り信号を選択的に通過させる下り信号
通過手段と，前記上り信号を吸収する上り信号吸収手段
と，で構成される。In order to solve the above-mentioned problems, the invention of claim 1 is such that a downlink signal of a predetermined frequency band is transmitted from a center device to a terminal side through a transmission line, and at the same time, the terminal transmits to the center. In a two-way CATV system in which an upstream signal in a predetermined frequency band different from the downstream signal is transmitted to the device side through the transmission line, the two-way CATV system is provided on the terminal side of the transmission line and connects the transmission line and an indoor service line. The protector includes an input terminal, an output terminal, and a common line, and the input terminal in which the outer conductor is directly connected to the common line and the outer conductor and the common line are connected via a capacitor. The output terminal grounded in high frequency, the switching means connected in series to the transmission path between the input terminal and the output terminal for selectively switching the predetermined frequency band, and the input terminal. One end of a transmission path between the input terminal and the input side capacitor, which is connected in series with the switching means and which passes a high frequency signal and blocks the passage of current. Connected in series with the arrester or choke coil whose other end is connected to the common line and the transmission circuit between the switching means and the output terminal, which outputs a high-frequency signal and cuts off the passage of current. The switching means includes a bidirectional transmission path for passing the up signal and the down signal, and a unidirectional transmission path for passing the down signal and blocking the up signal. Downstream signal passage means configured to switch and which blocks the passage of the upstream signal and selectively passes the downstream signal, and absorbs the upstream signal in the unidirectional transmission path. Signal absorbing means Ri, in constructed.

【００１２】請求項２の発明は，請求項１に記載の切換
手段を有した前記双方向ＣＡＴＶシステムに用いる保安
器であり，入力端子と少なくとも２つの出力端子と共通
線とを備え，外部導体が共通線と直接接続された前記入
力端子と，外部導体と共通線とがコンデンサーを介して
接続され，高周波的に接地された前記出力端子と，前記
入力端子と前記出力端子との間の伝送経路に直列に接続
され，少なくとも２系統の伝送経路を形成する分岐また
は分配回路からなる分岐分配手段と，前記入力端子と前
記分岐分配手段との間の伝送経路に直列に接続された，
高周波信号を通過させ電流の通過は遮断する入力側のコ
ンデンサーと，前記入力端子と前記入力側のコンデンサ
ーとの間の伝送経路に一端が接続され他端が共通線と接
続されたアレスター又はチョークコイルと，前記の少な
くとも２系統の伝送経路において，前記分岐分配手段の
出力端と前記出力端子との間に直列に接続された、前記
所定周波数帯域を選択的に切換える切換手段と，前記切
換手段と前記出力端子との間に直列に接続された，高周
波信号を通過させ電流の通過は遮断する出力側のコンデ
ンサーと，からなり，前記切換手段は，前記上り信号及
び下り信号を通過させる双方向の伝送経路と，前記下り
信号を通過させ，前記上り信号の通過を遮断する単方向
の伝送経路を切換えるよう構成され，前記単方向の伝送
経路には，前記上り信号の通過を遮断し，前記下り信号
を選択的に通過させる下り信号通過手段と，前記上り信
号を吸収する上り信号吸収手段と，で構成される。A second aspect of the present invention is a protector used in the bidirectional CATV system having the switching means according to the first aspect, comprising an input terminal, at least two output terminals, and a common line, and an external conductor. Is directly connected to the common line, the external conductor and the common line are connected via a capacitor, the output terminal is grounded in high frequency, and the transmission between the input terminal and the output terminal A branching / distributing means which is connected to the path in series and which comprises at least two branching or distributing circuits, and a transmission path between the input terminal and the branching / distributing means.
An arrester or choke coil, one end of which is connected to a transmission path between an input-side capacitor that allows high-frequency signals to pass and a current that is blocked and the other end of which is connected to a common line. Switching means for selectively switching the predetermined frequency band, which is connected in series between the output terminal and the output terminal of the branching / distributing means in the at least two transmission paths. And a switching capacitor connected in series between the output terminal and a capacitor on the output side for passing a high frequency signal and blocking a current from passing therethrough, and the switching means is a bidirectional circuit for passing the up signal and the down signal. It is configured to switch a transmission path and a unidirectional transmission path that allows the downlink signal to pass and blocks the uplink signal from passing. Blocking the passage of signals, and downlink signal passing means for selectively passing the downlink signal, the uplink signal absorbing means for absorbing the uplink signal, in constructed.

【００１３】請求項３の発明は，請求項１，２の保安器
において，上り信号は，前記下り信号よりも低い周波数
から成り，前記単方向の伝送経路の前記下り信号通過手
段はハイパスフィルタから成り，前記単方向の伝送経路
の前記上り信号吸収手段は，該上り信号を通過させるた
めに，前記単方向の伝送経路に一端が接続されたローパ
スフィルタと，該上り信号を吸収するために，該ローパ
スフィルタの他端に接続された終端抵抗と，からなるこ
とを特徴とした保安器。According to a third aspect of the present invention, in the protector according to the first and second aspects, the upstream signal has a frequency lower than that of the downstream signal, and the downstream signal passing means of the unidirectional transmission path is a high-pass filter. The upstream signal absorbing means of the unidirectional transmission path comprises a low-pass filter having one end connected to the unidirectional transmission path for passing the upstream signal, and the upstream signal absorbing means for absorbing the upstream signal. A protector comprising: a terminating resistor connected to the other end of the low-pass filter.

【００１４】[0014]

【発明の実施の形態】以下に，本発明の実施例につい
て，図面を基に詳細に説明する。図１は本発明の保安器
を用いた双方向ＣＡＴＶシステムの全体の構成を表す例
である。図２は，本発明に係る２出力型の保安器の外形
を示す斜視図であり，図３（ａ）は、１出力型の保安器
６ａの内部構成を示すブロック図、図４（ｂ）、（ｃ）
は，２出力型の保安器６ｂ、６ｃの内部構成を示すブロ
ック図、図５，６は保安器６ｂの使用例を示すブロック
図を示している。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an example showing the overall configuration of a two-way CATV system using the protector of the present invention. FIG. 2 is a perspective view showing an outer shape of a two-output type protector according to the present invention, and FIG. 3 (a) is a block diagram showing an internal configuration of the one-output type protector 6a, FIG. 4 (b). , (C)
Shows a block diagram showing an internal configuration of the two-output type protectors 6b and 6c, and FIGS. 5 and 6 are block diagrams showing an example of use of the protector 6b.

【００１５】２分配型の保安器６ｂの実施例について説
明する。図１，２に示すように，本実施例の双方向ＣＡ
ＴＶシステムおよび保安器６ｂでは，下り信号と上り信
号を伝送する伝送線として，センタ装置となるヘッドエ
ンド１（ＨＥ１）から延長された幹線２から，分配増幅
器３，タップオフ４を介して分岐された引込線５が保安
器６ｂの入力端子６２に接続されている。保安器６ｂの
出力端子６４には屋内伝送線７によってテレビ８等の受
信端末に配線されており，もう一つの出力端子６５には
屋内伝送線９によってケーブルモデム１０等の情報端末
に配線されている。An embodiment of the two-distribution type protector 6b will be described. As shown in FIGS. 1 and 2, the bidirectional CA of the present embodiment.
In the TV system and the protector 6b, as a transmission line for transmitting a down signal and an up signal, a trunk line 2 extended from a head end 1 (HE1) serving as a center device is branched via a distribution amplifier 3 and a tap-off 4. The service wire 5 is connected to the input terminal 62 of the protector 6b. The output terminal 64 of the protector 6b is wired to the receiving terminal such as the television 8 by the indoor transmission line 7, and the other output terminal 65 is wired to the information terminal such as the cable modem 10 by the indoor transmission line 9. There is.

【００１６】本願の双方向ＣＡＴＶシステムにおいて
は，上記伝送線を介して，ヘッドエンド１から受信端末
（ＴＶ８）及び情報端末（ケーブルモデム１０）へ，７
０〜７７０ＭＨｚの周波数帯域の下り信号が送出され，
情報端末（ケーブルモデム１０）からヘッドエンド１
へ，１０〜５５ＭＨｚの周波数帯域の上り信号が送出さ
れる。In the bidirectional CATV system of the present application, the head end 1 is connected to the receiving terminal (TV 8) and the information terminal (cable modem 10) via the transmission line.
The downlink signal of the frequency band of 0-770MHz is transmitted,
Information terminal (cable modem 10) to headend 1
An upstream signal in the frequency band of 10 to 55 MHz is transmitted to the.

【００１７】次に本発明の保安器６ｂの実施形態につい
て図２を参照して説明する。保安器６ｂは壁面に固定可
能なケース６６を備えている。そしてケース６６には，
円柱状で中空状のケース本体６１の一面に，Ｆ型接線６
２ａと，Ｆ型接線６４ａと，Ｆ型接線６５ａと，が突設
され，このＦ型接線６２ａ，６４ａ，６５ａが形成され
た面の縁端に，板状部材に螺子孔６６が形成された取付
部６７が突設されており，前記取付部６７の螺子孔６６
を用いて壁面にケース本体６１を固定できるようになっ
ている。Next, an embodiment of the protector 6b of the present invention will be described with reference to FIG. The protector 6b includes a case 66 that can be fixed to the wall surface. And in case 66,
The F-shaped tangent 6 is formed on one surface of the cylindrical and hollow case body 61.
2a, an F-type tangent line 64a, and an F-type tangent line 65a are projected, and a screw hole 66 is formed in the plate member at the edge of the surface on which the F-type tangent lines 62a, 64a, 65a are formed. The mounting portion 67 is provided so as to project, and the screw hole 66 of the mounting portion 67 is provided.
The case body 61 can be fixed to the wall surface by using.

【００１８】尚，本願においては，Ｆ型接線６２ａは，
引込線が接続され，Ｆ型接線６４ａは，受信端末と屋内
伝送線７で接続され，Ｆ型接線６５ａは，情報端末と屋
内伝送線９で接続されている。In the present application, the F-type tangent line 62a is
The service line is connected, the F-type tangent line 64a is connected to the receiving terminal by the indoor transmission line 7, and the F-type tangent line 65a is connected to the information terminal by the indoor transmission line 9.

【００１９】１出力型の保安器６ａについては、上述の
実施形態と同様であっても良いし、異なる形状でもかま
わないが、出力のＦ型接線が２出力型より一つ少なく、
出力端子６３はＦ型接線６３ａ一つで構成されている。
また尚，図に示した形状は１例であり，必要に応じて適
宜形状を変更してもかまわない。また，本願では接線が
Ｆ型で構成しているが，ＦＴ型のコネクターを用いても
かまわない。The one-output type protector 6a may be the same as the above-mentioned embodiment or may have a different shape, but the output F-type tangent is one less than that of the two-output type.
The output terminal 63 is composed of one F-type tangent line 63a.
In addition, the shape shown in the drawing is an example, and the shape may be changed as necessary. Further, in the present application, the tangent line is configured as an F type, but an FT type connector may be used.

【００２０】次に保安器の内部構成について図３、４を
用いて説明する。図３（ａ）は１出力型の保安器６ａの
内部構成を表すブロック図，図４（ｂ）は，２出力型で
あり分岐分配手段として分配回路３１を備えた分配回路
型の保安器６ｂを表すブロック図，図４（ｃ）は，２出
力型であり分岐分配手段として分岐回路３２を備えた分
岐回路型の保安器６ｃを表すブロック図である。Next, the internal structure of the protector will be described with reference to FIGS. 3A is a block diagram showing the internal configuration of the one-output type protector 6a, and FIG. 4B is a two-output type protector 6b of the distribution circuit type having a distribution circuit 31 as branch distribution means. 4C is a block diagram showing a branch circuit type protector 6c which is a two-output type and which has a branch circuit 32 as branch distribution means.

【００２１】保安器６ａは，図３（ａ）に示すように，
入力端子６２と出力端子６３を有し，入力端子６２から
入力された信号が切換手段４２によって単方向側と双方
向側の２系統の伝送回路を選択的に切換可能になってい
る。本願では単方向側とは、７０〜７７０ＭＨｚの周波
数帯域の下り信号のことで、双方向側とは、１０〜７７
０ＭＨｚの周波数帯の上り及び下り信号のことである。
入力端子６２と切換回路４２との間にはコンデンサー３
３が設けられるとともに，中心導体と共通線４１の間に
はアレスター３４とチョークコイル３５とが並列に接続
されており，本願では双方向ＣＡＴＶシステムの上り信
号及び下り信号である１０〜７７０ＭＨｚが通過するが
電流は遮断するよう構成されている。入力端子６２の外
部導体は共通線４１に接続されている。また，切換回路
４２と出力端子６３との間にはコンデンサー３７が設け
られ、高周波信号は通過するものの電流の通過は遮断す
るよう構成されている。The protector 6a, as shown in FIG.
It has an input terminal 62 and an output terminal 63, and a signal inputted from the input terminal 62 can be selectively switched by the switching means 42 between two unidirectional transmission circuits and bidirectional transmission circuits. In the present application, the unidirectional side is a downlink signal in the frequency band of 70 to 770 MHz, and the bidirectional side is 10 to 77.
It refers to upstream and downstream signals in the frequency band of 0 MHz.
A capacitor 3 is provided between the input terminal 62 and the switching circuit 42.
3 is provided, and the arrester 34 and the choke coil 35 are connected in parallel between the central conductor and the common line 41. In the present application, 10-770 MHz, which is an upstream signal and a downstream signal of the bidirectional CATV system, passes. However, the current is cut off. The outer conductor of the input terminal 62 is connected to the common line 41. Further, a capacitor 37 is provided between the switching circuit 42 and the output terminal 63 so that a high-frequency signal passes but a current does not pass.

【００２２】切換手段４２は、単方向側である７０〜７
７０ＭＨｚの周波数帯域の下り信号が通過し１０〜５５
ＭＨｚの周波数帯域の上り信号の通過は遮断する伝送経
路と、双方向側である１０〜７７０ＭＨｚの周波数帯域
の上り及び下り信号が通過する伝送経路を切換えるもの
であり、本願ではスイッチを用いている。The switching means 42 is a unidirectional side 70-7.
The downlink signal in the frequency band of 70 MHz passes and 10 to 55
A switch is used to switch between a transmission path that blocks passage of an upstream signal in the frequency band of MHz and a transmission path that passes upstream and downstream signals in the frequency band of 10 to 770 MHz on the bidirectional side. .

【００２３】前記単方向側の伝送経路にはハイパスフィ
ルタ３６（ＨＰＦ３６）とともに，中心導体と共通線の
間にはローパスフィルタ３８（ＬＰＦ３８）と終端抵抗
３９が直列に接続されており，本願では７０〜７７０Ｍ
Ｈｚの周波数帯域の下り信号が通過するが、１０〜５５
ＭＨｚの周波数帯域の上り信号の通過は遮断するととも
に低周波数帯域の雑音成分も阻止する用構成されてい
る。ＨＰＦ３６は，カットオフ周波数を７０ＭＨｚに設
定されて，受信端末側に伝送された前記下り信号をＨＰ
Ｆ３６で選択的に受信端末に伝送するようにし，下り信
号より低い周波数の信号を，ＨＰＦ３６で遮断して受信
端末側に伝送しないようにしている。そして更に，ＬＰ
Ｆ３８はカットオフ周波数が５５ＭＨｚに設定されてお
り，ＬＰＦ３８の出力端には，終端抵抗３９が接続され
ており、低周波数帯域の雑音成分を阻止する。A high-pass filter 36 (HPF 36) is connected to the transmission path on the unidirectional side, and a low-pass filter 38 (LPF 38) and a terminating resistor 39 are connected in series between the center conductor and the common line. ~ 770M
Downstream signals in the Hz frequency band pass, but 10 to 55
It is configured to block passage of upstream signals in the MHz frequency band and block noise components in the low frequency band. The HPF 36 sets the cutoff frequency to 70 MHz, and HPs the downlink signal transmitted to the receiving terminal side.
In F36, the signal is selectively transmitted to the receiving terminal, and a signal having a frequency lower than the downlink signal is blocked by the HPF 36 and is not transmitted to the receiving terminal side. And further, LP
The cutoff frequency of F38 is set to 55 MHz, and the terminating resistor 39 is connected to the output terminal of the LPF 38 to block noise components in the low frequency band.

【００２４】前記双方向の伝送経路は１０〜７７０ＭＨ
ｚが通過するパス回路となっている。The bidirectional transmission path is 10 to 770 MH.
It is a pass circuit through which z passes.

【００２５】出力端子の外部導体はコンデンサーを介し
て高周波的に共通線に接続されるよう構成されているの
で出力端子は中心導体も外部導体も電流は遮断されてい
る。Since the outer conductor of the output terminal is constructed so as to be connected to the common line in a high frequency manner via the capacitor, the current is cut off from both the center conductor and the outer conductor of the output terminal.

【００２６】つまり，１出力型の保安器６ａは、出力端
子６３にテレビ８等の受信端末を接続する場合は、切換
手段４２を単方向側に切換え、受信端末側から発生する
流合雑音が双方向ＣＡＴＶシステムのセンタ装置に流れ
込み、システムに妨害を与えることを防止可能とする。
また、出力端子６３にケーブルモデム１０等の情報端末
を接続する場合は、切換手段４２を双方向側に切換えて
使用する。この様に、出力端子６３に接続する機器によ
って、前記所定伝送帯域を切換えることが可能となる。That is, in the one-output type protector 6a, when the receiving terminal such as the television 8 is connected to the output terminal 63, the switching means 42 is switched to the unidirectional side, and the inflow noise generated from the receiving terminal side is generated. It is possible to prevent the interference with the system by flowing into the center device of the bidirectional CATV system.
When connecting an information terminal such as the cable modem 10 to the output terminal 63, the switching means 42 is switched to the bidirectional side for use. In this way, it is possible to switch the predetermined transmission band depending on the device connected to the output terminal 63.

【００２７】保安器６ｂは，図４（ｂ）に示すように，
入力端子６２と出力端子６４，６５を有し，入力端子６
２から入力された信号が分岐分配手段である分配回路３
１によって２系統の伝送経路を形成している。そして、
それぞれの伝送経路には切換手段４２が設けられ、単方
向側と双方向側の２系統の伝送回路を選択的に切換可能
になっている。入力端子６２と分岐分配手段である分配
回路３１との間にはコンデンサー３３が設けられるとと
もに，中心導体と共通線４１の間にはアレスター３４と
チョークコイル３５とが並列に接続されており，本願で
は双方向ＣＡＴＶシステムの上り信号及び下り信号であ
る１０〜７７０ＭＨｚの周波数帯域が通過するが電流は
遮断するよう構成されている。入力端子６２の外部導体
は共通線４１に接続されている。また，前記２系統の伝
送経路に設けられた切換回路４２と出力端子６４，６５
との間にはコンデンサー３７が設けられ、高周波信号は
通過するものの電流の通過は遮断するよう構成されてい
る。The protector 6b, as shown in FIG.
The input terminal 62 and the output terminals 64 and 65 are provided, and the input terminal 6
The distribution circuit 3 in which the signal input from 2 is the branch distribution means
1 forms two transmission paths. And
A switching means 42 is provided in each transmission path, and it is possible to selectively switch between two types of transmission circuits, that is, the unidirectional side and the bidirectional side. A capacitor 33 is provided between the input terminal 62 and the distribution circuit 31 serving as branch distribution means, and an arrester 34 and a choke coil 35 are connected in parallel between the central conductor and the common line 41. In the bidirectional CATV system, the frequency band of 10 to 770 MHz, which is the upstream signal and the downstream signal, passes, but the current is cut off. The outer conductor of the input terminal 62 is connected to the common line 41. In addition, the switching circuit 42 and the output terminals 64, 65 provided on the two transmission paths.
A capacitor 37 is provided between and, and is configured so that a high-frequency signal passes but a current is blocked.

【００２８】切換手段４２は、単方向側である７０〜７
７０ＭＨｚの周波数帯域の下り信号が通過し、１０〜５
５ＭＨｚの周波数帯域の上り信号の通過は遮断する伝送
経路と、双方向側である１０〜７７０ＭＨｚの周波数帯
域の上り及び下り信号が通過する伝送経路を切換えるも
のであり、本願ではスイッチを用いている。The switching means 42 is a unidirectional side 70-7.
A downlink signal in the frequency band of 70 MHz passes and 10 to 5
A switch is used to switch between a transmission path that blocks passage of an upstream signal in the frequency band of 5 MHz and a transmission path that passes upstream and downstream signals in the frequency band of 10 to 770 MHz on the bidirectional side. .

【００２９】前記単方向側の伝送経路にはＨＰＦ３６と
ともに，中心導体と共通線の間にはＬＰＦ３８と終端抵
抗３９が直列に接続されており，本願では７０〜７７０
ＭＨｚの周波数帯域の下り信号が通過するが、１０〜５
５ＭＨｚの周波数帯域の上り信号の通過は遮断するとと
もに低周波数帯域の雑音成分も阻止するよう構成されて
いる。An HPF 36 is connected to the transmission path on the unidirectional side, and an LPF 38 and a terminating resistor 39 are connected in series between the central conductor and a common line. In the present application, 70 to 770 are used.
Downstream signals in the MHz frequency band pass, but 10 to 5
It is configured to block passage of upstream signals in the frequency band of 5 MHz and block noise components in the low frequency band.

【００３０】前記双方向側の伝送経路は１０〜７７０Ｍ
Ｈｚの周波数帯域の上り及び下り信号が通過するパス回
路となっている。The bidirectional transmission path is 10 to 770M.
It is a path circuit through which upstream and downstream signals in the frequency band of Hz pass.

【００３１】出力端子６４，６５の外部導体はコンデン
サーを介して高周波的に共通線に接続されるよう構成さ
れているので出力端子は中心導体も外部導体も電流は遮
断されている。Since the outer conductors of the output terminals 64 and 65 are configured to be connected to a common line in a high frequency manner via a capacitor, the current is cut off from both the center conductor and the outer conductors of the output terminals.

【００３２】つまり，２出力型の保安器６ｂは、出力端
子６４，６５にテレビ８等の受信端末を接続する場合
は、切換手段４２を単方向側に切換え、受信端末側から
発生する流合雑音が双方向ＣＡＴＶシステムのセンタ装
置に流れ込み、システムに妨害を与えることを防止可能
とする。また、例えば出力端子６５にケーブルモデム１
０等の情報端末を接続する場合は、切換手段４２を双方
向側に切換えて使用する。この様に、出力端子６４，６
５に接続する機器によって、所定伝送帯域を切換えるこ
とが可能となる。That is, in the two-output type protector 6b, when the receiving terminals such as the television 8 are connected to the output terminals 64 and 65, the switching means 42 is switched to the unidirectional side, and the merger generated from the receiving terminal side. It is possible to prevent noise from flowing into the center device of the two-way CATV system and disturbing the system. Also, for example, the cable modem 1 is connected to the output terminal 65.
When connecting an information terminal such as 0, the switching means 42 is used by switching to the bidirectional side. In this way, the output terminals 64, 6
Depending on the device connected to 5, it is possible to switch the predetermined transmission band.

【００３３】２出力型の保安器６ｂの具体的な使用例を
図５，６に示す。図５は、２出力型の出力端子６４に
は、セットトップボックスを介してテレビ８が接続され
ており、この伝送経路の切換手段４２は単方向側に切換
えてある。出力端子にはケーブルモデム１０が接続され
ており、この伝送経路の切換手段４２は双方向側に切換
えてある。図６は、２出力ともテレビ８が接続されてお
り、切換手段４２はいずれも単方向側に切換えてある。5 and 6 show specific examples of use of the two-output type protector 6b. In FIG. 5, the television 8 is connected to the two-output type output terminal 64 via a set top box, and the transmission path switching means 42 is switched to the unidirectional side. The cable modem 10 is connected to the output terminal, and the transmission path switching means 42 is switched to the bidirectional side. In FIG. 6, the television 8 is connected to both of the two outputs, and the switching means 42 are both switched to the unidirectional side.

【００３４】上述の例を信号の流れで説明すれば，入力
端子６２から入力された前記下り信号は，分配回路３１
で，受信端末用の出力端子６４側と，情報端末用の出力
端子６５側と，に分配され，出力端子６５から入力され
た前記上り信号は，分配回路３１を介して入力端子６２
より双方向ＣＡＴＶシステムに送出される。To explain the above-mentioned example in terms of signal flow, the downlink signal inputted from the input terminal 62 is distributed to the distribution circuit 31.
Then, the upstream signal distributed to the output terminal 64 side for the receiving terminal and the output terminal 65 side for the information terminal and input from the output terminal 65 is input to the input terminal 62 via the distribution circuit 31.
Is sent to the interactive CATV system.

【００３５】ただし，既述のごとく，前記上り信号の一
部は，分配回路３１の端子間結合により，出力端子６４
側の伝送経路に漏れ出ることとなるため，保安器６ｂの
ＨＰＦ３６，ＬＰＦ３８，終端抵抗３９は，漏れ信号に
よる受信端末への影響を抑制するために必要な要素であ
り，以下に各要素の配置についての詳細に説明する。However, as described above, a part of the upstream signal is output to the output terminal 64 by the inter-terminal coupling of the distribution circuit 31.
The HPF 36, the LPF 38, and the terminating resistor 39 of the protector 6b are necessary elements for suppressing the influence of the leak signal on the receiving terminal. Will be described in detail.

【００３６】ＨＰＦ３６は，カットオフ周波数を７０Ｍ
Ｈｚに設定されて，切換手段４２によって形成された単
方向側の伝送経路に形成され，単方向側を選択したとき
に、分配回路３１を介して受信端末側に伝送された前記
下り信号をＨＰＦ３６で選択的に受信端末に伝送するよ
うにし，前記下り信号より低い周波数の信号を，ＨＰＦ
３６で遮断して受信端末側に伝送しないようにしてい
る。そして更に，ＨＰＦ３６にはカットオフ周波数が５
５ＭＨｚに設定されたＬＰＦ３８の入力が接続され，Ｌ
ＰＦ３８の出力端には，終端抵抗３９が接続されてい
る。つまり，双方向ＣＡＴＶシステムにおいて，情報端
末用のデータ端子としての出力端子６５から保安器６ｂ
に入力された前記上り信号のうち，分配回路３１を介し
て，伝送経路上に伝送された漏れ信号である前記上り信
号は，ＨＰＦ３６により，受信端末用の出力端子６４へ
の通過を阻止される一方，ＬＰＦ３８を通過して，終端
抵抗３９で吸収され，熱エネルギーとして消費される。
尚，終端抵抗３９では，前記上り信号だけでなく，前記
上り信号周波数帯域の雑音も吸収される。The HPF 36 has a cutoff frequency of 70M.
Is set to Hz and is formed in the transmission path on the unidirectional side formed by the switching means 42, and when the unidirectional side is selected, the downlink signal transmitted to the receiving terminal side via the distribution circuit 31 is transmitted to the HPF 36. To selectively transmit the signal to the receiving terminal with a signal having a frequency lower than that of the downlink signal.
It is blocked at 36 to prevent transmission to the receiving terminal side. Furthermore, the HPF 36 has a cutoff frequency of 5
The input of LPF38 set to 5MHz is connected and L
A terminating resistor 39 is connected to the output terminal of the PF 38. That is, in the bidirectional CATV system, from the output terminal 65 as the data terminal for the information terminal to the protector 6b.
The upstream signal, which is a leakage signal transmitted on the transmission path through the distribution circuit 31 among the upstream signals input to the above, is blocked by the HPF 36 from passing to the output terminal 64 for the receiving terminal. On the other hand, it passes through the LPF 38, is absorbed by the terminating resistor 39, and is consumed as heat energy.
The terminating resistor 39 absorbs not only the upstream signal but also noise in the upstream signal frequency band.

【００３７】尚，図４（ｂ）に示す保安器６ｂの代わり
に，保安器６ｂの分配回路３１を，下り信号を情報端子
用のデータ端子としての出力端子６５と受信端末用の出
力端子６４に分岐する分岐回路３２に変更した図４
（ｃ）の保安器６ｃを使用することができる。図４
（ｃ）に示す保安器６ｃでは，分岐回路３２により形成
された二つの伝送経路のうち，下り信号の小さい支線側
に，出力端子６５がくるよう形成しているが，特にこれ
に限定されるものではなく，支線側に受信端末用の出力
端子６４を形成し，他方の伝送経路に情報端末用の出力
端子６５を形成しても良い。In place of the protector 6b shown in FIG. 4 (b), the distribution circuit 31 of the protector 6b is provided with an output terminal 65 as a data terminal for the information terminal of the down signal and an output terminal 64 for the receiving terminal. 4 is changed to a branch circuit 32 that branches to
The protector 6c of (c) can be used. Figure 4
In the protector 6c shown in (c), the output terminal 65 is formed on the branch line side of the two transmission paths formed by the branch circuit 32, which has a smaller downlink signal, but is not particularly limited to this. Alternatively, the output terminal 64 for the receiving terminal may be formed on the branch line side, and the output terminal 65 for the information terminal may be formed on the other transmission path.

【００３８】以上のように，本願の保安器６ａ，６ｂ，
６ｃによると，出力端子に接続された端末の種類によっ
て，単方向側もしくは双方向側とを切換手段４２を用い
て選択的に切換可能となるので、出力端子にテレビ８等
の受信端末を接続する時は、受信端末からの雑音成分が
センタ装置へ流れていくのを防ぐことができる。また、
２出力型の場合、前記の通り、それぞれの出力端子に接
続される端末の種類によって、単方向側もしくは双方向
側とを切換手段４２を用いて選択的に切換可能となるだ
けでなく、一方の出力端子にケーブルモデム１０等の情
報端末を接続した場合、情報端末からセンタ装置へ送ら
れるレベルの高い上り信号による受信端末に与える影響
を抑制できる利点もある。As described above, the protectors 6a, 6b,
According to 6c, the unidirectional side or the bidirectional side can be selectively switched using the switching means 42 depending on the type of the terminal connected to the output terminal, so that the receiving terminal such as the television 8 is connected to the output terminal. When doing so, it is possible to prevent the noise component from the receiving terminal from flowing to the center device. Also,
In the case of the two-output type, as described above, depending on the type of terminal connected to each output terminal, not only the unidirectional side or the bidirectional side can be selectively switched using the switching means 42, but When an information terminal such as the cable modem 10 is connected to the output terminal of, there is also an advantage that it is possible to suppress the influence on the receiving terminal by a high level upstream signal sent from the information terminal to the center device.

【００３９】尚，本発明は上記実施の形態に限定される
ものではなく，本発明の趣旨を逸脱しない範囲で各部適
宜に変更して実施することも可能である。The present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention.

【００４０】[0040]

【発明の効果】以上詳述したように，請求項１，３の発
明によれば，センタ装置から端末側に伝送線を介して所
定周波数帯域の下り信号が伝送されるとともに，端末か
らセンタ装置側に該伝送線を介して該下り信号とは異な
る所定周波数帯域の上り信号が伝送される双方向ＣＡＴ
Ｖシステムにおいて，前記伝送線の端末側に設けられ，
前記伝送線と屋内引込線とを接続する保安器であり，前
記保安器は，入力端子と出力端子と共通線とを備え，外
部導体が共通線と直接接続された前記入力端子と，外部
導体と共通線とがコンデンサーを介して接続された前記
出力端子と，前記入力端子と前記出力端子との間の伝送
経路に直列に接続された，前記所定周波数帯域を選択的
に切換える切換手段と，前記入力端子と前記切換手段と
の間の伝送経路に直列に接続された，高周波信号を通過
させ，直流または低い周波数の電流を遮断する入力側の
コンデンサーと，前記入力端子と前記入力側のコンデン
サーとの間の伝送経路に一端が接続され他端が共通線と
接続されたアレスター又はチョークコイルと，前記切換
手段と前記出力端子との間に接続された，高周波信号を
通過させ，直流または低い周波数の電流を遮断する出力
側のコンデンサーと，からなり，前記切換手段は，前記
上り信号及び下り信号を通過させる双方向の伝送経路
と，前記下り信号を通過させ，前記上り信号の通過を遮
断する単方向の伝送経路を切換えるよう構成され，前記
単方向の伝送経路には，前記上り信号の通過を遮断し，
前記下り信号を選択的に通過させる下り信号通過手段
と，前記上り信号を吸収する上り信号吸収手段と，から
なるよう構成したので，単方向もしくは双方向の所定周
波数帯域が選択的に切換可能になるとともに、所定周波
数の切換を行っても、入力のＶＳＷＲが全帯域にわたり
良好で、双方向ＣＡＴＶシステムに影響を与えないな保
安器が提供できる。As described above in detail, according to the inventions of claims 1 and 3, the downlink signal of a predetermined frequency band is transmitted from the center device to the terminal side through the transmission line, and the terminal device transmits the downlink signal to the center device. Bidirectional CAT in which an upstream signal in a predetermined frequency band different from the downstream signal is transmitted to the side through the transmission line
In the V system, provided on the terminal side of the transmission line,
A protector for connecting the transmission line and the indoor service wire, the protector having an input terminal, an output terminal, and a common line, the external conductor being directly connected to the common line, and the external conductor. The output terminal connected to a common line via a capacitor, and switching means connected in series to a transmission path between the input terminal and the output terminal for selectively switching the predetermined frequency band; An input-side capacitor, which is connected in series to a transmission path between the input terminal and the switching means, allows a high-frequency signal to pass therethrough and blocks a direct current or a low-frequency current, and the input terminal and the input-side capacitor Between the switching means and the output terminal, and a high-frequency signal is passed through the arrester or the choke coil, one end of which is connected to the transmission path between Is a capacitor on the output side that cuts off low-frequency current, and the switching means is a bidirectional transmission path for passing the up signal and the down signal, and the down signal is passed for passing the up signal. Is configured to switch a unidirectional transmission path for blocking the transmission of the upstream signal to the unidirectional transmission path,
Since the down signal passing means for selectively passing the down signal and the up signal absorbing means for absorbing the up signal are configured, a unidirectional or bidirectional predetermined frequency band can be selectively switched. In addition, even if the predetermined frequency is switched, the VSWR of the input is good over the entire band, and a protector that does not affect the bidirectional CATV system can be provided.

【００４１】請求項２，３の発明によれば，前記双方向
ＣＡＴＶシステムに用いる保安器であり，入力端子と少
なくとも２つの出力端子と共通線とを備え，外部導体が
共通線と直接接続された前記入力端子と，外部導体と共
通線とがコンデンサーを介して接続された前記出力端子
と，前記入力端子と前記出力端子との間の伝送経路に直
列に接続され，少なくとも２系統の伝送経路を形成する
分岐または分配回路からなる分岐分配手段と，前記入力
端子と前記分岐分配手段との間の伝送経路に直列に接続
された，高周波信号を通過させ，直流または低い周波数
の電流を遮断する入力側のコンデンサーと，前記入力端
子と前記入力側のコンデンサーとの間の伝送経路に一端
が接続され他端が共通線と接続されたアレスター又はチ
ョークコイルと，前記の少なくとも２系統の伝送経路に
おいて，前記分岐分配手段の出力端と前記出力端子との
間に直列に接続された、前記所定周波数帯域を選択的に
切換える切換手段と，前記切換手段と前記出力端子との
間の少なくとも２系統の伝送回路に直列に接続された，
高周波信号を通過させ，直流または低い周波数の電流を
遮断する出力側のコンデンサーと，からなり，前記切換
手段は，前記上り信号及び下り信号を通過させる双方向
の伝送経路と，前記下り信号を通過させ，前記上り信号
の通過を遮断する単方向の伝送経路を切換えるよう構成
され，前記単方向の伝送経路には，前記上り信号の通過
を遮断し，前記下り信号を選択的に通過させる下り信号
通過手段と，前記上り信号を吸収する上り信号吸収手段
と，からなるよう構成したので，少なくとも２つの出力
端子の単方向もしくは双方向の所定周波数帯域が選択的
に切換可能になるとともに、情報端末からセンタ装置へ
送られるレベルの高い上り信号による受信端末に与える
影響を抑制できるばかりでなく、受信端末からの雑音成
分がセンタ装置へ流れていくのも防ぐことができる。ま
た、前記所定周波数帯域の切換を行っても、入力のＶＳ
ＷＲが全帯域にわたり良好で、双方向ＣＡＴＶシステム
に影響を与えないな保安器が提供できる。According to the second and third aspects of the present invention, there is provided a protector used in the bidirectional CATV system, comprising an input terminal, at least two output terminals, and a common line, and the external conductor is directly connected to the common line. The input terminal, the output terminal in which the outer conductor and the common line are connected via a capacitor, and the transmission path between the input terminal and the output terminal are connected in series, and at least two transmission paths are provided. And a branching / distributing means formed of a branching / dividing circuit and a transmission path between the input terminal and the branching / distributing means connected in series to pass a high-frequency signal and block a direct current or a low-frequency current. An input side capacitor, and an arrester or choke coil having one end connected to a transmission path between the input terminal and the input side capacitor and the other end connected to a common line, Switching means for selectively switching the predetermined frequency band, which is connected in series between the output end of the branching / distributing means and the output terminal in at least two transmission paths described above, the switching means and the output Connected in series with at least two transmission circuits between the terminals,
An output-side capacitor that passes a high-frequency signal and cuts off a direct current or a low-frequency current; and the switching means has a bidirectional transmission path that passes the up signal and the down signal, and the down signal. And a downlink signal for blocking the passage of the uplink signal and switching the unidirectional transmission path, and for blocking the passage of the uplink signal and selectively passing the downlink signal on the unidirectional transmission path. Since it comprises the passing means and the upstream signal absorbing means for absorbing the upstream signal, the unidirectional or bidirectional predetermined frequency band of at least two output terminals can be selectively switched and the information terminal Not only is it possible to suppress the effect on the receiving terminal due to high-level upstream signals sent from the receiving terminal to the center apparatus, but also noise components from the receiving terminal to the center apparatus. Also it is possible to prevent going to be. Even if the predetermined frequency band is switched, the VS
It is possible to provide a protector that has a good WR over the entire band and does not affect the interactive CATV system.

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

【図１】双方向ＣＡＴＶシステムの実施例の構成を示す
説明図である。FIG. 1 is an explanatory diagram showing a configuration of an embodiment of a bidirectional CATV system.

【図２】保安器の外形を示す説明図であり，概略斜視図
である。FIG. 2 is an explanatory view showing the outer shape of the protector, and is a schematic perspective view.

【図３】１出力型の保安器の内部構成を示す説明図であ
り，ブロック図である。FIG. 3 is an explanatory diagram showing an internal configuration of a one-output type protector, and is a block diagram.

【図４】２出力型の保安器の内部構成を示す説明図であ
り，ブロック図である。（ｂ）は分配型、（ｃ）は分岐
型を示す。FIG. 4 is an explanatory diagram showing an internal configuration of a two-output type protector, and is a block diagram. (B) shows a distribution type, (c) shows a branch type.

【図５】２出力型の保安器の使用例を示す説明図であ
り，ブロック図である。FIG. 5 is an explanatory diagram showing a usage example of a two-output type protector, and is a block diagram.

【図６】２出力型の保安器の使用例を示す説明図であ
り，ブロック図である。FIG. 6 is an explanatory diagram showing an example of use of a two-output type protector, and is a block diagram.

【符号の説明】[Explanation of symbols]

１…ヘッドエンド（ＨＥ），２…幹線，３…分岐増幅
器，４…タップオフ，５…引込線，６（６ａ，６ｂ，６
ｃ）…保安器，７…屋内引込線，８…テレビ受像機
（「テレビ（ＴＶ）」），９…屋内引込線，１０…ケー
ブルモデム，１１…パーソナルコンピュータ（パソコ
ン），１２…イーサネット（Ｒ）ケーブル，１３…ＡＣ
プラグ，１４…ＡＣプラグ，１５…ＡＣアダプター、１
６…セットトップボックス、１７…ＡＣプラグ，１８…
ＡＣコンセント，１９…アース線，３１…分配回路，３
２…分岐回路，３３…コンデンサー，３４…アレスタ
ー，３５…チョークコイル，３６…ハイパスフィルタ
（ＨＰＦ），３７…コンデンサー，３８…ローパスフィ
ルタ（ＬＰＦ），３９…終端抵抗，４０…コンデンサ
ー，４１…共通線，４２…切換手段，６１…ケース本
体，６２…入力端子，６２ａ…Ｆ型接線，６３…出力端
子，６４…出力端子、６４ａ…Ｆ型接線，６５…出力端
子，６５ａ…Ｆ型接線，６６…ケース，６７…螺子孔，
６８…取付部，６９…アース端子1 ... Headend (HE), 2 ... Trunk line, 3 ... Branch amplifier, 4 ... Tap off, 5 ... Drop line, 6 (6a, 6b, 6)
c) ... Security device, 7 ... Indoor service line, 8 ... Television receiver ("TV (TV)"), 9 ... Indoor service line, 10 ... Cable modem, 11 ... Personal computer (personal computer), 12 ... Ethernet (R) cable , 13 ... AC
Plug, 14 ... AC plug, 15 ... AC adapter, 1
6 ... Set top box, 17 ... AC plug, 18 ...
AC outlet, 19 ... Ground wire, 31 ... Distribution circuit, 3
2 ... Branch circuit, 33 ... Capacitor, 34 ... Arrestor, 35 ... Choke coil, 36 ... High pass filter (HPF), 37 ... Capacitor, 38 ... Low pass filter (LPF), 39 ... Termination resistor, 40 ... Capacitor, 41 ... Common Wire, 42 ... switching means, 61 ... case body, 62 ... input terminal, 62a ... F type tangent line, 63 ... output terminal, 64 ... output terminal, 64a ... F type tangent line, 65 ... output terminal, 65a ... F type tangent line, 66 ... Case, 67 ... Screw hole,
68 ... Mounting part, 69 ... Ground terminal

Claims

【特許請求の範囲】[Claims]

【請求項１】センタ装置から端末側に伝送線を介して所
定周波数帯域の下り信号が伝送されるとともに，端末か
らセンタ装置側に該伝送線を介して該下り信号とは異な
る所定周波数帯域の上り信号が伝送される双方向ＣＡＴ
Ｖシステムにおいて，前記伝送線の端末側に設けられ，
前記伝送線と屋内引込線とを接続する保安器であり，前
記保安器は，入力端子と出力端子と共通線とを備え，外
部導体が共通線と直接接続された前記入力端子と，外部
導体と共通線とがコンデンサーを介して接続された前記
出力端子と，前記入力端子と前記出力端子との間の伝送
経路に直列に接続された，前記所定周波数帯域を選択的
に切換える切換手段と，前記入力端子と前記切換手段と
の間の伝送経路に直列に接続された，高周波信号を通過
させ，直流または低い周波数の電流を遮断する入力側の
コンデンサーと，前記入力端子と前記入力側のコンデン
サーとの間の伝送経路に一端が接続され他端が共通線と
接続されたアレスター又はチョークコイルと，前記切換
手段と前記出力端子との間の伝送回路に直列に接続され
た，高周波信号を通過させ，直流または低い周波数の電
流を遮断する出力側のコンデンサーと，からなり，前記
切換手段は，前記上り信号及び下り信号を通過させる双
方向の伝送経路と，前記下り信号を通過させ，前記上り
信号の通過を遮断する単方向の伝送経路を切換えるよう
構成され，前記単方向の伝送経路には，前記上り信号の
通過を遮断し，前記下り信号を選択的に通過させる下り
信号通過手段と，前記上り信号を吸収する上り信号吸収
手段と，を備えたことを特徴とした保安器。1. A downlink signal of a predetermined frequency band is transmitted from a center device to a terminal side through a transmission line, and a downlink signal of a predetermined frequency band different from the downlink signal is transmitted from the terminal to the center device side through the transmission line. Bidirectional CAT for transmitting upstream signals
In the V system, provided on the terminal side of the transmission line,
A protector for connecting the transmission line and the indoor service wire, the protector having an input terminal, an output terminal, and a common line, the external conductor being directly connected to the common line, and the external conductor. The output terminal connected to a common line via a capacitor, and switching means connected in series to a transmission path between the input terminal and the output terminal for selectively switching the predetermined frequency band; An input-side capacitor, which is connected in series to a transmission path between the input terminal and the switching means, allows a high-frequency signal to pass therethrough and blocks a direct current or a low-frequency current, and the input terminal and the input-side capacitor Between the arrester or the choke coil, one end of which is connected to the transmission path between and the other end of which is connected to the common line, and the high frequency signal which is connected in series to the transmission circuit between the switching means and the output terminal. And a capacitor on the output side that cuts off a direct current or a low-frequency current, and the switching means has a bidirectional transmission path for passing the up signal and the down signal, and the down signal for passing the down signal. Downward signal passing means configured to switch a unidirectional transmission path that blocks passage of an upstream signal, wherein the unidirectional transmission path blocks a passage of the upstream signal and selectively passes the downstream signal. A protection device comprising: an upstream signal absorbing means for absorbing the upstream signal.

【請求項２】前記双方向ＣＡＴＶシステムに用いる保安
器であり，入力端子と少なくとも２つの出力端子と共通
線とを備え，外部導体が共通線と直接接続された前記入
力端子と，外部導体と共通線とがコンデンサーを介して
接続された前記出力端子と，前記入力端子と前記出力端
子との間の伝送経路に直列に接続され，少なくとも２系
統以上の伝送経路を形成する分岐または分配回路からな
る分岐分配手段と，前記入力端子と前記分岐分配手段と
の間の伝送経路に直列に接続された，高周波信号を通過
させ，直流または低い周波数の電流を遮断する入力側の
コンデンサーと，前記入力端子と前記入力側のコンデン
サーとの間の伝送経路に一端が接続され他端が共通線と
接続されたアレスター又はチョークコイルと，前記の少
なくとも２系統の伝送経路において，前記分岐分配手段
の出力端と前記出力端子との間に直列に接続された、前
記所定周波数帯域を選択的に切換える切換手段と，前記
切換手段と前記出力端子との間に直列に接続された，高
周波信号を通過させ，直流または低い周波数の電流を遮
断する出力側のコンデンサーと，からなり，前記切換手
段は，前記上り信号及び下り信号を通過させる双方向の
伝送経路と，前記下り信号を通過させ，前記上り信号の
通過を遮断する単方向の伝送経路を切換えるよう構成さ
れ，前記単方向の伝送経路には，前記上り信号の通過を
遮断し，前記下り信号を選択的に通過させる下り信号通
過手段と，前記上り信号を吸収する上り信号吸収手段
と，を備えたことを特徴とした請求項１に記載の前記切
換手段を用いた保安器。2. A protector for use in the two-way CATV system, comprising: an input terminal, at least two output terminals, and a common line, the external conductor being directly connected to the common line, and the external conductor. From a branching or distribution circuit that is connected in series with the output terminal to which a common line is connected via a capacitor and the transmission path between the input terminal and the output terminal to form at least two or more transmission paths Branch distribution means, an input-side capacitor that is connected in series to a transmission path between the input terminal and the branch distribution means, passes a high-frequency signal, and blocks a DC or low-frequency current; An arrester or a choke coil, one end of which is connected to the transmission path between the terminal and the input-side capacitor and the other end of which is connected to a common line; In the transmission path, switching means connected in series between the output end of the branching / distributing means and the output terminal, for selectively switching the predetermined frequency band, and serially connected between the switching means and the output terminal. A capacitor on the output side that passes a high-frequency signal and cuts off a direct current or a low-frequency current, and the switching means has a bidirectional transmission path that passes the upstream signal and the downstream signal; It is configured to switch a unidirectional transmission path that passes the downlink signal and blocks the uplink signal. The unidirectional transmission path blocks the uplink signal and selectively selects the downlink signal. The protector using the switching means according to claim 1, further comprising a down signal passing means for passing the up signal and an up signal absorbing means for absorbing the up signal.

【請求項３】請求項１，２の保安器において，上り信号
は，前記下り信号よりも低い周波数から成り，前記単方
向の伝送経路の前記下り信号通過手段はハイパスフィル
タから成り，前記単方向の伝送経路の前記上り信号吸収
手段は，該上り信号を通過させるために，前記単方向の
伝送経路に一端が接続されたローパスフィルタと，該上
り信号を吸収するために，該ローパスフィルタの他端に
接続された終端抵抗と，からなることを特徴とした保安
器。3. The protector according to claim 1, wherein the upstream signal has a frequency lower than that of the downstream signal, and the downstream signal passing means of the unidirectional transmission path comprises a high pass filter. The upstream signal absorbing means of the transmission path of the low-pass filter has one end connected to the unidirectional transmission path for passing the upstream signal, and the low-pass filter for absorbing the upstream signal. A protector characterized by comprising a terminating resistor connected to the end.