JP2002050985A - Hybrid transmission method and joint reception system using the method - Google Patents
Hybrid transmission method and joint reception system using the methodInfo
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- JP2002050985A JP2002050985A JP2000235362A JP2000235362A JP2002050985A JP 2002050985 A JP2002050985 A JP 2002050985A JP 2000235362 A JP2000235362 A JP 2000235362A JP 2000235362 A JP2000235362 A JP 2000235362A JP 2002050985 A JP2002050985 A JP 2002050985A
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- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
- Optical Communication System (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は光ファイバケーブル
と同軸ケーブルを用いて信号を伝送する伝送方式に関す
る。特に、高域高周波信号を光ファイバケーブルで低域
高周波信号を同軸ケーブルで伝送し、統合して需要家に
品質よく伝送する伝送方式に関する。又、その伝送方式
を用いた共同受信システムに関する。本発明は、従来の
ＣＡＴＶ放送とＢＳ・ＣＳ放送の両者を品質よく長距離
に伝送する伝送方法及びその方式を用いた共同受信シス
テムに適用できる。The present invention relates to a transmission system for transmitting a signal using an optical fiber cable and a coaxial cable. In particular, the present invention relates to a transmission system in which a high-frequency high-frequency signal is transmitted by an optical fiber cable and a low-frequency high-frequency signal is transmitted by a coaxial cable. Further, the present invention relates to a joint receiving system using the transmission method. INDUSTRIAL APPLICABILITY The present invention can be applied to a conventional transmission method for transmitting both a CATV broadcast and a BS / CS broadcast with high quality over a long distance, and a joint receiving system using the method.
【０００２】[0002]
【従来の技術】従来より、同軸ケーブル又は光ファイバ
ケーブルを用いた共同受信システムがある。例えば、Ｃ
ＡＴＶ共同受信システムがある。従来の同軸ケーブルを
用いたＣＡＴＶ共同受信システムを図４に、光ファイバ
ケーブルを用いたそれを図５に示す。同軸ケーブルを用
いたＣＡＴＶ共同受信システムは、送信側にＣＡＴＶ信
号用増幅器１１ａ、ＢＳ・ＣＳ信号用増幅器１１ｂ、両
信号を混合する混合器１２を備え、受信側に分波器２
０、増幅器２１ａ、２１ｂ、そして混合器２２を備えて
いる。送信側からは、増幅器１１ａ、１１ｂで増幅され
た低域高周波信号と高域高周波信号（ＢＳ・ＣＳ信号）
が混合器１２で混合され、周波数多重で同軸ケーブル１
３に送出される。そして、受信側の分波器２０によって
両信号が分別され、それぞれ増幅器２１ａ、２１ｂでの
増幅後、再度混合器２２によって混合されて例えば需要
家に伝送されている。尚、ここで上記ＢＳ・ＣＳ信号は
中間周波数に変換されたＩＦ信号である。以降、ＩＦ信
号を省略してＢＳ・ＣＳ信号、又はＢＳ信号、又はＣＳ
信号と記す。2. Description of the Related Art There has been a joint receiving system using a coaxial cable or an optical fiber cable. For example, C
There is an ATV joint reception system. FIG. 4 shows a conventional CATV joint receiving system using a coaxial cable, and FIG. 5 shows an example using an optical fiber cable. A CATV joint receiving system using a coaxial cable includes a CATV signal amplifier 11a, a BS / CS signal amplifier 11b, and a mixer 12 for mixing both signals on a transmitting side, and a duplexer 2 on a receiving side.
0, amplifiers 21a and 21b, and a mixer 22. From the transmitting side, a low-frequency high-frequency signal and a high-frequency high-frequency signal (BS / CS signal) amplified by the amplifiers 11a and 11b
Are mixed in the mixer 12, and the coaxial cable 1 is frequency-multiplexed.
3 is sent. Then, the two signals are separated by the duplexer 20 on the receiving side, amplified by the amplifiers 21a and 21b, respectively, mixed again by the mixer 22, and transmitted to, for example, a customer. Here, the BS / CS signal is an IF signal converted to an intermediate frequency. Hereafter, the IF signal is omitted and the BS / CS signal, the BS signal, or the CS signal is omitted.
It is described as a signal.
【０００３】又、光ファイバケーブルを用いた例（図
５）は上記システムにおいて、同軸ケーブル１３を光フ
ァイバケーブル３０に置き換え、そしてその両端に光電
変換器３１，３２を設けた例である。即ち、それぞれの
放送信号の電気信号を光信号に変換して伝送する方式で
ある。従来の共同住宅等ではこの何れかの方式でＣＡＴ
Ｖ放送とＢＳ・ＣＳ放送が受信されていた。An example using an optical fiber cable (FIG. 5) is an example in which the coaxial cable 13 is replaced with an optical fiber cable 30 in the above-described system, and photoelectric converters 31 and 32 are provided at both ends. That is, this is a method in which the electric signal of each broadcast signal is converted into an optical signal and transmitted. In conventional apartment houses, etc., CAT
V broadcast and BS / CS broadcast were received.
【０００４】[0004]
【発明が解決しようする課題】しかしながら、周波数が
ＧＨｚオーダーのＢＳ・ＣＳ信号は、同軸ケーブルでは
減衰が大きいため伝送距離が大きく制限されるという問
題がある。即ち、同軸ケーブルではＢＳ・ＣＳ放送は長
距離には伝送できなかった。そのため、従来のＣＡＴＶ
等の低域高周波信号とＢＳ・ＣＳ放送の高域高周波信号
を混合して光伝送する方式が考案されている（図５）。
しかしながら、この方式で全てのチャンネルを光ファイ
バケーブルで伝送させると、広帯域であるがために、レ
ーザーダイオードの入出力特性の直線性が十分に高くな
いと、変調歪みを生じる。従って、伝送品質を高くする
ためには、使用する全周波数帯域において、十分に直線
性の高いレーザを用いる必要があった。この結果、共同
住宅の需要家負担を増大させるという問題を生じる。However, a BS / CS signal having a frequency on the order of GHz has a problem in that the transmission distance is greatly limited due to the large attenuation of the coaxial cable. That is, BS / CS broadcasting could not be transmitted over a long distance using a coaxial cable. Therefore, the conventional CATV
A method of optically transmitting a mixture of a low-frequency high-frequency signal such as that described above and a high-frequency high-frequency signal of BS / CS broadcasting has been devised (FIG. 5).
However, if all channels are transmitted by an optical fiber cable in this method, modulation distortion occurs unless the linearity of the input / output characteristics of the laser diode is sufficiently high because of the wide band. Therefore, in order to improve the transmission quality, it is necessary to use a laser having sufficiently high linearity in all the frequency bands to be used. As a result, there arises a problem that the burden on the customers of the apartment house increases.
【０００５】本発明は上述した問題点を解決するために
なされたものであり、変調方式と使用周波数帯域の違い
に着目し、次に示す伝送特性を利用して問題点を解決し
ている。伝送性能を規定する主な項目としては、信号対
雑音比（以下、「ＣＮＲ」と記す）と歪みがある。これ
らの要求値は、伝送する信号の変調方式によって異なる
が、アナログのＴＶ信号であるＶＳＢ−ＡＭに対し、Ｂ
Ｓ、ＣＳのＴＶ信号であるＦＭ、デジタル（ＰＳＫ）で
は、ＣＮＲは低くても良く、２次歪みに対しても帯域内
に歪みが落ちてこないために、歪み性能が悪くても伝送
システムの要求する性能を満足することができる。従っ
て、本発明の目的は、歪とＣＮＲ性能が余り要求されな
い高域高周波信号は光ファイバケーブルで、歪とＣＮＲ
性能が要求される低域高周波信号は同軸ケーブルで別々
に伝送することにより、両信号とも品質良く長距離に伝
送する伝送方式を提供することである。又、送信側のレ
ーザダイオードに、直線性の要求の低いものを用いるこ
とができるようにして、共同受信システムを安価にする
ことである。The present invention has been made in order to solve the above-mentioned problems, and focuses on the difference between a modulation system and a used frequency band, and solves the problems using the following transmission characteristics. The main items that define the transmission performance include a signal-to-noise ratio (hereinafter, referred to as “CNR”) and distortion. These required values differ depending on the modulation method of the signal to be transmitted, but are different from those of the analog TV signal VSB-AM.
In the case of FM and digital (PSK), which are S and CS TV signals, the CNR may be low and the distortion does not fall in the band even for the second-order distortion. The required performance can be satisfied. Therefore, an object of the present invention is to provide a high-frequency high-frequency signal that does not require much distortion and CNR performance using an optical fiber cable,
An object of the present invention is to provide a transmission system in which low-frequency high-frequency signals requiring high performance are separately transmitted by a coaxial cable to transmit both signals over a long distance with high quality. Another object of the present invention is to make it possible to use a laser diode having a low linearity requirement for the laser diode on the transmitting side, thereby reducing the cost of the joint receiving system.
【０００６】[0006]
【課題を解決するための手段及び作用効果】上記の課題
を解決するために、請求項１に記載のハイブリッド型伝
送方式は、光ファイバケーブルと同軸ケーブルを伝送路
とするネットワークシステムにおける伝送方式であっ
て、高域高周波信号は光ファイバケーブルで低域高周波
信号は同軸ケーブルで送信し、受信側でその光ファイバ
ケーブルの出力を電気信号に変換して、その信号と同軸
ケーブルで伝送された低域高周波信号とを混合して送出
することを特徴とする。In order to solve the above problems, a hybrid transmission system according to claim 1 is a transmission system in a network system using an optical fiber cable and a coaxial cable as a transmission path. The high-frequency high-frequency signal is transmitted by an optical fiber cable and the low-frequency high-frequency signal is transmitted by a coaxial cable. The output of the optical fiber cable is converted into an electric signal on the receiving side, and the low-frequency signal is transmitted by the coaxial cable. And transmitting the mixed high-frequency signal.
【０００７】高域高周波信号とは、例えば、ＢＳ−Ｉ
Ｆ、ＣＳ−ＩＦ信号であって、例えば、１〜２ＧＨｚ帯
の信号である。しかし、この信号帯域は特に限定するも
のではない。この帯域の信号は、同軸ケーブルでは長距
離伝送ができない。そこで、本発明の伝送方式では、高
域高周波信号は光ファイバケーブルで受信側に伝送す
る。そして、例えば７０〜８００ＭＨｚ帯の低域高周波
信号は、従来通り同軸ケーブルで伝送する。即ち、別々
の伝送路で伝送する。そして、受信側で光ファイバケー
ブルの出力を電気信号に変換して、同軸ケーブルで伝送
された低域高周波信号と混合する。これにより、受信側
では減衰が低減された両信号が得られる。即ち、長距離
伝送を可能とする伝送方式となる。例えば、高域高周波
信号をＣＡＴＶ放送のＢＳ・ＣＳ放送信号、低域高周波
信号を従来のＦＭ，ＶＨＦ，ＵＨＦ帯域のＣＡＴＶ放送
信号として、本発明の伝送方式を適用すれば、より遠方
の需要家に映像に歪みを与えることなく伝送することが
できる。[0007] The high frequency signal is, for example, BS-I
F and CS-IF signals, for example, signals in the 1-2 GHz band. However, this signal band is not particularly limited. Signals in this band cannot be transmitted over long distances using coaxial cables. Therefore, in the transmission system of the present invention, the high-frequency high-frequency signal is transmitted to the receiving side via an optical fiber cable. Then, for example, a low-frequency high-frequency signal in the 70 to 800 MHz band is transmitted by a coaxial cable as in the related art. That is, transmission is performed through separate transmission paths. Then, on the receiving side, the output of the optical fiber cable is converted into an electric signal and mixed with the low-frequency high-frequency signal transmitted through the coaxial cable. As a result, both signals with reduced attenuation are obtained on the receiving side. That is, the transmission method enables long-distance transmission. For example, if the transmission method of the present invention is applied with the high-frequency high-frequency signal as the CATV broadcast BS / CS broadcast signal and the low-frequency high-frequency signal as the conventional FM, VHF, UHF band CATV broadcast signal, a further distant customer can be obtained. Can be transmitted without distorting the video.
【０００８】又、請求項２に記載の共同受信システム
は、請求項１に記載のハイブッリド型伝送方式を用いる
共同受信システムであって、送信側に高域高周波信号を
光信号に変換する光電変換器を備え、受信側にその光信
号を電気信号に変換する光電変換器とその変換された信
号と伝送された低域高周波信号を混合する混合器を備え
たことを特徴とする。According to a second aspect of the present invention, there is provided a joint receiving system using the hybrid transmission system according to the first aspect, wherein a photoelectric conversion device converts a high-frequency high-frequency signal into an optical signal on a transmitting side. The receiving side includes a photoelectric converter for converting the optical signal into an electric signal and a mixer for mixing the converted signal and the transmitted low-frequency high-frequency signal.
【０００９】送信側の光電変換器は入力された高域高周
波信号を光信号に変換し、光ファイバケーブルで伝送す
る。そして、低域高周波信号は従来通り同軸ケーブルで
伝送する。これにより、高域高周波信号及び低域高周波
信号は受信側に十分な強度で到達するよう伝送される。
受信側の光電変換器は伝送された光信号を電気信号に変
換し、変換された信号と伝送された低域高周波信号が混
合器で混合されて、周波数多重化される。そして、その
周波数多重化信号が例えば需要家に伝送される。従っ
て、減衰を抑えて両信号を確実に需要家まで伝送する共
同受信システムとなる。The transmitting-side photoelectric converter converts the input high-frequency high-frequency signal into an optical signal and transmits the optical signal through an optical fiber cable. Then, the low-frequency high-frequency signal is transmitted by a coaxial cable as in the related art. Thereby, the high band high frequency signal and the low band high frequency signal are transmitted so as to reach the receiving side with sufficient strength.
The receiving-side photoelectric converter converts the transmitted optical signal into an electric signal, and the converted signal and the transmitted low-frequency high-frequency signal are mixed by a mixer and frequency-multiplexed. Then, the frequency multiplexed signal is transmitted to a customer, for example. Therefore, it becomes a joint receiving system in which both signals are reliably transmitted to the customer while suppressing the attenuation.
【００１０】又、請求項３に記載の共同受信システム
は、光ファイバケーブルの送信側には、高域高周波信号
を所定波長の光信号に変換する複数の光電変換器と光合
波器とを備え、光合波器で複数の光電変換器の出力を合
波して、光ファイバケーブルに出力することを特徴とす
る。複数の光電変換器は、異なる周波数帯の高域高周波
信号を光信号に変換する。この変換とは、所定波長のキ
ャリア光を高域高周波信号で変調することである。ここ
で、異なる周波数帯の高域高周波信号とは、例えば共同
受信システムをＣＡＴＶ受信システムとすれば、ＢＳ放
送信号とＣＳ放送信号である。これらの高域高周波信号
が光信号に変換される。そして、光合波器がそれらの光
信号を合波（混合）して光ファイバケーブルに伝送す
る。光合波器を有しているので、１本の光ファイバケー
ブルで効率よく異なる高域高周波信号を伝送することが
できる。In a third aspect of the present invention, the transmitting side of the optical fiber cable includes a plurality of photoelectric converters for converting a high-band high-frequency signal into an optical signal having a predetermined wavelength and an optical multiplexer. The output of a plurality of photoelectric converters is multiplexed by an optical multiplexer and output to an optical fiber cable. The plurality of photoelectric converters convert high-frequency high-frequency signals in different frequency bands into optical signals. This conversion modulates carrier light of a predetermined wavelength with a high-frequency high-frequency signal. Here, the high-frequency high-frequency signals in different frequency bands are, for example, a BS broadcast signal and a CS broadcast signal if the joint receiving system is a CATV receiving system. These high frequency signals are converted into optical signals. Then, the optical multiplexer multiplexes (mixes) the optical signals and transmits the multiplexed optical signals to the optical fiber cable. Since the optical multiplexer is provided, different high-frequency high-frequency signals can be transmitted efficiently with one optical fiber cable.
【００１１】又、請求項４に記載の共同受信システム
は、所定波長が同一波長であることを特徴とする。複数
の光電変換器は、それぞれ異なる周波数帯の高域高周波
信号を同一波長のキャリア光で送出する。同一波長であ
っても、変調信号の帯域が分離されているで混信は生じ
ない。同一波長であるので、受信側では光電変換器は単
数でよい。又、その後段に増幅器を設ける場合にもその
増幅器は単数でよい。よって、共同受信システムを安価
とすることができる。Further, in the joint receiving system according to a fourth aspect, the predetermined wavelength is the same wavelength. The plurality of photoelectric converters transmit high-frequency high-frequency signals in different frequency bands with carrier light of the same wavelength. Even at the same wavelength, no interference occurs because the bands of the modulated signal are separated. Since the wavelengths are the same, a single photoelectric converter may be used on the receiving side. Also, when an amplifier is provided at the subsequent stage, the amplifier may be singular. Therefore, the joint receiving system can be made inexpensive.
【００１２】又、請求項５に記載の共同受信システム
は、所定波長は相互に異なる波長であることを特徴とす
る。異なる波長のキャリア光で伝送する場合は波長分割
多重となり、両高域高周波信号のＣＮＲ、相互変調歪み
が改善され、品質よく伝送することができる。Further, in the joint receiving system according to a fifth aspect, the predetermined wavelengths are different from each other. When transmission is performed using carrier lights of different wavelengths, wavelength division multiplexing is performed, the CNR and intermodulation distortion of both high-frequency high-frequency signals are improved, and transmission can be performed with high quality.
【００１３】又、請求項６に記載の共同受信システム
は、光ファイバケーブルの受信側には、光分波器と複数
の光電変換器を備え、その光分波器によって分波された
信号は複数の光電変換器によってそれぞれ電気信号に変
換されて混合器に送出されることを特徴とする。光分波
器は光ファイバケーブルを用いて所定のキャリア光で伝
送された高域高周波信号を所定波長毎に分波する。そし
て光電変換器がその分波された光信号を電気信号に変換
し、混合器に送出する。最後に、その混合器がそれぞれ
変換された信号を混合して、例えば需要家に伝送する。
異なる波長のキャリア光で伝送された高域高周波信号を
分波して受信するので、余剰雑音による劣化がなく、相
互変調なく両高域高周波信号を受信できる。即ち、高域
高周波信号を品質よく例えば需要家に伝送できる。According to a sixth aspect of the present invention, there is provided a joint receiving system comprising an optical demultiplexer and a plurality of photoelectric converters on the receiving side of the optical fiber cable, and a signal demultiplexed by the optical demultiplexer is provided. Each of the plurality of photoelectric converters is converted into an electric signal and transmitted to the mixer. The optical splitter splits a high-frequency high-frequency signal transmitted by a predetermined carrier light using an optical fiber cable for each predetermined wavelength. Then, the photoelectric converter converts the demultiplexed optical signal into an electric signal and sends it to the mixer. Finally, the mixer mixes the respective converted signals and transmits them, for example, to the consumer.
Since the high-frequency high-frequency signals transmitted by the carrier lights of different wavelengths are demultiplexed and received, the high-frequency high-frequency signals can be received without any intermodulation without deterioration due to the surplus noise. That is, a high-frequency high-frequency signal can be transmitted to a customer, for example, with good quality.
【００１４】又、請求項７に記載の共同受信システム
は、光ファイバケーブルの受信側には、受信した複数の
波長の光信号を電気信号に変換して混合器に出力する単
一の光電変換器を備えたことを特徴とする。複数の高域
高周波信号の信号の帯域が異なるため、それぞれの帯域
の信号を異なる波長の光信号で送信しても、受信側で一
度に強度復調すれば、複数の周波数多重化された高域高
周波信号が得られる。設備が簡単となる。この場合に、
送信側では、波長帯が異なっていても、同一波長帯であ
っても光干渉が起きない程に離れていれば、光信号をそ
れぞれの帯域の高域高周波信号で強度変調したものであ
っても良い。According to a seventh aspect of the present invention, there is provided a joint receiving system, comprising: a single photoelectric conversion unit for converting a received optical signal of a plurality of wavelengths into an electric signal and outputting the electric signal to a mixer on the receiving side of the optical fiber cable. It is characterized by having a vessel. Since the signal bands of the multiple high-frequency high-frequency signals are different, even if the signals in each band are transmitted as optical signals of different wavelengths, if the intensity demodulation is performed at once on the receiving side, multiple frequency-multiplexed high-frequency A high frequency signal is obtained. Equipment becomes simple. In this case,
On the transmitting side, even if the wavelength bands are different, even if they are in the same wavelength band, if they are separated so that optical interference does not occur, the optical signal is intensity-modulated with the high frequency high frequency signal of each band. Is also good.
【００１５】又、請求項８に記載の共同受信システム
は、低域高周波信号と高域高周波信号が送信側又は受信
側の少なくとも一方に設けられた増幅器でそれぞれ増幅
されることを特徴とする。これにより、低域高周波信号
と高域高周波信号をより遠方まで伝送することができ
る。又、より多くの分岐路に伝送することができる。In the joint receiving system according to the present invention, the low-frequency high-frequency signal and the high-frequency high-frequency signal are amplified by amplifiers provided on at least one of the transmitting side and the receiving side. As a result, the low-frequency high-frequency signal and the high-frequency high-frequency signal can be transmitted to a greater distance. In addition, it can be transmitted to more branches.
【００１６】[0016]
【発明の実施の形態】以下、本発明の実施の形態につい
て図面を参照して説明する。なお、本発明は下記実施例
に限定されるものではない。 （第１実施例）図１に本発明のハイブリッド型伝送方式
を用いたＣＡＴＶ共同受信システムの一実施例を示す。
図は、システム構成図である。本実施例の共同受信シス
テムは、送信側に設けられ従来のＣＡＴＶ信号等の低域
高周波信号を増幅する増幅器１、ＢＳ・ＣＳ信号等の高
域高周波信号を増幅する増幅器２、その増幅された高域
高周波信号を光信号に変換する光電変換器（Ｅ／Ｏ）
３、低域高周波信号を伝送する同軸ケーブル４、高域高
周波信号を伝送する光ファイバケーブル５、受信側に設
けられ低域高周波信号を増幅する増幅器８、高域高周波
信号を電気信号に変換する光電変換器（Ｏ／Ｅ）６、そ
の信号を増幅する増幅器７、両信号を混合する混合器９
から構成される。Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following examples. (First Embodiment) FIG. 1 shows an embodiment of a CATV joint reception system using the hybrid transmission system of the present invention.
The figure is a system configuration diagram. The joint receiving system according to the present embodiment includes an amplifier 1 provided on the transmission side for amplifying a low-frequency high-frequency signal such as a conventional CATV signal, an amplifier 2 for amplifying a high-frequency high-frequency signal such as a BS / CS signal, and the amplified signal. Photoelectric converter (E / O) that converts high-frequency high-frequency signals into optical signals
3, a coaxial cable 4 for transmitting a low-frequency high-frequency signal, an optical fiber cable 5 for transmitting a high-frequency high-frequency signal, an amplifier 8 provided on the receiving side for amplifying the low-frequency high-frequency signal, and converting the high-frequency high-frequency signal into an electric signal. Photoelectric converter (O / E) 6, amplifier 7 for amplifying the signal, mixer 9 for mixing both signals
Consists of
【００１７】上記構成において、送信側は例えばＣＡＴ
Ｖ局からの信号を中継する中継装置である。これは、例
えば集合住宅の棟内ネットワークの入り口に設けられ
る。送信側からは、７０〜８００ＭＨｚ帯のＣＡＴＶ信
号を増幅器１で増幅して同軸ケーブル４に送出する。そ
して、そのＣＡＴＶ信号は受信側で増幅器８によって増
幅されて受信される。これにより、従来のＣＡＴＶ信号
は受信側で十分な振幅強度が得られる。一方、図示しな
いＣＡＴＶ局又は図示しないアンテナ装置からは、１〜
２ＧＨｚ帯のＢＳ・ＣＳ信号（ＩＦ信号）が送出され
る。このＢＳ・ＣＳ信号は同軸ケーブル４では減衰が著
しい。そこで、本実施例では上記ＢＳ・ＣＳ信号に対し
ては光ファイバケーブル５を用いて伝送する。即ち、高
域高周波信号を増幅器２で増幅した後、光電変換器３で
光信号に変換して光ファイバケーブル５に送出する。In the above configuration, the transmitting side is, for example, a CAT
This is a relay device that relays a signal from the V station. This is provided, for example, at the entrance of the in-building network of the apartment house. From the transmitting side, the CATV signal in the 70 to 800 MHz band is amplified by the amplifier 1 and transmitted to the coaxial cable 4. Then, the CATV signal is amplified and received by the amplifier 8 on the receiving side. As a result, the conventional CATV signal has a sufficient amplitude intensity on the receiving side. On the other hand, from a CATV station not shown or an antenna device not shown,
A 2 GHz band BS / CS signal (IF signal) is transmitted. The BS / CS signal is significantly attenuated in the coaxial cable 4. Therefore, in the present embodiment, the BS / CS signal is transmitted using the optical fiber cable 5. That is, after the high frequency signal is amplified by the amplifier 2, it is converted into an optical signal by the photoelectric converter 3 and transmitted to the optical fiber cable 5.
【００１８】光ファイバケーブル５に送出された光信号
は、受信側で光電変換器６によって電気信号に変換され
増幅器７で増幅される。これにより、ＢＳ・ＣＳ信号は
減衰が抑制されて伝送され、受信側では十分な振幅強度
が得られる。そして、同軸ケーブル４を伝送した低域高
周波信号と光ファイバケーブル５を伝送した高域高周波
信号が混合器９で混合される。即ち、ＦＭ，ＶＨＦ，Ｕ
ＨＦ等のＴＶ信号とＢＳ・ＣＳ信号が周波数多重された
信号が形成される。The optical signal transmitted to the optical fiber cable 5 is converted into an electric signal by a photoelectric converter 6 on the receiving side and is amplified by an amplifier 7. Thereby, the BS / CS signal is transmitted with its attenuation suppressed, and a sufficient amplitude intensity is obtained on the receiving side. Then, the low-frequency high-frequency signal transmitted through the coaxial cable 4 and the high-frequency high-frequency signal transmitted through the optical fiber cable 5 are mixed by the mixer 9. That is, FM, VHF, U
A signal in which a TV signal such as HF and a BS / CS signal are frequency-multiplexed is formed.
【００１９】従って、本実施例の共同受信システムを採
れば、両信号とも十分な強度で需要家に伝送することが
できる。又、本実施例では従来のＣＡＴＶ信号は光信号
に変換せずに同軸ケーブルで伝送している。ＣＡＴＶ信
号をＢＳ・ＣＳ信号ともに光ファイバケーブル５で伝送
する場合は、変調歪みを回避するために直線性に優れた
高価なレーザダイオード等が必要となる。このため、需
要家負担が増大する。本実施例では、ＢＳ・ＣＳ信号の
み光ファイバケーブルで伝送しているので安価な厳密な
直線性のないレーザダイオードを使用することができ
る。よって、需要家負担を軽減することができる。Therefore, if the joint receiving system of this embodiment is adopted, both signals can be transmitted to the customer with sufficient strength. In this embodiment, the conventional CATV signal is transmitted by a coaxial cable without being converted into an optical signal. When transmitting both the CATV signal and the BS / CS signal through the optical fiber cable 5, an expensive laser diode or the like having excellent linearity is required to avoid modulation distortion. For this reason, the burden on the customer increases. In this embodiment, since only the BS / CS signal is transmitted by the optical fiber cable, an inexpensive laser diode without strict linearity can be used. Therefore, the burden on the customer can be reduced.
【００２０】（第２実施例）図２に本発明のＣＡＴＶ共
同受信システムの第２実施例を示す。図は、システム構
成図である。本実施例の共同受信システムは、送信側に
ＢＳ信号とＣＳ信号に対しそれぞれ増幅器２ａ、２ｂ、
光電変換器３ａ、３ｂを設け、更にそれらを混合する光
混合器１０Ａを設けたことが特徴である。ＢＳ信号、Ｃ
Ｓ信号にそれぞれ増幅器２ａ、２ｂを設けることによ
り、それぞえ最適な振幅を与えることができる。即ち、
受信側でそれぞれ最適な信号振幅を与えることができ
る。(Second Embodiment) FIG. 2 shows a second embodiment of the CATV joint receiving system according to the present invention. The figure is a system configuration diagram. The joint receiving system according to the present embodiment provides the transmitting side with amplifiers 2a and 2b for the BS signal and the CS signal, respectively.
It is characterized in that photoelectric converters 3a and 3b are provided and an optical mixer 10A for mixing them is further provided. BS signal, C
By providing the amplifiers 2a and 2b for the S signal, optimum amplitudes can be respectively provided. That is,
An optimum signal amplitude can be given on the receiving side.
【００２１】又、ＢＳ信号、ＣＳ信号にそれぞれ設けた
光電変換器３ａ、３ｂは、その出力波長を異なる波長λ
ａ、λｂとすることができる。これにより、ＢＳ信号と
ＣＳ信号の両帯域間の変調歪みを著しく低減させること
ができる。換言すれば、信号の両帯域間の変調歪みを著
しく低減させる運用又は変調度を上げた運用ができるた
め、ＣＮＲの性能を向上させることができる。この時、
光電変換器６を上記波長λａ、λｂに感応する受信素子
とすれば受信素子は単一でよい。更にその後段に設置す
る増幅器７も単一でよい。即ち、両信号が安価に受信さ
れる。即ち、品質のよいＢＳ信号とＣＳ信号が安価に伝
送されるシステムとなる。The photoelectric converters 3a and 3b provided for the BS signal and the CS signal respectively have output wavelengths of different wavelengths λ.
a and λb. Thereby, the modulation distortion between both bands of the BS signal and the CS signal can be significantly reduced. In other words, the operation of significantly reducing the modulation distortion between both bands of the signal or the operation of increasing the modulation degree can be performed, so that the CNR performance can be improved. At this time,
If the photoelectric converter 6 is a receiving element sensitive to the wavelengths λa and λb, a single receiving element may be used. Further, a single amplifier 7 may be provided at the subsequent stage. That is, both signals are received at low cost. In other words, a system in which high quality BS signals and CS signals are transmitted at low cost.
【００２２】（第３実施例）図３に本発明のＣＡＴＶ共
同受信システムの第３実施例を示す。図は、システム構
成図である。第２実施例と異なる所は、受信側に光分波
器１０Ｂを設け分波された信号を電気信号に変換する光
電変換器６ａ，６ｂ、そしてそれぞれの信号を増幅する
増幅器７ａ、７ｂを備えたことである。この構成によれ
ば、例えば波長λａで送出されたＢＳ信号、波長λｂで
送出されたＣＳ信号を分波器１０で精度よく確実に分離
することができる。これにより、ＢＳ信号とＣＳ信号の
両帯域間の変調歪みをなくすることができる。又、変調
歪みが少なくなる状態で運用できるために、ＣＮＲを大
きくすることが可能となる。又、光電変換器６ａ、６ｂ
が帯域毎に設けられているので、両信号を別々に受信
し、帯域内偏差を別々に調整できる。又、その後段に設
けた増幅器７ａ、７ｂによって両信号をより最適な振幅
に調整することができる。即ち、より品質のよいＢＳ信
号とＣＳ信号を需要家に伝送することができる。(Third Embodiment) FIG. 3 shows a third embodiment of the CATV joint receiving system according to the present invention. The figure is a system configuration diagram. The points different from the second embodiment are provided with an optical demultiplexer 10B on the receiving side, photoelectric converters 6a and 6b for converting the demultiplexed signals into electric signals, and amplifiers 7a and 7b for amplifying the respective signals. That is. According to this configuration, for example, the BS signal transmitted at the wavelength λa and the CS signal transmitted at the wavelength λb can be accurately and reliably separated by the demultiplexer 10. Thereby, modulation distortion between both bands of the BS signal and the CS signal can be eliminated. In addition, since the operation can be performed in a state where the modulation distortion is reduced, the CNR can be increased. Also, the photoelectric converters 6a, 6b
Is provided for each band, so that both signals can be separately received and the in-band deviation can be adjusted separately. Also, both signals can be adjusted to more optimal amplitudes by the amplifiers 7a and 7b provided at the subsequent stage. That is, it is possible to transmit a better quality BS signal and CS signal to the customer.
【００２３】（変形例）以上、本発明を表わす一実施例
を示したが、他にさまざまな変形例が考えられる。例え
ば、第１実施例乃至第３実施例では、伝送する信号をＣ
ＡＴＶ信号、ＢＳ信号、ＣＳ信号で説明したがデジタル
化されたデータ信号でもよい。この信号を低域高周波信
号で送出する場合は同軸ケーブル４で伝送し、高域高周
波信号で送出する場合は光ファイバケーブル５で伝送す
ればよい。(Modifications) Although one embodiment of the present invention has been described above, various other modifications are possible. For example, in the first to third embodiments, the signal to be transmitted is C
The ATV signal, the BS signal, and the CS signal have been described, but a digitized data signal may be used. When transmitting this signal as a low-frequency high-frequency signal, the signal may be transmitted through the coaxial cable 4. When transmitting this signal as a high-frequency high-frequency signal, the signal may be transmitted through the optical fiber cable 5.
【００２４】又、第１実施例乃至第３実施例では低域高
周波信号の伝送路及び高域高周波信号の伝送路の全てに
増幅器を設けたが、必要な信号振幅が得られる場合は全
てに設けなくともよい。必要な個所に設けるだけでも差
し支えない。又、必要であれば光ファイバケーブルの途
中に光増幅器を設けることもできる。In the first to third embodiments, amplifiers are provided in all of the transmission path of the low-frequency high-frequency signal and the transmission path of the high-frequency high-frequency signal. It is not necessary to provide. It can be simply provided at the required location. If necessary, an optical amplifier can be provided in the middle of the optical fiber cable.
【００２５】又、第２実施例では異なる波長λａ、λｂ
を出力する光電変換器３ａ、３ｂを用いたが、同一波長
の光を出力する光電変換器を用いてもよい。第１実施例
と同等の効果がある。In the second embodiment, different wavelengths λa and λb
Although the photoelectric converters 3a and 3b that output light are used, a photoelectric converter that outputs light of the same wavelength may be used. There is an effect equivalent to that of the first embodiment.
【図１】本発明の第１実施例に係わる共同受信システム
構成図。FIG. 1 is a configuration diagram of a joint receiving system according to a first embodiment of the present invention.
【図２】本発明の第２実施例に係わる共同受信システム
構成図。FIG. 2 is a configuration diagram of a joint receiving system according to a second embodiment of the present invention.
【図３】本発明の第３実施例に係わる共同受信システム
構成図。FIG. 3 is a configuration diagram of a joint receiving system according to a third embodiment of the present invention.
【図４】従来の同軸ケーブルを用いた共同受信システム
構成図。FIG. 4 is a configuration diagram of a conventional joint receiving system using a coaxial cable.
【図５】従来の光ファイバケーブルを用いた共同受信シ
ステム構成図。FIG. 5 is a configuration diagram of a joint reception system using a conventional optical fiber cable.
１、２、 増幅器 ２ａ、２ｂ 増幅器 ３、３ａ、３ｂ 光電変換器 ４ 同軸ケーブル ５ 光ファイバケーブル ６、６ａ、６ｂ 光電変換器 ７、７ａ、７ｂ 増幅器 ８ 増幅器 ９ 混合器 １０Ａ 光混合器 １０Ｂ 光分波器 1, 2, amplifier 2a, 2b amplifier 3, 3a, 3b photoelectric converter 4 coaxial cable 5 optical fiber cable 6, 6a, 6b photoelectric converter 7, 7a, 7b amplifier 8 amplifier 9 mixer 10A optical mixer 10B Wave device
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｈ０４Ｎ 7/22 Ｆターム(参考） 5C056 FA02 FA08 FA11 GA11 HA01 HA04 HA11 HA20 5C064 BA02 BB05 BC12 DA09 EA01 EA03 5K002 AA01 AA03 BA05 CA16 DA02 FA01 GA01 GA02 5K046 AA02 AA08 BB03 CC02 PP04 YY01 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification code FI Theme coat ゛ (Reference) H04N 7/22 F term (Reference) 5C056 FA02 FA08 FA11 GA11 HA01 HA04 HA11 HA20 5C064 BA02 BB05 BC12 DA09 EA01 EA03 5K002 AA01 AA03 BA05 CA16 DA02 FA01 GA01 GA02 5K046 AA02 AA08 BB03 CC02 PP04 YY01
Claims (8)
たハイブリッド型伝送方式であって、 高域高周波信号は光ファイバケーブルで低域高周波信号
は同軸ケーブルで送信し、 受信側で前記光ファイバケーブルの出力を電気信号に変
換し、前記同軸ケーブルで伝送された前記低域高周波信
号と混合して出力することを特徴とするハイブリッド型
伝送方式。1. A hybrid transmission system using an optical fiber cable and a coaxial cable, wherein a high-frequency high-frequency signal is transmitted by an optical fiber cable and a low-frequency high-frequency signal is transmitted by a coaxial cable. A hybrid transmission system comprising: converting an output into an electric signal; mixing the output with the low-frequency high-frequency signal transmitted through the coaxial cable;
を用いる共同受信システムであって、 送信側に高域高周波信号を光信号に変換する光電変換器
を、 受信側に前記光信号を電気信号に変換する光電変換器
と、その変換された信号と伝送された前記低域高周波信
号を混合する混合器とを備えたことを特徴とする共同受
信システム。2. A joint receiving system using the hybrid transmission system according to claim 1, wherein a transmitting side is provided with a photoelectric converter for converting a high frequency high-frequency signal into an optical signal, and a receiving side is provided with an optical signal. A joint receiving system comprising: a photoelectric converter for converting a signal; and a mixer for mixing the converted signal and the transmitted low-frequency high-frequency signal.
記高域高周波信号を所定波長の光信号に変換する複数の
前記光電変換器と光合波器とを備え、 該光合波器で複数の前記光電変換器の出力を合波して、
前記光ファイバケーブルに出力することを特徴とする請
求項２に記載の共同受信システム。3. The transmitting side of the optical fiber cable includes a plurality of photoelectric converters and an optical multiplexer for converting the high-frequency high-frequency signal into an optical signal having a predetermined wavelength. Combining the outputs of the photoelectric converters,
The joint receiving system according to claim 2, wherein the signal is output to the optical fiber cable.
とする請求項３に記載の共同受信システム。4. The joint receiving system according to claim 3, wherein said predetermined wavelengths are the same wavelength.
とを特徴とする請求項３に記載の共同受信システム。5. The joint receiving system according to claim 3, wherein said predetermined wavelengths are different from each other.
分波器と複数の光電変換器を備え、前記光分波器によっ
て複数に分波された信号は、複数の光電変換器によって
それぞれ電気信号に変換されて前記混合器に送出される
ことを特徴とする請求項３乃至請求項５の何れか１項に
記載の共同受信システム。6. A receiving side of the optical fiber cable includes an optical demultiplexer and a plurality of photoelectric converters, and a plurality of signals demultiplexed by the optical demultiplexer are respectively output by the plurality of photoelectric converters. The joint receiving system according to any one of claims 3 to 5, wherein the joint receiving system is converted into an electric signal and transmitted to the mixer.
信した複数の波長の光信号を電気信号に変換して前記混
合器に出力する単一の光電変換器を備えたことを特徴と
する請求項３乃至請求項５の何れか１項に記載の共同受
信システム。7. The receiving side of the optical fiber cable is provided with a single photoelectric converter that converts received optical signals of a plurality of wavelengths into electric signals and outputs the electric signals to the mixer. The joint receiving system according to claim 3.
号は、送信側又は受信側の少なくとも一方に設けられた
増幅器でそれぞれ増幅されることを特徴とする請求項２
乃至請求項６の何れか１項に記載の共同受信システム。8. The apparatus according to claim 2, wherein said low-frequency high-frequency signal and said high-frequency high-frequency signal are respectively amplified by amplifiers provided on at least one of a transmission side and a reception side.
The joint receiving system according to claim 6.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000235362A JP2002050985A (en) | 2000-08-03 | 2000-08-03 | Hybrid transmission method and joint reception system using the method |
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|---|---|
| JP2002050985A true JP2002050985A (en) | 2002-02-15 |
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