JP2006345273A - Broadcast wave optical transmitter, optical append device, electric wave re-sending device, optical distribution device, and optical relay system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a very small broadcast wave optical relay system at low cost and each device applied to this system. <P>SOLUTION: The broadcast wave optical transmitter can be applied to the broadcast wave optical relay system. The broadcast wave optical transmitter includes two or more antennae 2a, 2b for receiving two or more kinds of broadcast electric waves 1a, 1b; two or more electric/optical conversion devices 4a, 4b for subjecting each electric signal, which was received from two or more antennae 2a, 2b, to electric/optical conversion into optical signals with optical wavelength λ1, λ2 different mutually; and an optical multiplexing device 7a provided at an upper end of an optical fiber transmission path 9 for subjecting two or more optical signals, which was received from two or more electric/optical conversion devices 4a, 4b, to optical multiplex through wavelength division multiplex and generating an output. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a broadcast signal pass-through transmission technology for converting an electrical signal based on a broadcast radio wave into an electrical / optical (E / O) transmission and transmitting an optical fiber transmission line network, and in particular, a broadcast wave optical repeater system using this technology, and The present invention relates to an apparatus applied to this system.

  In recent years, as a means for transmitting a signal to a CATV, a joint reception facility, etc., or as a means for transmitting a signal to an area or facility inferior in the reception state of a broadcast wave, transmission loss is small and large capacity transmission is possible. For this reason, a system is used in which broadcast signals are frequency division multiplexed and transmitted through an optical fiber transmission line.

  When a new broadcast signal is additionally transmitted during transmission on the optical fiber transmission line, optical / electrical (O / E) conversion is once performed, the new broadcast signal is frequency-division multiplexed, and then again E / O. It was converted and sent out to the optical fiber transmission line.

  Also, if a signal corresponding to a desired broadcast radio wave is extracted from the frequency-division multiplexed optical signal and used for another purpose, once the O / E conversion is performed, an electric signal corresponding to the desired broadcast radio wave is obtained. Equipment such as a high-performance filter that extracts signals is required. The reason is that when an unnecessary electrical signal is present adjacent to the desired electrical signal in a frequency-division multiplexed optical signal converted to an electrical signal, it has a very steep high-performance filtering characteristic. This is because a desired signal cannot be extracted unless it is a waver.

  Furthermore, the same processing as described above is performed when optical transmission is stopped (radio wave re-transmission) in the middle of some signals.

  In Patent Document 1, analog broadcast radio waves such as medium wave AM radio, VHF-FM radio, VHF / UHF-TV, etc. are converted into analog light intensity signals, transmitted through an optical fiber transmission line, and converted back to electrical signals. A system for transmitting radio waves is disclosed. Further, Patent Document 2 is applied to a relay device for terrestrial digital broadcasting of an orthogonal frequency division multiplexing modulation system, and has a polarization beam splitter / combiner composed of a Faraday rotator, a half-wave plate, and a polarization beam splitter, An apparatus for canceling a wraparound phenomenon between transmission and reception is disclosed.

JP 2002-51025 A JP 2002-290303 A

  However, in the above-mentioned broadcast signal pass-through transmission, in the case of the conventional method, in order to add a signal, extract a part of a signal, stop optical transmission in the middle of a part of a signal (retransmission of radio waves), etc., an optical modulation signal Is once converted into an electric signal and converted again into an optical modulation signal, resulting in a complicated and expensive system.

  Further, signal deterioration is caused by modulation / demodulation.

  Furthermore, when a signal corresponding to a desired broadcast radio wave is taken out and used for another purpose, a high-performance filter is required.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a broadcast wave optical repeater system that is low in cost and extremely low in signal deterioration and an apparatus applied to this system.

  According to the present invention, a plurality of antennas that are applied to a broadcast wave optical repeater system that transmits multiplexed optical signals based on a plurality of types of broadcast radio waves through an optical fiber transmission line, and that receives the plurality of types of broadcast radio waves; A plurality of electrical / optical converters for electrical / optical conversion so that each electrical signal from the antenna becomes an optical signal having a different optical wavelength; and an upper end of the optical fiber transmission line; There is obtained a broadcast wave optical transmitter characterized by having an optical multiplexer that optically multiplexes and outputs a plurality of optical signals from the electrical / optical converter by wavelength division multiplexing.

  The broadcast wave optical transmitter may include a plurality of optical attenuators that adjust the intensity of each optical signal from the plurality of electrical / optical converters. The broadcast wave optical transmitter may also include an optical amplifier that optically amplifies the optical signal from the optical multiplexer.

  According to the present invention, an antenna that is applied to a broadcast wave optical repeater system that transmits multiplexed optical signals based on a plurality of types of broadcast radio waves via an optical fiber transmission line, and that receives a broadcast radio wave other than the plurality of types of broadcast radio waves; An electric / optical converter that converts an electric signal from the antenna into an optical signal having a specific optical wavelength, and an optical / optical transmission line that is inserted in the middle of the optical fiber transmission line. There is obtained a broadcast wave light adding device comprising an optical multiplexer for optically multiplexing and outputting an optical signal from the electrical / optical converter by wavelength division multiplexing with respect to an optical signal arriving from the upstream side.

  The broadcast wave light adding device may include an optical attenuator that adjusts the intensity of an optical signal from the electrical / optical converter. The broadcast wave light adding device may also include an optical amplifier that optically amplifies the optical signal from the optical multiplexer.

  Further, according to the present invention, the present invention is applied to a broadcast wave optical repeater system that transmits multiplexed optical signals based on a plurality of types of broadcast radio waves through an optical fiber transmission line, and is inserted and arranged in the middle of the optical fiber transmission line. A part of the optical signal coming from the upstream side of the transmission line is optically branched and the remaining part is passed through, and an optical signal having an optical wavelength corresponding to a predetermined broadcast radio wave is separated from the optical signal from the optical brancher. An optical demultiplexer that oscillates, an optical / electrical converter that optically / electrically converts an optical signal from the optical demultiplexer, and an antenna that transmits an electric signal from the optical / electrical converter to a radio wave. A characteristic broadcast wave radio wave retransmitting apparatus is obtained.

  Further, according to the present invention, the present invention is applied to a broadcast wave optical repeater system that transmits multiplexed optical signals based on a plurality of types of broadcast radio waves through an optical fiber transmission line, and is inserted and arranged in the middle of the optical fiber transmission line. An optical branching device that optically branches a part from an optical signal arriving from the upstream side of the fiber transmission line and passes the remainder, an optical amplifier that optically amplifies the optical signal from the optical branching device, and an optical signal from the optical amplifier A broadcast light distribution apparatus having a second optical branching device for optically branching a signal is obtained.

  Furthermore, according to the present invention, a plurality of electrical signals based on a plurality of types of broadcast radio waves are converted into optical signals, and the plurality of optical signals are optically multiplexed by wavelength division multiplexing and transmitted through an optical fiber transmission line. A broadcast wave optical repeater system characterized by the above can be obtained.

  In addition, according to the present invention, a plurality of electric signals based on a plurality of types of broadcast radio waves are converted into optical signals, and the plurality of optical signals are optically multiplexed by wavelength division multiplexing and transmitted through an optical fiber transmission line. A broadcast wave optical relay system is provided that includes at least one of the broadcast wave light transmission device, the broadcast wave light addition device, the broadcast wave radio wave retransmission device, and the broadcast wave light distribution device.

  Each of the plurality of types of broadcast radio waves may be any one of terrestrial digital television broadcast radio waves, terrestrial analog television broadcast radio waves, and down-converted satellite broadcast radio waves.

  According to the present invention, in a broadcast signal pass-through transmission line using an optical fiber transmission line network, it is possible to electrically add signals, extract some signals, and stop optical transmission (retransmission of radio waves) in the middle of some signals. Therefore, a broadcast wave optical repeater system can be obtained with a low cost and easy system construction without any modulation / demodulation.

  The present invention relates to a broadcast signal pass-through transmission line using an optical fiber transmission line network, a plurality of E / O converters that generate optical modulation signals having different optical wavelengths for each purpose of use, and the intensity of the optical modulation light. An optical attenuator to be adjusted; a plurality of optical multiplexers that combine the plurality of optical modulation signals; an optical amplifier that amplifies the output of the optical multiplexer; an optical fiber transmission line that transmits the output of the optical amplifier; Having a plurality of optical amplifiers arranged in the fiber transmission line, adding broadcast wave signals in the middle of transmission, extracting some broadcast wave signals, stopping transmission from the middle of some signals, without electrical modulation and demodulation, This is a broadcast wave optical repeater system that is performed by an optical wavelength multiplexer or optical wavelength splitter.

  Further, the present invention is a broadcast wave optical repeater system that combines wavelengths of optical modulation signals having different optical wavelengths for each purpose of use after adjusting the optical intensity by the optical attenuator according to the required performance.

  Further, the present invention provides a plurality of optical modulation signals on a broadcast wave pass-through transmission line that are optically branched in the middle of the line, amplified by an optical amplifier, then multi-branched by a second optical branching unit, and light having a plurality of wavelengths. This is a broadcast wave optical relay system that delivers a modulated signal to each home.

  Further, according to the present invention, the optical signal branched from the broadcast wave pass-through transmission line is taken out by the optical wavelength demultiplexer and only the desired optical modulation signal is extracted and used as a signal for retransmission by radio waves. Since only the wavelength of the desired optical modulation signal is extracted with an optical wavelength demultiplexer, it can be retransmitted without inserting a high-performance bandpass filter that allows only the desired transmission frequency signal to pass through the retransmitter using radio waves. This is a broadcast wave optical relay system that realizes the device.

  In addition, according to the present invention, the O / E converter that converts the plurality of optical modulation signals into electrical broadcast signals in each home can be used without depending on the wave number of the optical wavelength. System.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a broadcast wave optical relay system according to an embodiment of the present invention.

  This broadcast wave optical repeater system is a broadcast wave optical repeater system that performs electrical / optical conversion of electrical signals based on a plurality of types of broadcast radio waves, and optically transmits them through the optical fiber transmission line 9. A device 70, a broadcast wave radio wave retransmitting device 80, and a broadcast wave light distribution device 90;

  Note that the broadcast wave optical relay system according to the present invention does not have to include all of the devices shown in FIG. In the broadcast wave optical relay system according to the present invention, each device is not limited to one device, and a plurality of devices may be provided. Furthermore, although the broadcast wave light distribution device 90 described in detail later is connected in the middle of the optical fiber transmission line 9, it may be connected to the end of the optical fiber transmission line 9.

  Referring to FIG. 1, in the broadcast wave optical transmitter 60, reference numeral 1a denotes a terrestrial digital TV signal, 1b denotes a terrestrial analog TV signal, 2a denotes a terrestrial digital TV signal antenna (for reception), and 2b denotes an terrestrial analog TV signal antenna ( For reception), 3a and 3b are band-pass filters that pass only the respective signals. Reference numerals 4a and 4b denote E / O converters for converting the terrestrial digital TV signal 1a and the terrestrial analog TV signal 1b into light intensity signals, respectively. The output light wavelengths λ1 and λ2 from the E / O converters 4a and 4b were 1530 nm and 1550 nm, respectively.

  Optical signals having different optical wavelengths, which have undergone light intensity modulation by the terrestrial digital TV signal 1a and the terrestrial analog TV signal 1b, pass through optical fiber transmission lines 5a and 5b and level adjusting optical attenuators 6a and 6b, respectively, and an optical multiplexer 7a. Is input. In this embodiment, the optical multiplexer 7a is composed of a dielectric multilayer film.

The required performance of the broadcast signal is as follows.
Terrestrial digital TV signal: C / N (carrier to noise ratio) ≧ 24 dB
・ Terrestrial analog TV signal: C / N ≧ 45dB
BS-IF TV signal: C / N ≧ 26 dB

  The BS-IF TV signal is a signal obtained by down-converting a broadcast radio wave (artificial satellite wave) using a broadcast artificial satellite or an information communication artificial satellite.

  The required performance varies greatly depending on the signal system, and if it is designed for the highest performance, the other signals will have excessive performance and high cost. Therefore, the light intensity was set according to the required performance. This time, 2 mW is the intensity modulated with the terrestrial analog TV signal that requires extremely high performance for the optical multiplexer output, and 1 mW is the intensity modulated with the terrestrial digital TV signal.

  The optical signal output from the optical multiplexer 7 a is amplified by the optical amplifier 8 to 14 dBm (terrestrial digital) and 17 dBm (terrestrial analog), respectively, and input to the optical fiber transmission line 9. The input light is optically amplified to the same level by an optical amplifier 8 every 50 km, for example, and an optical network line is constructed.

  Next, addition of an optical signal will be described.

  In the broadcast wave light adding device 70, the BS-IF TV signal 1c that has passed through the BS-IF TV signal antenna (for reception) 2c and the band-pass filter 3c is input to the E / O converter 4c and converted into an optical modulation signal. Is done. The light output wavelength λ3 at this time was 1560 nm. The optical signal optically modulated by the BS-IF TV signal is optically wavelength-multiplexed by an optical multiplexer 7b disposed in the middle of the optical network line. The intensity ratio of the three light wavelengths was set to terrestrial digital: terrestrial analog: BS-IF = 1: 2: 1.

  FIG. 2 shows an arrangement of optical wavelengths of optical signals based on the three types of broadcast radio waves used in this embodiment.

  Next, re-transmission of electrical signals will be described. As the optical multiplexer 7b, as in the optical multiplexer 7a, one constituted by a dielectric multilayer film was used.

  In the broadcast wave radio wave retransmitting apparatus 80, the optical branching unit 10a disposed in the middle of the network line is optically branched to an optical intensity ratio of 100: 1, with one (100) being the optical line and the other (1) being the optical demultiplexing. Only an optical signal having a wavelength of 1530 nm that is input to the device 11 and is modulated by the terrestrial digital TV signal is selected, led to the O / E converter 12, and converted into an electrical signal. The signal converted into the electrical signal is amplified by the transmitter 13 and output as a radio wave by the terrestrial digital TV signal antenna (for transmission) 2a '. As the optical branching device 10a, an optical branching optical coupler is used.

  FIG. 3 shows the light transmission characteristics of the optical demultiplexer 11. A terrestrial analog TV signal (wavelength 1550 nm) or a BS-IF TV signal (wavelength 1560 nm), which is an optical signal separated by, for example, 20 nm or more from an optical signal (wavelength 1530 nm) modulated by the terrestrial digital TV signal, is an optical demultiplexer. 11 is attenuated by 30 dB or more, and when converted to an electric signal, the attenuation is 60 dB or more (the electric output is the square of the photocurrent). As described above, although the light transmission characteristic of the optical demultiplexer 11 is not so sharp, it is possible to transmit a signal other than the terrestrial digital TV signal without any problem in transmitting the radio wave without inserting an output filter. Become.

  In this example, an optical demultiplexer for an optical signal (wavelength 1530 nm) whose light intensity is modulated by a terrestrial digital TV signal is taken as an example, but a terrestrial analog TV signal (wavelength 1550 nm) or a BS-IF TV signal (wavelength 1560 nm). The same effect can be obtained with the optical demultiplexer. When the wavelength difference between the optical signal to be extracted and the optical signal not to be extracted is 10 nm, the attenuation difference does not occur as compared with the case where the wavelength difference is 20 nm, but the attenuation difference is practically sufficient.

  Next, the distribution of optical signals to each home (or each house in an apartment house) will be described.

  In the broadcast wave light distribution apparatus 90, the optical branching unit 10b splits the light 100: 1, one (100) is input to the optical line, and the other (1) is input to the optical amplifier. Is distributed with equal intensity by the 1 × 8 optical splitter 14 and distributed to each home (each house). As the optical branching device 10b, the one composed of a fusion type optical coupler was used as in the optical branching device 10a. Further, as the 1 × 8 optical branching device 14, one constituted by a fusion type optical coupler was used.

  In each home, an O / E converter 15 is installed. After being converted into an electric broadcast signal, the electric signal is demultiplexed by a known technique, and each broadcast is received arbitrarily.

  The broadcast wave optical repeater system according to the present invention is capable of adding a signal, extracting a part of a signal, stopping optical transmission from the middle of a part of the signal (retransmission of radio waves), without using an optical modulation / demodulation, It is possible to re-transmit the optical modulation signal extracted by the optical wavelength demultiplexer without using a bandpass filter that allows only the transmission frequency signal to pass, and the system can be constructed. Easy and inexpensive. Further, a general-purpose O / E converter can be used in the broadcast wave optical relay system of the present invention without depending on the wave number of the optical wavelength.

  While the present invention has been described in terms of several embodiments, it will be apparent to those skilled in the art that the present invention can be variously modified within the scope of the claims.

  For example, broadcasts transmitted by the system according to the present invention are not limited to terrestrial digital television broadcasts, terrestrial analog television broadcasts, and down-converted artificial satellite broadcasts, but also include regional information broadcasts and disaster prevention broadcasts. Further, the broadcast method of the source signal may be wired broadcast in addition to wireless broadcast. Needless to say, when the source signal is cable broadcasting, a configuration relating to wireless broadcasting such as an antenna in each apparatus according to the present invention is not necessary. Furthermore, the broadcast content is not limited to video and audio, but may be only audio or general data.

It is a block diagram which shows the structure of the broadcast wave optical relay system by the Example of this invention. It is a figure which shows the example of the optical intensity difference of the optical signal of each optical wavelength in the broadcast wave optical relay system by the Example of this invention. It is a figure which shows an example of the filtering characteristic of the optical demultiplexer which the broadcast wave radio wave re-transmission apparatus in the broadcast wave optical relay system by the Example of this invention has.

Explanation of symbols

1a Terrestrial digital TV signal 1a 'Terrestrial digital TV signal (transmitted wave)
1b Terrestrial analog TV signal 1c BS-IF TV signal 2a Terrestrial digital TV signal antenna 2a 'Terrestrial digital TV signal antenna (for transmission)
2b Terrestrial analog TV signal antenna 2c BS-IF TV signal antenna 3a-3c Band pass filter (BPF)
4a to 4c E / O converter 5a to 5c Optical fiber transmission line 6a to 6c Optical attenuator (ATT)
7a, 7b Optical multiplexer 8 Optical amplifier 9 Optical fiber transmission line 10a, 10b Optical splitter 11 Optical demultiplexer 12 O / E converter 13 Transmitter (AMP)
14 1 × 8 optical splitter 15 O / E converter 60 broadcast wave light transmitter 70 broadcast wave light adder 80 broadcast wave radio wave retransmitter 90 broadcast wave light distributor

Claims (11)

Applied to broadcast optical repeater systems that transmit multiplexed optical signals based on multiple types of broadcast radio waves over optical fiber transmission lines,
A plurality of antennas for receiving the plurality of types of broadcast radio waves;
A plurality of electrical / optical converters for electrical / optical conversion of the electrical signals from the plurality of antennas so as to be optical signals having different optical wavelengths;
An optical multiplexer disposed at an upper end of the optical fiber transmission line and configured to optically multiplex and output a plurality of optical signals from the plurality of electrical / optical converters by wavelength division multiplexing; apparatus.   The broadcast wave optical transmitter according to claim 1, further comprising a plurality of optical attenuators that respectively adjust the intensity of each optical signal from the plurality of electrical / optical converters.   The broadcast wave optical transmitter according to claim 1, further comprising an optical amplifier that optically amplifies an optical signal from the optical multiplexer. Applied to broadcast optical repeater systems that transmit multiplexed optical signals based on multiple types of broadcast radio waves over optical fiber transmission lines,
An antenna for receiving broadcast waves other than the plurality of types of broadcast waves;
An electrical / optical converter that performs electrical / optical conversion so that the electrical signal from the antenna becomes an optical signal having a specific optical wavelength;
An optical signal that is inserted in the middle of the optical fiber transmission line, and that combines the optical signal from the electrical / optical converter with the optical signal coming from the upstream side of the optical fiber transmission line by wavelength division multiplexing and outputs it. A broadcast wave light adding device, comprising:   5. The broadcast wave light adding apparatus according to claim 4, further comprising an optical attenuator for adjusting an intensity of an optical signal from the electric / optical converter.   6. The broadcast wave light adding apparatus according to claim 4, further comprising an optical amplifier that optically amplifies an optical signal from the optical multiplexer. Applied to broadcast optical repeater systems that transmit multiplexed optical signals based on multiple types of broadcast radio waves over optical fiber transmission lines,
An optical branching device that is inserted and arranged in the middle of the optical fiber transmission line, and optically branches a part of the optical signal coming from the upstream side of the optical fiber transmission line and allows the remainder to pass through,
An optical demultiplexer for demultiplexing an optical signal having an optical wavelength corresponding to a predetermined broadcast radio wave from the optical signal from the optical splitter;
An optical / electrical converter that optically / electrically converts an optical signal from the optical demultiplexer;
A broadcast wave radio wave retransmitting device comprising an antenna for radio wave transmission of an electric signal from the optical / electrical converter. Applied to broadcast optical repeater systems that transmit multiplexed optical signals based on multiple types of broadcast radio waves over optical fiber transmission lines,
An optical branching device that is inserted and arranged in the middle of the optical fiber transmission line, and optically branches a part of the optical signal coming from the upstream side of the optical fiber transmission line and allows the remainder to pass through,
An optical amplifier for optically amplifying the optical signal from the optical splitter;
A broadcast wave optical distribution apparatus comprising: a second optical branching unit that optically branches an optical signal from the optical amplifier.   A broadcast wave optical repeater system that converts a plurality of electrical signals based on a plurality of types of broadcast radio waves into optical signals, optically multiplexes the plurality of optical signals by wavelength division multiplexing, and transmits the optical fiber transmission path. . A broadcast wave optical repeater system that converts a plurality of electrical signals based on a plurality of types of broadcast radio waves into optical signals, optically multiplexes the plurality of optical signals by wavelength division multiplexing, and transmits an optical fiber transmission line,
The broadcast wave light transmitting apparatus according to claim 1, the broadcast wave light adding apparatus according to claim 4, the broadcast wave radio wave retransmitting apparatus according to claim 7, and the broadcast wave light distributing apparatus according to claim 8. A broadcast wave optical relay system having at least one of the above. The broadcast wave optical relay system according to claim 9 or 10, wherein each of the plurality of types of broadcast radio waves is one of a digital terrestrial television broadcast radio wave, a terrestrial analog television broadcast radio wave, and a down-converted satellite broadcast radio wave. .

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