JP6434784B2 - Optical repeater system - Google Patents

Description

  The present invention relates to an optical repeater system in which each relay station converts a broadcast wave received from a mobile station into an optical signal and transmits the optical signal to a demodulation unit via an optical line, and in particular, an optical signal capable of selecting an optical signal. It relates to an optical repeater system using a router.

  In live broadcasting of long-distance competitions such as marathons, relay races, triathlons, and bicycle road races, mobile stations such as mobile relay vehicles, mobile relay motorcycles, helicopters equipped with photographic equipment, and multiple relays installed around the competition track Live broadcasts that broadcast the competition in real time using stations. In the live broadcast, the runners and bicycles photographed by the television camera mounted on the mobile relay vehicle and the television camera held by the cameraman riding on the mobile relay motorcycle, and the video is transmitted to each relay station as a broadcast wave . Each relay station transmits, for example, a broadcast wave received from each mobile relay vehicle or each mobile relay motorcycle to a television station, that is, a broadcast station by an analog transmission method using microwaves. As a prior art, a relay system in which a receiver of each relay station has a reception state determination unit and transmits the reception state of the relay station to a television station via a separate line is described in Patent Document 1 and passes through a plurality of relay stations. Patent Document 2 discloses a relay system in which a difference in radio wave transmission time in each radio wave transmission path is corrected according to a detection result of a position detection unit.

  When a broadcast wave is transmitted to a television station using a microwave analog transmission method, if the transmission distance of the broadcast wave transmitted from each relay station to the television station is long, the signal level of the broadcast wave decreases, and a clear image does not reach the television station. In some cases, video cannot be broadcast from a TV station. In addition, unnecessary noise may be generated by lightning strikes or other electromagnetic waves, which may disrupt live images. In order to avoid such a situation, the broadcast wave received at the relay station is converted into an optical signal and the optical signal is transmitted to the television broadcast room via the optical line, and the television broadcast room is transmitted from the relay station. An optical repeater system using an optical transmission system that converts an optical signal into a broadcast wave is employed.

JP-A-2005-51755 JP 2008-236244 A

  In the optical relay system as described above, broadcast waves from each mobile station are received by a plurality of relay stations, and the received signals are signal-processed and simultaneously transmitted from the plurality of relay stations to the demodulation unit. A plurality of optical signals are transmitted to the demodulation unit for the broadcast wave from one mobile station. However, in broadcasting, the original signals such as video and audio included in the broadcast wave of one mobile station are the same, so the highest quality optical signal that most faithfully contains the original signal for one mobile station. There should be only one.

  However, in the conventional optical repeater system, the demodulation unit demodulates the optical signal including the broadcast wave signal from the mobile station transmitted from all the repeater stations, and selects a high-quality signal with less noise and distortion from them. Broadcast to the broadcast receiver for relay or input all demodulated signals to the broadcast receiver for relay and receive broadcast waves from the broadcast receiver or broadcast receiver The station selected the best signal. That is, in the conventional optical repeater system, a demodulation unit, a relay broadcast receiver, or a broadcast station demodulates a signal that is not required later, and thus cannot be said to be an efficient system.

  An object of the present invention is to solve the above-described problems and provide an optical repeater system based on an efficient optical transmission system that does not need to constantly demodulate unnecessary signals.

  In order to solve the above-mentioned problem, in a first aspect, an optical repeater system according to the present invention is installed around a plurality of mobile stations used for live broadcasting and the mobile route of those mobile stations and transmitted from each mobile station. A plurality of relay stations that receive the broadcast wave and a demodulation unit that receives a signal transmitted from the relay station, the relay station performing signal processing on the broadcast wave received from the mobile station Then, in an optical relay system that converts the optical signal into an optical signal and transmits the optical signal to the demodulation unit via an optical line, the number of the mobile stations is M, and the number of the relay stations is N (where N , M is an integer greater than or equal to 2 and N ≧ M), M signals including signals respectively corresponding to broadcast waves from the M mobile stations out of the optical signals from the N relay stations. Equipped with an optical router that selects and outputs the optical signal And transmitting the router output of the demodulation unit.

  As described above, an optical router is provided that selects and outputs M optical signals each including a signal corresponding to a broadcast wave from M mobile stations from among N optical signals transmitted to the demodulation unit. Thus, instead of sending all the optical signals transmitted from each relay station to the demodulation unit, only one optical signal having a high quality signal having good image quality etc. is selected for each mobile station. By sending to the demodulation unit, only the necessary signals can be demodulated, and the system can be configured more efficiently than when all signals are demodulated and then signals are selected. The selection of the M optical signals in the optical router is determined based on the result of evaluating the demodulated signal in the demodulation unit or the demodulation unit and the like, and the optical router is determined by the instruction signal from the demodulation unit and the device after the demodulation unit. Is controlled. In the present invention, the broadcast wave refers to a broadcast radio signal or an electric signal obtained by receiving the broadcast radio signal with an antenna.

  In a second aspect, the present invention provides the optical repeater system according to the first aspect, wherein the broadcast wave has signals of the first to nth channels (where n is an integer of 2 or more) frequency-multiplexed. The signal processing includes first distribution means for distributing the broadcast wave transmitted from the mobile station to the first to nth transmission lines, and the first to nth transmission lines for the first to nth transmission lines, respectively. First frequency changing means for changing to the same intermediate frequency common to each channel lower than the frequency of the broadcast wave for each channel corresponding to each transmission path, corresponding to the signal of the channel; Necessary frequency extraction means for extracting unnecessary frequency components by attenuating unnecessary frequency components from the intermediate frequency signals of the nth channel and the level of the extracted intermediate frequency signals of the first to nth channels are made constant. Level adjustment means The second frequency changing means for changing the level adjusted intermediate frequency signals of the first to n-th channels to the optical transmission frequency having the same frequency as the broadcast wave, and the first to first frequencies changed to the optical transmission frequencies. And a first synthesizing unit for synthesizing the frequency signal for optical transmission of the nth channel.

  Even in an optical relay system that employs an optical transmission system, when shooting a runner or bicycle using a mobile relay vehicle or mobile relay motorcycle, the broadcast radio wave depends on the distance between the relay vehicle or relay motorcycle and each relay station. In other words, various types of interference waves having unnecessary frequencies may enter the broadcast wave, resulting in distortion in the received broadcast wave. When the broadcast wave is distorted, the image quality of the image is lowered and it is impossible to broadcast a clear image in the live broadcast of the competition.

Although it is difficult to extract only necessary frequency components while removing unnecessary frequency components such as interference waves in a high frequency state such as broadcast waves, each relay station receives it as in the invention of this aspect. After changing the frequency of the broadcast waves of the first to nth channels to an intermediate frequency lower than that, unnecessary frequency components such as interference waves are removed from the intermediate frequency signals of the first to nth channels. When extracting only the intermediate frequency component, the unnecessary frequency component can be reliably removed as compared with the case where only the necessary frequency is extracted while removing the unnecessary frequency while the frequency is high. Only the intermediate frequency component can be reliably extracted. As a result, unnecessary frequency components such as jamming waves can be reliably removed, so that the DU ratio (Desired to Undesired Signal Raitio) of the broadcast wave can be increased and the signal received by the demodulation unit during the live broadcast Generation of distortion can be prevented, and a clear video can be broadcast at a broadcasting station. Further, by making the level of the intermediate frequency signal of the first to nth channels constant, it is possible to transmit a signal having no level variation for each channel to the demodulation unit. The optical signal is not affected by lightning strikes or other electromagnetic waves, and there is little degradation of the optical signal during transmission, so a high-quality signal having image quality of almost the same level as the broadcast wave received by each relay station can be obtained. Can be transmitted to the demodulation unit. Further, by using the same intermediate frequency common to each channel, electrical components such as a filter can be shared by each channel, and the manufacturing cost of the apparatus can be reduced.
In the present invention, an example of the frequency band of the broadcast wave is a range of 1.2 to 2.37 GHz, and an example of the same intermediate frequency common to each channel for converting the frequency of the broadcast wave is a range of 10 to 200 MHz. There is.

In a third aspect, the present invention provides the optical relay system according to the second aspect, wherein the relay station includes a plurality of receiving antennas having different receivable frequency bands and a plurality of receiving circuits corresponding to the respective frequency bands. And a signal switch for switching between the receiving circuit and the electric circuit for performing the signal processing.
In the optical signal relay system, the frequency band used for the broadcast wave may differ depending on the sporting event to be relayed. In the invention of this aspect, each relay station is provided with a receiving circuit corresponding to the plurality of frequency bands in advance, and a signal switch for switching between the receiving circuit and the signal processing circuit. It can be used for various sports events. Examples of the plurality of frequency bands include a 1.2 GHz band and a 2.3 GHz band. The signal processing circuit may include a switch for switching a filter for removing extra harmonics, noise, and the like included in the high-frequency signal in synchronization with the signal switch.

  In a fourth aspect, the present invention provides the optical repeater system according to the second or third aspect, wherein the demodulation unit converts the optical signal transmitted from the optical router into an electrical signal to obtain a received broadcast wave. O / E conversion means, second distribution means for distributing the received broadcast wave to the first to n-th transmission paths, and the first to n-th transmission paths for the first to n-th channel signals, respectively. A third frequency changing means for changing the received broadcast wave to the same reception intermediate frequency common to each channel lower than the frequency of the received broadcast wave for each channel corresponding to each transmission path; broadcast wave transmitting means for transmitting an n-channel received intermediate frequency signal to a broadcast receiver for relay.

  In the invention of this aspect, the demodulation unit converts the optical signal transmitted from each relay station into a received broadcast wave having the same signal component as the broadcast wave received by the relay station by performing O / E conversion, and thereafter The first to nth channel signals separated for each channel are converted into the same reception intermediate frequency signal common to each channel. Since this signal has an unnecessary frequency component such as an interference wave removed at each relay station, the signal is input to a relay broadcast receiver, generally an FPU (Field Pickup Unit) receiver. Can broadcast an image with good image quality with little influence of the DU ratio, and can provide a clear and easy-to-view image to the viewer. Further, since the above signal is set at a constant level in each channel at each relay station, a signal at a constant level can be input to the FPU receiver, and a video at a constant level can be provided to the viewer. .

  In a fifth aspect, the present invention provides the optical relay system according to the fourth aspect, wherein each of the relay stations transmits a part of the intermediate frequency signals of the first to n-th channels extracted by the necessary frequency extracting unit. Signal separating means for separating, signal level detecting means for detecting each of the separated signal levels, and A / D converting means for converting the detected signal levels of the first to n-th channels from analog signals to digital signals Parallel / serial signal conversion means for converting the converted first to n-th channel digital signals into one serial signal; digital modulation means for modulating a carrier wave using the serial signal to form a digital modulation signal; Second combining means for combining the digital modulation signal and the frequency signal for optical transmission into a level combined signal, and the E / O converter Converts the level composite signal into the optical signal, and the demodulation unit converts the optical signal into the level composite signal by the O / E conversion means, and separates the digital modulation signal from the level composite signal. Level signal separating means for extracting and level display means for displaying the signal level of the intermediate frequency signals of the first to n-th channels based on the digital modulation signal.

In the invention of this aspect, the received signal level for each channel of the broadcast wave received at each relay station is extracted from the intermediate frequency signal separated into the signal for each channel, the signal level is converted to a digital signal, Serial conversion is carried on a carrier wave and superimposed on the optical transmission frequency signal consisting of the signal of each channel and transmitted to the demodulation unit. The demodulation unit separates and extracts the signal containing signal level information and receives the signal level of each channel. Is displayed.
In live broadcasting, the level of the broadcast wave changes depending on the separation distance between the mobile station and each relay station. In the invention of this aspect, the demodulation unit separates and extracts the signal containing signal level information and receives the received signal of each channel. Since it has means for displaying the level, the operator operating the demodulation unit can select the signal from the relay station by looking at the displayed received signal level. In this way, it is possible to know the level of the broadcast wave for each channel from each mobile station received at each relay station, and to select a good level broadcast wave and input the broadcast wave to the FPU receiver. Therefore, it is possible to broadcast an image with good and clear image quality in broadcast relay.
Also, after switching the optical router, all the optical signals from each relay station are received by the demodulation unit and their signal levels are confirmed, and the optical router is controlled based on the result, and the optimum for each mobile station The optical signal may be selected, and thereafter, only the optimum optical signal may be controlled to be received by the demodulation unit.

  In a sixth aspect, the present invention provides the optical repeater system according to the fifth aspect, wherein the optical router selects the M optical signals depending on the signal level displayed by the level display means. It has the means. Thus, for example, a signal level comparison means is provided in the demodulation unit, and at any time, at a planned time, or by switching the optical router according to an instruction from the operator, all the optical signals from each relay station are temporarily switched. Signals are received by the demodulation unit, their signal levels are input to the comparison means, and the optical router is automatically controlled to select the signal from the relay station having the highest received signal level based on the comparison result. be able to.

In a seventh aspect, the present invention provides the optical relay system according to the first or second aspect, wherein the mobile station includes a plurality of transmission antennas for transmitting signals in the same frequency band, and the relay station Performs signal transmission between the mobile station and the relay station using MIMO (Multiple Input Multiple Output) technology by having a plurality of receiving antennas for receiving signals from the plurality of transmitting antennas,
The relay station, after performing the signal processing on the broadcast wave, converts the optical signal into an optical signal having a different wavelength for each of the receiving antennas, and multiplexes these optical signals for wavelength multiplexing. Wavelength synthesizing means for making an optical signal, and transmitting the wavelength-multiplexed optical signal to the demodulation unit via the optical router.

In a relay system, the frequency band that can be used for communication is limited, and the required frequency capacity increases as the quality of video signals and the like increases and the number of mobile stations increases. . In recent years, in the field of wireless communication, MIMO (Multiple Input Multiple Output) technology that can increase the communication capacity using the same frequency band has attracted attention. In this method, signals on the same frequency band are transmitted by a plurality of transmission antennas on the transmission side, and signals from the plurality of transmission antennas are independently received by a plurality of reception antennas on the reception side in the same manner. Since the signal corresponding to the transmission antenna can be separated and received by processing, the communication capacity can be increased.
In the invention of this aspect, the mobile station and the relay station each have a plurality of transmission or reception antennas in order to use the MIMO technology, and the broadcast waves received by the reception antennas in the relay station are the same as those in the conventional optical relay system. After performing the signal processing, the signals are converted into optical signals having different wavelengths corresponding to the respective receiving antennas. These optical signals are combined and transmitted to the demodulation unit as wavelength-multiplexed optical signals. As a result, the demodulation unit can select only the required optical signal from the relay station and demultiplex the wavelength-multiplexed optical signal to extract it as an optical signal for each receiving antenna at the relay station. A MIMO signal separation process can be performed after the unit. The signal processing at the relay station is the signal processing of the conventional optical repeater system, except that multiple broadcast waves for each antenna are processed and combined after being converted into optical signals of different wavelengths. Therefore, the conventional technology and equipment can be used effectively, and when the communication capacity is increased by increasing the number of transmission / reception antennas, it is flexible by increasing the number of signal processing circuits and the number of optical signal wavelengths. It can correspond to.

  In an eighth aspect, the present invention relates to the optical repeater system according to the seventh aspect, wherein the repeater station receives a plurality of receive antenna groups having different receivable frequency bands (here, the same reception necessary for the MIMO technology is possible). A plurality of receiving antennas having different frequency bands as one group), a plurality of receiving circuits corresponding to the respective frequency bands, and switching between the receiving circuits and the electric circuit for performing the signal processing And a signal switch. The invention of this aspect is applicable when the MIMO technology is applied to the optical relay system, as in the case of the third aspect of the invention, when the frequency band used for the broadcast wave differs depending on the sporting event to be relayed. It becomes possible.

  As described above, according to the present invention, it is possible to obtain an optical repeater system based on an efficient optical transmission system that does not need to constantly demodulate unnecessary signals.

1 is a block configuration diagram of an optical relay system according to Embodiment 1. FIG. 1 is a block configuration diagram showing an example of the configuration of an optical router used in Embodiment 1. FIG. FIG. 2 is a schematic configuration diagram illustrating an example of a specific arrangement configuration of the optical relay system according to the first embodiment. The figure which shows an example of transmission of the broadcast wave and received signal between a mobile relay vehicle, a relay station, and a demodulation unit. The figure which shows typically an example of the monitor room of the television broadcasting room installed in the athletic field. FIG. 6 is a block configuration diagram of a signal processing circuit of a relay station used in the optical repeater system according to the second embodiment. FIG. 9 is a block configuration diagram of a relay station used in the optical repeater system according to the third embodiment. FIG. 9 is a block configuration diagram of a demodulation unit used in an optical repeater system according to a fourth embodiment. FIG. 10 is a block configuration diagram of a signal processing circuit of a relay station used in the optical repeater system according to the fifth embodiment. FIG. 10 is a block configuration diagram of a demodulation unit used in an optical repeater system according to a fifth embodiment. FIG. 10 is a block diagram of an optical repeater system according to a sixth embodiment. FIG. 10 is a block configuration diagram of a relay station used in the optical repeater system according to the seventh embodiment.

  Hereinafter, an optical repeater system according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description thereof is omitted.

  FIG. 1 is a block diagram of an optical repeater system according to the first embodiment. The optical repeater system 10 of this embodiment includes a plurality of mobile stations 11 used for live broadcasting, and a plurality of relays installed around the mobile route of these mobile stations and receiving broadcast waves transmitted from the mobile stations. A station 13 and a demodulation unit 14 that receives signals transmitted from the relay stations 13 are provided. Each of the mobile stations 11 has a transmission antenna 5 for transmitting a signal, and the relay station 13 receives a signal from the transmission antenna 5 of each mobile station by the reception antenna 6 and the reception circuit 7. The received signal is subjected to signal processing by the signal processing circuit 8 and then converted to an optical signal by an E / O conversion device 9 as E / O conversion means, and the optical signal is demodulated by an optical line 19 comprising an optical fiber cable. Transmit to unit 14. Here, the contents of signal processing in the signal processing circuit 8 of each relay station include various signal processing such as removal of unnecessary signals and noise, adjustment of received signal level, and frequency conversion of signals. Also good. The receiving circuit 7 connected to the receiving antenna 6 is an amplifier or the like.

  In this embodiment, the number of mobile stations 11 is M, the number of relay stations 13 is N (where N, M is an integer equal to or greater than 2 and N ≧ M), and optical signals from N relay stations are used. The optical router 4 is provided for selecting and outputting M optical signals each including a signal corresponding to a broadcast wave from M mobile stations, and the output of the optical router 4 is transmitted to the demodulation unit 14. For example, 2 to 6 can be considered as an example of the number M of the mobile stations 11 in the marathon relay, and 8 to 40 can be considered as an example of the number N of the relay stations 13. In this way, only one optical signal including a high quality signal having good image quality and the like for each mobile station 11 is selected by the optical router 4 and sent to the demodulation unit 14, so that only the necessary signal is obtained. The system can be demodulated more efficiently than when demodulating all signals from the relay station 11 and then selecting the necessary signals.

  FIG. 2 is a block diagram showing an example of the configuration of the optical router used in this embodiment. The optical router 4a in FIG. 2 shows an example of an optical router used when the number of mobile stations is 3 and the number of relay stations is 8, and shows an example of the configuration of an 8-input 3-output optical router. The optical router 4a includes eight 1 × 3 optical distributors 36, three 8 × 1 optical switches 37, and three optical amplifiers 35. Each of the input lights is divided into three by the 1 × 3 optical distributor 36, then selected by one of the 8 × 1 optical switches 37, amplified by the optical amplifier 35, and then connected to the output side. Therefore, it is possible to select and output three optical signals including the signals of the respective mobile stations with respect to the optical signals from the eight relay stations. As the optical amplifier, an EDFA (Erbium-doped fiber amplifier) or the like can be used.

  FIG. 3 is a schematic configuration diagram illustrating an example of a specific arrangement configuration of the optical relay system according to the present exemplary embodiment. The optical relay system 10 of the present embodiment broadcasts each of these sports in real time in the live broadcasting of long-distance events such as marathons and relay races, endurance races such as triathlons, road races such as bicycle races and public road motorcycle races. Used for live broadcasts. FIG. 3 shows an example of an arrangement configuration taking a live broadcast of a marathon competition as an example. In FIG. 3, a plurality of mobile relay vehicles 11A and 11B for television broadcasting used as mobile stations for live broadcasting, and a plurality of relay stations 13 installed around a marathon course 12 which is a moving route of the mobile station, 2 shows a demodulation unit 14 installed in the athletic stadium 15. In FIG. 3, the optical router 4 and the optical line 19 are omitted. FIG. 4 is a diagram illustrating an example of transmission of broadcast waves and reception signals between the mobile relay vehicle, the relay station, and the demodulation unit. The demodulation unit 14 is installed in a television broadcasting room in the athletic stadium 15. A monitor room is provided in the television broadcasting room. FIG. 5 is a diagram schematically showing an example of a monitor room of a television broadcasting room installed in an athletic stadium.

  In FIG. 3, two mobile relay vehicles 11A and 11B are illustrated, but in addition to the mobile relay vehicles 11A and 11B, a plurality of mobile relay motorcycles carrying a photographer, a helicopter equipped with photographing equipment, and photographing equipment A motor boat equipped with can be used as a mobile station. Further, the number of mobile relay vehicles is not limited to two, and three or more mobile relay vehicles can be used. Further, the number of relay stations 13 is not limited to the illustrated number.

  In the mobile relay vehicles 11A and 11B, a television camera and a sound collecting microphone are installed at the rear of the vehicle body, and a live seat is made. When the marathon runner 18 that has passed the marathon gate of the athletic stadium enters the marathon course 12, the mobile relay vehicles 11 </ b> A and 11 </ b> B are located in front of the runner 18 and are running on the marathon course 12 together with the runner 18 sprinting. The runner 18 in the race is photographed by the television camera and the sound is collected by the sound collecting microphone. The mobile relay vehicles 11A and 11B transmit video and audio captured by the television camera to the relay station 13 as broadcast waves that are radio waves. At this time, broadcast waves are transmitted from the mobile relay vehicles 11 </ b> A and 11 </ b> B to the relay stations 13 by the transmission antenna 5. Each relay station 13 processes the broadcast wave received by the receiving antenna 6 as described above. As the broadcast wave, for example, a radio wave having a frequency band of 1.2 to 2.37 GHz is used.

  The relay station 13 is installed around the marathon course 12 at least the day before the marathon race. The relay station 13 receives broadcast waves transmitted from the mobile relay vehicles 11A and 11B, processes the received broadcast waves, converts them into optical signals, and transmits the optical signals to the demodulation unit 14 via the optical router 4. Send. The transmission of the optical signal is performed using the optical line 19. The demodulation unit 14 converts the optical signal transmitted from each relay station 13 into an electrical signal, performs signal processing, and transmits the signal to an FPU receiver (not shown).

  In FIG. 5, a plurality of monitors 20 a to 20 p and a plurality of level gauges 21 a to 21 p are installed in the monitor room 17 of the television broadcast room 16. Each staff of the television broadcast room 16 controls the optical router 4 and switches the broadcast channel while checking the monitors 20a to 20p and the level gauges 21a to 21p.

FIG. 6 is a block diagram of a signal processing circuit of a relay station used in the optical multiplexing type relay system according to the second embodiment. The signal processing circuit 70 in FIG. 6 shows the configuration of the signal processing circuit 8 in FIG. The overall basic configuration of the optical repeater system of this embodiment is the same as that of the first embodiment. In the optical repeater system of this embodiment, the broadcast wave has a four-channel signal composed of first to fourth channels that are frequency-multiplexed. An example of the center frequency of the broadcast waves of the first to fourth channels is 1241 MHz for the first channel, 1252 MHz for the second channel, 1259 MHz for the third channel, and 1270 MHz for the fourth channel. As shown in FIG. 6, the signal processing circuit 70 of the optical repeater system of the present embodiment includes a distributor 23, four down converters 24 corresponding to the first to fourth channels, and four band pass filters 25, respectively. And four AGC devices 26, four up-converters 27, and a synthesizer 28. The output from the multiplexer 28 is input to the E / O converter 9.

  In the signal processing in this embodiment, first, the broadcast wave signal transmitted from the mobile station 11 and received by the receiving antenna 6 and the receiving circuit 7 is divided into four transmission lines 30a, 30b, 30c, by the distributor 23 as the first distributing means. Distribute to 30d. Coaxial cables can be used as these transmission lines. Next, the transmission lines 30a to 30d are made to correspond to the signals of the first to fourth channels, respectively, and the broadcast wave signal is transmitted to each channel corresponding to each transmission line by the four down converters 24 which are frequency first changing means. The frequency is changed to the same intermediate frequency common to each channel lower than the frequency of the broadcast wave. In this case, any frequency between 10 and 200 MHz is desirable as the intermediate frequency. For example, 150 MHz can be selected as the intermediate frequency.

Next, the bandpass filter 25 is used as a necessary frequency extracting unit, and unnecessary frequency components are attenuated from the intermediate frequency signals of the first to fourth channels to extract necessary frequency components. In this case, the amount of attenuation of unnecessary frequency components is preferably 40 to 80 dB. As these band-pass filters, a SAW (surface acoustic wave) filter having a small size, low cost, and excellent attenuation characteristics can be used. In this embodiment, since the intermediate frequencies of the respective channels are the same common frequency, all four SAW filters having the same characteristics can be used as the bandpass filters 25, and the cost of the apparatus can be further reduced. Thus, by attenuating the unnecessary frequency level in the range of 40 to 80 dB, the unnecessary frequency component can be surely removed from the intermediate frequency signal, and only the necessary intermediate frequency signal can be extracted. .

Next, an AGC device 26 having an auto gain control function is used as a level adjusting means, and the level of the extracted intermediate frequency signals of the first to fourth channels is made constant. That is, when the intensity of the intermediate frequency signal of each channel is smaller than the set level, it is amplified, and when it is larger than the set level, it is attenuated. Further, the up-converter 27 as the second frequency changing means changes the level-adjusted intermediate frequency signals of the first to fourth channels to the frequency for optical transmission having the same frequency as the broadcast wave for each channel. When the frequency of the broadcast wave is the above-described specific example, the optical transmission frequencies are 1241 MHz for the first channel, 1252 MHz for the second channel, 1259 MHz for the third channel, and 1270 MHz for the fourth channel. Next, the first to fourth channel optical transmission frequency signals, which have been changed to the optical transmission frequency by the combiner 28, are combined as first combining means. The synthesized signal is sent to the E / O converter 9 and converted into an optical signal.

  As described above, in the optical repeater system of the present embodiment, unnecessary frequency components can be reliably removed from the intermediate frequency signal, so that the DU ratio of the broadcast wave can be increased and the demodulator unit can be used during live broadcasting. Generation of distortion of a received signal can be prevented, and clear video can be broadcast at a broadcasting station. Further, by making the level of the intermediate frequency signal of each channel constant, a signal having no level variation for each channel can be transmitted to the demodulation unit.

  In this embodiment, the number of broadcast wave channels received by the relay station is four, but the number of channels may be larger. In this case, a distributor that distributes to the same number of channels as the number of channels is used instead of the distributor 23, and a down converter, a bandpass filter, an AGC device, and an up converter are arranged in each transmission path. For example, when the broadcast wave is composed of the first to eighth channels, the received signal is distributed to eight transmission lines by a distributor, and eight down converters, eight band pass filters, eight AGC devices, and eight up converters are provided. Installed.

  FIG. 7 is a block diagram of a relay station used in the optical repeater system according to the third embodiment. As shown in FIG. 7, the relay station 61 of this embodiment includes two receiving antennas 62 and 63 having different receivable frequency bands. The receiving antenna 62 is an antenna that receives a broadcast wave having a frequency of 1.2 GHz. The receiving antenna 63 is an antenna that receives a broadcast wave having a frequency of 2.3 GHz. In addition, a reception circuit 64 corresponding to a broadcast wave with a frequency of 1.2 GHz band and a reception circuit 65 corresponding to a broadcast wave with a frequency of 2.3 GHz band are provided, and a signal processing circuit 66 for performing signal processing with these reception circuits. The signal switcher 67 which switches between is provided.

  Except for the above, the overall basic configuration of the optical repeater system of this embodiment is the same as that of the second embodiment. However, in the optical repeater system of the present embodiment, the signal from the two channels consisting of the first and second channels frequency-multiplexed in the 1.2 GHz band and the third and fourth channels frequency-multiplexed in the 2.3 GHz band. A broadcast wave having a two-channel signal is used. An example of the center frequencies of the broadcast waves of the first to fourth channels is 1252 MHz for the first channel, 1270 MHz for the second channel, 2341 MHz for the third channel, and 2359 MHz for the fourth channel. In the optical relay system of the present embodiment, whether to receive and relay the first and second channel signals or to receive and relay the third and fourth channel signals according to the purpose of the relay broadcast. The signal switcher 67 connects the signal of the channel to be processed to the signal processing circuit 66.

  As shown in FIG. 7, the signal processing circuit 66 of the optical repeater system of the present embodiment has the same function as the signal processing circuit 70 of the second embodiment, and the distributor 23 and the first to fourth channels respectively. Corresponding four down converters 24, four band pass filters 25, four AGC devices 26, four up converters 27, and a combiner 28 are further provided. The output from the multiplexer 28 is input to the E / O converter 29. Thereby, it is possible to increase the DU ratio of the broadcast wave by reliably removing unnecessary frequency components from the intermediate frequency signal, and to prevent the distortion of the signal received by the demodulation unit during the live broadcasting, By making the level of the intermediate frequency signal of the channel constant, there is an advantage similar to that of the second embodiment, such that a signal having no level variation for each channel can be transmitted to the demodulation unit.

  When the signal processing circuit includes a component having characteristics according to the frequency band to be used, such as a filter for removing extra harmonics and noise included in the high-frequency signal, the signal processing circuit 67 is synchronized with the signal switching device 67. A switcher for switching between 1.2 GHz band parts and 2.3 GHz parts may be provided.

  FIG. 8 is a block diagram of a demodulation unit used in the optical repeater system according to the fourth embodiment. As shown in FIG. 8, the demodulation unit 80 of this embodiment is an O / E conversion means that converts an optical signal optically transmitted from the optical router 4 through the optical line 19 into an electric signal to be a received broadcast wave. The E converter 32, the distributor 33 as the second distribution means for distributing the received broadcast wave to the four transmission lines 82a to 82d, and the four transmission lines 82a to 82d to the first to fourth channel signals, respectively. Four down converters 34 as frequency third changing means for changing the received broadcast wave to the same reception intermediate frequency common to each channel lower than the frequency of the received broadcast wave for each channel corresponding to each transmission path; Broadcast wave transmission means 83 for transmitting the first to fourth channel received intermediate frequency signals to the FPU receiver 100 is provided. Except for the above, the overall basic configuration of the optical repeater system of this embodiment is the same as that of the second embodiment. Here, the broadcast wave transmission means 83 is a coaxial cable which is a signal transmission path.

  FIG. 9 is a block diagram of a signal processing circuit of a relay station used in the optical repeater system according to the fifth embodiment, and FIG. 10 is a block diagram of a demodulation unit. In this embodiment, as shown in FIG. 9, the signal processing circuit 71 of each relay station is one of the intermediate frequency signals of the first to fourth channels extracted by the four band pass filters 25 which are necessary frequency extracting means. Four couplers 39 which are signal separating means for separating the respective parts, four log amplifiers 40 for inputting the output values of the separated signals and changing them into logarithmic functions, and their logarithmic functions. And a microcomputer 41 having signal level detecting means for detecting the signal level of the detected signal.

  The microcomputer 41 has four A / D conversion devices 42 as A / D conversion means for converting the detected signal levels of the first to fourth channels from analog signals to digital signals. The digital signal of the fourth channel is transmitted to the parallel / serial conversion device 50 which is a parallel / serial signal conversion means in the microcomputer 41 and is converted into one serial signal. The serial signal is transmitted to the switching circuit 44 which is a digital modulation means, and the carrier wave generated by the oscillator 43 is modulated by the serial signal to become a digital modulation signal. The digital modulation signal is transmitted to the synthesizer 45 as the second synthesizing means, and the digital modulation signal and the optical transmission frequency signals of the first to fourth channels are synthesized to form a level synthesized signal. The level composite signal is transmitted to the E / O conversion device 29 and becomes an optical signal.

  As shown in FIG. 10, in the demodulation unit 85, the optical signal input from the optical router 4 is converted into the original level composite signal by the O / E converter 32. A distributor 86 is provided as level signal separation means for separating and extracting the digital modulation signal from the level composite signal. The separated digital modulation signal is demodulated into the original serial signal by the demodulator 89 and input to the microcomputer 52. In the microcomputer 52, after being converted into digital signals of the first to fourth channels by the serial / parallel converter 53, the signals of the intermediate frequency signals of the first to fourth channels are converted by the four D / A converters 54. Convert to analog signal corresponding to level. Those analog signals are respectively input to four level gauges 21 which are level display means, and the respective signal levels are displayed. These level gauges are placed in the monitor room 17, for example, as shown in FIG.

  The first to fourth channel optical transmission frequency signals distributed to the other side by the distributor 86 are processed in the same manner as in the fourth embodiment, and the received intermediate frequency signal is input to the FPU receiver 100. In addition to the above, the basic configuration of the entire optical repeater system of this embodiment is the same as that of the fourth embodiment.

In the optical relay system of this embodiment, the operator who operates the demodulation unit 85 can select the signal from the relay station by looking at the received signal level displayed on the level gauge 21. In this way, it is possible to know the level of the broadcast wave for each channel from each mobile station received at each relay station, and to select a good level broadcast wave and input the broadcast wave to the FPU receiver. Therefore, it is possible to broadcast an image with good and clear image quality in broadcast relay. Also, after switching the optical router, all the optical signals from each relay station are received by the demodulation unit and their signal levels are confirmed, and the optical router is controlled based on the result, and the optimum for each mobile station The optical signal may be selected, and thereafter, only the optimum optical signal may be controlled to be received by the demodulation unit.
For example, the staff of the television broadcasting room 16 in FIG. 5 visually recognizes the monitors 20a to 20p in the monitor room 17, and checks the signal level of each signal with the level gauges 21a to 21p, and switches the signal with the optical router. Thus, a relay station can be selected and a broadcast wave from a predetermined mobile station can be obtained. As a result, a signal having good image quality and video can be selected, and the selected video can be provided to each recipient.

  Further, there may be provided means for controlling the optical router so as to automatically select and output an optical signal having a good signal level depending on the signal level displayed by the level display means. For example, a signal level comparison means is provided in the demodulation unit, the optical router is switched according to an instruction from the operator, and once the optical signal from each relay station is received by the demodulation unit, the signal level is used as the comparison means. The optical router may be automatically controlled so as to select a signal from the relay station having the highest received signal level based on the comparison result. This control may be performed automatically at arbitrary time intervals or at scheduled times.

FIG. 11 is a block diagram of an optical repeater system according to the sixth embodiment. The optical repeater system 90 of this embodiment includes a plurality of mobile stations 91 used for live broadcasting, and a plurality of relays installed around the mobile route of those mobile stations and receiving broadcast waves transmitted from the mobile stations. A station 93 and a demodulation unit 94 that receives a signal transmitted from the relay station 93 are provided. The mobile station 91 has two transmission antennas 5a and 5b for transmitting signals in the same frequency band, and the relay station 93 has two transmission antennas 5a and 5b for receiving signals from the transmission antennas 5a and 5b. By having the receiving antennas 6a and 6b, the mobile station 91 and the relay station 93 perform signal transmission using a MIMO (Multiple Input Multiple Output) technique. The relay station 93 receives broadcast waves from the respective mobile stations by the receiving circuits 7a and 7b corresponding to the receiving antennas 5a and 5b, respectively, and performs signal processing by the signal processing circuits 8a and 8b, respectively. E / O converters 9a and 9b, which are / O conversion means, convert optical signals having different wavelengths for the receiving antennas 5a and 5b, and combine these optical signals by a multiplexer 60 which is a wavelength synthesis means. The optical signal is wavelength-multiplexed. The wavelength-multiplexed optical signal is transmitted to the demodulation unit 94 via the optical router 4 through the optical line 19 made of an optical fiber cable.

Here, the number of transmitting antennas of each mobile station and the number of receiving antennas of each relay station used for the MIMO technology may be three or more in order to obtain a larger communication capacity. The contents of signal processing in the signal processing circuits 8a and 8b of each relay station are the same as those of the signal processing circuit 8 of the second embodiment.
In this embodiment, the relay station 93 does not perform the MIMO signal separation process, but performs signal processing on each signal received by the reception antennas 6a and 6b of the relay station 93 to the demodulation unit 94. After that, the optical signals having different wavelengths are transmitted. The demodulating unit 94 demultiplexes the received wavelength-multiplexed optical signal and then O / E converts each wavelength to obtain a signal for each original receiving antenna. That is, the signal for each receiving antenna including the spatial separation information of the MIMO signal is transmitted as it is, and the MIMO signal separation processing is performed after the demodulation unit.

  FIG. 12 is a block diagram of a relay station used in the optical multiplexing relay system according to the seventh embodiment. As shown in FIG. 12, the relay station 69 of this embodiment includes two receiving antenna groups 72 and 73 having different receivable frequency bands. The reception antenna group 72 is an antenna group that receives a broadcast wave having a frequency of 1.2 GHz, and includes reception antennas 62a and 62b. The receiving antenna group 73 is an antenna group that receives a broadcast wave having a frequency of 2.3 GHz, and includes receiving antennas 63a and 63b. Here, the receiving antennas 62a and 62b and the receiving antennas 63a and 63b are two receiving antennas having the same receivable frequency band necessary for the MIMO technology. In addition, a reception circuit 64 corresponding to a broadcast wave with a frequency of 1.2 GHz band and a reception circuit 65 corresponding to a broadcast wave with a frequency of 2.3 GHz band are provided, and a signal processing circuit 66 for performing signal processing with these reception circuits. Switchers 67a and 67b that switch between the two.

  Except for the above, the overall basic configuration of the optical repeater system of this embodiment is the same as that of the sixth embodiment. However, in the optical repeater system of the present embodiment, the signal from the two channels consisting of the first and second channels frequency-multiplexed in the 1.2 GHz band and the third and fourth channels frequency-multiplexed in the 2.3 GHz band. A broadcast wave having a two-channel signal is used. An example of the center frequencies of the broadcast waves of the first to fourth channels is 1252 MHz for the first channel, 1270 MHz for the second channel, 2341 MHz for the third channel, and 2359 MHz for the fourth channel. In the optical multiplexing type relay system of the present embodiment, the first and second channel signals are received and relayed or the third and fourth channel signals are received and relayed depending on the purpose of the relay broadcast. The signal of the channel to be processed by the signal switchers 67a and 67b is connected to the signal processing circuit 66. The signal switchers 67a and 67b operate in synchronization.

  As shown in FIG. 12, the signal processing circuit 66 of the optical repeater system according to the present embodiment has the same function as the signal processing circuit 70 according to the second embodiment, and each of the distributor 23 and the first to fourth channels. Corresponding four down converters 24, four band pass filters 25, four AGC devices 26, four up converters 27, and a combiner 28 are further provided. The output from the multiplexer 28 is input to the E / O converter 29.

  In each embodiment, a band pass filter that allows only the frequency component of each signal to pass may be inserted in the transmission path of each signal.

4, 4a Optical router 5, 5a, 5b Transmitting antenna 6, 6a, 6b, 62, 62a, 62b, 63, 63a, 63b Receiving antenna 7, 7a, 7b, 64, 65 Receiving circuit 8, 8a, 8b, 66, 70, 71 Signal processing circuit 9, 9a, 9b, 29 E / O converter 10, 90 Optical repeater system 11, 91 Mobile station 11A, 11B Mobile repeater 12 Marathon course 13, 61, 69, 93 Relay station 14, 80 , 85, 94 Demodulation unit 15 Athletic field 16 Television broadcast room 17 Monitor room 18 Marathon runner 19 Optical line 20a-20p Monitor 21, 21a-21p Level gauge 23, 33, 86 Distributor 24, 34 Down converter 25 Band pass Filter 26 AGC device 27 Up converter 28, 45 Synthesizer 30a 30d, 82a to 82d Transmission path 32 O / E converter 35 Optical amplifier 36 1 × 3 optical distributor 37 8 × 1 optical switch 39 Coupler 40 Log amplifier 41, 52 Microcomputer 42 A / D converter 43 Oscillator 44 Switching Circuit 54 D / A converter 50 Parallel / serial converter 53 Serial / parallel converter 60 Multiplexer 72, 73 Reception antenna group 67, 67a, 67b Signal switch 83 Broadcast wave transmission means 89 Demodulator 100 FPU receiver

Claims (7)

Multiple mobile stations used for live broadcasting, multiple relay stations installed around the mobile route of those mobile stations and receiving broadcast waves transmitted from each mobile station, and transmitted from those relay stations A demodulating unit for receiving a signal, and the relay station performs signal processing on the broadcast wave received from the mobile station, converts the signal into an optical signal, and converts the optical signal to the optical signal via an optical line. In an optical repeater system that transmits to a demodulation unit,
When the number of mobile stations is M and the number of relay stations is N (where N, M is an integer equal to or greater than 2 and N ≧ M), the optical signals from the N relay stations are An optical router for selecting and outputting M optical signals each including a signal corresponding to a broadcast wave from each of the M mobile stations is provided, and an output of the optical router is transmitted to the demodulation unit. An optical repeater system ,
The broadcast wave has first to n-th channel signals (where n is an integer equal to or greater than 2) frequency-multiplexed, and the signal processing includes first to n-th broadcast waves transmitted from the mobile station. First distribution means for distributing the first to nth transmission paths, the first to nth transmission paths corresponding to the first to nth channel signals, and the broadcast wave for each channel corresponding to each transmission path. Frequency first changing means for changing to the same intermediate frequency common to each channel lower than the frequency of the broadcast wave, and necessary frequency components by attenuating unnecessary frequency components from each of the intermediate frequency signals of the first to nth channels Required frequency extracting means for extracting the level, level adjusting means for making the level of the extracted intermediate frequency signals of the first to nth channels constant, and the level adjusted intermediate frequency signals of the first to nth channels. Above Frequency second changing means for changing to the optical transmission frequency having the same frequency as the transmission, and first combining means for combining the first to n-th channel optical transmission frequency signals changed to the optical transmission frequency. An optical repeater system comprising: The relay station switches between a plurality of receiving antennas having different receivable frequency bands, a plurality of receiving circuits corresponding to the respective frequency bands, and the receiving circuits and an electric circuit for performing the signal processing. The optical repeater system according to claim 1 , further comprising a signal switch. The demodulating unit converts the optical signal transmitted from the optical router into an electrical signal to generate a received broadcast wave, and an O / E converter for distributing the received broadcast wave to the first to nth transmission lines. 2 distribution means and the first to n-th transmission paths correspond to the signals of the first to n-th channels, respectively, and the received broadcast wave is determined from the frequency of the received broadcast wave for each channel corresponding to each transmission path. A third frequency changing means for changing the frequency to the same reception intermediate frequency common to each lower channel, and a broadcast wave transmission means for sending the reception intermediate frequency signals of the first to n-th channels to the broadcast receiver for relay. The optical repeater system according to claim 1 or 2 , characterized by the above. The relay station separates a part of the intermediate frequency signals of the first to n-th channels extracted by the necessary frequency extracting unit, and a signal level detection for detecting the separated signal levels. Means, A / D conversion means for converting the detected first to n-th channel signal levels from analog signals to digital signals, and the converted first to n-th channel digital signals to one serial signal Parallel / serial signal conversion means, digital modulation means for modulating a carrier wave using the serial signal to make a digital modulation signal, and synthesizing the digital modulation signal and the optical transmission frequency signal to make a level synthesis signal Second combining means; and E / O converting means for converting the level combined signal into the optical signal ,
The demodulating unit converts the optical signal into the level composite signal by the O / E converter, and separates and extracts the digital modulation signal from the level composite signal, and based on the digital modulation signal 4. The optical repeater system according to claim 3 , further comprising level display means for displaying a signal level of the intermediate frequency signal of the first to n-th channels. 5. The optical repeater system according to claim 4 , wherein the optical router has means for selecting the M optical signals depending on the signal level displayed by the level display means. The mobile station has a plurality of transmission antennas for transmitting signals in the same frequency band, and the relay station has a plurality of reception antennas for receiving signals from the plurality of transmission antennas. The station and the relay station perform signal transmission using MIMO (Multiple Input Multiple Output) technology,
The relay station, after performing the signal processing on the broadcast wave, converts the optical signal into an optical signal having a different wavelength for each of the receiving antennas, and multiplexes these optical signals for wavelength multiplexing. 2. The optical repeater system according to claim 1 , further comprising: a wavelength synthesizing unit configured as an optical signal, and transmitting the wavelength-multiplexed optical signal to the demodulation unit via the optical router. The relay station includes a plurality of receiving antenna groups having different receivable frequency bands (here, a plurality of receiving antennas having the same receivable frequency band necessary for the MIMO technology are grouped) and respective frequencies. The optical repeater system according to claim 6 , further comprising: a plurality of receiving circuits corresponding to bands, and a signal switching unit that switches between the receiving circuits and an electric circuit for performing the signal processing.

Images