JP2001308765A - Gap filler system for tunnel, and device for reception and device for transmission used in the gap filler system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gap filler system for a tunnel having a high fail safe characteristic and capable of easily performing sufficient electric power supply to each device for transmission placed in the tunnel. SOLUTION: The gap filler system for making a receiving terminal in the tunnel receive a broadcast signal from a satellite is provided with a main control unit 8 to receive the broadcast signal from the satellite with a reception antenna 6, and a plurality of slave units 12 for transmission placed at different positions in the tunnel and connected one on one with the main control unit 8 through optical fibers 14d. Besides, the main control unit 8 transforms the signal received from the satellite into an optical signal to output to each optical fiber 14d, then each slave unit 12 for transmission generates a relay broadcast signal Sc from the optical signal transmitted through the optical fiber 14d receivable at the receiving terminal to send the signal Sc by wireless in the tunnel from a transmitting antenna 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gap filler system used for a satellite broadcasting system,
The present invention relates to a tunnel gap filler system for enabling a receiving terminal to acquire information from a satellite even in a tunnel.

[0002]

2. Description of the Related Art In recent years, construction of satellite broadcasting systems using satellites (specifically, artificial satellites such as broadcasting satellites and communication satellites) has been promoted.
A broadcast signal (radio wave) transmitted from a terrestrial broadcast station to a satellite is relayed by the satellite (more specifically, a repeater provided on the satellite) and transmitted to a terrestrial service area. According to such a satellite broadcasting system, it is possible to provide information to each receiving terminal existing in a wide range of service area without maintaining a large infrastructure on the ground.

However, radio waves used in a satellite broadcasting system have a very high frequency, for example, S band (2.6 to 4 GHz). Therefore, the radio waves travel straight and fly far, but if there are obstacles, It has the property of being reflected immediately. Therefore, in particular, when the receiving terminal is a mobile receiving terminal (a receiving terminal as a portable or vehicle-mounted mobile station), the receiving terminal is located in a tunnel or a building behind where direct waves from satellites do not reach. If it does, broadcast information cannot be obtained.

Accordingly, for example, Japanese Patent Application Laid-Open No. Hei 10-308695
As disclosed in Japanese Unexamined Patent Publication, a broadcast signal from a satellite is received, and a radio signal (relay broadcast signal) having the same content as the received broadcast signal and a frequency receivable by a receiving terminal is provided.
Is transmitted to a non-receivable area where a broadcast signal from a satellite cannot be directly received in a service area, and a device for a gap filler is provided on the roof of a high-rise building or the like.

[0005] By adding such a gap filler device as a terrestrial relay device as a component of the satellite broadcasting system, information can be reliably provided to receiving terminals located in various places on the ground. Become like The above publication discloses that: a gap filler device receives an S-band broadcast signal transmitted from a satellite, and wirelessly transmits a signal of the same frequency as the received broadcast signal to the non-receivable area; : A satellite transmits a broadcast signal transmitted from a terrestrial broadcast station to a first broadcast signal of S band and a Ku band (12 to 1) having a higher frequency than the first broadcast signal.
8 GHz) or the second in the Ka band (27-40 GHz)
And converts the two broadcast signals to a terrestrial service area. The gap filler device transmits the first broadcast signal and the second broadcast signal transmitted from the satellite to the higher frequency. While receiving the second broadcast signal,
It describes that the received second broadcast signal is frequency-converted into an S-band signal having the same frequency as the first broadcast signal, and the frequency-converted signal is wirelessly transmitted to the unreceivable area.

[0006] If the above method is adopted, the frequency of the second broadcast signal received from the satellite and the frequency of the relay broadcast signal transmitted by the present device are different in the gap filler device. Owing to this, the gap filler device can reliably prevent the oscillation caused by sneaking into the broadcast signal. A signal (in this example, an S-band signal) is wirelessly transmitted to the unreceivable area.

[0007]

By the way, in order to make a receiving terminal in a tunnel receive a broadcast signal from a satellite,
When a system for the above-mentioned gap filler is installed in a tunnel, such a gap filler system for a tunnel (a tunnel installation type gap filler device)
Receiving device as means for receiving broadcast signals from satellites provided outside the tunnel (in other words, receiving point facilities)
And a transmission device (in other words, a transmission point facility) provided as a means for wirelessly transmitting a relay broadcast signal provided in a tunnel, and the reception device and the transmission device are provided with a predetermined signal. They will be connected via a transmission path.

In the case of a long tunnel of, for example, 3 km or more, a single transmitting device cannot transmit radio waves to all necessary areas in the tunnel.
A plurality of transmitting devices are provided at equal intervals in the tunnel, for example. Here, as a specific configuration of such a gap filler system for a tunnel, for example, FIG.
As shown in FIG.
Are connected in a daisy chain by a coaxial cable 106, one end of the coaxial cable 106 is connected to a receiving device 102 for receiving a broadcast signal from a satellite 108 outside the tunnel 100, and further, each transmitting device 104 ,
From the high-frequency signal transmitted from the receiving apparatus 102 side via the coaxial cable 106, a relay broadcast signal to be wirelessly transmitted is generated and transmitted into the tunnel 100, and the high-frequency signal transmitted via the coaxial cable 106 is generated. It is conceivable to configure so as to play a role as a relay amplifier that amplifies a signal and outputs the amplified signal to the transmission device 104 at the subsequent stage.

However, in the gap filler system for tunnels shown in FIG. 5, since the signal transmission loss in the coaxial cable 106 is relatively large, the amplification gain in each transmitting device 104 must be set large. The power consumption of each transmitting device 104 increases. And generally, inside the tunnel, compared to outside the tunnel,
Since the total amount of power that can be supplied to each device is small, it becomes difficult to supply sufficient power to each transmitting device 104 in the tunnel.

Further, in the tunnel gap filler system shown in FIG. 5, the coaxial cable 106 serving as a signal transmission line may be cut at any position or may be disconnected from the coaxial cable 106 in any of the transmitting devices 104. If a contact failure occurs in the connection portion, the signal from the receiving device 102 will not be transmitted to the transmitting device 104 downstream of such an abnormal location, and the overall function of the gap filler system will be greatly impaired. Will be lost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has a high fail-safe property and easily supplies a sufficient power to transmission means (transmission apparatuses) disposed in a tunnel. The purpose of the present invention is to provide a gap filler system for tunnels.

[0012]

According to the first aspect of the present invention, there is provided a tunnel gap filler system which relays a broadcast signal transmitted by a terrestrial broadcast station by a satellite to a terrestrial broadcast station. In a satellite broadcasting system for broadcasting to a service area, a satellite broadcast signal is used to cause a receiving terminal in a tunnel to receive a broadcast signal from the satellite. As in the case of the above-described conventional system, the system includes a receiving means for receiving a broadcast signal from a satellite, and a plurality of transmitting means arranged at different positions in the tunnel.

In this case, in particular, in the gap filler system for a tunnel according to the first aspect, each transmitting means is connected one-to-one to the receiving means via an optical fiber for transmitting an optical signal. Then, the receiving means converts the signal received from the satellite into an optical signal and outputs it to each optical fiber connected to each of the transmitting means, and each transmitting means transmits the optical fiber from the receiving means side. From the optical signal transmitted through the, to generate a relay broadcast signal of a frequency that can be received by the receiving terminal,
The relay broadcast signal is wirelessly transmitted into the tunnel.

According to the gap filler system for a tunnel of the first aspect, the following effects (1) to (3) can be obtained. (1): Even if the optical fiber connecting the receiving means and any of the transmitting means is cut or a contact failure occurs at any of the transmitting means with the optical fiber, a plurality of transmitting means are provided. Only one of them becomes unable to wirelessly transmit the relay broadcast signal, and the other transmitting means can operate normally, so that a high fail-safe property is obtained.

(2): Each transmitting means does not need to play a role as a relay amplifier as in the conventional system, and the optical fiber has a lower signal transmission loss than other signal transmission paths such as a coaxial cable. Is very small, the power consumption of each transmitting means can be reduced, and as a result, it becomes easy to supply sufficient power to each transmitting means. Specifically, the power line for supplying power to each transmitting means in the tunnel can be thinned, and a power supply device having a small power output capacity is used as a power supply device for outputting power to the power line. Will be able to do it. For this reason, installation work of this gap filler system becomes easy.

(3) The existing optical fiber (optical fiber provided when the tunnel was created) can be used in the tunnel, and it is not necessary to separately provide a signal transmission path. The receiving means converts the broadcast signal received from the satellite into an optical signal as it is, or converts the broadcast signal received from the satellite into a signal in another frequency band, and converts the frequency-converted signal into an optical signal. It can be configured to convert to a signal. Further, for example, a broadcast signal received from a satellite may be demodulated, and the demodulated signal may be converted into an optical signal. Then, the configuration for generating the relay broadcast signal in each transmitting means may be appropriately set according to the form of the signal output from the receiving means.

In order to convert an electric signal into an optical signal (E / O conversion), an E / O converter is used. In general, an E / O converter converts the electric signal into an optical signal. There is an upper limit on the frequency of possible electrical signals. For this reason, the signal to be converted into an optical signal by the receiving means must be a signal in a frequency band lower than the highest frequency of the electric signal that can be E / O converted by the E / O converter used in the receiving means. There is.

Therefore, based on this fact, the tunnel gap filler system according to claim 1 can be configured, for example, as described in claim 2. That is, claim 2
In the gap filler system for a tunnel described in above, the receiving means receives the broadcast signal from the satellite and the E / O conversion means for converting the electric signal into the optical signal, and converts the received broadcast signal into the E / O conversion. Means for converting the frequency into a transmission signal in a predetermined frequency band lower than the highest frequency of the electrical signal convertible into the optical signal and outputting the signal; and transmitting the transmission signal output from the reception conversion means to E Signal supply means for causing the I / O conversion means to convert the optical signal into an optical signal; and output means for outputting the optical signal converted by the E / O conversion means to each optical fiber connected to each of the transmission means. I have.

Each transmitting means includes an O / E converting means for converting an optical signal transmitted from the receiving means via the optical fiber into an electric signal (O / E conversion); A transmitting-side frequency converter for extracting the transmission signal from the electric signal converted by the E converter, converting the extracted transmission signal into a relay broadcast signal having a frequency receivable by the receiving terminal, and transmitting the transmission signal; Transmitting means for wirelessly transmitting the relay broadcast signal frequency-converted by the side frequency converting means into the tunnel.

That is, in the gap filler system for a tunnel according to the second aspect, the receiving means converts the broadcast signal from the satellite to a predetermined frequency lower than the highest frequency of the electric signal which can be converted by the E / O converter. The frequency is converted into a transmission signal in a frequency band, and the transmission signal is converted into an optical signal by an E / O conversion means and transmitted to each transmission means. In each transmitting means, the optical signal transmitted from the receiving means via the optical fiber is converted into an electric signal by the O / E conversion means, and a transmission signal is extracted from the electric signal. The frequency of the broadcast signal is converted into a relay broadcast signal, and the broadcast signal is wirelessly transmitted into the tunnel.

According to the tunnel gap filler system of the second aspect, the signal received from the satellite by the receiving means can be reliably transmitted to each transmitting means in the tunnel in the form of an optical signal. . And the above (1)-
The effect of (3) can be reliably obtained.

Next, in the gap filler system for a tunnel according to the third aspect, in the gap filler system according to the second aspect, the receiving means mixes the transmission signal with the transmission signal to thereby transmit the transmission signal to the relay broadcast. There is provided a signal generation means capable of frequency conversion into a signal and generating a frequency conversion signal having a constant frequency lower than the maximum frequency. The signal supply means superimposes the frequency conversion signal generated by the signal generation means on the transmission signal, and causes the E / O conversion means to convert the superimposed signal into an optical signal. It is configured.

Further, the transmission-side frequency conversion means of each of the transmission means extracts the transmission signal and the frequency conversion signal from the electric signal converted by the O / E conversion means, and extracts the transmission signal and the frequency conversion signal. By mixing the transmission signal thus obtained and the frequency conversion signal, the extracted transmission signal is frequency-converted into a relay broadcast signal.

According to the third aspect of the present invention, the power consumption of each transmitting means can be reduced, and as a result, sufficient power can be supplied to each transmitting means. It becomes even easier. Further, the size of the internal circuit of each transmitting means can be reduced.

That is, in order for each transmitting means to frequency-convert a transmission signal obtained from the receiving means into a relay broadcast signal, generally, each transmitting means is controlled to have a constant oscillation frequency by a PLL circuit. It is conceivable to provide a local oscillation circuit, and mix the output of the local oscillation circuit and the transmission signal obtained from the receiving means by a mixer. However, with such a configuration, a PLL circuit and a local oscillation circuit must be provided for each of the transmitting means, and power consumption is increased by providing such circuits.

On the other hand, in the gap filler system for a tunnel according to the third aspect, a frequency conversion signal for frequency-converting a transmission signal into a relay broadcast signal is supplied from the reception means to each transmission means. Therefore, the power consumption of each transmitting means can be further reduced, and the internal circuit of each transmitting means can be downsized.

Next, in the gap filler system for a tunnel according to a fourth aspect, in the gap filler system according to the first to third aspects, each transmission means generates monitor information indicating its own state and monitors the monitor information. The information, the optical fiber for receiving an optical signal from the receiving means, or an optical fiber separate from the optical fiber and provided in advance for transmitting a signal from the transmitting means to the receiving means. It is configured to transmit to the receiving means via the signal optical fiber. And the receiving means,
It is configured to receive monitor information from each transmitting means and perform processing for monitoring the state of each transmitting means.

The state of the transmitting means includes the operating state of each part of the transmitting means and an environmental state such as the temperature inside or around the transmitting means. As a process for monitoring the state of each transmitting means, the monitor information transmitted from each transmitting means or information obtained by analyzing the monitor information is stored in a central location provided on the ground. For example, processing such as transmission to a monitoring center may be considered. At this time, information indicating the operation state of each unit of the receiving means may be transmitted to the monitoring center.

According to the gap filler system for a tunnel of the fourth aspect, it is possible to detect an abnormality occurring in each transmission means in the tunnel at an early stage, so that a higher fail-safe property is obtained. Can be next,
A receiving device according to a fifth aspect is used as a receiving means in the gap filler system for a tunnel according to the first aspect, and converts an electric signal into an optical signal.
O-converting means and a broadcast signal received from a satellite, and converting the received broadcast signal into a transmission signal in a predetermined frequency band lower than the highest frequency of an electric signal which can be converted into an optical signal by the E / O converting means. Receiving conversion means for frequency-converting and outputting, and the transmission signal can be frequency-converted into a relay broadcast signal of a frequency receivable by a receiving terminal by mixing with the transmission signal, and the highest frequency Signal generating means for generating a signal for frequency conversion of a lower constant frequency,
The frequency conversion signal generated by the signal generation means is superimposed on the transmission signal output from the reception conversion means,
A signal supply unit that causes the E / O conversion unit to convert the superimposed signal into an optical signal, and outputs the optical signal converted by the E / O conversion unit to each optical fiber connected to the device. And output means.

According to this receiving apparatus, it is possible to constitute the tunnel gap filler system according to claim 3 described above, and each transmitting means connected to the apparatus via an optical fiber performs O / E conversion. From the electrical signal converted by the means, to extract the signal for transmission and the signal for frequency conversion,
By simply mixing the extracted transmission signal and frequency conversion signal, the transmission signal can be frequency-converted into a relay broadcast signal to be transmitted to the receiving terminal.

Next, the transmitting device according to claim 6 is used as a transmitting means in the tunnel gap filler system according to claim 3, and is transmitted from the receiving means side via an optical fiber. O / E conversion means for converting an incoming optical signal into an electric signal, and the transmission signal and the frequency conversion signal are extracted from the electric signal converted by the O / E conversion means. By mixing the transmission signal and the frequency conversion signal, the extracted transmission signal, the transmission-side frequency conversion means for frequency conversion to a relay broadcast signal of a frequency receivable by the receiving terminal,
A transmission unit that wirelessly transmits a relay broadcast signal frequency-converted by the transmission-side frequency conversion unit into a tunnel,
It has.

According to the transmitting apparatus, the receiving apparatus according to claim 5 is used as receiving means.
The tunnel gap filler system according to claim 3 can be configured.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 is a configuration diagram illustrating a configuration of a gap filler system for a tunnel according to a first embodiment to which the present invention is applied, and FIG. 2 is a schematic diagram illustrating an installation state of the gap filler system.

The tunnel gap filler system according to the first embodiment uses a broadcast signal transmitted from a terrestrial broadcast station (not shown) to the satellite 2, and the satellite 2 uses the first S-band broadcast signal (the present broadcast signal). In the first embodiment, the center frequency is 2.6.
A 4 GHz broadcast signal) Sa and a second Ku band broadcast signal having a higher frequency (broadcast signal transmitted for gap filler, and in the first embodiment, a broadcast signal having a center frequency of 12.45 GHz) ) Sb, and in a satellite broadcasting system for transmitting both of the broadcast signals Sa and Sb to a terrestrial service area, a broadcast signal from the satellite 2 is received by a receiving terminal in the tunnel 4.

The gap filler system for a tunnel according to the first embodiment (hereinafter, also simply referred to as a gap filler system) transmits the first broadcast signal Sa and the second broadcast signal Sb having the same contents transmitted from the satellite 2. Of which, Ku
Receiving the second broadcast signal Sb of the band, converting the received second broadcast signal Sb into a relay broadcast signal Sc having the same frequency (2.64 GHz) as the first broadcast signal Sa, and Sc is wirelessly transmitted into the tunnel 4.

In this satellite broadcasting system, each receiving terminal located in the terrestrial service area including the inside of the tunnel 4 transmits an S band broadcast signal (ie, the first broadcast signal Sa directly transmitted from the satellite 2). , The relay broadcast signal Sc) transmitted by the gap filler device.

As shown in FIGS. 1 and 2, the gap filler system according to the first embodiment uses a satellite receiving antenna 6 installed outside the tunnel 4 to receive the second broadcast signal Sb from the satellite 2. And a plurality of transmission antennas respectively arranged at equal distances in the tunnel 4 in order to transmit the relay broadcast signal Sc into the tunnel 4 in which the first broadcast signal Sa from the satellite 2 cannot be directly received. 10 and a slave unit 12 for transmission.

Each of the transmitting slave units 12 includes a downstream signal optical fiber 14d for transmitting an optical signal from the main control unit 8 to the transmitting slave unit 12, and a main control unit from the transmitting slave unit 12. 8 for transmitting an optical signal to the optical fiber 8.
4u, they are connected to the main control device 8 one by one.

In the first embodiment, the satellite receiving antenna 6 and the main control device 8 correspond to a receiving means and a receiving device, and the transmitting antenna 10 and the transmitting handset 12 are
It corresponds to a transmitting means and a transmitting device. Here, first, the satellite receiving antenna 6 includes the reflecting mirror 16 and the reflecting mirror 1.
6 is an offset type parabolic antenna including a receiving unit 18 disposed at a focal position of No. 6.

The receiving unit 18 is a unit that functions as a so-called LNB (low noise block converter). That is, the receiving unit 18 receives the radio wave from the satellite 2 collected by the reflecting mirror 16 by a probe (not shown), and, based on the received radio wave, a second broadcast signal Sb (center frequency = 12.45 GHz). Then, the extracted second broadcast signal Sb is provided with a lower constant frequency (11.3 GH in the first embodiment).
By mixing the local oscillation signal Lo of z), the extracted second broadcast signal Sb is converted to have a center frequency of 1.15 GHz.
The frequency is converted into an intermediate frequency signal IF of z, and the intermediate frequency signal IF is output to a coaxial cable 20 connecting the receiving unit 18 and the main controller 8.

Next, the main controller 8 has a terminal 22 connected to the coaxial cable 20. In the main controller 8, the intermediate frequency signal IF from the receiver 18, which is taken in via the terminal 22, is supplied to the directional coupler 24 as a mixing circuit and a band-pass filter (hereinafter, referred to as BPF). The signal is input to an amplifier circuit 28 via an amplifier 26, amplified to a predetermined level by the amplifier circuit 28, and then input to the BPF 30. In addition, BPF26,3
0 is the intermediate frequency signal IF (center frequency = 1.15 GHz)
z) only.

The main controller 8 also includes a frequency-variable local oscillation circuit 32, an oscillation circuit 34 for outputting a reference signal Fref having a constant frequency, and a PLL circuit 36. Then, the PLL circuit 36 outputs the output signal Loh of the local oscillator 32 and the reference signal F output from the oscillator 34.
ref is divided by a dividing ratio set by the control unit 38, which will be described later, and a control signal for matching the phases of the divided signals is generated and output to the local oscillation circuit 32. As a result, the frequency of the output signal Loh of the local oscillation circuit 32 (oscillation frequency of the local oscillation circuit 32) is converted to a constant frequency for converting the intermediate frequency signal IF into a relay broadcast signal Sc (1. 49 GHz (= 2.
64 GHz-1.15 GHz)).

In the following, the output signal Loh of the local oscillation circuit 32 whose frequency is controlled to be constant in this manner is
The signal is referred to as a frequency conversion signal Loh. In this embodiment,
The reference signal Fref output from the oscillation circuit 34 is output to the coaxial cable 20 via the directional coupler 24 and the terminal 22. Then, the receiving unit 1 of the satellite receiving antenna 6
Reference numeral 8 generates a local oscillation signal Lo of 11.3 GHz using the reference signal Fref supplied from the main controller 8 in this manner.

Further, the main control unit 8 includes a communication unit 40 and a communication unit 40 for performing wireless communication between a control unit 38 mainly composed of a microcomputer and a central monitoring center provided on the ground. Antenna 42, an E / O converter 44 for converting an electric signal into an optical signal, and an optical signal transmitted from each transmitting slave unit 12 through each upstream signal optical fiber 14u. O to convert to and output
/ E converter 46.

The control unit 38 communicates with the monitoring center via the communication unit 40 and the communication antenna 42, and based on a command sent from the monitoring center,
It outputs a control signal (hereinafter, referred to as a downlink control signal) for controlling the wireless transmission output and the like of each transmitting slave unit 12.

As will be described later, each of the transmitting slave units 12
Since the optical signal transmitted from the controller to the main control device 8 is a signal obtained by converting a monitoring signal including monitor information indicating the state of the transmitting slave unit 12 into an optical signal, the O / E converter 4
Each electric signal output from 6 becomes a monitor signal including monitor information of each transmitting slave unit 12. Therefore, the control unit 38
Is, from each monitoring signal output from the O / E converter 46,
The monitor information indicating the state of each transmission slave unit 12 is extracted, and the extracted monitor information of each transmission slave unit 12 is sent to the monitoring center together with the information indicating the operation state of the main controller 8.

In this embodiment, the control section 38 sets the frequency division ratio in the PLL circuit 36. Therefore, if the program executed by the microcomputer of the control unit 38 is changed, the frequency of the frequency conversion signal Loh output from the local oscillation circuit 32 can be changed. The reference signal Fref and the output signal L of the local oscillation circuit 32 are sent from the PLL circuit 36 to the control unit 38.
The lock detection signal LK1 is output in the locked state where the phases coincide with the oh (that is, when the oscillation frequency of the local oscillation circuit 32 can be controlled to 1.49 GHz). Then, the control unit 38 controls the PLL circuit 3
If the lock detection signal LK1 is not continuously input for a predetermined time or more, it is determined that an abnormality has occurred, and information indicating the abnormality is transmitted to the communication unit 40 and the communication antenna 42.
Via the central monitoring center.

In the main controller 8, the frequency conversion signal Loh output from the local oscillation circuit 32 is
Directional coupler 5 as a mixing circuit via BPF 48
0 is input to one input terminal and the downlink control signal output from the control unit 38 is input to the other input terminal of the directional coupler 50 via the BPF 52. And
The directional coupler 50 outputs the frequency conversion signal Loh.
And a signal in which a downlink control signal is superimposed.

The frequency band of the downlink control signal is lower than the highest frequency (2.5 GHz in this embodiment) of the electric signal which can be E / O converted by the E / O converter 44 and the intermediate frequency signal IF And the frequency of the frequency conversion signal Loh. The BPF 48 generates the frequency conversion signal L
oh, and the BPF 52 allows only the downlink control signal to pass.

Further, in the main controller 8, B
The intermediate frequency signal IF output from the PF 30 is input to one input terminal of a directional coupler 54 as a mixing circuit, and the output of the directional coupler 50 is
4 is input to the other input terminal. The directional coupler 54 converts the intermediate frequency signal IF into the frequency conversion signal L.
A signal in which oh and the downstream control signal are superimposed is output, and the signal is converted by the E / O converter 44 into an optical signal.

In the main controller 8, the optical signal E / O converted by the E / O converter 44 is output to the output unit 5.
6, the signal is output to each downstream signal optical fiber 14d connected to each of the transmitting slave units 12. Further, main controller 8 includes a power supply unit 58. Then, the power supply unit 58
Converts the AC voltage supplied from the power line 60 provided outside the main control device 8 into a DC power supply voltage VD, and supplies the power supply voltage VD to each unit in the main control device 8.

The power line 60 extends into the tunnel 4 because it is also used to supply power to each of the transmitting slave units 12. Next, an O / E converter 61 that converts an optical signal transmitted from the main controller 8 via the down-signal optical fiber 14d into an electric signal and outputs the electric signal is provided to each transmitting slave unit 12.
Is provided.

Here, in each transmitting slave unit 12, O
The electric signal output from the / E converter 61 is distributed to three systems, and the BPF 6 that allows only the intermediate frequency signal IF to pass therethrough.
2 and a BPF that passes only the frequency conversion signal Loh
64 and a BPF 66 that passes only the downlink control signal. Therefore, the intermediate frequency signal IF is output from the BPF 62, and the frequency conversion signal Lo is output from the BPF 64.
h is output, and the downstream control signal is output from the BPF 66.

Then, in each transmitting slave unit 12, B
After the frequency conversion signal Loh output from the PF 64 is amplified to a predetermined level by the amplifier circuit 68, the mixer 70 outputs the intermediate frequency signal IF output from the BPF 62.
And the intermediate frequency signal IF sent from the main controller 8 in the form of an optical signal is
The frequency is converted to a relay broadcast signal Sc (center frequency = 2.64 GHz) having the same frequency as the broadcast signal Sa.

Further, in each transmitting slave unit 12, unnecessary frequency components (frequency components other than the relay broadcast signal Sc) are removed from the output of the mixer 70 by the BPF 72. After the relay broadcast signal Sc output from the BPF 72 is amplified to a predetermined level by the amplifier circuit 74, an attenuator (not shown) for signal attenuation,
The signal is supplied to the transmission antenna 10 through the BPF 76 for passing the relay broadcast signal Sc and the directional coupler 78 as a distribution circuit, and is transmitted from the transmission antenna 10 to the tunnel 4 by radio.

Each of the transmission slave units 12 includes a monitoring unit 80 mainly composed of a microcomputer, and various types of sensors such as a temperature sensor 82 and a humidity sensor for detecting an environmental state in the transmission slave unit 12. A sensor and an E / O converter 84 similar to the E / O converter 44 provided in the main controller 8
And a power supply unit 86 that converts an AC voltage supplied from the power line 60 into a DC power supply voltage VD and supplies the power supply voltage VD to each unit in the transmission slave unit 12.

The monitoring unit 80 includes a down control signal from the main control unit 8 output from the BPF 66, signals from various sensors including the temperature sensor 82, and a power supply output from the power supply unit 86. Voltage VD is input.
Further, in each of the transmission slave units 12, a part of the relay broadcast signal Sc output from the BPF 76 is branched by the directional coupler 78, and the detection circuit 8 including a diode is formed.
8 and the output of the detection circuit 88 is a signal representing the actual transmission output level from the transmission antenna 10,
The data is input to the monitoring unit 80.

The monitoring unit 80 adjusts the transmission level of the relay broadcast signal Sc wirelessly transmitted from the transmission antenna 10 by controlling, for example, the attenuation of the attenuator according to the downlink control signal from the main control device 8. I do.
Further, the monitoring unit 80 detects the temperature, humidity, and the like in the transmission slave unit 12 based on the signals from the various sensors, and based on the output of the detection circuit 88, the actual output from the transmission antenna 10 The transmission output level is detected, and the power supply voltage VD output from the power supply unit 86 is detected.
Then, the monitoring unit 80 generates a monitoring signal by digitally modulating the data of the various kinds of information (that is, the monitor information indicating the state of the transmitting slave unit 12) thus detected, and converts the monitoring signal into an E / E signal. Output to the O converter 84.

In each of the transmission slave units 12, the monitoring signal output from the monitoring unit 80 is transmitted to the E / O converter 84.
Is converted into an optical signal, and the optical signal is transmitted to the main controller 8 via the upstream signal optical fiber 14u.
As described above, the monitor signal transmitted as an optical signal from each of the transmission slave units 12 is transmitted to the main controller 8 as described above.
Is input to the control unit 38 via the O / E converter 46. Then, the monitor information included in the monitoring signal is transmitted to the main control device 8 together with information indicating the operation state of the main control device 8.
To the central monitoring center.

As described above, in the gap filler system according to the first embodiment, each of the transmission slave units 12 disposed in the tunnel 4 is provided with an independent downstream signal optical fiber 14.
It is connected one-to-one with main controller 8 via d.
Then, the main controller 8 converts the signal received by the satellite receiving antenna 6 into an optical signal, and outputs the optical signal to each downstream signal optical fiber 14 d connected to each of the transmitting slave units 12. The device 12 generates a relay broadcast signal Sc having a frequency that can be received by the receiving terminal from an optical signal transmitted from the main control device 8 via the downstream signal optical fiber 14d, and converts the relay broadcast signal Sc to Radio transmission is performed from the transmission antenna 10 into the tunnel 4.

More specifically, the satellite receiving antenna 6 and the main controller 8 control the second broadcast signal Sb received from the satellite 2
Is converted into an intermediate frequency signal IF as a transmission signal in a frequency band lower than the highest frequency of the electric signal that can be E / O converted by the E / O converter 44, and the intermediate frequency signal IF
Is converted into an optical signal by the E / O converter 44 and transmitted to each transmitting slave unit 12. Then, in each of the transmission slave units 12, the optical signal transmitted from the main control device 8 via the down signal optical fiber 14d is converted into an electric signal by the O / E converter 61, and the electric signal is converted from the electric signal. An intermediate frequency signal IF as a transmission signal is extracted, the frequency of the intermediate frequency signal IF is converted into a relay broadcast signal Sc, and the relay broadcast signal Sc is wirelessly transmitted into the tunnel 4.

Therefore, according to the gap filler system of the first embodiment, the downstream signal optical fiber 14d connecting the main controller 8 and any of the transmission slave units 12 is cut off,
Even if contact failure occurs at the connection with the downstream signal optical fiber 14d in any of the transmission slaves 12, one of the transmission slaves 12 and one of the transmission antennas 10 transmit the relay broadcast signal Sc wirelessly. Only the transmission becomes impossible, and the other transmitting slave unit 12 and the transmitting antenna 10 can operate normally, so that a high fail-safe property is obtained.

Further, according to the gap filler system of the first embodiment, each transmitting slave unit 12 does not need to play the role of a relay amplifier as in the conventional device, and the optical fiber is a coaxial cable or the like. Since the signal transmission loss is very small as compared with the other signal transmission lines, the power consumption of each transmitting slave unit 12 can be reduced, and as a result,
It becomes easy to supply sufficient electric power to each transmitting slave unit 12. That is, the power line 60 can be thinned, and a power supply device having a small power output capacity can be used as a power supply device that outputs power to the power line 60. For this reason, installation work of this gap filler system becomes easy.

In particular, in the gap filler system of the first embodiment, the local oscillation circuit 3 is
2 and a PLL circuit 36 to generate a frequency conversion signal Loh, superimpose the frequency conversion signal Loh on the intermediate frequency signal IF, convert the superimposed signal into an optical signal, and To the device 12. Then, in each of the transmission slave units 12, the O / E converter 61
BPF 62 and B
The intermediate frequency signal IF and the frequency conversion signal Loh are separated and extracted by the PF 64, and the extracted intermediate frequency signal IF and the frequency conversion signal Loh are directly extracted by the mixer 7.
By mixing at 0, the intermediate frequency signal IF is frequency-converted into a relay broadcast signal Sc.

Accordingly, the power consumption of each transmitting slave unit 12 can be further reduced, and as a result, each transmitting slave unit 12
It is easier to supply sufficient power to the power supply. Also,
The internal circuit of each transmitting slave unit 12 can be downsized. That is, the frequency conversion signal L is transmitted to each transmitting slave unit 12.
This is because there is no need to provide a PLL circuit and a local oscillation circuit for generating oh.

Further, according to the gap filler system of the first embodiment, the optical fiber provided when the tunnel 4 is formed can be used, and there is no need to separately provide a signal transmission line. Further, in the gap filler system according to the first embodiment, each of the transmission slave units 12 monitors its own state (environmental state such as temperature and humidity, and operation state such as power supply voltage VD and actual transmission output level). The supervisory signal composed of information is converted into an optical signal and transmitted to the main controller 8 via the optical fiber 14u for the upstream signal. Then, the main control device 8 receives the monitoring signal from each of the transmission slave units 12 and extracts the monitor information, and extracts the monitor information of each of the transmission slave units 12 from the main control unit 8.
The information is transmitted to the central monitoring center together with the information indicating the operation state.

For this reason, an abnormality occurring in the main controller 8 and each transmitting slave unit 12 in the tunnel 4 is detected at an early stage.
Appropriate measures can be taken promptly, and a higher fail-safe property can be obtained. In the first embodiment, the E / O converter 44 corresponds to E / O conversion means, the satellite receiving antenna 6 corresponds to reception conversion means, and the local oscillation circuit 32, the oscillation circuit 34, and the PLL circuit 36. Corresponds to a signal generating unit, the directional coupler 54 corresponds to a signal supplying unit, and the output unit 56 corresponds to an output unit. Also, O /
The E converter 61 corresponds to the O / E converter, and the BPF 62,
BPF 64, amplification circuit 68, mixer 70, and BPF 7
Reference numeral 2 corresponds to a transmission-side frequency conversion unit, and the transmission antenna 10 corresponds to a transmission unit.

On the other hand, in the first embodiment, the transmission of the monitor information (the transmission of the optical signal obtained by E / O conversion of the monitor signal) from each of the transmitting slave units 12 to the main controller 8 is performed by the downstream signal optical fiber. 14d may be used. That is, the main controller 8 and the transmitting slave unit 12 may be configured to perform bidirectional communication using the downstream signal optical fiber 14d. In this case, the upstream signal optical fiber 14u can be omitted. This also applies to other embodiments described later.

Next, a description will be given of a tunnel gap filler system according to a second embodiment. The gap filler system of the second embodiment is different from the gap filler system of the first embodiment in that the center frequency of the second broadcast signal Sb transmitted from the satellite 2 to the ground (ie, the second broadcast signal Sb)
The present invention is designed to be able to cope with a change in the channel frequency without changing the hardware configuration.
In the second embodiment, the second broadcast signal Sb from the satellite 2
Is assumed to be any one of 12.25 GHz to 12.75 GHz.

Therefore, first, in the gap filler system of the second embodiment, the receiving section 18 of the satellite receiving antenna 6 will include the second broadcast signal Sb from the radio wave received from the satellite 2. 12.25 GHz-12.
Extract the signal of all bands (all channels) of 75 GHz,
By mixing the extracted signal with a lower local oscillation signal Lo of 11.3 GHz, 0.95 GHz
An intermediate frequency signal IF of z to 1.45 GHz is output to the coaxial cable 20.

In the gap filler system of the second embodiment, a main controller 90 shown in FIG. 3 is used instead of the main controller 8 having the structure shown in FIG. still,
In FIG. 3, components having the same functions as those shown in FIG. 1 are given the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 3, the main control device 90 constituting the gap filler system of the second embodiment is the same as that shown in FIG.
As compared with the main controller 8 shown in FIG.
(D) is different. (A): The characteristic of the BPF 26 is 0.95 GHz to 1.45 GHz output from the receiving unit 18 of the satellite receiving antenna 6.
The intermediate frequency signal IF of z is set to pass.

(B): Variable frequency local oscillation circuit 91
, A PLL circuit 92, a mixer 93, and a BPF 94 are additionally provided. And the PLL circuit 92
The output signal Lo2 of the local oscillation circuit 91 and the reference signal Fref output from the oscillation circuit 34 are each frequency-divided at the frequency division ratio set by the control unit 38, and the phases of these frequency-divided signals are matched. Signal for the local oscillation circuit 91 (oscillation frequency of the local oscillation circuit 91).
fLo2 is changed to the frequency of the intermediate frequency signal IF (0.95 GHz
(z〜1.45 GHz).

The mixer 93 mixes the intermediate frequency signal IF output from the BPF 26 with the output signal Lo2 of the local oscillation circuit 91, thereby producing the intermediate frequency signal IF.
And a second intermediate frequency signal IF2 having a lower frequency
(Center frequency = 400 MHz in the second embodiment). Then, the BPF 94 extracts only the second intermediate frequency signal IF2 from the output of the mixer 93 and inputs the same to the amplifier circuit 28.

Here, the frequency division ratio in the PLL circuit 92 is determined by the frequency fLo of the output signal Lo2 of the local oscillation circuit 91.
2 is set by the control unit 38 so that the following equation 1 is obtained. In Equation 1, fSb is the actual center frequency of the second broadcast signal Sb, and fLo is the frequency (11.3 GHz) of the local oscillation signal Lo in the receiving unit 18.
FIF is the center frequency of the intermediate frequency signal IF, and fIF2 is the center frequency (400 MHz) of the second intermediate frequency signal IF2.

FLo2 = fSb−fLo−fIF2 = fIF−fIF2 (1) That is, in the main control device 90 of the second embodiment, the intermediate frequency signal I output from the receiving unit 18 of the satellite receiving antenna 6
F, a local oscillation circuit 91, a PLL circuit 92, a mixer 9
3, a signal corresponding to the second broadcast signal Sb actually transmitted from the satellite 2 is selected by the BPF 94 and
The frequency is converted to a second intermediate frequency signal IF2 of 0 MHz. Therefore, the frequency fLo2 of the output signal Lo2 of the local oscillation circuit 91 is set to 0.55
GHz to 1.05 GHz (= 0.95 to 0.4 GHz
(1.45-0.4 GHz).

Incidentally, similarly to the above-described PLL circuit 36, P
The lock detection signal LK2 is output from the LL circuit 92 to the control unit 38 when the reference signal Fref and the output signal Lo2 of the local oscillation circuit 91 are in a locked state where the phase is the same. When the lock detection signal LK2 is not continuously input for a predetermined time or more, the control unit 38 determines that an abnormality has occurred. When the abnormality is determined, information indicating the abnormality is sent to the central monitoring center via the communication unit 40 and the communication antenna 42.

(C): Further, in the main controller 90 of the second embodiment, the characteristics of the BPF 30 are set so as to pass the second intermediate frequency signal IF2. Therefore, the second intermediate frequency signal I output from the BPF 94
F2 is input to the E / O converter 44 via the amplifier circuit 28, the BPF 30, and the directional coupler 54. And
The second intermediate frequency signal IF2 is converted into an optical signal by the E / O converter 44 as a signal for transmission to each transmitting slave unit 12, and is output to each downstream signal optical fiber 14d. .

(D): The frequency division ratio in the PLL circuit 36 is determined by the output signal of the local oscillation circuit 32 (frequency conversion signal).
1. The frequency of Loh can be frequency-converted by each transmitting slave unit 12 from the second intermediate frequency signal IF2 to the relay broadcast signal Sc.
It is set to be 24 GHz (= 2.64 GHz-400 MHz). Further, the characteristic of the BPF 48 is set so as to pass only the frequency conversion signal Loh of 2.24 GHz.

Therefore, in the second embodiment, this 2.2
The frequency conversion signal Loh of 4 GHz is transmitted to the directional coupler 5.
4, the second intermediate frequency signal IF2 as a transmission signal
And is supplied to each transmitting slave unit 12 in the form of an optical signal. On the other hand, in the gap filler system of the second embodiment, due to the differences (a) to (d), each of the transmission slave units 12 has the following (E) and (f) are different.

(E): The characteristics of the BPF 62 are set so that only the second intermediate frequency signal IF2 sent from the main controller 90 via the downstream signal optical fiber 14d is passed. (F): The characteristic of the BPF 64 is 2.24 sent from the main controller 90 via the downstream signal optical fiber 14d.
It is set to pass only the GHz frequency conversion signal Loh.

In the second embodiment as well, in each transmitting slave unit 12, after the frequency conversion signal Loh output from the BPF 64 is amplified to a predetermined level by the amplifier circuit 68, the mixer 70 The second intermediate frequency signal IF2, which is mixed with the second intermediate frequency signal IF2 output from the BPF 62, is transmitted from the main controller 8 in the form of an optical signal to the first broadcast signal Sa from the satellite 2. Is converted to a relay broadcast signal Sc (center frequency = 2.64 GHz) having the same frequency as the above.

On the other hand, in the second embodiment, the satellite receiving antenna 6, the oscillation circuit 34, the local oscillation circuit 91, the PLL circuit 92, the mixer 93, and the BPF 94 correspond to the reception conversion means. According to the tunnel gap filler system of the second embodiment as described above, the same effect as that of the gap filler system of the first embodiment can be obtained, and the program executed by the control unit 38 of the main controller 90 can be executed. Only by changing the frequency division ratio (and hence the oscillation frequency of the local oscillation circuit 91) in the PLL circuit 92,
It is possible to cope with a change in the channel frequency of the second broadcast signal Sb transmitted from the satellite 2.

That is, the main control unit 90 of the second embodiment is
The local oscillation circuit 9 determines the channel frequency of the second broadcast signal Sb to be received from the satellite 2 and transmitted to each of the transmission slave units 12.
1, a tuning circuit including a PLL circuit 92, a mixer 93, and a BPF 94 is configured to select a channel.
The channel frequency tuned by the tuning means is
This is because it can be arbitrarily set only by changing the program executed by the microcomputer of the control unit 38.

Incidentally, the main controller 9 of the second embodiment is described.
0, the oscillation frequency fLo of the local oscillation circuit 91 for channel selection.
2 is set lower than the frequency of the intermediate frequency signal IF input to the mixer 93. In this case, the oscillation frequency fLo
2 is assumed to be the expected variation in the frequency of the second broadcast signal Sb (500 MHz (= 12.75 GHz−12.25 G in the above example).
Hz), a high-performance local oscillation circuit 91 is required. This is the oscillation frequency fLo2
To 0.55 GHz to 1.05 GHz,
This is because the change must be made approximately twice, and the ratio of the change amount to the oscillation frequency fLo2 becomes large.

Next, a description will be given of a tunnel gap filler system according to a third embodiment capable of avoiding this problem. First, the gap filler system of the third embodiment differs from the gap filler system of the second embodiment in that a main controller 95 shown in FIG. 4 is used instead of the main controller 90 shown in FIG. I have. still,
In FIG. 4, components having the same functions as those shown in FIGS. 1 and 3 are denoted by the same reference numerals, and a detailed description thereof will be omitted.

As shown in FIG. 4, the main control unit 95 constituting the gap filler system according to the third embodiment is the same as that shown in FIG.
The following points (A) to (D) are different from the main controller 90 of the second embodiment shown in FIG. (A): The frequency division ratio in the PLL circuit 92 is
The control unit 38 sets the oscillation frequency fLo2 of 1 so that the following equation 2 is obtained. Note that in Equation 2, fS
Each of b, fLo, fIF, and fIF2 is the same as Equation 1 described above.

FLo2 = fSb−fLo + fIF2 = fIF + fIF2 (Equation 2) That is, also in the main controller 95 of the third embodiment, the intermediate frequency signal IF from the receiving unit 18 is converted into the second intermediate frequency signal IF2 of 400 MHz by the mixer 93. However, the oscillation frequency fLo2 of the local oscillation circuit 91 for tuning is set higher than the frequency of the intermediate frequency signal IF input to the mixer 93.

For this reason, the oscillation frequency fLo2 of the local oscillation circuit 91 is controlled by the control section 38 to be 1.35 GHz to 1.35 GHz.
It will be set to any of 85 GHz. (B): A local oscillation circuit 96 of a variable frequency type, a PLL circuit 97, and a mixer 98 are additionally provided.

The PLL circuit 97 frequency-divides the output signal Lo3 of the local oscillation circuit 96 and the reference signal Fref output from the oscillation circuit 34 at the frequency division ratio set by the control unit 38, respectively. By generating a control signal for matching the phases of the signals after the rotation and outputting the control signal to the local oscillation circuit 96, the frequency of the output signal Lo3 of the local oscillation circuit 96 (the oscillation frequency of the local oscillation circuit 96) is adjusted to the above value. Second
The frequency is controlled to a constant frequency higher than the frequency of the intermediate frequency signal IF2 (1.55 GHz in the third embodiment).

The mixer 98 mixes the 400 MHz second intermediate frequency signal IF2 output from the BPF 94 with the output signal Lo3 of the local oscillation circuit 96,
The second intermediate frequency signal IF2 is converted to a third intermediate frequency signal IF3 having a frequency higher than that and lower than the oscillation frequency of the local oscillation circuit 96 (the center frequency = 1.
15 GHz) and outputs it to the amplifier circuit 28.

(C): Further, in the main controller 95 of the third embodiment, the characteristics of the BPF 30 are set so as to pass the third intermediate frequency signal IF3. Therefore, the third intermediate frequency signal I output from the mixer 98
F3 is input to the E / O converter 44 via the amplifier circuit 28, the BPF 30, and the directional coupler 54. And
The third intermediate frequency signal IF3 is converted into an optical signal by the E / O converter 44 as a signal for transmission to each transmitting slave unit 12, and is output to each downstream signal optical fiber 14d. .

(D): The frequency division ratio of the PLL circuit 36 is determined by the output signal of the local oscillation circuit 32 (frequency conversion signal).
The frequency of Loh can be frequency-converted by each transmitting slave unit 12 from the third intermediate frequency signal IF3 to the relay broadcast signal Sc.
The frequency is set to be 49 GHz (= 2.64 GHz-1.15 GHz). Further, the characteristic of the BPF 48 is set so that only the frequency conversion signal Loh of 1.49 GHz is passed.

For this reason, in the third embodiment, this 1.4 is used.
The 9 GHz frequency conversion signal Loh is transmitted to the directional coupler 5.
4, the third intermediate frequency signal IF3 as a transmission signal
And is supplied to each transmitting slave unit 12 in the form of an optical signal. In the main controller 95 of the third embodiment, the phase of the reference signal Fref and the phase of the output signal Lo3 of the local oscillation circuit 96 are sent from the PLL circuit 97 to the control unit 38 in the same manner as the PLL circuits 36 and 92 described above. Are locked, a lock detection signal LK3 is output. If the lock detection signal LK3 is not continuously input for a predetermined time or more, the control unit 38 determines that an abnormality has occurred. When the abnormality is determined, information indicating the abnormality is sent to the central monitoring center via the communication unit 40 and the communication antenna 42.

On the other hand, in the gap filler system according to the third embodiment, the transmission signal and the frequency conversion signal output from the main controller 95 to each of the transmitting slave units 12 are the same as those in the first embodiment. Frequency, so that each transmitting slave unit 12
Is exactly the same as the transmitting slave unit 12 of the first embodiment.

That is, in each transmitting slave unit 12, the BP
The characteristic of F62 is that the third intermediate frequency signal IF transmitted from the main controller 95 via the downstream signal optical fiber 14d.
3 is set to pass through, and the BPF 64
The characteristic of the optical fiber 1 for the down signal from the main controller 95 is
It is set so that only the 1.49 GHz frequency conversion signal Loh sent via 4d is passed.
Then, in each transmitting slave unit 12, the frequency conversion signal Loh output from the BPF 64 is converted by the mixer 70 into the third intermediate frequency signal IF 3 output from the BPF 62.
Thus, the third intermediate frequency signal IF3 sent in the form of an optical signal from the main controller 95 is frequency-converted into a relay broadcast signal Sc to be transmitted wirelessly.

According to the main controller 95 used in the tunnel gap filler system of the third embodiment as described above, the oscillation frequency fLo of the local oscillation circuit 91 for channel selection is used.
2 is set higher than the frequency of the intermediate frequency signal IF input to the mixer 93,
Has an oscillation frequency fLo2 of 1.35 GHz to 1.85 G
It is sufficient if the frequency can be changed by about 1.4 times, such as Hz. Therefore, the same effects as those of the gap filler system of the second embodiment can be obtained without using a high-performance local oscillation circuit 91.

In the third embodiment, the satellite receiving antenna 6, the oscillation circuit 34, the local oscillation circuit 91, and the PLL circuit 9
2, mixer 93, BPF 94, local oscillation circuit 96, PL
The L circuit 97, the mixer 98, and the BPF 30 correspond to a reception conversion unit. By the way, in the main controller 95 of the third embodiment, the second intermediate frequency signal
The frequency conversion to the intermediate frequency signal IF3 is performed for the following reason.

First, in the third embodiment, since the oscillation frequency fLo2 of the local oscillation circuit 91 is set higher than the frequency of the intermediate frequency signal IF, the second intermediate frequency after the frequency conversion by the mixer 93 is performed. The signal IF2 has a frequency increase / decrease characteristic opposite to that of the intermediate frequency signal IF input to the mixer 93. That is, the frequency of the second intermediate frequency signal IF2 decreases as the frequency of the intermediate frequency signal IF increases, and conversely increases as the frequency of the intermediate frequency signal IF decreases.

Since the receiving section 18 of the satellite receiving antenna 6 generates the intermediate frequency signal IF using the local oscillation signal Lo having a lower frequency than the second broadcast signal Sb transmitted from the satellite 2, The intermediate frequency signal IF has the same frequency increase / decrease characteristics as the second broadcast signal Sb from the satellite 2.

Therefore, in the main controller 95 of the third embodiment, the output signal Lo3 of the local oscillation circuit 96 having a higher frequency is mixed with the second intermediate frequency signal IF2 frequency-converted by the mixer 93. As a result, a third intermediate frequency signal IF3 having a frequency increasing / decreasing characteristic opposite to that of the second intermediate frequency signal IF2 (that is, the same frequency increasing / decreasing characteristic as the intermediate frequency signal IF from the receiving unit 18) is generated. The intermediate frequency signal IF3 is converted into an optical signal and output to each transmitting slave unit 12.

On the other hand, in the gap filler system of the third embodiment, the main controller 95 converts the second intermediate frequency signal IF2, which has been frequency-converted by the mixer 93, into an optical signal, and sends the optical signal to each of the transmission slave units 12. And at the same time, each transmitting slave unit 12 outputs the second intermediate frequency signal I from the main controller 95.
F2 (400 MHz), a frequency conversion signal having a higher frequency than the relay broadcast signal Sc (specifically, 3.04 GHz).
(= 400 MHz + 2.64 GHz)), and the second intermediate frequency signal IF2 may be frequency-converted into the relay broadcast signal Sc.

However, in this case, the frequency conversion signal Lo to be supplied from the main controller 95 to each of the transmitting slave units 12 is used.
h is the highest frequency (2.5 GHz in the above example) of the electric signal that can be E / O converted by the E / O converter 44 described above.
z), and an extremely high-performance E / O converter 44 is required. Also,
If each transmitting slave 12 is configured to generate the frequency conversion signal Loh, the power consumption of each transmitting slave 12 increases.

Thus, the configuration of the third embodiment shown in FIG. 4 is very effective. As mentioned above, although one Example of this invention was described, this invention is not limited to said each Example, You can take various aspects. For example, the tunnel gap filler system of each of the above embodiments includes a first broadcast signal Sa and a second broadcast signal S transmitted from the satellite 2.
b, the second broadcast signal Sb of the Ku band is received, but the first broadcast signal Sa may be received. However, it is more advantageous to receive the second broadcast signal Sb, since even if the transmission power from each transmitting antenna 10 is increased, the transmission wave does not oscillate into the reception wave, thereby causing oscillation.

In a satellite broadcasting system in which only the first broadcast signal Sa is transmitted from the satellite 2, the first broadcast signal Sa may be received.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of a tunnel gap filler system according to a first embodiment.

FIG. 2 is a schematic diagram illustrating an installation state of a gap filler system for a tunnel according to a first embodiment.

FIG. 3 is a configuration diagram illustrating a configuration of a main control device used in a tunnel gap filler system according to a second embodiment.

FIG. 4 is a configuration diagram illustrating a configuration of a main control device used in a gap filler system for a tunnel according to a third embodiment.

FIG. 5 is a configuration diagram illustrating a conventional configuration example of a gap filler system for a tunnel.

[Explanation of symbols]

2 satellite, 4 tunnel, 6 satellite receiving antenna, 8,
90, 95 ... main control device, 10 ... transmission antenna, 12 ...
Transmission slave unit, 14d ... Downlink signal optical fiber, 14u ...
Optical fiber for upstream signal, 16 ... Reflector, 18 ... Receiver,
20 ... coaxial cable, 22 ... terminal, 24, 50, 54,
78 directional coupler, 26, 30, 48, 52, 62,
64, 66, 72, 76, 94... BPF (bandpass filter), 28, 68, 74.
96 local oscillation circuit, 34 oscillation circuit, 36, 92, 9
7, PLL circuit, 38, control unit, 40, communication unit, 42,
Communication antenna, 44, 84 ... E / O converter, 46, 6
DESCRIPTION OF SYMBOLS 1 ... O / E converter, 56 ... output part, 58, 86 ... Power supply part, 60 ... Power line, 70, 93, 98 ... Mixer, 80 ...
Monitoring unit, 82: temperature sensor, 88: detection circuit

Claims (6)

[Claims] 1. A satellite broadcasting system for broadcasting a broadcasting signal transmitted by a terrestrial broadcasting station to a terrestrial service area by relaying the broadcasting signal through a satellite, wherein the broadcasting signal from the satellite is received by a receiving terminal in a tunnel. A gap filler system for a tunnel, comprising: a receiving means for receiving a broadcast signal from the satellite, and each of the receiving means being arranged at a different position in the tunnel, and each of the means via an optical fiber for transmitting an optical signal. A plurality of transmitting means connected one-to-one with the receiving means, wherein the receiving means converts a signal received from the satellite into an optical signal and is connected to each of the transmitting means. Output to each optical fiber, and each of the transmitting means relays a frequency receivable by the receiving terminal from an optical signal transmitted from the receiving means side via the optical fiber. It generates a signal, the gap filler system for tunnel that is configured, and wherein to wirelessly transmit the relay broadcast signal into the tunnel. 2. A satellite broadcasting system for broadcasting a broadcasting signal transmitted by a terrestrial broadcasting station by a satellite and broadcasting the broadcasting signal to a terrestrial service area, wherein the broadcasting signal from the satellite is received by a receiving terminal in a tunnel. A gap filler system for a tunnel, comprising: a receiving means for receiving a broadcast signal from the satellite, and each of the receiving means being arranged at a different position in the tunnel, and each of the means via an optical fiber for transmitting an optical signal. A plurality of transmitting means connected one-to-one with the receiving means, further comprising: an E / O converting means for converting an electric signal into an optical signal; and a broadcasting signal from the satellite. The E / O converting means frequency-converts the received broadcast signal into a transmission signal in a predetermined frequency band lower than the highest frequency of the electrical signal convertible into an optical signal, and outputs the signal. Conversion means; signal supply means for converting the transmission signal output from the reception conversion means to an optical signal by the E / O conversion means; and an optical signal converted by the E / O conversion means. Output means for outputting to each of the optical fibers, each of the transmitting means, an O / E converting means for converting an optical signal transmitted from the receiving means side via the optical fiber into an electric signal; A transmitting-side frequency converter for extracting the transmission signal from the electric signal converted by the O / E conversion means and frequency-converting the extracted transmission signal into a relay broadcast signal having a frequency receivable by the receiving terminal; Means; and a transmission means for wirelessly transmitting, in the tunnel, a relay broadcast signal frequency-converted by the transmission-side frequency conversion means, the tunnel gap filler system comprising: . 3. The tunnel gap filler system according to claim 2, wherein the receiving unit is capable of frequency-converting the transmission signal into the relay broadcast signal by mixing the transmission signal with the transmission signal. And signal generation means for generating a frequency conversion signal having a constant frequency lower than the highest frequency, and the signal supply means superimposes the frequency conversion signal generated by the signal generation means on the transmission signal. The superimposed signal is converted by the E / O conversion means into an optical signal, and the transmission-side frequency conversion means of each of the transmission means is converted by the O / E conversion means. The transmission signal and the frequency conversion signal are extracted from the extracted electric signal, and the extracted transmission signal and the frequency conversion signal are mixed, thereby extracting the signal. Tunnel gap filler system that is configured, characterized such that a frequency converting the transmission signal to the relay broadcast signals. 4. The tunnel gap filler system according to claim 1, wherein each of the transmitting units generates monitor information indicating a state of the transmission unit, and transmits the monitor information to the monitor. The optical fiber for receiving an optical signal from the receiving means, or an optical fiber separate from the optical fiber, and for an upstream signal provided in advance for transmitting a signal from the transmitting means to the receiving means. It is configured to transmit to the receiving means via an optical fiber, wherein the receiving means receives monitor information from each of the transmitting means and monitors a state of each of the transmitting means. A gap filler system for a tunnel. 5. A receiving device used as a receiving means in the gap filler system for a tunnel according to claim 1, wherein the E / O converting means converts an electric signal into an optical signal, and a broadcast signal from a satellite. Receiving conversion means for receiving the broadcast signal, converting the received broadcast signal into a transmission signal in a predetermined frequency band lower than the highest frequency of the electric signal convertible to the optical signal by the E / O conversion means, and outputting the signal. By mixing with the transmission signal, the transmission signal,
A signal generating means capable of frequency conversion into a relay broadcast signal of a frequency receivable by the receiving terminal and generating a frequency conversion signal of a constant frequency lower than the highest frequency; and a signal generating means generated by the signal generating means. The frequency conversion signal is superimposed on the transmission signal output from the reception conversion means,
A signal supply unit for causing the E / O conversion unit to convert the superimposed signal into an optical signal; and outputting the optical signal converted by the E / O conversion unit to each optical fiber connected to the device. An output device, comprising: a receiving device. 6. A transmitting device used as a transmitting means in the tunnel gap filler system according to claim 3, wherein an optical signal transmitted from the receiving means side via an optical fiber is an electric signal. O / E conversion means for converting the transmission signal and the frequency conversion signal from the electric signal converted by the O / E conversion means, and the extracted transmission signal and frequency conversion signal A transmission-side frequency conversion unit that converts the extracted transmission signal into a relay broadcast signal having a frequency receivable by a receiving terminal by mixing the transmission signal with the signal; and a relay frequency-converted by the transmission-side frequency conversion unit. A transmission device, comprising: transmission means for wirelessly transmitting a broadcast signal in a tunnel.