Rebroadcasting system, rebroadcasting device, and method for notifying of interruption

Abstract

To provide a rebroadcasting system capable of detecting a stop of rebroadcast audio in a non-interruption facility.SOLUTION: According to an embodiment, a rebroadcasting system includes a rebroadcasting device that receives broadcast radio waves and rebroadcasts the broadcast radio waves to a provision area, and a center device connected to the rebroadcasting device via a communication network. The rebroadcasting device includes a receiving unit, a retransmitting antenna, a disconnection detection unit, and a notification unit. The receiving unit receives the broadcast radio waves. The retransmitting antenna is installed in the provision area and rebroadcasts the broadcast radio waves received by the receiving unit. The disconnection detection unit detects a disconnection of the retransmitting antenna. When the disconnection detection unit detects a disconnection, the notification unit notifies the center device of the disconnection of the retransmitting antenna via the communication network.SELECTED DRAWING: Figure 2

Description

Technical Field

[0006] ,

[0001] Embodiments of the present invention relate to a rebroadcast system, a rebroadcast apparatus, and a disconnection notification method.

Background Art

[0002] Since it becomes a radio dead zone inside tunnels such as roads, a radio rebroadcast system that receives radio broadcasts and rebroadcasts them inside the tunnel is known. In tunnels where this system is installed, drivers can listen to car radios even inside the tunnel.

[0003] In addition, tunnels are classified according to their importance based on factors such as tunnel length, traffic volume, and number of lanes. Radio retransmission devices in tunnels with a high tunnel class (for example, Class A tunnels) are required to be equipped with a radio rebroadcast system (hereinafter referred to as "equipment with interruption function") with equipment for performing interrupt broadcasts in case of emergency. In such equipment called equipment with interruption function, normally radio broadcasts are retransmitted, and in case of emergency such as an accident or a fire, an emergency interrupt broadcast is started, so that drivers can receive information on the occurrence of a fire and instructions for evacuation guidance on the same channel.

[0004] On the other hand, tunnels with a low tunnel class are not required to have equipment with interruption function. Therefore, in many tunnels with a low tunnel class, there is no radio rebroadcast system itself, or even if there is one, a radio rebroadcast system without an interruption function (hereinafter referred to as "equipment without interruption function") is installed.

[0005] Here, the equipment with interruption function has a function for monitoring the voice inside the tunnel from a remote control station for device health check and confirmation of the implementation of emergency broadcasts. On the other hand, the equipment without interruption function does not have a function for remotely monitoring the voice transmitted inside the tunnel.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Utility Model Publication No. 4-43033 [Patent Document 2] Japanese Patent Publication No. 2015-232878 [Patent Document 3] Japanese Patent Application Publication No. 11-17590 [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, in systems without interruption, even if the rebroadcasting equipment malfunctions due to aging or other reasons and the radio broadcast is interrupted, the control center cannot detect this. Consequently, in systems without interruption, the only way to confirm whether the radio broadcast is being transmitted normally was for maintenance patrol officers involved in road management to drive through the tunnel and actually listen to the radio broadcast. However, having maintenance patrol officers drive through the entire section 24 hours a day to listen and confirm presents challenges in terms of costs and personnel allocation. Therefore, the objective is to provide a rebroadcasting system, a rebroadcasting device, and a method for notifying interruptions that can detect the cessation of rebroadcast audio even in equipment without interruption. [Means for solving the problem]

[0008] According to one embodiment, the rebroadcasting system comprises a rebroadcasting device that receives broadcast radio waves and rebroadcasts the broadcast radio waves to the service area, and a center device connected to the rebroadcasting device via a communication network. The rebroadcasting device comprises a receiving unit, a transmitting unit, a disconnection detection unit, and a notification unit. The receiving unit receives broadcast radio waves. The transmitting unit outputs the audio of the broadcast radio waves received by the receiving unit as a monitor audio signal. The disconnection detection unit detects a disconnection in the monitor audio signal. When the disconnection detection unit detects a disconnection, the notification unit notifies the center device of the disconnection in the monitor audio signal via the communication network. [Brief explanation of the drawing]

[0009] [Figure 1]A diagram illustrating a radio rebroadcasting system according to the first embodiment. [Figure 2] A functional block diagram showing an example of the configuration of a radio rebroadcasting device and a service center of a radio rebroadcasting system according to the first embodiment. [Figure 3] A functional block diagram showing an example of a radio rebroadcasting device 5, as shown in Figure 2. [Figure 4] A diagram illustrating a radio rebroadcasting system according to a second embodiment. [Figure 5] Figure 4 shows a functional block diagram of the radio rebroadcasting equipment and service center. [Figure 6] Figure 5 is a functional block diagram showing the detailed configuration of the radio rebroadcasting device. [Figure 7] Figure 6 shows an example of the external appearance of the control panel and display panel. [Figure 8] A flowchart illustrating the operation of the radio rebroadcasting device shown in Figure 6. [Modes for carrying out the invention]

[0010] [First Embodiment] Figure 1 is a diagram illustrating a radio rebroadcasting system according to an embodiment.

[0011] The radio rebroadcasting system shown in Figure 1 provides radio rebroadcasting services in tunnels, but it is a so-called "non-interruption" system that cannot make emergency interrupt broadcasts. Below, we will explain the technology that enables the control station to detect when a failure occurs in a non-interruption system.

[0012] In Figure 1, broadcasting station 1 is a radio broadcasting station, and transmitting antenna 2 is the broadcasting station's transmitting antenna. On the other hand, receiving antenna 4 is a receiving antenna that receives AM and / or FM broadcast radio waves transmitted from the transmitting antenna. Radio receiving device 3 is a receiving unit that demodulates the broadcast radio waves received by receiving antenna 4 for each channel.

[0013] The radio rebroadcasting device 5 amplifies the broadcast radio waves received by the radio receiving device 3. The induction wire 6 and the leaky coaxial cable 7 are laid in the tunnel, and are a rebroadcasting system that rebroadcasts the broadcast radio waves of both AM broadcast and FM broadcast, or either one, into the tunnel. Thereby, the driver of the vehicle 8 can enjoy music and the like by radio broadcast. Here, the band of the broadcast radio wave may include the frequency band of V-Low multimedia.

[0014] FIG. 2 is a functional block diagram showing an example of the configuration of the radio rebroadcasting device and the service center of the radio rebroadcasting system according to the embodiment. In FIG. 2, a service center 9 as a center device is communicably connected to the radio rebroadcasting device 5 via an IP (Internet Protocol) network 10 as a communication network.

[0015] First, the configuration of the radio rebroadcasting device 5 will be described. The radio rebroadcasting device 5 includes a broadcast retransmission unit 11, a monitoring unit 12, an IP transmission device 13, and a VoIP (Voice over IP) device 14.

[0016] The broadcast retransmission unit 11 is a transmission unit that amplifies the broadcast radio waves of AM broadcast and FM broadcast received by the radio receiving device 3 (FIG. 1) for rebroadcasting into the tunnel. The broadcast radio waves amplified by the radio receiving device 3 are output to the induction wire 6 and the leaky coaxial cable 7 as retransmission antennas laid in the tunnel.

[0017] Here, the details of the configuration of the broadcast retransmission unit 11 will be described later using FIG. 3.

[0018] The service center 9 includes a monitor 27, an alarm lamp 28, a PC terminal 29, a speaker 30, a monitor amplifier unit 31, an IP transmission device 32, and a VoIP device 33. Further, the service center 9 includes, for example, a tunnel selection function, a channel selection function, a monitoring time setting function, etc. implemented on the PC terminal 29.

[0019] Here, the tunnel selection function allows you to arbitrarily select and specify one tunnel from the tunnels under management. The channel selection function allows the user (maintenance service personnel, etc.) to specify the broadcast channel whose audio they want to monitor for the selected tunnel. This allows you to select and specify one channel from multiple channels, regardless of whether it is AM or FM. The monitoring time setting function allows you to set the monitoring time for each of the tunnels under management.

[0020] The IP transmission device 32 of the service center 9 is a transmission device that forms a communication link with the IP transmission device 13 of the radio rebroadcasting device 5 via the IP network 10. The IP transmission device 32 then specifies the channel of the broadcast radio wave and transmits a signal to the radio rebroadcasting device 5 via this communication link requesting the acquisition of the monitoring audio for that channel. The VoIP device 33 is a device that forms a communication link with the VoIP device 14 of the radio rebroadcasting device 5 via the IP network 10.

[0021] Figure 3 is a functional block diagram showing an example of the radio rebroadcasting device 5 shown in Figure 2. In Figure 3, the FM transmission unit 15 is a transmission unit that amplifies the FM broadcast signal sent from the radio receiver 3 (Figure 1). The transmission output of the FM transmission unit 15 is output to the FM mixer 16 and the level adjustment unit 17. The FM transmission unit 15 also outputs a monitor audio demodulated from the FM transmission output to the monitoring unit 12.

[0022] The FM mixer 16 is a mixing unit that mixes the broadcast signals of each channel in the FM band. The output signal generated by the FM mixer 16 is sent to the FM distribution unit 19.

[0023] The FM distribution unit 19 is a distribution unit that distributes the output signal of the FM mixer 16. The output signal of the FM broadcast wave output from the FM distribution unit 19 is connected to the leaky coaxial cable 7 via the cable disconnection detection unit 18.

[0024] The cable break detection unit 18 is a break detection unit that detects the breakage of the leaky coaxial cable 7. When the cable break detection unit 18 detects the breakage of the leaky coaxial cable 7, it immediately notifies the monitoring unit 12 of this fact.

[0025] On the other hand, the AM transmission unit 20 is a transmission unit that amplifies the AM broadcast signal sent from the radio receiving device 3 (Figure 1). The AM transmission output of the AM transmission unit 20 is output to the AM mixer 21 and the level adjustment unit 17. In addition, the AM transmission output from the AM transmission unit 20 is also output to the monitoring unit 12.

[0026] The cable break detection unit 18 is a break detection unit that detects the break of the leaky coaxial cable 7, which serves as a retransmission antenna. Specifically, the cable break detection unit 18 detects the break of the leaky coaxial cable 7, which serves as a retransmission antenna, for example by detecting a change in impedance.

[0027] The AM mixer 21 is a mixing unit that mixes the broadcast signals of each channel in the AM band and outputs the generated output signal to the AM distribution unit 23.

[0028] The AM distribution unit 23 is a distribution unit that distributes the output signal of the AM mixer 21, and the output signal of the AM broadcast is connected to the induction wire 6 via the induction wire break detection unit 22.

[0029] The guide wire break detection unit 22 is a break detection unit that detects when the guide wire 6 is broken. When the guide wire break detection unit 22 detects that the guide wire 6 is broken, it immediately notifies the monitoring unit 12 of this fact.

[0030] The induction wire break detection unit 22 is a detection unit that detects breaks in the induction wire 6, which serves as a retransmission antenna. Specifically, the induction wire break detection unit 22 detects breaks in the induction wire 6 by detecting changes in impedance, for example, or by detecting changes in the length of the induction wire 6.

[0031] On the other hand, the level adjustment unit 17 is an adjustment unit that adjusts the master level of the monitor audio for AM broadcasts and FM broadcasts output from the FM transmission unit 15 and AM transmission unit 20. The monitor audio with the adjusted master level is output to the VoIP device 25. The VoIP device 25 is a device that converts the monitor audio from the level adjustment unit 17 into IP packets.

[0032] The Layer 2 switch 24 is a switch that switches between monitor audio from the VoIP device 25 and packets from the IP transmission device 13 and the VoIP device.

[0033] IP node 26 is an interface that connects to IP network 10.

[0034] Next, the monitoring unit 12 includes a voice input interruption detection unit 12a and a voice switching unit 12b as processing functions related to this embodiment. The audio input disconnection detection unit 12a is a disconnection detection unit that detects the disconnection of the guide wire 6 or the leaky coaxial cable 7 using an audio monitor. The audio switching unit 12b is a switching unit that switches the broadcast radio wave channel in response to a request from the service center 9. This makes it possible to switch the audio channel monitored at the service center 9.

[0035] The IP transmission device 13 is a device that converts control signals such as disconnection detection signals and voice switching signals output from the monitoring unit 12 into IP packets. In other words, the IP transmission device 13 is a notification unit, and when a disconnection of the leaky coaxial cable 7 or the guide line 6 is detected, it notifies the service center 9 of this fact via the IP network 10.

[0036] The VoIP device 14 is a device that forms a voice communication link with the service center 9 via the IP network 10. The VoIP device 14 transmits monitor audio on a specified radio channel to the service center 9 in response to a request from the service center 9. This allows radio audio in the tunnel to be transmitted to the service center 9 via the voice communication link. In other words, the VoIP device 14 is a voice communication unit that transmits monitor audio on a specified channel to the service center 9 in response to a request from the service center 9.

[0037] Next, we will explain the operation of the above configuration. (Normal operation of the radio rebroadcasting device) In Figure 1, AM and / or FM broadcast signals transmitted from the transmitting antenna 2 of broadcasting station 1 are received by the receiving antenna 4 of radio receiver 3. The received broadcast signals are demodulated channel by channel by radio receiver 3 and then output to the FM transmitting unit 15 and AM transmitting unit 20 of radio retransmission device 5.

[0038] In the radio rebroadcasting device 5, the broadcast signal from the FM transmission unit 15 is input to the mixer 16, and the broadcast signal from the AM transmission unit 20 is input to the mixer 21. The FM mixer 16 receives the FM broadcast waves received and demodulated by the radio receiver 3 shown in Figure 1, mixes the broadcast signals from each FM channel, and sends the generated output signal to the FM distribution unit 19.

[0039] The FM distribution unit 19 distributes the FM broadcast signal as power and outputs it to the leaky coaxial cable 7 via the cable disconnection detection unit 18.

[0040] Furthermore, the AM mixer 21 receives the AM broadcast waves received and demodulated by the radio receiver 3 shown in Figure 1, mixes the broadcast signals of each AM channel, and sends the generated output signal to the AM distribution unit 23. The AM distribution unit 23 distributes the AM broadcast signals and outputs them to the induction wire 6 via the induction wire break detection unit 22.

[0041] In this way, the broadcast waves are retransmitted into the tunnel via the guide wire 6 or the leaky coaxial cable 7.

[0042] (Detection of retransmission antenna failure) Here, when the audio input disconnection detection unit 12a of the monitoring unit 12 detects a disconnection of the guide wire 6 based on the output from the guide wire disconnection detection unit 22, it notifies the IP transmission device 13 of this. Similarly, when the audio input disconnection detection unit 12a of the monitoring unit 12 detects a disconnection of the leaky coaxial cable 7 based on the output from the cable disconnection detection unit 18, it notifies the IP transmission device 13 of this.

[0043] In response, the IP transmission device 13 transmits a signal to the IP transmission device 32 at the service center 9 to notify it of the disconnection of the retransmission antenna.

[0044] Upon receiving this, the IP transmission device 32 at the service center 9 decodes the information contained in the transmitted signal and outputs the result to the PC terminal 29 at the service center 9.

[0045] The PC terminal 29 of the service center 9 notifies the user, via screen display and sound, that an audio stoppage has been detected due to a power interruption. The PC terminal 29 also sends a signal to the alarm light 28, causing it to illuminate and indicating that an alarm has occurred. If a Patlite® or similar product is used as the alarm light 28, it is possible to distinguish the alarm rank by changing the color of the light.

[0046] With the above configuration, the disconnection of the retransmission antenna in the tunnel, and the resulting cessation of radio audio, can be detected remotely (at the service center 9).

[0047] (Detection of audio stoppage) Furthermore, the AM transmission unit 20 and the FM transmission unit 15 output monitor audio, which is demodulated from the transmission output, to the monitoring unit 12.

[0048] The monitoring unit 12 monitors the monitor audio input from the FM transmission unit 15 and the AM transmission unit 20, and when it detects that the audio has stopped, it notifies the IP transmission device 13 of the audio stoppage using a signal such as a contact.

[0049] Upon receiving this, the IP transmission device 13 transmits a signal to the service center 9 to notify it of the audio cessation. This configuration makes it possible to detect the cessation of audio and transmit it to the remote service center 9.

[0050] (Procedure for acquiring monitor audio) Next, we will explain the procedure for acquiring monitor audio from Service Center 9.

[0051] In this case, the user operates the PC terminal 29 to first specify the channel of the broadcast radio wave from which they want to acquire the monitor audio in the target tunnel. The PC terminal 29, acting as a requesting unit, receives this specification and outputs a control signal to the IP transmission device 32 to request the acquisition of the monitor audio for the channel specified by the user from among the broadcast radio waves.

[0052] The IP transmission device 32 transmits this control signal to the IP transmission device 13 of the radio rebroadcasting device 5 via the IP network 10.

[0053] The IP transmission device 13 outputs a channel selection signal to the monitoring unit 12 via a contact or the like. The audio switching unit 12b of the monitoring unit 12 controls the switching of broadcast radio wave channels in response to a request from the service center 9.

[0054] Meanwhile, the level adjustment unit 17 adjusts the master levels of the monitor audio for AM and FM broadcasts and inputs them to the VoIP device 25. The signals from the VoIP device 25 are sent to the IP network 10 via the Layer 2 switch 24 and the IP node 26.

[0055] Furthermore, when a signal for selecting a monitor audio channel is transmitted from the service center 9, the IP transmission device 13 outputs a channel selection signal to the monitoring unit 12 via a contact or the like. Based on this contact signal or the like, the monitoring unit 12 outputs the monitor audio of the specified channel to the VoIP device 14.

[0056] The VoIP device 14 converts the monitor audio into audio packets and transmits them to the service center 9 via the IP network 10. The monitoring unit 12 outputs a response signal to the IP transmission device 13 via a contact or the like indicating that the specified channel has been selected, and the IP transmission device 13 transmits the response signal to the service center 9. With this configuration, the monitor audio of the desired channel is transmitted to the service center 9, and the user can listen to the monitor audio remotely.

[0057] (AM transmitter / FM transmitter fault detection) Furthermore, if the AM transmission unit 20 or the FM transmission unit 15 malfunctions, this is immediately detected by the monitoring unit 12. The monitoring unit 12 then notifies the IP transmission device 13 of a signal indicating that the function for radio rebroadcasting has failed, and the IP transmission device 13 notifies the service center 9 of the malfunction via the IP network 10.

[0058] As described above, in this embodiment, in the non-interruption equipment of the radio retransmission system, when a break in the retransmission antenna (inductor wire 6 or leaky coaxial cable 7) on the tunnel side is detected, the service center 9 is notified via the IP network 10. In addition, the monitoring audio from the radio retransmission is transmitted from the radio retransmission device 5 to the service center 9 via VoIP. Furthermore, the service center 9 can select and specify the channel of the broadcast signal to be monitored.

[0059] As a result, even in equipment without interruption, it becomes possible to detect the cessation of rebroadcast audio and notify a remote service center 9, etc. Therefore, service providers can take immediate action, and the quality of service to users will not be compromised. Thus, according to the embodiment, it is possible to provide a rebroadcast system, a rebroadcast device, and a method for notifying interruptions that can detect the cessation of rebroadcast audio in equipment without interruption.

[0060] [Second Embodiment] Figure 4 shows a schematic configuration of a radio rebroadcasting system according to the embodiment. The radio rebroadcasting system shown in Figure 4 provides radio rebroadcasting services in tunnels, but it is a so-called "non-interruption" system that cannot make emergency interrupt broadcasts. Below, we will describe a technology that enables the control station to detect when a radio rebroadcasting failure occurs in a non-interruption system.

[0061] In Figure 4, broadcasting station 1a is an AM radio broadcasting station, and transmitting antenna 2a is a transmitting antenna for transmitting the broadcast radio waves of broadcasting station 1a. Similarly, broadcasting station 1b is an FM radio broadcasting station, and transmitting antenna 2b is a transmitting antenna for transmitting the broadcast radio waves of broadcasting station 1b.

[0062] Note that while Figure 4 shows only one AM and one FM broadcasting station, in a real environment, multiple broadcasting stations exist for each. Furthermore, broadcasting stations 1a and 1b may be transmitting stations or relay stations that transmit radio waves for multiple broadcasting stations.

[0063] On the other hand, the receiving antenna 4 is installed near the tunnel that is subject to radio retransmission and is equipped with antennas that receive AM and FM radio waves transmitted from the transmitting antennas 2a and 2b, respectively.

[0064] The radio receiving device 3 is installed in an electrical room in a tunnel or the like, and is a receiving unit equipped with multiple tuners that can simultaneously receive broadcast signals from multiple broadcasting stations received by the receiving antenna 4, and outputs the signals from each broadcasting station obtained through reception as broadcast signals.

[0065] The radio retransmission device 5 includes a retransmission function that retransmits the broadcast radio waves received by the radio receiver 3 into the tunnel via the guide wire 6 and leaky coaxial cable 7 in response to instructions from the service center 9, described later; a relay function that relays the audio signal of the radio broadcast to a transmitting device installed in another tunnel; and a monitor audio output function that demodulates the received broadcast signal and transmits the audio of the radio broadcast as a monitor audio signal to the service center 9.

[0066] Furthermore, the transmitting equipment installed in the other tunnels mentioned above receives audio signals or audio data from the radio retransmission device 5 and retransmits them as radio waves within the other tunnels. The connection between the radio retransmission device 5 and the transmitting equipment may be via an optical fiber line or a copper cable.

[0067] The guide wire 6 and leaky coaxial cable 7 are laid inside the tunnel and function as antennas that receive AM and FM broadcast signals from the radio retransmission device 5 and retransmit the respective broadcast waves inside the tunnel.

[0068] As a result, a radio broadcast receiver (not shown) installed in vehicle 8 inside the tunnel receives the rebroadcast radio waves, allowing the driver of vehicle 8 to enjoy music and other radio broadcasts. The frequency band of the broadcast radio waves may also include the frequency band for V-Low multimedia.

[0069] The service center 9 is a control station (center equipment) for the radio rebroadcasting system where an administrator is stationed as needed, and is connected to the radio rebroadcasting device 5 via an IP (Internet Protocol) network 10 so as to be able to communicate.

[0070] Figure 5 is a diagram showing the configuration of the radio rebroadcasting device 5 and service center 9 of the radio rebroadcasting system shown in Figure 4, using functional blocks.

[0071] First, let's explain the configuration of the radio rebroadcasting device 5. The radio rebroadcasting device 5 includes, as its main components, a broadcast retransmission unit 11, a monitoring unit 12, an IP transmission device 13, a VoIP (Voice over IP) device 14, an operation unit 121, a display unit 122, and the like.

[0072] The broadcast retransmission unit 11 performs control related to the retransmission of radio broadcasts, such as the aforementioned retransmission function, relay function, and monitor audio output function.

[0073] The monitoring unit 12 is the control center for the radio retransmission device 5 and is responsible for monitoring the status of radio broadcast retransmission by the broadcast retransmission unit 11, detecting malfunctions, and switching the monitor audio signals transmitted to the service center 9.

[0074] The IP transmission device 13 converts information such as monitoring results and detection results from the monitoring unit 12 into IP packets and transmits them to the service center 9 via the IP network 10. Conversely, it also receives IP packets from the service center 9 and outputs them to the monitoring unit 12. In other words, the IP transmission device 13 functions as a data communication unit that communicates data with the service center 9.

[0075] The VoIP device 14 establishes a voice communication link with the service center 9 via the IP network 10. The VoIP device 14 then converts the monitor audio signal of the designated broadcasting station channel from the service center 9 into an audio packet via the IP transmission device 13 and transmits it to the service center 9. In other words, the VoIP device 14 functions as a voice communication unit that can transmit the radio audio of the broadcasting station retransmitted through the tunnel to the service center 9 via the voice communication link.

[0076] The control unit 121 is an input interface that receives instructions, operations, and settings from the operator. The display unit 122 is a display device that provides information to workers visually.

[0077] Next, we will describe the configuration of Service Center 9. The service center 9 includes, as its main components, a monitor 27, an alarm light 28, a PC terminal 29, a speaker 30, a monitor amplifier unit 31, an IP transmission device 32, and a VoIP device 33.

[0078] The monitor 27 is a display device such as an LCD display, which displays various information output from the PC terminal 29 and visually communicates information to the administrator.

[0079] The alarm lights 28 are controlled by a PC terminal 29 to visually notify the administrator of any malfunctions or failures. Multiple alarm lights 28, such as Patlite®, may be used, and the alarm rank may be distinguished by changing the lighting color according to the type of malfunction.

[0080] The PC terminal 29 is an information processing device such as a personal computer, and is equipped with a remote control function for remotely controlling the radio rebroadcasting device 5, a function for monitoring the audio broadcast by radio rebroadcasting, and a function for receiving notifications of failures from the radio rebroadcasting device 5 when a failure related to radio rebroadcasting occurs. These functions are realized by the processor of the PC terminal 29 executing a control program stored in memory and performing processing using control data.

[0081] The remote control functions described above include a tunnel selection function that allows the user to arbitrarily select a tunnel to be monitored from among multiple tunnels under management, a channel selection function that allows the user to select a broadcasting station (channel) to be monitored in the tunnel to be monitored, and a monitoring time setting function that allows the user to set the monitoring time for the radio rebroadcasting device 5.

[0082] Speaker 30 amplifies the radio broadcast and is used by the administrator to check the status of radio rebroadcasts performed by the radio rebroadcasting device 5.

[0083] The monitor amplifier section 31 is an amplifier for amplifying the audio signal for outputting amplified sound from the speaker 30.

[0084] The IP transmission device 32 establishes a data communication link with the IP transmission device 13 of the radio rebroadcasting device 5 and other devices via the IP network 10 and performs data communication.

[0085] The VoIP device 33 establishes a voice communication link with the VoIP device 14 of the radio rebroadcasting device 5 via the IP network 10 and performs voice communication.

[0086] Next, with reference to Figure 6, the configuration of the radio rebroadcasting device 5 will be explained in more detail.

[0087] Figure 6 is a functional block diagram showing the configuration of the radio rebroadcasting device 5 shown in Figure 5 in more detail.

[0088] The FM transmitter 15 is a transmitter that amplifies the broadcast signals of each broadcasting station's FM broadcast sent from the radio receiver 3 shown in Figure 4. The amplified broadcast signals from each broadcasting station are output to the FM mixer 16.

[0089] Furthermore, the FM transmission unit 15 demodulates the broadcast signal of the FM broadcast from the broadcasting station (channel or frequency) specified by the monitoring unit 12, and outputs the resulting audio signal as a monitor audio signal to the monitoring unit 12 and the level adjustment unit 17.

[0090] The FM mixer 16 is a mixing unit that combines the broadcast signals from each broadcasting station (each channel) in the FM band amplified by the FM transmission unit 15. The FM band signals mixed by the FM mixer 16 are output to the FM distribution unit 19.

[0091] The FM distribution unit 19 is a distribution unit that distributes the output signal of the FM mixer 16 and outputs it. The output signal of the FM broadcast output from the FM distribution unit 19 is output to the leaky coaxial cable 7 via the cable break detection unit 18.

[0092] The cable break detection unit 18 is a break detection unit that detects a break in the leaky coaxial cable 7, which functions as a retransmission antenna for FM broadcast waves. When a break is detected, it immediately notifies the monitoring unit 12 of that fact.

[0093] Specifically, the cable break detection unit 18 detects a break by, for example, detecting a change in the impedance of the leaky coaxial cable 7.

[0094] The AM transmitter 20 is a transmitter that amplifies the AM broadcast signals from each broadcasting station sent from the radio receiver 3. The amplified broadcast signals from each broadcasting station are output to the AM mixer 21.

[0095] Furthermore, the AM transmission unit 20 demodulates the AM broadcast signal of the broadcasting station (channel or frequency) specified by the monitoring unit 12, and outputs the resulting audio signal as a monitor audio signal to the monitoring unit 12 and the level adjustment unit 17.

[0096] The AM mixer 21 is a mixing unit that combines the broadcast signals from each broadcasting station (each channel) in the AM band amplified by the AM transmission unit 20. The AM band signals mixed in the AM mixer 21 are output to the AM distribution unit 23.

[0097] The AM distribution unit 23 is a distribution unit that distributes the power of the output signal from the AM mixer 21 and outputs it. The output signal of the AM broadcast output from the AM distribution unit 23 is output to the induction wire 6 via the induction wire break detection unit 22.

[0098] The induction wire break detection unit 22 is a break detection unit that detects a break (non-conductive state) in the induction wire 6, which functions as a retransmission antenna for AM broadcast waves. When a break is detected, it immediately notifies the monitoring unit 12 of that fact.

[0099] Specifically, the guide wire break detection unit 22 detects a break in the guide wire 6 by, for example, detecting a change in the impedance at both ends of the guide wire 6 (for example, a change in the length of the guide wire 6).

[0100] The level adjustment unit 17 is an adjustment unit that adjusts the master level of the monitor audio signal of the FM broadcast output from the FM transmission unit 15 and the monitor audio signal of the AM broadcast output from the AM transmission unit 20. Both monitor audio signals, with their master levels adjusted, are output to the VoIP device 25.

[0101] The VoIP device 25 is a device that samples the monitor audio signal from the level adjustment unit 17, converts it into audio data, and then packages it into an IP packet.

[0102] The Layer 2 switch (L2-SW) 24 is a network device that performs data transfer. For example, it outputs data packets from the IP transmission device 13 and voice packets from the VoIP device 14 and VoIP device 25 to the IP node 26. Conversely, it outputs data packets from the IP node 26 to the IP transmission device 13.

[0103] IP node 26 is a network interface that connects to the IP network 10.

[0104] As mentioned above, the monitoring unit 12 is the control center of the radio rebroadcasting device 5 and is equipped with a processor and memory. Control programs and control data are stored in the memory, and the processor executes the control programs and performs various controls and processes according to the control data.

[0105] The monitoring unit 12 functions as an audio input interruption detection unit 12a, an audio switching unit 12b, an AM / FM fault detection unit 12c, and a notification control unit 12d through the control and processing described above.

[0106] The audio input interruption detection unit 12a monitors the FM broadcast monitor audio signal output from the FM transmission unit 15 and the AM broadcast monitor audio signal output from the AM transmission unit 20, and detects when the audio input is interrupted according to parameters set by a worker or the like.

[0107] The audio switching unit 12b switches the broadcasting station (channel) of the monitor audio signal according to instructions from the service center 9. The AM / FM fault detection unit 12c detects faults in the FM transmission unit 15 and the AM transmission unit 20.

[0108] The notification control unit 12d converts the detection results from the cable disconnection detection unit 18, the induction wire disconnection detection unit 22, the voice input disconnection detection unit 12a, and the AM / FM fault detection unit 12c into data and transmits it to the service center 9 via the VoIP device 14.

[0109] As described above, the operation unit 121 is an input interface that receives instructions, operations, and settings from the worker, and includes a detection time setting unit 121a, a timer setting unit 121b, and a release switch 121c.

[0110] The detection time setting unit 121a is an input unit such as a switch that sets the detection time which serves as the judgment criterion for the voice input interruption detection unit 12a to determine that voice input has been interrupted.

[0111] The timer setting unit 121b is an input unit, such as a switch, for setting the time period for monitoring operations by the monitoring unit 12.

[0112] The release switch 121c is an input section for a switch that resets the indicator showing the broadcasting station (channel) for which broadcast reception has been lost.

[0113] As described above, the display unit 122 is a display device that provides information to workers visually, and includes a timer setting display unit 122a and a disconnection detection display unit 122b.

[0114] The timer setting display unit 122a is a display unit that displays the time period set by the timer setting unit 121b, and for example, a liquid crystal display panel may be used.

[0115] The interruption detection display unit 122b is an indicator that shows a broadcasting station (channel) that can no longer be received. Information identifying the broadcasting station or channel (for example, numbers or the name of the broadcasting station) is associated with an indicator light, which is controlled to light up when broadcasting cannot be received.

[0116] Figure 7 shows an example of the operation unit 121 and the display unit 122. Figure 7(a) shows the external appearance of the control module on which the monitoring unit 12 is mounted, and its side view shows the detection time setting unit 121a, timer setting unit 121b, release switch 121c, timer setting display unit 122a, and disconnection detection display unit 122b.

[0117] Figure 7(b) shows a magnified view of the disconnection detection indicator 122b and the release switch 121c. As mentioned above, the disconnection detection indicator 122b is provided with a corresponding numerical value for information identifying the broadcasting station and channel, and an indicator light P.

[0118] Figure 7(c) shows an enlarged view of the detection time setting unit 121a, illustrating a case where the detection time is set using a volume-type switch that varies the resistance value.

[0119] Next, we will explain the operation of the radio rebroadcasting system with the above configuration. (Radio rebroadcast operation) As shown in Figure 4, AM and FM broadcast signals transmitted from the transmitting antennas 2a and 2b of broadcasting stations 1a and 1b are received by the receiving antenna 4 of the radio receiver 3. The received broadcast signals are received by the radio receiver 3 for each broadcasting station (channel), and the broadcast signals obtained from each broadcasting station are output to the FM transmitting unit 15 or AM transmitting unit 20 of the radio retransmission device 5, respectively, as shown in Figure 6.

[0120] The broadcast signals received from each FM broadcasting station are amplified by the FM transmission unit 15, mixed together by the FM mixer 16, and distributed by the FM distribution unit 19. One of these distributions is then output to the leaky coaxial cable 7 via the cable disconnection detection unit 18.

[0121] In this way, the FM band signal output to the leaky coaxial cable 7 is radiated into the tunnel using the leaky coaxial cable 7 as an antenna, thereby enabling the retransmission of FM broadcast waves. The cable break detection unit 18 monitors the leaky coaxial cable 7 for breaks.

[0122] Meanwhile, the broadcast signals received from each AM broadcasting station are amplified by the AM transmission unit 20, mixed together by the AM mixer 21, and distributed by the AM distribution unit 23. One of these distributions is then output to the induction wire 6 via the induction wire break detection unit 22.

[0123] In this way, the AM band signal output to the guide wire 6 is radiated into the tunnel using the guide wire 6 as an antenna, thereby enabling the retransmission of AM broadcast waves. The guide wire break detection unit 22 monitors the guide wire 6 for breaks.

[0124] (Detection of retransmission antenna failure) When a break occurs in the leaky coaxial cable 7 or the guide wire 6, the cable break detection unit 18 or the guide wire break detection unit 22 detects the break, and the break is immediately notified to the monitoring unit 12.

[0125] In response, the monitoring unit 12 generates fault notification data indicating that a break has occurred in the leaky coaxial cable 7 or the guide wire 6, and instructs the notification control unit 12d to notify the fault. The fault notification data includes information indicating the location of the fault, such as identification information of the tunnel in which it is installed, and identification information of the leaky coaxial cable 7 or the guide wire 6.

[0126] The notification control unit 12d controls the IP transmission device 13 to send the fault notification data to the service center 9. Specifically, the fault notification data is converted into IP packet data in the IP transmission device 13, and then the IP address of the IP transmission device 32 at the service center 9 is assigned as the destination. The data is then transmitted to the service center 9 (IP transmission device 32) via the IP network 10 through the Layer 2 switch 24 and IP node 26.

[0127] In response, when the IP transmission device 32 receives the IP packet data at the service center 9, it outputs it to the PC terminal 29. The IP packet data is then reconstructed into fault notification data by the processor of the PC terminal 29.

[0128] The processor of the PC terminal 29 analyzes the fault notification data to identify the tunnel where the antenna failure occurred, displays the identification information of the identified tunnel on the monitor 27, and controls the illumination of the alarm light 28 to visually notify the administrator that an antenna failure has occurred.

[0129] As described above, by notifying the remote service center 9 of the antenna disconnection detected by the radio rebroadcasting device 5, it is possible to remotely detect that the rebroadcast audio has stopped even in equipment without interruption.

[0130] (Detection of voice input interruption) The detection of a voice input interruption is performed by the voice input interruption detection unit 12a of the monitoring unit 12.

[0131] Figure 8 is a flowchart illustrating the processing performed by the audio input interruption detection unit 12a. The control program for this processing is stored, for example, in the memory of the monitoring unit 12, and the processor of the monitoring unit 12 performs the processing according to the control program. This process is started when the power to the radio rebroadcasting device 5 is turned on.

[0132] First, in step S801, the voice input interruption detection unit 12a reads the setting information for the monitoring operation time period from the memory and proceeds to step S802. As mentioned above, the time period is set in advance by a worker via the timer setting unit 121b, but it may also be a time period instructed by the service center 9.

[0133] In step S802, the voice input interruption detection unit 12a compares the time period indicated by the setting information read in step S801 with the current time to determine whether the current time is within the monitoring period. If the current time is within the monitoring period, the unit proceeds to step S803. If it is not within the monitoring period, the unit proceeds back to step S802 to continue the determination and wait for the monitoring period to begin.

[0134] In step S803, the voice input interruption detection unit 12a reads the detection setting data from the memory and proceeds to step S804. The detection setting data includes the detection time, which is the criterion for determining whether the voice input has been interrupted. As mentioned above, this detection time is set in advance by an operator through the detection time setting unit 121a.

[0135] In step S804, the audio input disconnection detection unit 12a selects one radio broadcast channel (broadcasting station) from the memory to be determined to have an audio input disconnection, instructs the FM transmission unit 15 or AM transmission unit 20 to output the audio signal obtained from the broadcast signal of the selected channel (broadcasting station) as a monitor audio signal, and proceeds to step S805.

[0136] In response, the FM transmission unit 15 or AM transmission unit 20, upon receiving the above instruction from the audio input interruption detection unit 12a, demodulates the broadcast signal of the specified channel (broadcasting station) and outputs the audio of the radio broadcast as a monitor audio signal to the monitoring unit 12.

[0137] Furthermore, the memory stores a list of channels (broadcasting stations) that perform rebroadcasts in the tunnel, with each channel (broadcasting station) associated with identification information. Each time the system proceeds to step S804, channels (broadcasting stations) are selected sequentially from this list.

[0138] In step S805, the audio input interruption detection unit 12a monitors the monitor audio signal output from the FM transmission unit 15 or the AM transmission unit 20 and determines whether or not it has detected silence. If silence is detected, the process proceeds to step S806; otherwise, the process proceeds to step S801. Silence is determined when the level of the monitor audio signal is below a predetermined threshold.

[0139] In step S806, the audio input interruption detection unit 12a determines whether the state of silence (the state in which the level of the monitor audio signal is below a predetermined value) has continued for longer than the detection time read in step S803. If the state of silence has continued for longer than the detection time, the process proceeds to step S807; otherwise, the process proceeds to step S801.

[0140] In step S807, the audio input interruption detection unit 12a controls the interruption detection display unit 122b to light up the indicator corresponding to the channel (broadcasting station) selected in step S804, thereby notifying that an audio input interruption has occurred for that channel (broadcasting station).

[0141] The illuminated indicator will remain lit until the release switch 121c is operated and a reset is requested by the operator. In other words, once a loss of audio input is detected, the indicator latches to remain lit until a reset is performed.

[0142] Furthermore, the voice input interruption detection unit 12a generates voice input interruption notification data indicating this fact and instructs the notification control unit 12d to notify the voice input interruption. The voice input interruption notification data includes information indicating the location and channel (broadcasting station) of the failure, such as identification information of the tunnel where it is installed and identification information of the broadcasting station.

[0143] The notification control unit 12d controls the IP transmission device 13 to send the voice input disconnection notification data to the service center 9. Specifically, the voice input disconnection notification data is converted into IP packet data in the IP transmission device 13, and then the IP address of the IP transmission device 32 of the service center 9 is assigned as the destination. The data is then transmitted to the service center 9 (IP transmission device 32) via the IP network 10 through the Layer 2 switch 24 and IP node 26.

[0144] In response, when the IP transmission device 32 receives the IP packet data at the service center 9, it outputs it to the PC terminal 29. The IP packet data is then reconstructed into voice input interruption notification data by the processor of the PC terminal 29.

[0145] The processor of the PC terminal 29 analyzes the voice input interruption notification data to identify the tunnel and broadcasting station where the voice input interruption occurred. It also displays the identification information of the identified tunnel and broadcasting station on the monitor 27 and controls the illumination of the alarm light 28 to visually notify the administrator that a voice input interruption has occurred.

[0146] In step S808, the audio input interruption detection unit 12a sets the channel (broadcasting station) that detected the audio input interruption in the list above to be excluded from monitoring, and proceeds to step S801. As mentioned above, the excluded channel (broadcasting station) remains excluded (detection latched) until the release switch 121c is operated and a reset is requested by the worker.

[0147] As described above, the audio input interruption detection unit 12a monitors the audio broadcast on channels (broadcasting stations) that can be rebroadcast by the radio rebroadcasting device 5 during a preset time period to detect an audio input interruption and notifies workers and managers of the input interruption at the radio rebroadcasting device 5 and the service center 9. Therefore, the cessation of rebroadcast audio can be detected even remotely.

[0148] Furthermore, since the detection of audio input interruption is performed only during pre-set time periods, it is possible to prevent false detections in situations such as when broadcasting is suspended late at night or when rebroadcasting is intentionally stopped due to construction or inspection.

[0149] Furthermore, since the system detects audio input interruption only when the level of the monitored audio signal remains below a predetermined value for a preset period of time, it can prevent false detections in cases where the playback signal level is low, such as with classical music.

[0150] Furthermore, when an audio input interruption is detected, the release switch 121c is operated, and the indicator light showing the occurrence of the audio input interruption remains lit until a reset is requested by the worker. Therefore, even if audio input interruptions occur irregularly, the worker can recognize the occurrence of the audio input interruption without having to continuously observe the detection results.

[0151] (Switching monitor audio) When the administrator of the service center 9 operates the PC terminal 29 to specify the tunnel and broadcasting station (channel) to be monitored, the PC terminal 29 generates monitoring instruction data addressed to the radio rebroadcasting device 5 installed in the tunnel based on the above specification. This monitoring instruction data includes identification information of the above-specified broadcasting station (channel).

[0152] The above monitoring instruction data is converted by the IP transmission device 32 into IP packet data with the IP address of the IP transmission device 13 of the radio rebroadcasting device 5 set as the destination, and sent to the IP transmission device 13 of the radio rebroadcasting device 5 via the IP network 10.

[0153] In response, the radio rebroadcasting device 5 receives the IP packet data via the IP transmission device 13, and the identification information of the designated broadcasting station (channel) is output to the monitoring unit 12. The monitoring unit 12 then uses the audio switching unit 12b to instruct the FM transmission unit 15 or the AM transmission unit 20 to output a monitor audio signal for the broadcasting station (channel) specified by the service center 9.

[0154] As a result, the FM transmission unit 15 or the AM transmission unit 20 demodulates the broadcast signal of the broadcasting station (channel) instructed by the service center 9, and outputs the resulting audio signal to the monitoring unit 12 as a monitor audio signal.

[0155] The monitor audio signal is output to the VoIP device 14 via the monitoring unit 12. The VoIP device 14 samples the monitor audio signal, converts it into audio data, and then packets it into audio packets.

[0156] The voice packetized monitoring voice signal is transmitted via the Layer 2 switch 24 and IP node 26 through the IP network 10 to the VoIP device 33 at the service center 9.

[0157] In response, at the service center 9, when the IP transmission device 32 receives the voice packet data, it outputs it to the PC terminal 29. The voice packet data is restored to a monitor audio signal by the sound source board of the PC terminal 29. The restored monitor audio signal is amplified by the monitor amplifier unit 31 and output amplified from the speaker 30.

[0158] As described above, when the administrator of the service center 9 specifies a broadcasting station (channel) via the PC terminal 29, the audio that can be rebroadcast by the radio rebroadcasting device 5 is amplified and output within the service center 9, allowing the status of radio rebroadcasting in the desired tunnel to be monitored remotely.

[0159] (AM transmitter / FM transmitter fault detection) The operating status of the AM transmitter 20 and the FM transmitter 15 is monitored by the AM / FM fault detection unit 12c, and a fault is detected if one occurs.

[0160] When a malfunction occurs, the AM / FM malfunction detection unit 12c immediately generates malfunction notification data to notify the AM transmitter 20 or FM transmitter 15, instructing the notification control unit 12d to notify the service center 9 of the malfunction. The malfunction notification data includes information indicating the location of the malfunction, such as identification information of the tunnel where the system is installed, and identification information of the AM transmitter 20 or FM transmitter 15.

[0161] The notification control unit 12d controls the IP transmission device 13 to send the fault notification data to the service center 9. Specifically, the fault notification data is converted into IP packet data in the IP transmission device 13, and then the IP address of the IP transmission device 32 at the service center 9 is assigned as the destination. The data is then transmitted to the service center 9 (IP transmission device 32) via the IP network 10 through the Layer 2 switch 24 and IP node 26.

[0162] In response, when the IP transmission device 32 receives the IP packet data at the service center 9, it outputs it to the PC terminal 29. The IP packet data is then reconstructed into fault notification data by the processor of the PC terminal 29.

[0163] The processor of the PC terminal 29 analyzes the failure notification data to identify the tunnel where the AM transmitter 20 or FM transmitter 15 has failed, and displays the identification information of the identified tunnel and the AM transmitter 20 or FM transmitter 15 on the monitor 27.

[0164] The processor of the PC terminal 29 controls the illumination of the alarm light 28 to visually notify the administrator that a malfunction has occurred in the AM transmission unit 20 or the FM transmission unit 15.

[0165] (summary) As described above, in the above embodiment, in the radio retransmission system, if a break in the retransmission antenna (inductor wire 6 or leaky coaxial cable 7) installed in the tunnel is detected in the non-interruption equipment, the system is configured to notify the service center 9 via the IP network 10.

[0166] Furthermore, the monitoring audio of the broadcast signal transmitted by the radio rebroadcasting device 5 is transmitted to the service center 9. In addition, the service center 9 can select and specify the broadcasting station (channel) to be monitored according to its instructions.

[0167] Therefore, according to the above embodiment, it becomes possible to detect the cessation of rebroadcast audio even in equipment without interruption and notify a remote service center 9, etc. As a result, the administrator stationed at the service center 9 can take countermeasures immediately, and the quality of service to users will not be impaired. In other words, according to this embodiment, it is possible to provide a rebroadcast system, a rebroadcast device, and a method for notifying interruption that can detect the cessation of rebroadcast audio in equipment without interruption.

[0168] While embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications are permitted without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the claims and their equivalents.

[0169] For example, in the second embodiment described above, the radio rebroadcasting device 5 indicates the broadcasting station (channel) from which broadcasting can no longer be received, as shown in Figure 7, but this may be done by the service center 9. Specifically, a similar display is made by controlling the PC terminal 29 based on the audio input interruption notification data (step S807) sent from the radio rebroadcasting device 5 via the IP network 10. It goes without saying that the invention can also be implemented in a similar manner by making various modifications without departing from the spirit of the invention. [Explanation of symbols]

[0170] 1...Broadcasting station, 1a...Broadcasting station, 1b...Broadcasting station, 2...Transmitting antenna, 2a...Transmitting antenna, 2b...Transmitting antenna, 3...Radio receiver, 4...Receiving antenna, 5...Radio retransmission device, 6...Induction wire, 7...Leaky coaxial cable, 8...Vehicle, 9...Service center, 10...IP network, 11...Broadcast retransmission unit, 12...Monitoring unit, 12a...Audio input disconnection detection unit, 12b...Audio switching unit, 12c...AM / FM fault detection unit, 12d...Notification control unit, 13...IP transmission device, 14...VoIP device, 15...FM transmission unit, 16...FM mixer, 17...Level adjustment 18... Cable break detection unit, 19... FM distribution unit, 20... AM transmission unit, 21... AM mixer, 22... Inductive wire break detection unit, 23... AM distribution unit, 24... Switch, 25... VoIP device, 26... IP node, 27... Monitor, 28... Alarm light, 29... PC terminal, 30... Speaker, 31... Monitor amplifier unit, 32... IP transmission device, 33... VoIP device, 121... Operation unit, 121a... Detection time setting unit, 121b... Timer setting unit, 121c... Release switch, 122... Display unit, 122a... Timer setting display unit, 122b... Break detection display unit.

Claims

1. A rebroadcasting system comprising a rebroadcasting device that receives broadcast radio waves and rebroadcasts said broadcast radio waves to the service area, and a center device connected to the rebroadcasting device via a communication network, The aforementioned rebroadcasting device is A receiving unit that receives the aforementioned broadcast radio waves, A transmitting unit that outputs the audio of the broadcast radio waves received by the receiving unit as a monitor audio signal, A disconnection detection unit that detects the interruption of the monitor audio signal, A setting unit for setting the time period to be monitored, When the interruption detection unit detects the interruption, the notification unit notifies the central device of the interruption of the monitor audio signal via the communication network, but only for the time period set by the setting unit. A rebroadcasting system equipped with [a specific feature / feature].

2. A rebroadcasting system comprising a rebroadcasting device that receives broadcast radio waves and rebroadcasts the broadcast radio waves to a service area, and a center device connected to the rebroadcasting device via a communication network, The aforementioned rebroadcasting device is A receiving unit that receives the aforementioned broadcast radio waves, A transmitting unit that outputs the audio of the broadcast radio waves received by the receiving unit as a monitor audio signal, A setting unit for setting the judgment time, A disconnection detection unit detects when the monitor audio signal is below a predetermined threshold level for a judgment time set by the setting unit, When the interruption detection unit detects the interruption, a notification unit notifies the center device of the interruption of the monitor audio signal via the communication network. A rebroadcasting system equipped with [a specific feature / feature].

3. A rebroadcasting system comprising a rebroadcasting device that receives broadcast radio waves and rebroadcasts the broadcast radio waves to a service area, and a center device connected to the rebroadcasting device via a communication network, The aforementioned rebroadcasting device is A receiving unit that receives the aforementioned broadcast radio waves, A transmitting unit that outputs the audio of the broadcast radio waves received by the receiving unit as a monitor audio signal, A disconnection detection unit that detects the interruption of the monitor audio signal, When the interruption detection unit detects the interruption, a notification unit notifies the center device of the interruption of the monitor audio signal via the communication network. When the disconnection detection unit detects a disconnection, a display unit displays the channel on which the disconnection was detected. A rebroadcasting system equipped with [a specific feature / feature].

4. Furthermore, the rebroadcasting device is It is equipped with an operating unit that receives instructions to release, When the disconnection detection unit detects a disconnection, the display unit displays the channel on which the disconnection was detected until the operation unit receives a release instruction. The rebroadcasting system according to claim 3.

5. A retransmission device that receives broadcast radio waves and retransmits said broadcast radio waves to a service area, A receiving unit that receives the aforementioned broadcast radio waves, A transmitting unit that outputs the audio of the broadcast radio waves received by the receiving unit as a monitor audio signal, A disconnection detection unit that detects the interruption of the monitor audio signal, A setting unit for setting the time period to be monitored, When the interruption detection unit detects the interruption, the notification unit notifies the central device of the interruption of the monitor audio signal via the communication network, but only for the time period set by the setting unit. A rebroadcasting device equipped with the following features.

6. A retransmission device that receives broadcast radio waves and retransmits those broadcast radio waves to the service area, A receiving unit that receives the aforementioned broadcast radio waves, A transmitting unit that outputs the audio of the broadcast radio waves received by the receiving unit as a monitor audio signal, A setting unit for setting the judgment time, A disconnection detection unit detects when the monitor audio signal is below a predetermined threshold level for a judgment time set by the setting unit, When the interruption detection unit detects the interruption, a notification unit notifies the central device of the interruption of the monitor audio signal via the communication network. A rebroadcasting device equipped with the following features.

7. A retransmission device that receives broadcast radio waves and retransmits said broadcast radio waves to a service area, A receiving unit that receives the aforementioned broadcast radio waves, A transmitting unit that outputs the audio of the broadcast radio waves received by the receiving unit as a monitor audio signal, A disconnection detection unit that detects the interruption of the monitor audio signal, When the interruption detection unit detects the interruption, a notification unit notifies the central device of the interruption of the monitor audio signal via the communication network. When the disconnection detection unit detects a disconnection, a display unit displays the channel on which the disconnection was detected. A rebroadcasting device equipped with the following features.

8. Furthermore, it is equipped with an operating unit that receives instructions to release, When the disconnection detection unit detects a disconnection, the display unit displays the channel on which the disconnection was detected until the operation unit receives a release instruction. The rebroadcasting device according to claim 7.

9. A method for notifying a service interruption by a retransmission device that receives a broadcast radio wave and retransmits the said broadcast radio wave to a service area, The aforementioned rebroadcasting device receives the broadcast radio waves, The aforementioned rebroadcasting device outputs the audio of the received broadcast radio waves as a monitor audio signal. The rebroadcasting device detects the interruption of the monitor audio signal, The aforementioned rebroadcasting device accepts and sets the time period for monitoring, A method for notifying a disconnection, wherein when the rebroadcasting device detects the disconnection, it notifies the central device of the disconnection of the monitor audio signal via the communication network, but only during the set time period.

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