Broadcasting system and broadcasting method

Abstract

To provide a broadcasting system and a broadcasting method that enable a downstream device to determine whether broadcasting is suspended or an abnormality has occurred, and that allows the system status to be easily grasped.SOLUTION: A broadcasting system include a transmitting device 1 that transmits a broadcast signal and a receiving device 2 that receives the broadcast signal and outputs it to a downstream device, and when transmitting device 1 transmits a broadcast signal, it adds a pilot signal to the broadcast signal and transmits it, when broadcasting is paused, it transmits only the pilot signal, when receiving device 2 receives both the broadcast signal and the pilot signal, it cancels phase noise on the basis of the pilot signal and outputs the broadcast signal, when receiving only the pilot signal, it outputs a signal indicating that broadcasting is paused, and when not receiving the pilot signal, it outputs a signal indicating an abnormality has occurred, and there is also provided a broadcasting method.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a broadcasting system for transmitting broadcast signals, and more particularly to a broadcasting system and a broadcasting method that enable a downstream device to easily grasp the state of the system. [Background technology]

[0002] [Prior art: Figure 4] There is a broadcasting system that transmits terrestrial digital broadcasting signals using SHF (Super High Frequency) signals. A conventional broadcasting system will be described with reference to Fig. 4. Fig. 4 is an explanatory diagram showing the schematic configuration of a conventional broadcasting system. Here, an IF (Intermediate Frequency)-TTL (Transmitter to Transmitter Link) device that relays signals between a master station and a relay station, or between relay stations, is shown. Fig. 4 also shows the state when broadcasting is paused.

[0003] As shown in FIG. 4, the conventional broadcasting system includes a transmitting device 3 and a receiving device 4. Furthermore, a subsequent device that receives the broadcast signal from the receiving device 4 is connected to the subsequent stage of the receiving device 4.

[0004] The transmitting device 3 includes digital modulators 31a and 31b, transmitting converters 32a and 32b, an SHF switch 33, and an antenna 34. The transmitting device 3 has a dual (redundant) configuration with a system consisting of the digital modulator 31a and transmitting converter 32a and a system consisting of the digital modulator 31b and transmitting converter 32b, so that if one system fails, operation continues using the other system. When there is no need to distinguish between the digital modulators 31a and 31b, they may be referred to as digital modulators 31. When there is no need to distinguish between the transmission converters 32a and 32b, they may be referred to as transmission converters 32.

[0005] The digital modulator 31 modulates the input terrestrial digital broadcast signal using Orthogonal Frequency Division Multiplex (OFDM) to generate an IF signal for relay transmission. The transmission converter 32 up-converts the frequency of the IF signal output from the digital modulator 31 to a microwave to generate an SHF signal, and performs power amplification.

[0006] The SHF switch 33 switches the SHF signal from either the transmitting converter 32 a or 32 b so as to be output to the antenna 34 . When the equipment is operating normally during the broadcast time, SHF signals are input to the SHF switch 33 from both the transmitting converters 32a and 32b, and one of them is output to the antenna 34. The system selection is performed according to a preset method. The antenna 34 radiates the SHF signal output from the SHF switch 33 into the air.

[0007] The receiving device 4 includes an antenna 41, a shared receiving distributor 42, and receiving converters 43a and 43b. When there is no need to distinguish between the receiving converters 43a and 43b, they may be referred to as the receiving converter 43. The receiving device 4 also has redundancy in case the receiving converter 43 fails.

[0008] The antenna 41 picks up the SHF signal. The shared receiving distributor 42 distributes the SHF signal input from the antenna 41 to the receiving converters 43a and 43b. The receiving converter 43 down-converts and demodulates the received SHF signal to an IF signal, generates an IF signal (digital terrestrial broadcasting signal), and relays and outputs it.

[0009] [Conventional operation during broadcast pause: Figure 4] Next, the operation of a conventional broadcasting system during a broadcast pause will be described with reference to FIG. During a broadcast break, no terrestrial digital broadcast signal (broadcast signal) is input to the digital modulators 31a and 32b (indicated by an "x" mark in the figure). If no broadcast signal is input, the digital modulator 31 outputs an input signal loss alarm to the SHF switch 33.

[0010] When an input signal loss alarm is input from both the digital modulators 31a and 31b, the SHF switch 33 determines that broadcasting is suspended and outputs a control signal to the broadcast converters 32a and 32b to stop outputting the SHF signal (stop control signal). This stops output of the SHF signal from the transmitter. Then, in the receiving device 4, the SHF signal is not input to the receiving converter 43, and the receiving converter 43 stops relaying the IF signal (broadcast signal) to the subsequent stage.

[0011] Furthermore, if the SHF switch 33 receives an input signal loss alarm from one digital modulator 31 but does not receive an input signal loss alarm from the other digital modulator 31, it determines that an abnormality has occurred in the system that is not issuing the input signal loss alarm, and switches to the other system to continue relaying the broadcast waves. At this time, the SHF switch 33 reports the abnormality to a monitor device that monitors the device status, attaching the number (identification information) of the system in which the abnormality was detected.

[0012] [Conventional SHF signal waveform: Figure 5] Next, the waveform of the SHF signal output from the transmitting device in a conventional broadcasting system will be explained using Fig. 5. Fig. 5 is a schematic explanatory diagram of the waveform of the SHF signal in a conventional broadcasting system, where (a) shows the waveform under normal conditions, and (b) shows the waveform when broadcasting is suspended or when a failure occurs on the transmitting side. In Figure 5, the horizontal axis represents frequency and the vertical axis represents output level. When broadcasting is in progress (normally), as shown in Figure 5(a), the waveform is one in which a roughly rectangular IF signal and a pilot signal added to the high-frequency side of the signal are up-converted to microwaves.

[0013] The pilot signal is added to the IF signal (OFDM signal) in the transmitting converter 32 of the transmitting device, and its frequency is set to IF signal + 4 MHz. The broadcasting system uses a slave synchronization low noise method, and the pilot signal is used in the receiving device to cancel the phase noise of the received signal.

[0014] In conventional broadcasting systems, when broadcasting is interrupted or a failure occurs on the transmitting side, neither the up-converted IF signal nor the pilot signal is output, resulting in an SHF signal interruption, as shown in Figure 5(b).

[0015] In other words, when a stop control signal is input from the SHF switch 33 during a broadcast interruption, the conventional broadcast converter 32 stops all SHF signals, resulting in a waveform that is the same as when an SHF signal cannot be output due to a fault.

[0016] Therefore, in conventional broadcasting systems, when an IF signal is not input to a relay destination device (post-stage device) connected downstream of the receiving device 2, it is not possible to distinguish whether this is due to a broadcast interruption or a failure on the transmitting side.

[0017] [Related Technology] Incidentally, a related prior art is JP 2022-118293 A, "Wireless Communication Device" (Patent Document 1). Patent document 1 describes that a wireless communication device recognizes a line disconnection state or a state on the verge of line disconnection based on the number of times and amount of changes in the electric field strength on the receiving side, and determines the state of the air line or the state of equipment failure. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] Japanese Patent Publication No. 2022-118293 Summary of the Invention [Problem to be solved by the invention]

[0019] As mentioned above, in conventional broadcasting systems, when the IF signal (broadcast signal) is not input to the downstream device at the relay destination, there is a problem in that it is not possible to determine whether this is due to a broadcast interruption or a malfunction, and therefore it is not possible to grasp the status of the system.

[0020] Incidentally, Patent Document 1 does not describe a configuration in which a transmitting device transmits only a pilot signal during a broadcast pause, and a receiving device determines that a broadcast pause has occurred based on the received signal and notifies a downstream device of the broadcast pause.

[0021] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a broadcasting system and a broadcasting method that enable a downstream device to determine whether broadcasting is suspended or an abnormality has occurred, and that makes it easy to grasp the system status. [Means for solving the problem]

[0022] The present invention, which solves the problems of the above-mentioned conventional examples, is a broadcasting system comprising a transmitting device that transmits a broadcast signal of terrestrial digital broadcasting and a receiving device that receives the broadcast signal and outputs it to a subsequent stage, wherein the transmitting device adds a pilot signal to the broadcast signal when transmitting the broadcast signal and transmits only the pilot signal when broadcasting is suspended, and the receiving device, when receiving both the broadcast signal and the pilot signal, outputs the broadcast signal after canceling phase noise based on the pilot signal, when receiving only the pilot signal, outputs a signal indicating that broadcasting is suspended, and when not receiving the pilot signal, outputs a signal indicating an abnormality has occurred.

[0023] The present invention also provides the above-mentioned broadcasting system, wherein the transmitting device comprises a first digital modulator that modulates a broadcast signal into an IF signal, a second digital modulator that modulates the broadcast signal into an IF signal, a first transmitting converter that adds a pilot signal to the IF signal from the first digital modulator, up-converts the signal to microwaves, and performs power amplification, a second transmitting converter that adds a pilot signal to the IF signal from the second digital modulator, up-converts the signal to microwaves, and performs power amplification, and a switch that selects and outputs either the output of the first transmitting converter or the second transmitting converter, wherein the switch controls the first transmitting converter and the second transmitting converter to transmit only the pilot signal when it detects a broadcasting pause.

[0024] Furthermore, in the above-mentioned broadcasting system, the present invention is characterized in that the receiving device comprises a distributor that receives and distributes broadcast signals from the transmitting device, a first receiving converter that converts one of the broadcast signals distributed by the distributor into an IF signal, and a second receiving converter that converts the other of the broadcast signals distributed by the distributor into an IF signal, wherein the first receiving converter cancels the phase noise of the IF signal using the added pilot signal, and outputs a signal indicating that broadcasting is suspended if only the pilot signal is received, and outputs a signal indicating that an abnormality has occurred if no pilot signal is received, and the second receiving converter cancels the phase noise of the IF signal using the added pilot signal, and outputs a signal indicating that broadcasting is suspended if only the pilot signal is received, and outputs a signal indicating that an abnormality has occurred if no pilot signal is received.

[0025] Furthermore, the present invention is characterized in that in the above-mentioned broadcasting system, a subsequent device is provided subsequent to the receiving device, and when the subsequent device receives a signal indicating a broadcast pause, it operates in a standby state, and when it receives a signal indicating an abnormality, it operates in a maintenance state.

[0026] The present invention also provides a broadcasting method in a broadcasting system that includes a transmitting device that transmits a terrestrial digital broadcasting signal and a receiving device that receives the broadcast signal and outputs it to a downstream device, wherein when the transmitting device transmits the broadcast signal, it adds a pilot signal to the broadcast signal and transmits it; the receiving device receives both the broadcast signal and the pilot signal and outputs the broadcast signal after canceling phase noise based on the pilot signal; and when broadcasting is suspended, the transmitting device transmits only the pilot signal; and when the receiving device receives only the pilot signal, it outputs a signal indicating that broadcasting is suspended, and when it does not receive the pilot signal, it outputs a signal indicating an abnormality has occurred. [Effects of the Invention]

[0027] According to the present invention, a broadcasting system is provided which comprises a transmitting device which transmits terrestrial digital broadcasting broadcast signals and a receiving device which receives the broadcast signals and outputs them to a subsequent stage, wherein when the transmitting device transmits the broadcast signal, it adds a pilot signal to the broadcast signal and transmits it, and when there is a broadcast pause, it transmits only the pilot signal, and when it receives both the broadcast signal and the pilot signal, it outputs the broadcast signal after canceling phase noise based on the pilot signal, and when it receives only the pilot signal, it outputs a signal indicating that broadcasting is paused, and when it does not receive the pilot signal, it outputs a signal indicating an abnormality has occurred.Therefore, when the subsequent stage of the receiving device does not receive the broadcast signal, it can determine whether the cause is a broadcast pause or an abnormality on the transmitting side, and has the effect of making it easy to grasp the status of the system.

[0028] Furthermore, according to the present invention, there is provided a broadcasting method in a broadcasting system comprising a transmitting device that transmits terrestrial digital broadcasting signals and a receiving device that receives the broadcast signals and outputs them to a downstream device, wherein when the transmitting device transmits a broadcast signal, it adds a pilot signal to the broadcast signal and transmits it, the receiving device receives both the broadcast signal and the pilot signal and outputs the broadcast signal after canceling phase noise based on the pilot signal, and when broadcasting is paused, the transmitting device transmits only the pilot signal, and when the receiving device receives only the pilot signal, it outputs a signal indicating that broadcasting is paused, and when it does not receive the pilot signal, it outputs a signal indicating an abnormality has occurred. Therefore, when a broadcast signal is not received at a downstream device of the receiving device, it can determine whether the cause is a broadcasting pause or an abnormality on the transmitting side, and there is an effect that the state of the system can be easily grasped. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of the present broadcasting system. [Figure 2] FIG. 1 is a schematic diagram illustrating the waveform of an SHF signal in this broadcasting system. [Figure 3] 10 is a flowchart showing the processing in the receiving converter. [Figure 4] FIG. 1 is an explanatory diagram showing a schematic configuration of a conventional broadcasting system. [Figure 5] FIG. 1 is a schematic explanatory diagram of the waveform of an SHF signal in a conventional broadcasting system. DETAILED DESCRIPTION OF THE INVENTION

[0030] An embodiment of the present invention will be described with reference to the drawings. [Outline of the embodiment] A broadcasting system (this broadcasting system) according to an embodiment of the present invention comprises a transmitting device that transmits a broadcast signal, and a receiving device that receives the broadcast signal and outputs it to a downstream device; when the transmitting device transmits a broadcast signal, it adds a pilot signal to the broadcast signal and transmits it; when there is a broadcast pause, it transmits only the pilot signal; when the receiving device receives both the broadcast signal and the pilot signal, it outputs the broadcast signal after canceling phase noise based on the pilot signal; when it receives only the pilot signal, it outputs a signal indicating that there is a broadcast pause; and when it does not receive the pilot signal, it outputs a signal indicating an abnormality has occurred; and when the downstream device does not receive a broadcast signal, it can determine whether this is due to a broadcast pause or an abnormality, making it easy to grasp the status of the system.

[0031] [Outline of the broadcasting system: Figure 1] The general configuration of this broadcasting system will be explained using Fig. 1. Fig. 1 is an explanatory diagram showing the general configuration of this broadcasting system. Fig. 1 shows the state when broadcasting is paused. As shown in Fig. 1, this broadcasting system has basically the same configuration as the conventional broadcasting system shown in Fig. 4, and includes a transmitting device 1 and a receiving device 2. In addition, a subsequent device is connected to the subsequent stage of the receiving device 2. The transmitting device 1 is made redundant by a system including a digital modulator 11a and a transmitting converter 12a and a system including a digital modulator 11b and a transmitting converter 12b, and the receiving device 2 is made redundant by receiving converters 23a and 23b. Explanation of the same parts as in the conventional method will be omitted.

[0032] In this broadcasting system, the operation of the transmitting converter 11 of the transmitting device 1, the SHF switch 13, and the receiving converter 23 of the receiving device 2 during broadcast interruptions and when an abnormality occurs differs slightly from conventional systems, and details will be described later.

[0033] [Transmitter operation: Figure 1] The operation of the transmitting device 1 of this broadcasting system will be described with reference to FIG. When a broadcast signal is input to the transmitting device 1 (normally), the operation is the same as conventional, with the digital modulator 11 performing OFDM modulation, the transmitting converter 12 inserting a pilot signal and up-converting the signal, power amplifying it and outputting it to the SHF switcher 13. The SHF switch 13 outputs one of the SHF signals from the duplicated transmitting converter 12 to the antenna 14 .

[0034] Furthermore, the digital modulator 11 outputs an input signal loss alarm to the SHF switch 13 when no broadcast signal is input. As in the conventional case, the SHF switch 13 detects that a broadcast is suspended when an input signal loss alarm is input from both the digital modulators 11a and 11b of the dual system. A feature of this broadcasting system is that when the SHF switch 13 detects a broadcasting pause, it outputs a broadcasting pause control signal to the transmitting converter 12 to instruct it to output a pilot signal.

[0035] Furthermore, when the transmitting converter 12 receives a broadcast pause control signal from the SHF switch 13, it inserts a pilot signal even when no broadcast signal is being input, upconverts it to microwaves, amplifies it, and outputs it as an SHF signal. The SHF switch 13 outputs the SHF signal from the transmitting converter 12 of the selected system to the antenna 14 . As a result, in the transmitter 1 of this broadcasting system, when the SHF switch 13 detects that a broadcast is not in progress, the output of the broadcast signal is stopped but the output of the pilot signal continues.

[0036] On the other hand, if an abnormality occurs in the transmitting converter 12, the transmitting converter 12 will not be able to add, upconvert, or amplify the pilot signal, and neither the broadcast signal nor the pilot signal will be output from the transmitting converter 12. If both of the transmitting converters 12 of the two systems are in an abnormal state, the SHF signal from the transmitting device 1 is cut off.

[0037] Conventionally, when broadcasting is paused, no SHF signals are input to the SHF switch 13, so even if an abnormality occurs in the transmitting converter 12 in that state, the SHF switch 13 is unable to detect the abnormality. However, in this broadcasting system, since no pilot signal is input from the broadcast converter 12, an abnormality in the broadcast converter 12 can be detected even when broadcasting is paused, and a prompt response can be made.

[0038] Even if one of the transmission converters 12 fails, the other transmission converter 12 will output a broadcast signal and a pilot signal if the other system is operating normally. In this case, the SHF switch 13 continues to output the SHF signal using the other system, as in the conventional case, and notifies the monitor device of the abnormality detection by assigning the number of the abnormal system.

[0039] [Operation of receiving device 2: Figure 1] The receiving converter 23 of the receiving device 2 of this broadcasting system determines whether the broadcast is suspended or there is an abnormality based on the signal received from the transmitting device 1, and outputs a message to that effect to the device connected downstream (the downstream device). Specifically, during normal broadcasting, the receiving converter 23 receives a broadcast signal plus a pilot signal. In this case, as in the past, it down-converts the signal, offsets the phase shift of the IF signal with an inverse phase based on the pilot signal to cancel phase noise, demodulates it, and outputs it as a broadcast signal to a subsequent device.

[0040] Furthermore, when the receiving converter 23 receives only the pilot signal, it determines that broadcasting is suspended, stops outputting the IF signal, and outputs a signal indicating "broadcasting is suspended" (broadcasting suspension signal) to the subsequent device. When the latter device receives the broadcasting pause signal, it outputs an indication that broadcasting is paused using a lamp or the like, and goes into a standby state to prepare for the resumption of broadcasting.

[0041] Furthermore, if the receiving converter 23 does not receive the pilot signal, it determines that an abnormality has occurred in the transmitting device 1, stops outputting the IF signal, and outputs an alarm (abnormality occurrence alarm signal) indicating that an "abnormality has occurred." When the downstream device receives an abnormality alarm, it outputs a warning display indicating the abnormality, and also enters a maintenance state (maintenance mode), where it accumulates a history (log) of received signals and reports it to the monitoring device.

[0042] In addition, if the subsequent device receives the pilot signal normally in the maintenance state, it transitions to a standby state, and if it receives the broadcast signal and pilot signal normally, it transitions to normal operation and broadcasts.

[0043] This allows the downstream device to determine whether a broadcast signal is not being input due to a broadcast interruption or an abnormality on the transmitting side, making it easy to grasp the system status and improving convenience.

[0044] [SHF signal waveform of this broadcasting system: Figure 2] Next, the waveform of the SHF signal in this broadcasting system will be explained using Figure 2. Figure 2 is a schematic diagram of the waveform of the SHF signal in this broadcasting system, with (a) showing the waveform under normal conditions, (b) showing the waveform when broadcasting is suspended, and (c) showing the waveform when an abnormality occurs on the transmitting side. As shown in FIG. 2(a), during normal broadcasting, the transmitting device 1 outputs a broadcast signal that has been up-converted to microwaves and a pilot signal, as in the conventional case.

[0045] 2(b), when there is a broadcast pause, the transmitting device 1 outputs only a pilot signal. When the receiving device 2 receives only the pilot signal, it determines that there is a broadcast pause, stops outputting the IF signal to the subsequent device, and outputs a broadcast pause signal.

[0046] Furthermore, as shown in Fig. 3(c), if an abnormality occurs on the transmitting side, the SHF signal is not output. If the receiving device 2 does not receive either the broadcast signal or the pilot signal, it determines that an abnormality has occurred on the transmitting side, stops outputting the IF signal to the subsequent device, and outputs an abnormality alarm signal.

[0047] In this way, in this broadcasting system, the receiving device 2 determines the state of the transmitting device from the waveform of the received signal and communicates that state to the subsequent device, so that when a broadcast signal is not input to the subsequent device, it can easily determine whether broadcasting is suspended or a problem has occurred in the transmitting device 1.

[0048] [Processing by the receiving converter: Figure 3] Next, the processing in the receiving converter 23 of the receiving device 2 will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the processing in the receiving converter 23. The receiving converter 23 determines whether or not a pilot signal has been received from the transmitting device 1 (S11), and if no pilot signal has been received (No), it stops the output operation of the broadcast signal, outputs an abnormality occurrence alarm signal indicating that an abnormality has occurred on the transmitting side to the subsequent device (S12), and returns to processing S11.

[0049] Furthermore, if a pilot signal is received in step S11 (Yes), the receiving converter 23 further determines whether or not the received signal includes a broadcast signal (S13). If the received signal contains a broadcast signal (Yes), that is, if the received signal is a broadcast signal plus a pilot signal, the receiving converter 23 cancels the phase shift of the broadcast signal with an inverse phase based on the pilot signal to reduce phase noise (S14), outputs the broadcast signal to a downstream device (S15), and returns to processing S11.

[0050] Also, in process S13, if the received signal does not contain a broadcast signal (No), that is, if the received signal is only a pilot signal, the receiving converter 23 stops outputting the broadcast signal, outputs a broadcast pause signal indicating that broadcasting is paused to the downstream device (S16), and returns to process S11. In this manner, the processing of the receiving converter 23 is carried out.

[0051] [Effects of the embodiment] According to this broadcasting system and method, when the SHF switch 13 of the transmitting device 1 detects a broadcasting pause, it controls the transmitting converter 12 to output only a pilot signal. This means that when the transmitting device 1 transmits a broadcast signal, it adds a pilot signal to the broadcast signal and transmits it, and when there is a broadcasting pause, it transmits only the pilot signal. When the receiving device 2 receives both the broadcast signal and the pilot signal, it outputs the broadcast signal after canceling the phase noise based on the pilot signal, and when it receives only the pilot signal, it outputs a signal indicating that there is a broadcasting pause. If the pilot signal is not received, it outputs a signal indicating an abnormality. This has the effect of making it easy to understand the status of the system when a subsequent device does not receive a broadcast signal, by determining whether the cause is a broadcasting pause or an abnormality on the transmitting side. [Industrial Applicability]

[0052] The present invention is suitable for a broadcasting system and a broadcasting method that enable a subsequent device to determine whether broadcasting is suspended or an abnormality has occurred, and that allows the system status to be easily grasped. [Explanation of symbols]

[0053] 1,3...Transmitting device, 2,4...Receiving device, 11,31...Digital modulator, 12,32...Transmitting converter, 13,33...SHF switch, 14,21,34,41...Antenna, 22,42...Receiving shared distributor, 23,43...Receiving converter

Claims

1. A broadcasting system including a transmitting device that transmits a broadcasting signal of a terrestrial digital broadcasting and a receiving device that receives the broadcasting signal and outputs it to a subsequent stage, the transmitting device, when transmitting the broadcast signal, adds a pilot signal to the broadcast signal and transmits it, and when broadcasting is paused, transmits only the pilot signal; The receiving device, when receiving both the broadcast signal and the pilot signal, outputs the broadcast signal after canceling phase noise based on the pilot signal, when receiving only the pilot signal, outputs a signal indicating that broadcasting is suspended, and when not receiving the pilot signal, outputs a signal indicating an abnormality has occurred.

2. The transmitting device a first digital modulator that modulates the broadcast signal into an IF signal; a second digital modulator that modulates the broadcast signal into an IF signal; a first transmitting converter that adds the pilot signal to the IF signal from the first digital modulator to up-convert it to a microwave and perform power amplification; a second transmitting converter that adds the pilot signal to the IF signal from the second digital modulator to up-convert it to a microwave and perform power amplification; a switch that selects and outputs either the output of the first transmission converter or the output of the second transmission converter, 2. The broadcasting system according to claim 1, wherein said switch controls said first transmission converter and said second transmission converter to transmit only said pilot signal when said switch detects a broadcasting pause.

3. The receiving device a distributor that receives and distributes the broadcast signal from the transmitter; a first receiving converter that converts one of the broadcast signals split by the splitter into an IF signal; a second receiving converter that converts the other of the broadcast signals distributed by the distributor into an IF signal, the first receiving converter cancels the phase noise of the IF signal using the added pilot signal, and outputs a signal indicating that broadcasting is suspended when only the pilot signal is received, and outputs a signal indicating that an abnormality has occurred when the pilot signal is not received; 3. The broadcasting system according to claim 2, wherein the second receiving converter cancels the phase noise of the IF signal using the added pilot signal, outputs a signal indicating that broadcasting is suspended when only the pilot signal is received, and outputs a signal indicating an abnormality when the pilot signal is not received.

4. a subsequent device is provided at the subsequent stage of the receiving device; 2. The broadcasting system according to claim 1, wherein said subsequent device operates in a standby state when said broadcasting suspension signal is input, and operates in a maintenance state when said abnormality occurrence signal is input.

5. A broadcasting method in a broadcasting system including a transmitting device that transmits a broadcasting signal of a terrestrial digital broadcasting and a receiving device that receives the broadcasting signal and outputs it to a subsequent device, When the transmitting device transmits the broadcast signal, it adds a pilot signal to the broadcast signal and transmits it, and the receiving device receives both the broadcast signal and the pilot signal, cancels phase noise in the broadcast signal based on the pilot signal, and outputs the broadcast signal, A broadcasting method characterized in that, during a broadcasting pause, the transmitting device transmits only the pilot signal, and the receiving device outputs a signal indicating that a broadcasting pause has occurred if it receives only the pilot signal, and outputs a signal indicating an abnormality has occurred if it does not receive the pilot signal.

Images