JP2007201856A - Method and program of monitoring sneak in apparatus for retransmitting digital broadcast - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and program of monitoring sneak for achieving an inexpensive and high-performance digital broadcast retransmitting apparatus insusceptible to sneaking interference with a simple configuration, and suitable for retransmission of a digital broadcast. <P>SOLUTION: If a receiving BER is the same as or smaller than a predetermined reference value, an output is set at a predetermined level. If the receiving BER is larger than the predetermined reference value, an output is set at an operation level lower than the predetermined level by a predetermined quantity. If a state determined that the receiving BER is larger than the predetermined reference value continues for a predetermine period; a signal attenuating means is caused to perform a squelch operation, and the value of the receiving BER determined to be larger than the predetermined reference value is stored as a first reference value. Then, if the receiving BER is determined to be smaller than the first reference value in a state where the signal attenuating means is performing the squelch operation; a newly acquired receiving BER is stored as a second reference value instead of the first reference value, and the output after amplification by the signal amplifying means is set at an operation level. Further, if the newly acquired receiving BER is smaller than the second reference value in a state where the output is an operation level, the output after amplification by the signal amplifying means is set at the predetermined level. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a digital broadcast retransmission apparatus at a relay station that retransmits terrestrial digital broadcasts, and more particularly, a digital broadcast retransmission apparatus that detects and prevents interference due to wraparound between a reception antenna and a transmission antenna provided in the retransmission apparatus. The present invention relates to a wraparound monitoring method and a monitoring program.

In terrestrial digital broadcasting, it is considered to retransmit by SFN (Single Frequency Network) as a retransmitting device to a radio interference area. In this case, if the radio wave radiated from the transmitting antenna provided in the retransmitting device wraps around the receiving antenna provided in the retransmitting device and receiving the radio wave from the master station, the signal may deteriorate or in the worst case. The re-transmission device may oscillate. To cope with this, the physical distance between the receiving antenna and the transmitting antenna is maintained, the wraparound phenomenon is electrically canceled, the characteristics of the receiving antenna are improved, etc. The method has been taken.
For example, first frequency conversion means for frequency conversion to an intermediate frequency for signal processing, intermediate frequency signal processing means for signal processing the output of the first frequency conversion means, and output of the intermediate frequency signal processing means A second frequency converting means for converting the frequency into the frequency band of the received digital broadcast; and a local signal generating means for generating a signal for frequency conversion of the first frequency converting means and the second frequency converting means. In this conventional retransmission apparatus, the purpose of use is to retransmit to a radio interference area, the target area is small, and the output power of the retransmission apparatus can be reduced. Therefore, in order to avoid the wraparound phenomenon that occurs between the reception antenna and the transmission antenna, the wraparound phenomenon is avoided by physically separating the reception antenna and the transmission antenna. It had been made.
(For example, see Patent Document 1)
There has also been proposed a single frequency broadcast wave repeater configured to compensate for a sneak component using a pilot signal.
(For example, see Patent Document 2)

JP 2003-060997 A JP 2004-328286 A

However, according to the digital broadcast retransmitting apparatus as shown in Patent Document 1, in order to avoid the wraparound phenomenon that occurs between the receiving antenna and the transmitting antenna, the receiving antenna and the transmitting antenna are physically separated. However, if it is too far away, it is disadvantageous in terms of cost because it is necessary to secure the installation location and consider the support brackets. Furthermore, during operation after the digital broadcast retransmission device is installed, if a wraparound phenomenon occurs due to changes in the device characteristics or environmental changes due to buildings or trees in the surrounding area, There was a problem that reception interference occurred in the entire radio interference area.
In addition, in a relay device that compensates the sneak component using a pilot signal as shown as a representative example in Patent Document 2, a circuit is complicated because a pilot signal generator and a canceller for compensating the sneak component are required. As a result, there is a problem that the cost of the retransmission apparatus is high.
Therefore, in this application, it was made to solve these problems.
The purpose is to provide a wraparound monitoring method and a monitoring program for realizing an inexpensive and high-performance digital broadcast retransmission apparatus suitable for digital broadcast retransmission.
Another object is to provide a wraparound monitoring method and a monitoring program in order to realize a digital broadcast retransmission apparatus that is resistant to wraparound interference with a simple configuration.
Another object is to provide a monitoring method and a monitoring program for a digital broadcast retransmission apparatus that can detect and prevent interference due to wraparound.

In order to solve the above-mentioned problems, the invention of claim 1 is configured to receive a digital broadcast wave by a receiving antenna and retransmit the signal from the receiving antenna as a digital broadcast wave from the transmitting antenna by performing predetermined signal processing. In the monitoring method for detecting and preventing the sneak interference of the digital broadcast retransmitting apparatus configured as described above, the digital broadcast retransmitting apparatus passes at least a signal received by the receiving antenna and a part of the signal. A signal processing unit comprising: a signal branching unit for branching the signal; a signal attenuating unit for attenuating the output of the signal branching unit by a predetermined level; and a signal amplifying unit for amplifying the output of the signal attenuating unit to a predetermined level; And selectively selecting a signal of a predetermined broadcast channel from the branch output of the means and a predetermined data from the signal of the broadcast channel. Channel selection / demodulation means for demodulating, processing predetermined data demodulated by the channel selection / demodulation means to calculate a reception bit error rate, and a reception bit error rate obtained from the result, Attenuation amount of the signal attenuating means is compared / determined with a predetermined reference value of a bit error rate provided in advance in the demodulating means, and the output after amplification by the signal amplifying means becomes a predetermined level based on the determination result Monitoring / control means for controlling the output of the signal amplification means when the reception bit error rate is determined to be equal to or smaller than the predetermined reference value. The signal attenuating means controls the attenuation amount so as to reach a level. When the received bit error rate is determined to be greater than the predetermined reference value, the signal amplifying means amplifies the signal. Output of the to a predetermined level than a predetermined amount lower operational level, to control the attenuation of the signal No. damping means, as configured.

According to a second aspect of the present invention, there is provided a monitoring method for detecting and preventing sneaking interference of the digital broadcast retransmitting apparatus according to the first aspect, wherein the monitoring / control means has a reception bit error rate that is equal to the predetermined reference value. If it is determined that they are the same or smaller, the attenuation amount of the signal attenuating means is controlled so that the output after amplification by the signal amplifying means becomes a predetermined level. If it is determined, the received bit error rate controls the attenuation amount of the signal signal attenuating means so that the output after amplification by the signal amplifying means becomes an operation level lower than the predetermined level by a predetermined amount. If the state determined to be greater than the value continues for a predetermined period, control is performed so that the attenuation amount of the signal attenuation means is maximized and the squelch operation is performed. A value of the received bit error rate determined to be larger than the predetermined reference value is stored as a first reference value. In a state where the signal attenuating means is in a squelch operation, the newly acquired received bit error rate is the first value. When it is determined that the received bit error rate is smaller than the first reference value, the newly received bit error rate is stored as the second reference value instead of the first reference value, and the output after amplification by the signal amplification means is The amount of attenuation of the signal attenuating means is controlled so as to be at the operational level. In the state where the output is at the operational level, it is determined that the newly acquired received bit error rate is smaller than the second reference value. In this case, the output after amplification by the signal amplification means is controlled to be the predetermined level.

According to a third aspect of the present invention, there is provided a monitoring method for detecting and preventing sneak interference of the digital broadcast retransmission apparatus according to any one of the first or second aspects, wherein the monitoring / control means includes a signal Control of the amount of attenuation of the signal signal attenuating means so that the output after amplification by the amplifying means is a predetermined level lower than the predetermined level, and the output after amplification by the signal amplifying means is a predetermined amount from the operational level. When controlling the amount of attenuation of the signal attenuation means to a high predetermined level, the predetermined amount is divided into a plurality of times step by step, and the output is controlled to vary stepwise.

According to a fourth aspect of the present invention, there is provided a monitoring method for detecting and preventing sneak interference of the digital broadcast retransmitting apparatus according to any one of the first to third aspects, at least by the monitoring / controlling means. The processing is configured to be performed within the guard interval added to the digital broadcast signal.

According to a fifth aspect of the present invention, there is provided a monitoring method for detecting and preventing sneak interference of the digital broadcast retransmitting apparatus according to any one of the first to fourth aspects, wherein the digital broadcast retransmitting apparatus includes a plurality of the digital broadcast retransmitting apparatuses. Provided on the input side is provided with a distribution means for distributing the signal received by the receiving antenna into a predetermined number, and on the output side is provided with a synthesis means for synthesizing the output signal, for each digital broadcast retransmitting device. Configured to monitor.

The invention of claim 6 is a program used in a monitoring method for detecting and preventing sneaking interference of a digital broadcast retransmission apparatus.
The monitoring method for detecting and preventing the sneak interference of the digital broadcast retransmission apparatus according to any one of claims 1 to 5 is configured to be executed.

According to the first aspect of the present invention, a digital broadcast configured to receive a digital broadcast wave by a receiving antenna and retransmit the signal from the receiving antenna as a digital broadcast wave from the transmitting antenna by performing predetermined signal processing. In the monitoring method for detecting and preventing sneaking interference of the retransmitting apparatus, the digital broadcast retransmitting apparatus passes at least a signal received by the receiving antenna and branches a part of the signal. A signal processing means comprising a signal attenuating means for attenuating the output of the signal branching means by a predetermined level, a signal amplifying means for amplifying the output of the signal attenuating means to a predetermined level, and a branch output of the signal branching means, Channel selection / demodulation that selectively tunes a signal of a predetermined broadcast channel and demodulates predetermined data from the signal of the broadcast channel And a reception bit error rate obtained by processing predetermined data demodulated by the channel selection / demodulation means, and a reception bit error rate obtained from the result, provided in the channel selection / demodulation means in advance. Monitoring / control for comparing and determining a predetermined reference value of the bit error rate, and controlling the attenuation amount of the signal attenuating means so that the output after amplification by the signal amplifying means becomes a predetermined level based on the determination result And when the reception bit error rate is determined to be equal to or smaller than the predetermined reference value, the monitoring / control unit is configured so that the output after amplification by the signal amplification unit becomes a predetermined level. When it is determined that the received bit error rate is greater than the predetermined reference value, which controls the attenuation amount of the signal attenuating means, the output after amplification by the signal amplifying means is As a predetermined amount lower operational level than level, to control the attenuation of the signal No. attenuation means, it is arranged that,
Even if a signal sneaks from the transmitting antenna to the receiving antenna due to changes in the surrounding environment after installation, changes in the installation status, changes over time in electrical characteristics, etc., a "bit error rate error" By constantly monitoring the signal degradation due to "abnormal bit error rate", the signal attenuation means is controlled by a predetermined amount, the output level radiated from the transmitting antenna is lowered by a predetermined amount, and the wraparound of the radio wave is avoided. With this simple and inexpensive method, it is possible to prevent signal degradation due to sneaking in and, in the worst case, the retransmission apparatus oscillating and destroying the apparatus.

According to a second aspect of the present invention, in the monitoring method for detecting and preventing sneak interference of the digital broadcast retransmitting apparatus according to the first aspect, the monitoring / controlling unit is configured such that the received bit error rate is the predetermined reference. When it is determined that the value is equal to or smaller than the value, the attenuation amount of the signal attenuating means is controlled so that the output after amplification by the signal amplifying means becomes a predetermined level. If determined to be large, the received bit error rate for controlling the attenuation amount of the signal signal attenuating means is such that the output after amplification by the signal amplifying means is an operation level lower than the predetermined level by a predetermined amount. If the state determined to be larger than the predetermined reference value continues for a predetermined period, the control is performed so that the squelch operation is performed by setting the attenuation amount of the signal attenuation means to the maximum value. The received bit error rate value determined to be greater than the predetermined reference value is stored as a first reference value. When the signal attenuating means is in a squelch operation, the newly acquired received bit error rate is If it is determined that the received bit error rate is smaller than the first reference value, first, the newly acquired reception bit error rate is stored as the second reference value instead of the first reference value, and after the amplification by the signal amplification means The amount of attenuation of the signal attenuating means is controlled so that the output is at the operation level. When the output is at the operation level, it is determined that the newly acquired received bit error rate is smaller than the second reference value. In this case, since the output after amplification by the signal amplification means is controlled so as to be the predetermined level,
Even if a signal sneaks from the transmitting antenna to the receiving antenna due to changes in the surrounding environment after installation, changes in the installation status, changes over time in electrical characteristics, etc., a "bit error rate error" By constantly monitoring the signal degradation due to "abnormal bit error rate", the signal attenuation means is controlled by a predetermined amount, the output level radiated from the transmitting antenna is lowered by a predetermined amount, and the wraparound of the radio wave is avoided. In this simple and inexpensive method, it is possible not only to prevent signal degradation due to wraparound, and in the worst case, the retransmission apparatus oscillates and destroys the apparatus, but also "abnormal bit error rate" Judgment is made in the system between the receiving antennas, the output level can be stopped, and unnecessary radio waves can be prevented from being emitted. Can.
In addition, the input bit error rate is constantly monitored, and when the bit error rate is restored, retransmission can be automatically resumed, saving labor for facility management maintenance.

According to a third aspect of the present invention, in the monitoring method for detecting and preventing sneak interference of the digital broadcast retransmission apparatus according to any one of the first or second aspects, the monitoring / control means comprises: , Control of the attenuation amount of the signal number attenuating means so that the output after amplification by the signal amplifying means is a predetermined level lower than the predetermined level, and the output after amplification by the signal amplifying means is higher than the operating level. When controlling the amount of attenuation of the signal signal attenuating means, which is a predetermined level that is high only by a fixed amount, the predetermined amount is divided into a plurality of times step by step, and the output is controlled to be varied step by step. So
Rather than suddenly stopping the output level, the output level is decreased step by step by a predetermined amount, and the radio wave radiated from the transmitting antenna is controlled to gradually weaken, while maintaining retransmission and the “bit error rate” "Abnormal" can be avoided.
In addition, since the wraparound phenomenon is avoided while gradually reducing the output level in this way, in the state where the wraparound is avoided by lowering the output level, the service area when the retransmitter is at full power and In comparison, although the target service area covers a slightly narrow area, it is possible to maintain retransmission with a signal that does not wrap around, and all households in the service area subject to retransmission are subject to signal degradation due to the sneak phenomenon. Therefore, it is possible to prevent a reception failure from occurring.

According to a fourth aspect of the present invention, in the monitoring method for detecting and preventing sneak interference of the digital broadcast retransmitting apparatus according to any one of the first to third aspects, at least the monitoring / controlling. Since the processing by means is configured to be performed within the guard interval added to the digital broadcast signal,
TV images can be processed without block noise or blackouts.

According to a fifth aspect of the present invention, in the monitoring method for detecting and preventing wraparound interference of the digital broadcast retransmitting apparatus according to any one of the first to fourth aspects, the digital broadcast retransmitting apparatus And a distribution means for distributing the signals received by the receiving antennas to a predetermined number on the input side, and a synthesis means for synthesizing the output signals on the output side. Because it was configured to monitor for
A multi-channel retransmission apparatus can be provided.

According to a sixth aspect of the present invention, in the program used for the monitoring method for detecting and preventing the sneak interference of the digital broadcast retransmitting apparatus, the digital broadcast according to any one of the first to fifth aspects is provided. Since the monitoring method for detecting and preventing the sneaking interference of the retransmitting apparatus is executed, it can be realized with a simple configuration.

Hereinafter, an example of an embodiment embodying the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic block diagram of a digital broadcast retransmission apparatus according to the first embodiment of the present invention, and FIG. 2 shows an example of a flowchart showing signal processing in the monitoring / control means provided for the first embodiment of the present invention. .
In the following embodiments, those having the same functions are given the same reference numerals unless otherwise specified, and detailed description thereof is omitted.

FIG. 1 is a schematic block diagram showing the configuration of a digital broadcast retransmission apparatus according to the first embodiment of the present invention. In FIG. 1, 1 is a digital broadcast retransmitting device, 2 is a receiving antenna, and 3 is a transmitting antenna. The high-frequency signal path includes at least a signal branching unit 11, a signal attenuating unit 15, and a signal amplifying unit 18, and a data signal path includes a channel selection / demodulation unit 12 and a monitoring / control unit 13. Yes. Reference numeral 28 denotes signal processing means. In the embodiment of the present invention, this signal processing means is a filter means.

Next, details of the digital broadcast retransmission apparatus 1 will be described. The receiving antenna 2 is an antenna for receiving terrestrial digital broadcast waves, so-called UHF band radio waves. In the embodiment of the present invention, for example, by using a parabolic antenna having excellent directivity characteristics, Can be cut off. The signal of the terrestrial digital broadcast wave received by the receiving antenna 2 passes through this signal and is output, and is input to the signal branching means 11 for branching a part of the signal. The signal branching means 11 is composed of a branch circuit provided with a branch transformer formed by winding a polyurethane wire around a ferrite core, for example.
The output from the signal branching means 11 is input to the signal processing means 28. This signal processing means 28 is for restricting the passage of the signal or for compensating the signal. In the embodiment of the present invention, for example, a signal in a predetermined band is selectively passed and blocked outside the predetermined band. It comprises filter means. The signal that has passed through the filter means 28 is input to a signal attenuating means 15 that attenuates the output by a predetermined level. In the embodiment of the present invention, the signal attenuating means 15 is composed of, for example, a PIN diode as a high-frequency element, and is configured such that the amount of attenuation can be appropriately varied by controlling the voltage.
The output from the signal attenuating means 15 is appropriately amplified by a signal amplifying means 18 for amplifying a high frequency signal composed of, for example, a diode or an IC as a high frequency element, supplied to the transmission antenna 3, and digital broadcasting from the transmission antenna 3. It is emitted as a wave.
In the first embodiment of the present invention, at least the signal branching unit 11, the signal attenuator 15, and the signal amplifying unit 18 constitute the signal processing unit 10 described in the claims.

Next, the channel selection / demodulation means 12 accepts a terrestrial digital broadcast wave from the branch output of the signal branching means 11, selectively selects a signal of a predetermined broadcast channel from the broadcast wave, This is a so-called tuner that demodulates predetermined data from a signal included in a channel.
In the embodiment of the present invention, the channel selection / demodulation means 12 obtains a basic BER (Bit Error Rate: hereinafter referred to as BER) of a signal received by the receiving antenna 2. Is obtained.

The monitoring / control unit 13 acquires predetermined data demodulated by the channel selection / demodulation unit 12 (basic data on which BER is based in the embodiment of the present invention), calculates the BER from the data, Control for comparing / determining the BER obtained from the result and a predetermined reference value of BER provided in advance in the monitoring / control unit 13 and controlling the attenuation amount of the signal attenuation unit 15 based on the result It is configured to generate a voltage.
That is, when the monitoring / control unit 13 according to the first embodiment of the present invention determines that the acquired BER is the same as the predetermined reference value (no change) or small (good), the signal amplification unit 18 performs the amplification. The amount of attenuation of the signal attenuating means 15 is controlled so that the output becomes a predetermined level, and when the BER is determined to be larger (bad) than the predetermined reference value, the output after amplification by the signal amplifying means 18 is predetermined. The attenuation amount of the signal attenuation means 15 is controlled so as to be lower than the level by a predetermined amount.
In the embodiment of the present invention, an example of a single retransmission apparatus is shown. However, a distributor is provided on the input side of the signal processing unit 10 and a mixer is provided on the output side. Also good.

Here, an example of the operation of the monitoring / control means 13 will be described with reference to the flowchart shown in FIG.
S10 shows the initial state of the digital broadcast retransmitting apparatus, and the attenuation amount of the signal attenuation means 15 is set to be the minimum value. Next, in S12, the BER is calculated using the data acquired by the channel selection / demodulation means 12 from the signal received by the receiving antenna. In S14, it is determined whether the calculated BER value is larger than a predetermined reference value provided in the monitoring / control means 13 in advance (BER is bad) or smaller (BER is good). At this time, if it is determined that the BER of the received signal is equal to or smaller than the predetermined reference value, the process returns to S10 and the BER is continuously monitored. This monitoring is configured so that the timing for measuring the BER can be arbitrarily set in advance, and can be continuously monitored every predetermined time.

Next, if it is determined in S14 that the BER of the received signal is larger than the predetermined reference value, the process proceeds to S16, and a warning signal for notifying the occurrence of “BER abnormality” is generated. This “BER abnormality” warning signal is used to display “BER abnormality” on the retransmission apparatus by turning on a display means such as an LED which is not shown in the figure provided in the retransmission apparatus. Or, based on the warning signal of “BER abnormality”, the terminal device provided in the re-transmission device is used to notify the facility manager through the public telephone network. Is for. The “BER abnormality” warning signal may be continuously output once the “BER abnormality” is detected, or may be continuously output until a predetermined time elapses.

Next, in S18, the number of times that “BER abnormality” is detected in the BER measurement is counted. Further, in S20, an arbitrary first reference number n (times) is set in advance as a pass / fail judgment criterion for the number of measurements for which “BER abnormality” is measured, and the number of measurements for which “BER abnormality” is detected is set. If the predetermined first reference number n (times) is not exceeded, the process proceeds to S202, and the signal attenuating means 15 is controlled and amplified to determine whether the "BER abnormality" is continuous or temporary. Change the output level later and measure the BER again. That is, in the embodiment of the present invention, if the “BER abnormality” is first confirmed (first measurement), the attenuation amount of the signal attenuation means 15 is increased from the monitoring / control means 13 by a predetermined amount α (dB). A control signal is generated and output so as to be performed (lower the output level). Next, when the output level is lowered by a predetermined amount in this way, the process returns to S12, and data is again obtained from the channel selection / demodulation means 12, and the BER is calculated.

Next, if the BER newly acquired in S14 is within the normal value, the process returns to S10 and monitoring is continued. Further, if the BER newly acquired in S14 again shows an abnormal value, the warning signal “BER abnormal” is continuously generated in S16, and the “BER abnormal” is counted for the second time in S18, and the signal is attenuated. The attenuation amount of the means 15 is increased by 2α (dB), and the process returns to S12. Then, in S20, this operation is repeated until the number of measurement of “BER abnormality” reaches the first reference number n (times). Therefore, if the number of times of measurement of “BER abnormality” is recognized n times, the attenuation amount of the signal attenuation means 15 is α × n (dB), and the output level is lowered by that amount and radiated.

Next, if it is determined in S20 that the number of times of measurement of “BER abnormality” exceeds the first reference number n (times) and becomes n + 1 (times), the attenuation amount of the signal attenuation means 15 is set to the maximum value in S22. The signal attenuating means 15 operates as a squelch circuit. Further, in S24, the BER acquired when the number of times of measurement of “BER abnormality” is n + 1 (times) is stored as a first reference value. Then, in S26, an “output stop” warning signal for notifying that the retransmission apparatus is in the output stop state is generated. This “output stop” warning signal may also be used to display the display means provided in the re-transmission device in the same manner as the above-mentioned “BER abnormality” warning signal. May be used to notify the administrator.

In the above embodiment, the output level is sequentially lowered to change the amount of wraparound, and the output level is set to the point where the BER is improved. However, the present invention is not particularly limited to this example. , If it is determined that the BER is larger than the predetermined reference value, the output level may be decreased by a predetermined amount (for example, an amount corresponding to the above-described attenuation amount α × n (dB)) at a time. In addition, the BER measurement result may be set such that the BER can be maintained within a predetermined reference value while gradually increasing the output level while monitoring the BER from a state where the output level has decreased by a predetermined amount. If the output level is changed by a predetermined amount based on this, the present invention is not particularly limited to the embodiment.
Further, a series of processing time until the output level by the monitoring / control means 13 is set to a predetermined level is a guard added to the digital broadcast signal by using, for example, a CPU having a high operating frequency and a high processing capability. If it is performed within the interval period (126 μs), it is possible to process without causing block noise or blackout (video loss) in the television image. In addition, the number of times of processing can be increased by using a high processing capability.

Next, the operation state after the output stop state is shown. In the embodiment of the present invention, monitoring of BER at the input is continued even when the output is stopped.
In the timer circuit of S30, if a predetermined time has elapsed after the squelch circuit is operated, the BER is recalculated in S32 using the latest data obtained from the channel selection / demodulation means 12. Further, in S34, the BER remeasured in S32 is compared with the BER as the first reference value stored in S24, and the BER remeasured in S32 is stored in the first memory stored in S24. If it is determined that it is equal to or larger than the reference value (no improvement is seen in the BER), the process proceeds to S306.
In S306, if it is determined that the BER remeasured in S32 is larger than the predetermined reference value, the process returns to S22 and the monitoring of the BER is continued in the squelch operation state in which the attenuation amount of the signal attenuation means is the maximum value. In S306, if it is determined that the BER remeasured in S32 is smaller than the predetermined reference value, the process returns to S30 to continue monitoring the BER.

Next, in S34, if it is determined that the BER reacquired in S32 is smaller than the BER as the first reference stored in S24 (BER has been improved), the process proceeds to S36. In S36, the BER as the first reference value stored in S24 is reset, and the BER recalculated in S32 is newly stored as the second reference value. Further, in S38, the number of times when it is confirmed that the newly acquired BER is improved by comparing the recalculated BER with the stored BER is counted.
Furthermore, in S40, an arbitrary second reference number n (times) is set in advance as a determination criterion for this count. The second reference number is set to be the same as the first reference number determined in S20, and the BER improvement confirmation does not exceed the predetermined second reference number n (times) in S402. The attenuation amount of the signal attenuating means 15 is controlled, and a series of operations such as re-measurement of the BER is repeated in S32, and it is determined whether or not the BER is in a recovery tendency.

That is, in S402, when it is confirmed (first time) that the BER is in a recovery tendency at the time of re-measurement after a predetermined time has passed after entering the squelch operation state, the attenuation amount of the signal attenuation means 15 is set in S22. The maximum value (squelch operation state) is controlled to be α × n (dB) so that the radio wave is retransmitted from the transmission antenna. Along with this, the generation of the “output stop” warning signal is canceled in S404, and the fact that the retransmission has been resumed is displayed on the display means or the administrator is notified. Next, when the output level is increased in this way, the process returns to S32, and the BER of the input signal is calculated in the state where the data is acquired again from the channel selection / demodulation means 12 and the output level is increased. Next, if the BER newly acquired with the output level raised in S34 is larger than the BER as the second reference value stored in the memory, the process proceeds to S306. In S306, the BER newly acquired with the output increased is compared with the predetermined reference value. If it is determined that the BER newly acquired with the output increased is larger than the predetermined reference value, the process proceeds to S22. Monitoring of the BER is continued in a squelch operation state in which the return signal attenuation means has the maximum attenuation. Further, if it is determined that the newly acquired BER with the output increased in S32 is smaller than the predetermined reference value, the attenuation amount of the signal attenuation means 15 is maintained at α × n (dB) set in S402. Returning to S30, monitoring of BER is continued.

If the newly acquired BER in the state where the output level is increased in S34 shows a value smaller than the stored BER, and "BER improvement" is confirmed (second time), the second stored in S36 is stored. BER as a reference value of the BER is reset, and a newly acquired BER value is newly stored in a state where the output level is raised. Further, in S38, the number of “BER improvement” confirmations is counted. In this example, after the squelch circuit is activated, the first BER improvement is confirmed for the first time, and the first BER improvement is confirmed. When the output level is first raised, the BER improvement is confirmed. Then it will be the second “BER improvement” confirmation. This operation is repeated until the “BER improvement” confirmation count reaches the second reference count n (times). That is, in S402, based on the “BER improvement” confirmation count in S38, if the count is 1, the attenuation of the signal attenuation means 15 is α × n (dB), and if the count is 2, α × n−α ( dB), if the count is 3, α × n−2α (dB)..., when the count reaches the second reference number n (times), α × n−α × (n−1) (dB ), The output level is gradually increased, the BER value is confirmed in S32, and the emission of the retransmitted radio wave is resumed.

If “BER improvement” is confirmed to be n + 1 in S40, the attenuation amount of the signal attenuating means is controlled to the minimum value in S42, and a cancellation signal for the “BER abnormal” warning signal is generated in S44, indicating that the BER is normal. Is displayed on the display means or notified to the administrator. When the “BER abnormality” is not detected in this way, the process returns to S10 and continues to monitor BER.

The output level control in this squelch state has shown an example in which the output level is sequentially raised to change the amount of wraparound and the output level is set at a point where the BER is improved. However, the output level control is not particularly limited to this embodiment. Alternatively, if it is determined that the BER is smaller than the predetermined reference value, the output level may be increased by a predetermined amount at a time.
In addition, a series of processing time until the output level by the monitoring / control means 13 described above is set to a predetermined level is added to the digital broadcast signal by using, for example, a CPU whose operating frequency is high and processing capability is high. If the processing is performed within the guard interval period (126 μs), processing can be performed without causing block noise or blackout in the television image. In addition, the number of times of processing can be increased by using a high processing capability.

Here, the operation and effect of the digital broadcast retransmitting apparatus 1 configured as described above will be described. The digital broadcast retransmitting apparatus 1 of the present invention is suitable as a retransmitting apparatus for a radio wave disturbance area in terrestrial digital broadcasting, and it is considered to retransmit by SFN. In this case, if the radio wave radiated from the transmission antenna 3 provided in the retransmitting device 1 wraps around the receiving antenna 2 provided in the retransmitting device 1 and receiving the radio wave from the master station, the signal deterioration or worst case may occur. In this case, the retransmission apparatus may oscillate. To cope with this, it is possible to maintain the physical distance between the receiving antenna and the transmitting antenna. However, if it is too far away, it will be disadvantageous in terms of cost because it is necessary to secure the installation location and to consider the support brackets. become. Furthermore, when the digital broadcast retransmitting apparatus 1 is installed, a wraparound phenomenon may occur due to a change in characteristics or an environmental change due to buildings or trees in the surrounding area. A reception failure occurs in the entire radio interference area to be retransmitted.

Therefore, in the present invention, in the state when the wraparound phenomenon occurs, attention is paid to the change in BER that greatly affects the received image in the data obtained from the received signal of the terrestrial digital broadcast, and the deterioration of the BER. A limit value that affects the image is set in the monitoring / control unit 13 in advance as a predetermined reference value, and the BER at the input is always monitored by the channel selection / demodulation unit 12 and the monitoring / control unit 13. , Compare and determine the data obtained from the monitoring and a predetermined reference value, and if it is determined that a “BER abnormality” has occurred, the output level is lowered by a predetermined amount to avoid signal deterioration due to wraparound It is configured to do.

Furthermore, if the “BER abnormality” is not improved even if the output level is lowered by a predetermined amount, a “BER abnormality” in the system between the master station and the receiving antenna or a failure of the retransmission apparatus itself can be considered. After lapse of time, the squelch circuit can be operated to prevent unnecessary radio waves from being radiated from the output.

Furthermore, even when the squelch circuit is in operation, the BER at the input is continuously monitored. If “BER abnormality” is not recognized, the output level is set to a predetermined amount while confirming whether or not BER abnormality occurs again. It is configured so that retransmission can be automatically restored by raising it little by little.

In other words, according to the digital broadcast retransmitting apparatus 1 of the present invention, a signal wraps around from the transmitting antenna 3 to the receiving antenna 2 due to changes in the surrounding environment after installation, changes in the installation state, secular changes in electrical characteristics, and the like. Even if signal degradation occurs due to this, by constantly monitoring the “BER abnormality” of the input signal that accompanies this, if the “BER abnormality” is confirmed, the output level is lowered by a predetermined amount. Since the radio wave radiated from the transmitting antenna 3 is weakened so that the sneak phenomenon can be avoided, the signal degradation due to sneaking or the retransmission device oscillates and destroys the device by a simple and inexpensive method. Can be prevented.

Also, is it possible to avoid the wraparound phenomenon by controlling the electric wave radiated from the transmitting antenna 3 to be gradually weakened while decreasing the output level step by step by a predetermined amount instead of suddenly stopping the output level? Since it is configured to check whether or not, it is easy to know whether the cause of the “BER abnormality” is caused by wraparound or in the system between the master station and the receiving antenna 2. In addition, if a “BER error” occurs in the system between the master station and the receiving antenna 2 or if it is determined that it cannot be avoided due to malfunction of the device itself, a squelch circuit will operate, causing unnecessary radio waves to be interrupted. Is not given.

In addition, since the wraparound phenomenon is avoided while gradually reducing the output level in this way, in the state where the wraparound is avoided by lowering the output level, the service area when the retransmitter is at full power and In comparison, although the target service area covers a slightly narrow area, it is possible to maintain retransmission with a signal that does not wrap around, and all households in the service area subject to retransmission are subject to signal degradation due to the sneak phenomenon. Therefore, it is possible to prevent a reception failure from occurring.

Furthermore, when “BER abnormality” is detected, the “BER abnormality” is displayed on the display means provided in the re-transmission device, or the mobile phone held by the facility manager is warned via the public telephone network. By generating a warning signal of “BER abnormality”, it is possible to quickly cope with “BER abnormality”.
In addition, when a state where “BER abnormality” cannot be avoided continues, that is, when it cannot be avoided only by controlling the output level, or when “BER abnormality” occurs in the system between the master station and the receiving antenna, After a predetermined time, the signal attenuating means 15 is configured as a squelch circuit so that the amount of attenuation is maximized, and a warning signal of “output stop” is displayed using the display means provided in the retransmitting apparatus 1 or a public telephone network. It is possible to report to the facility manager's mobile phone, etc., and to quickly deal with the “output stop”.

Furthermore, even when the squelch circuit is in operation, the BER at the input is continuously monitored. If the “BER abnormality” is no longer recognized, the squelch circuit is released and the output level is gradually increased by a predetermined amount. However, the transmission is automatically restored while confirming whether or not a BER abnormality due to wraparound has occurred, and output stop cancellation notification and BER normality notification are displayed on the display means according to the recovery status. , You can contact the facility manager, and you can save the labor for maintenance of the facility management.

Note that the present invention is not limited to the above-described embodiment, and the configuration of each part can be appropriately changed and implemented without departing from the spirit of the present invention.

1 shows a schematic block diagram of a first embodiment according to the present invention. It is an example of the flowchart which shows operation | movement of the monitoring and control means with which 1st Embodiment concerning this invention was equipped.

DESCRIPTION OF SYMBOLS 1 ... Digital broadcast re-transmission apparatus, 2 ... Reception antenna, 3 ... Transmission antenna, 5 ... Distribution means, 6 ... Mixing means, 10 ... Signal processing apparatus, 11 ... Signal branching means, 12 ... Channel selection / demodulation means, 13 ... Monitoring / control means, 15... Signal attenuating means, 18... Signal amplifying means, 28... Signal processing means (filter means).

Claims (6)

A digital broadcast wave is received by a receiving antenna, and a signal from the receiving antenna is subjected to predetermined signal processing to detect sneak interference of a digital broadcast retransmission apparatus configured to retransmit the digital broadcast wave from the transmission antenna. In the monitoring method to prevent
The digital broadcast retransmission apparatus includes at least a signal branching unit that passes a signal received by the receiving antenna and branches a part of the signal, a signal attenuating unit that attenuates an output of the signal branching unit by a predetermined level, A signal amplifying means for amplifying the output of the signal attenuating means to a predetermined level;
A channel selection / demodulation means for selectively selecting a signal of a predetermined broadcast channel from a branch output of the signal branching means, and demodulating predetermined data from the signal of the broadcast channel;
The predetermined data demodulated by the channel selection / demodulation means is processed to calculate the reception bit error rate, and the reception bit error rate obtained from this result and the bit error provided in advance in the channel selection / demodulation means Monitoring / controlling means for comparing and judging a predetermined reference value of the rate, and controlling the attenuation amount of the signal attenuating means so that the output after amplification by the signal amplifying means becomes a predetermined level based on the judgment result; With
When it is determined that the reception bit error rate is equal to or smaller than the predetermined reference value, the monitoring / control unit reduces the attenuation of the signal attenuation unit so that the output after amplification by the signal amplification unit becomes a predetermined level. Control the amount,
When it is determined that the received bit error rate is greater than the predetermined reference value, the attenuation amount of the signal attenuation means is such that the output after amplification by the signal amplification means is an operation level that is lower than the predetermined level by a predetermined amount. Control
A monitoring method for detecting and preventing sneaking interference of a digital broadcast retransmission apparatus characterized by the above.
The monitoring / control means, when it is determined that the received bit error rate is equal to or smaller than the predetermined reference value, the attenuation of the signal attenuation means so that the output after amplification by the signal amplification means becomes a predetermined level. Control the amount,
When it is determined that the received bit error rate is greater than the predetermined reference value, the attenuation amount of the signal attenuation means is such that the output after amplification by the signal amplification means is an operation level that is lower than the predetermined level by a predetermined amount. Control
When the state in which the received bit error rate is determined to be greater than the predetermined reference value continues for a predetermined period, the signal attenuation means is controlled to perform a squelch operation with the maximum attenuation, and the predetermined reference value A received bit error rate value determined to be greater than is stored as a first reference value;
When it is determined that the newly acquired received bit error rate is smaller than the first reference value in a state where the signal attenuating means is in the squelch operation, first, the newly acquired received bit error rate is set to the first The amount of attenuation of the signal attenuating means is controlled so that the output after amplification by the signal amplifying means becomes the operation level, instead of being stored as a second reference value instead of the reference value of
When it is determined that the newly obtained received bit error rate is smaller than the second reference value in a state where the output is at the operation level, the output after amplification by the signal amplification means becomes the predetermined level. To control,
A monitoring method for detecting and preventing sneaking interference of the digital broadcast retransmitting apparatus according to claim 1.
The monitoring / control means controls the attenuation amount of the signal signal attenuating means so that the output after amplification by the signal amplifying means is a predetermined level lower than the predetermined level, and the output after amplification by the signal amplifying means , When controlling the attenuation amount of the signal attenuation means to a predetermined level higher by a predetermined amount than the operation level, the predetermined amount is divided into a plurality of times and the output is controlled to be variable in stages. A monitoring method for detecting and preventing sneaking interference of the digital broadcast retransmitting apparatus according to claim 1, characterized in that:
The digital broadcast retransmission apparatus according to any one of claims 1 to 3, wherein at least the processing by the monitoring / control means is performed within a guard interval added to a digital broadcast signal. Monitoring method to detect and prevent sneaking interference.
A plurality of the digital broadcast retransmitting devices are provided, the input side is provided with distribution means for distributing the signals received by the receiving antenna into a predetermined number, and the output side is provided with combining means for combining the output signals, The monitoring method for detecting and preventing the wraparound interference of the digital broadcast retransmitting apparatus according to any one of claims 1 to 4, wherein the digital broadcast retransmitting apparatus is configured to monitor the digital broadcast retransmitting apparatus.
In a program used for a monitoring method for detecting and preventing sneaking interference of a digital broadcast retransmitter,
A monitoring program for executing a monitoring method for detecting and preventing sneak interference of the digital broadcast retransmitting apparatus according to any one of claims 1 to 5.

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