JP2007288625A - Output switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To switch a plurality of relay devices irrespective of presence/absence of alarm generation. <P>SOLUTION: A first relay part 54 and a second relay part 56 output transmitting signals, respectively by executing relay processing to a receiving signal received in a receiving antenna 50. A measurement part 64 inputs a plurality of transmitting signals output from each of the first relay part 54 and the second reproducing part 56 and generated from the same receiving signal. respectively and generated from the same receiving signal, respectively. The measurement part 64 measures quality of the plurality of input transmission signals. A measurement part 62 determines selection of either of the plurality of transmitting signals based on the product quality measured in the measurement part 64. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an output switching device, and more particularly to an output switching device that selects a relay device on which an operation is to be performed among a plurality of relay devices.

In a broadcasting system such as a television broadcasting system, a signal is transmitted as an electromagnetic wave from a broadcasting station. The receiver receives a signal transmitted from the broadcast station, and acquires image information, audio information, and the like from the received signal. For signals transmitted by a broadcasting station, provisions such as transmission power and desired signal-to-interference wave ratio are established so that information of a predetermined quality can be obtained at a receiver existing in an area where the broadcasting station is a broadcasting area. . However, even if a broadcasting station transmits a signal that satisfies the regulations, if there are electromagnetic wave obstacles or the like in the broadcasting area, the electric field strength of the signal received by the receiver becomes insufficient, and the predetermined quality in the broadcasting area. There is a region where information on this is not available. Therefore, in order to reduce such quality degradation areas, a relay device that receives a signal transmitted from a broadcasting station, amplifies and transmits the signal is installed in the broadcasting area (see, for example, Patent Document 1).
JP-A-2005-45728

  When a relay device fails, a receiver in the broadcasting area formed by the relay device cannot receive electromagnetic waves and cannot reproduce image information and the like. In order to reduce the probability of occurrence of such a failure, generally one relay device forms a redundant system by a plurality of relay devices, and any one of the plurality of relay devices included in the redundant system. Is operating. In such a redundant system, the alarms of a plurality of relay devices are monitored, and when a failure of the relay device is detected based on the occurrence of the alarm, the relay devices are switched. For example, an alarm is generated when the transmission power is reduced or the oscillator is unlocked.

  However, in such an operation, it is assumed that an alarm is always generated at the time of failure, and even if a failure that is not detected by the alarm occurs in the relay device, the relay device is not switched. For example, faults that are not detected by an alarm include a decrease in radio wave quality and relay of radio waves that should not be relayed. An increase in noise components included in the signal or a deterioration in error rate can be caused by a decrease in radio wave quality. There is. In addition, assuming such an operation, the relay device is provided with an alarm circuit. However, when various failures are assumed, a plurality of alarm circuits are required. On the other hand, from the viewpoint of reducing the size and cost of the relay device, it is desirable that the number of alarm circuits is small, and there is a case where it is desired to configure a redundant system based on a relay device that is not equipped with an alarm circuit. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an output switching device that switches between a plurality of relay devices regardless of whether or not an alarm is generated.

  In order to solve the above-described problem, an output switching device according to an aspect of the present invention includes a plurality of transmission signals output from a plurality of relay devices, and a plurality of transmission signals generated from the same reception signal, respectively. An input unit that inputs the signal, a measurement unit that measures the quality of the plurality of transmission signals input at the input unit, and the selection of any one of the plurality of transmission signals based on the quality measured by the measurement unit A selection unit.

  According to this aspect, the quality of the transmission signal output from each of the plurality of relay apparatuses is measured, and the transmission signal to be selected is determined according to the measured quality. Can be switched.

  Another embodiment of the present invention is also an output switching device. The apparatus includes a selection unit that determines a selection of a plurality of transmission signals that are respectively output from a plurality of relay apparatuses and that is generated from the same reception signal, and a selection unit. And a measurement unit that measures the quality of the transmission signal determined to be selected by the unit. The selection unit switches the transmission signal to be selected when the quality measured by the measurement unit deteriorates.

  According to this aspect, any one of the transmission signals output from each of the plurality of relay apparatuses is selected, and the transmission signal to be selected is switched according to the quality of the selected transmission signal. Regardless, a plurality of relay devices can be switched.

  The plurality of transmission signals include an identification number assigned to the device that transmitted the reception signal. The selection unit obtains the identification number included in the transmission signal, and the acquired identification number is relayed. And means for canceling selection of a plurality of transmission signals when the target is not a target. In this case, if the identification number is included in the transmission signal and the acquired identification number is not a relay target, the relay process is not executed, so that unnecessary signal transmission can be avoided.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, a plurality of relay devices can be switched regardless of whether or not an alarm has occurred.

  Before describing the present invention in detail, an outline will be described. Embodiments of the present invention relate to a relay device that receives a signal transmitted as an electromagnetic wave from a broadcasting station, amplifies the received signal, and transmits the amplified signal. Here, the relay device further includes a plurality of relay devices (hereinafter referred to as “relay unit”). One of the plurality of relay units actually performs the relay, and another relay unit does not perform the relay and has a redundant role. Generally, if an alarm is not generated in one predetermined relay unit, the relay unit continues to be selected. When the relay unit generates an alarm, another relay unit is selected.

  However, even when no alarm is generated, the quality of the signal output from the relay unit may be deteriorated. In addition, a signal input to the relay device may be a signal transmitted from a broadcasting station that is not originally a relay target. For example, when a broadcast station or relay device that is a relay target stops transmission due to a broadcast stop at night, a signal from another station is received. In such a case, if the relay device relays such a signal, it may cause interference, so it is preferable not to relay it. In the present embodiment, in order to solve the above points, the following processing is executed.

  Each of the plurality of relay units included in the relay device according to the present embodiment executes relay processing in parallel. Further, by measuring the quality of a signal relayed by each of the plurality of relay units, for example, MER (Modulation Error Ratio), the relay unit outputting a signal corresponding to the MER having the best characteristics is selected. Finally, the relay device transmits a signal from the selected relay unit. Further, when measuring the MER, the relay apparatus confirms the identification number included in those signals and the identification number assigned to the broadcasting station that first transmitted the signal. If the confirmed identification number is not the identification number assigned to the broadcast station to be relayed, the relay device stops relaying.

  FIG. 1 shows a configuration of a relay device 100 according to an embodiment of the present invention. The relay device 100 includes a reception antenna 50, a distribution unit 52, a first relay unit 54, a second relay unit 56, an output switching unit 58, a transmission antenna 60, and a control unit 30. The output switching unit 58 includes a selection unit 62 and a measurement unit 64.

  The receiving antenna 50 receives a signal transmitted from a broadcast station (not shown), that is, a broadcast electromagnetic wave. The receiving antenna 50 may transmit a signal transmitted from another relay device (not shown). In that case, the starting point of the signal received by another relay apparatus is a broadcasting station. The signal received by the receiving antenna 50 includes an identification number given to the device that transmitted the signal, for example, an identification number given to the broadcasting station that transmitted the signal. The received signal is transmitted by a carrier wave having a predetermined radio frequency. The distribution unit 52 inputs a signal received by the reception antenna 50 to the first relay unit 54 and the second relay unit 56.

  The first relay unit 54 generates a signal to be transmitted by executing a relay process on the signal received from the distribution unit 52. Although details of the configuration of the first relay unit 54 will be described later, the first relay unit 54 performs filtering after converting the frequency of the received signal from a radio frequency to an intermediate frequency. Further, the first relay unit 54 converts the frequency from the intermediate frequency to the radio frequency again, amplifies the converted signal, and outputs the amplified signal.

  The second relay unit 56 performs relay processing in the same manner as the first relay unit 54. Here, the second relay unit 56 may be configured to execute the same processing as the first relay unit 54, but even if the characteristics of the amplifier and filter included therein are different from those of the first relay unit 54. Good. Further, the second relay unit 56 may be configured to be different from the first relay unit 54. For example, the second relay unit 56 may perform baseband filtering by performing frequency conversion up to the baseband. Here, for the sake of brevity, it is assumed that two relay units are included as relay units, but in reality, the relay device 100 may include three or more relay units.

  The measuring unit 64 inputs a plurality of transmission signals that are respectively output from the first relay unit 54 and the second relay unit 56 and generated from the same received signal. Moreover, the measurement part 64 measures the quality of the several input transmission signal, respectively. Here, it is assumed that MER is measured as the quality of the transmission signal. However, the measurement unit 64 may measure output power and BER (Bit Error Rate) in addition to MER as quality. The measurement unit 64 may measure any of MER, C / N, BER, and power, and may output a result obtained by performing a logical sum operation on these as a measurement result. Here, when the output power decreases, the broadcastable area becomes narrower. Further, the deterioration of MER and BER corresponds to the deterioration of IM and C / N, and the broadcastable area is narrowed even in such a state. Note that a known technique may be used for measuring MER, BER, and output power, and the measurement unit 64 may perform frequency conversion to an intermediate frequency band or a baseband for measurement. The measurement in the measurement unit 64 is executed at a predetermined timing. Measurements may also be performed periodically.

  The selection unit 62 receives the transmission signals output from the first relay unit 54 and the second relay unit 56, respectively. In addition, the selection unit 62 inputs measurement results for the two transmission signals, for example, MER values, from the measurement unit 64. The selection unit 62 determines the selection of one of the two transmission signals based on the MER measured by the measurement unit 64. Specifically, the selection unit 62 determines the selection of the transmission signal with the higher MER value. The selection unit 62 holds an identification number assigned to a broadcast station to be relayed, that is, a broadcast station that first transmitted a signal to be relayed.

  The selection unit 62 acquires an identification number included in the transmission signal from the input transmission signal, and compares the acquired identification number with an identification number held in advance. When the two match, the selection unit 62 performs the above-described selection. However, when the two do not match, that is, when the acquired identification number is not a relay target, the selection unit 62 selects the plurality of transmission signals. Cancel the selection. That is, the output is signal cut off. The selection process in the selection unit 62 may be executed at a predetermined timing, for example, at a timing when quality is received from the measurement unit 64. Finally, the selection unit 62 outputs the selected transmission signal.

  The transmission antenna 60 transmits the transmission signal selected by the selection unit 62 as an electromagnetic wave. The control unit 30 controls processing, operation timing, and the like of each component included in the relay device 100.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it is realized by a program having a communication function loaded in the memory. Describes functional blocks realized by collaboration. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  FIG. 2 shows a configuration of the first relay unit 54. The first relay unit 54 includes a reception filter 12, a reception amplification unit 14, a frequency converter 16, a frequency converter 22, a transmission amplification unit 24, a transmission filter 26, an AGC (Automatic Gain Control) 40, a preamplifier 42, a local oscillator 44, A local oscillator 46 is included.

  The reception filter 12 attenuates a portion outside the band of the plurality of channels with respect to a signal received by a reception antenna 50 (not shown). The reception amplification unit 14 amplifies the signal from the reception filter 12. The frequency converter 16 converts the radio frequency band signal from the reception amplifying unit 14 into an intermediate frequency band signal. In addition to the signal in the radio frequency band from the reception amplification unit 14, the local frequency signal from the local oscillator 46 is also input to the frequency converter 16. The frequency converter 16 multiplies the radio frequency band signal by the local oscillator signal to convert the radio frequency band signal into an intermediate frequency band signal.

  The AGC 40 adjusts the signal in the intermediate frequency band so that the amplitude or power approaches a predetermined value, and outputs the adjusted signal in the intermediate frequency band. Here, the configuration of the AGC may be a known technique, and thus the description thereof is omitted. The local oscillator 44 outputs a local oscillation signal similarly to the local oscillator 46. Here, the frequency of the local oscillation signal output from the local oscillator 44 and the frequency of the local oscillation signal output from the local oscillator 46 have different values.

  The frequency converter 22 converts the intermediate frequency band signal into a radio frequency band signal. The frequency converter 22 multiplies the signal in the intermediate frequency band from the AGC 40 by the local oscillator signal from the local oscillator 44 to convert the signal in the intermediate frequency band into a signal in the radio frequency band.

  If the radio frequency band of the signal converted by the frequency converter 22 is equal to the radio frequency band of the signal input from the receiving antenna 50, a sneak wave is generated between the two. Therefore, the first relay unit 54 may be provided with a wraparound canceller (not shown). Here, since the wraparound canceller is realized by a known technique, description thereof is omitted. The preamplifier 42 and the transmission amplifying unit 24 amplify the radio frequency band signal and input the amplified signal to the transmission filter 26. The transmission filter 26 attenuates and outputs an image signal included outside the radio frequency band of the input signal, a harmonic component signal due to nonlinearity of the transmission amplifier 24, and the like. Here, the first relay unit 54 and the second relay unit 56 may correspond to either an MFN (Multi Frequency Network) relay system or an SFN (Single Frequency Network) relay system, and the preceding relay system is a micro relay system. A relay system using wavebands may be used.

  The operation of the relay device 100 configured as above will be described. FIG. 3 is a flowchart showing a switching procedure in the output switching unit 58. The measurement unit 64 detects signal input from each of the first relay unit 54 and the second relay unit 56 (S10). The measurement unit 64 measures MER (S12), and the selection unit 62 selects one transmission signal according to the measurement result (S14). The selection unit 62 confirms the identification number included in the selected transmission signal, and if the transmission signal is a relay target (Y in S16), the selection unit 62 executes the relay (S18). On the other hand, if the transmission signal is not a relay target (N in S16), the selection unit 62 stops the relay (S20). If the signal continues (Y in S22), the process returns to Step 10, but if the signal does not continue (N in S22), the process is terminated. Note that the measurement unit 64 and the selection unit 62 may execute Step 12 and Step 14 after the selection unit 62 executes Step 16 to Step 20. That is, after the selection unit 62 checks the identification number, the measurement unit 64 may measure the MER, and the selection unit 62 may select the transmission signal. In this case, since the MER is measured after the transmission is interrupted by executing the identification number check first, unnecessary radio wave transmission can be reduced.

  Hereinafter, modifications of the relay device 100 will be described. The modification aims to further reduce the circuit scale as compared with the embodiment. FIG. 4 shows a configuration of the relay device 100 according to the modification. The components included in the relay device 100 are the same as the components included in the relay device 100 in FIG. However, the configuration of the output switching unit 58 shown in FIG. 4 is different from the configuration of the output switching unit 58 shown in FIG.

  The selection unit 62 determines the selection of any of the transmission signals output from the first relay unit 54 and the second relay unit 56 and generated from the same reception signal. Similar to the selection unit 62 in FIG. 1, the selection unit 62 performs selection based on the measurement result in the measurement unit 64. In the initial state where the measurement result from the measurement unit 64 is not input, the selection unit 62 selects a predetermined transmission signal. For example, the selection unit 62 selects the transmission signal output from the first relay unit 54. In addition, as in the selection unit 62 in FIG. 1, the selection unit 62 confirms the identification number included in the transmission signal and determines whether or not the transmission signal should be relayed.

  The measuring unit 64 measures the quality of the transmission signal determined to be selected by the selection unit 62. The measurement unit 64 measures the MER of the transmission signal in the same manner as the measurement unit 64 in FIG. The measuring unit 64 in FIG. 1 measures the MER for each of the transmission signal from the first relay unit 54 and the transmission signal from the second relay unit 56. That is, MER is measured for two transmission signals. However, the measurement unit 64 in FIG. 4 measures the MER with respect to the transmission signal from the selection unit 62, and the MER is measured for one transmission signal. Therefore, the processing amount in the measurement unit 64 in FIG. 4 is smaller than the processing amount in the measurement unit 64 in FIG. 1, and the circuit scale is also reduced. The selection unit 62 holds a threshold value in advance, and switches the transmission signal to be selected when the MER value measured by the measurement unit 64 is worse than the threshold value.

  FIG. 5 is a flowchart showing a switching procedure in the output switching unit 58. The selection unit 62 detects signal input from each of the first relay unit 54 and the second relay unit 56 (S40). The selector 62 selects one transmission signal (S42). The selection unit 62 confirms the identification number included in the selected transmission signal, and if the transmission signal is a relay target (Y in S44), the selection unit 62 executes the relay (S46). On the other hand, if the transmission signal is not a relay target (N in S44), the selection unit 62 stops the relay (S48).

  The measurement unit 64 measures MER (S50). If the measured MER value is better than the threshold value (Y in S52), the selection unit 62 does not perform switching of the selection target, but the measured MER value is not better than the threshold value. (N in S52), the selection unit 62 performs switching of the selection target (S54). If the signal continues (Y in S56), the process returns to Step 40. If the signal does not continue (N in S56), the process is terminated.

  According to the embodiment of the present invention, the MER of the transmission signal output from each of the plurality of relay units is measured, and the transmission signal to be selected is determined according to the measured MER value. Multiple relay units can be switched regardless of the presence or absence. Further, since the selection is performed based on the MER value of the transmission signal, it is possible to detect the deterioration of the quality of the transmission signal even when no alarm is generated. In addition, since the deterioration of the quality of the transmission signal is detected and the transmission signal is selected, a transmission signal with high quality can be transmitted.

  Further, since MER is used as an evaluation criterion, transmission signals can be switched according to a criterion corresponding to C / N. In addition, since the transmission signal is switched regardless of whether an alarm is generated or not, even if the relay unit is not provided with a function for generating an alarm, a redundant system can be configured by such a relay unit. Further, if the identification number included in the transmission signal and the acquired identification number is not a relay target, the relay process is not executed, so that unnecessary signal transmission can be avoided. Further, since unnecessary signal transmission is avoided, interference in the broadcast area can be reduced.

  In addition, since one of the transmission signals output from each of the plurality of relay units is selected and the transmission signal to be selected is switched according to the quality of the selected transmission signal, a plurality of transmission signals can be selected regardless of whether the relay unit generates an alarm. Can be switched. In addition, since the quality is measured for the selected transmission signal, the amount of measurement processing can be reduced. In addition, the circuit scale of the measurement unit can be reduced.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the embodiment of the present invention, the first relay unit 54 and the second relay unit 56 are included in one relay device 100. However, the present invention is not limited to this. For example, the first relay unit 54 and the second relay unit 56 are configured as separate devices, and the output switching unit 58 is connected externally to the relay device 100 by connecting them to each other. May be configured. According to this modification, a redundant system can be configured by the first relay unit 54 and the second relay unit 56 already prepared.

  In the embodiment of the present invention, the first relay unit 54 and the second relay unit 56 do not generate an alarm. However, the present invention is not limited to this. For example, the first relay unit 54 and the second relay unit 56 may generate an alarm. In this case, the alarm may be input to the output switching unit 58, and the output switching unit 58 may execute selection according to the alarm. According to this modification, the output switching unit 58 executes switching based on an alarm in addition to switching based on the measured quality, so that the switching accuracy can be improved.

  In the embodiment of the present invention, when the identification number included in the input transmission signal is different from the identification number held in advance, the selection unit 62 performs transmission without performing the selection operation on the input transmission signal. It has stopped. However, the present invention is not limited to this. For example, when the quality of the input transmission signal is deteriorated, the selection unit 62 may stop the transmission without performing the selection operation on the input transmission signal. Specifically, when the value of MER is worse than the threshold value, the selection unit 62 stops transmission. According to this modification, since transmission of a signal whose quality is deteriorated is stopped, transmission of an unnecessary signal can be avoided. In addition, the area that is difficult to view in the case of SFN can be reduced.

  In the embodiment of the present invention, the first relay unit 54 and the second relay unit 56 regularly perform the relay operation. However, the present invention is not limited to this. For example, one of the first relay unit 54 and the second relay unit 56 that is not selected by the selection unit 62 may be in a cold standby state. The cold standby is a state in which the power is cut off for some of the components such as the transmission amplification unit 24. When an unselected relay unit is in a cold standby state, the selection unit 62 may output an activation signal for activating a power source to the unselected relay unit before switching. . According to this modification, the present invention can be applied even in the cold standby state.

It is a figure which shows the structure of the relay apparatus based on the Example of this invention. It is a figure which shows the structure of the 1st relay part of FIG. It is a flowchart which shows the switching procedure in the output switching part of FIG. It is a figure which shows the structure of the relay apparatus which concerns on the modification of FIG. It is a flowchart which shows the switching procedure in the output switching part of FIG.

Explanation of symbols

  30 control unit, 50 reception antenna, 52 distribution unit, 54 first relay unit, 56 second relay unit, 58 output switching unit, 60 transmission antenna, 62 selection unit, 64 measurement unit, 100 relay device.

Claims (3)

An input unit that inputs a plurality of transmission signals that are respectively output from a plurality of relay devices and that are respectively generated from the same reception signal;
A measurement unit for measuring the quality of a plurality of transmission signals input at the input unit;
Based on the quality measured in the measurement unit, a selection unit that determines the selection of any of a plurality of transmission signals;
An output switching device comprising: A selection unit that determines a selection of a plurality of transmission signals that are respectively output from a plurality of relay devices and that are respectively generated from the same reception signal;
A measuring unit that measures the quality of the transmission signal determined to be selected by the selecting unit,
The output switching device, wherein the selection unit switches a transmission signal to be selected when the quality measured in the measurement unit deteriorates. The plurality of transmission signals include an identification number given to the device that transmitted the reception signal,
The selection unit includes means for acquiring an identification number included in a transmission signal, and means for canceling selection of a plurality of transmission signals when the acquired identification number is not a relay target. Item 3. The output switching device according to Item 1 or 2.

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