JP2020005021A - Signal monitoring device, transmission device, signal monitoring method, and signal monitoring program - Google Patents

Abstract

To provide a signal monitoring device capable of monitoring the quality of transmitting signals while suppressing the increase of the circuit size, a transmission device, a signal monitoring method, and a signal monitoring program.SOLUTION: A signal selection part 31 selects a transmitting signal for quality measurement from multiple transmitting signals input from multiple transmitting signal generation parts. A quality measurement part 32 measures the quality of the transmitting signal for the quality measurement selected by the signal selection part 31. A transmitting signal determination part 37 determines the transmitting signals to be transmitted on the basis of the quality measured by the quality measurement part 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a signal monitoring device for monitoring a transmission signal, a transmission device, a signal monitoring method, and a signal monitoring program.

  A broadcasting station is provided with a plurality of transmission systems in a transmitter in order to prevent interruption of broadcasting such as digital terrestrial broadcasting. Specifically, for example, a transmitter of a broadcasting station is provided with one transmission system (also referred to as a first transmission system) and the other transmission system (also referred to as a second transmission system). Have been. The transmission signal generated by the first transmission system (also referred to as the first transmission signal) and the transmission signal generated by the second transmission system (also referred to as the second transmission signal) are appropriately used. It is switched and output from the transmitter.

  Patent Document 1 discloses a transmitter that measures and compares the amount of noise of a transmission signal of system 1 and the amount of noise of a transmission signal of system 2 and outputs a transmission signal with a smaller amount of noise. Has been described.

JP 2004-096468 A

  As described in Patent Literature 1, in order to measure the amount of noise of the transmission signal of the first system and the amount of noise of the transmission signal of the second system, modulation processing and coding performed on each transmission signal are performed. It is necessary to perform demodulation processing and decoding processing according to the conversion processing on each transmission signal. In particular, since a signal for transmission in digital broadcasting such as terrestrial digital broadcasting is subjected to encoding processing and modulation processing for each of the three layers A, B, and C, decoding and demodulation are also performed for each layer. Must be applied to the transmission signal.

  Since a large amount of calculation is required for such a demodulation process and a decoding process, a circuit for processing such a large amount of calculation is required in the transmitter, and the circuit scale of the transmitter increases. There is a problem of doing.

  Therefore, an object of the present invention is to provide a signal monitoring device, a transmitting device, a signal monitoring method, and a signal monitoring program that can monitor the quality of a transmission signal while suppressing an increase in circuit scale. .

  A signal monitoring device according to the present invention includes a signal selection unit that selects a transmission signal for quality measurement among a plurality of transmission signals input from a plurality of transmission signal generation units, and a quality measurement unit that is selected by the signal selection unit. Quality measuring means for measuring the quality of the transmission signal for transmission, and transmission signal determining means for determining the transmission signal to be transmitted based on the quality measured by the quality measuring means.

  The transmission device according to the present invention is a signal monitoring device according to any one of the embodiments, and at least one of a transmission unit that transmits a transmission signal determined to be transmitted by a plurality of transmission signal generation units and a transmission signal determination unit. It is characterized by having.

  In the signal monitoring method according to the present invention, a transmission signal for quality measurement is selected from among a plurality of transmission signals input from a plurality of transmission signal generation units, and the quality of the selected transmission signal for quality measurement is determined. The transmission signal to be transmitted is determined based on the measured quality.

  The signal monitoring program according to the present invention includes a signal selection process for selecting a transmission signal for quality measurement from among a plurality of transmission signals input from a plurality of transmission signal generation units, and a signal selection process. A quality measurement process for measuring the quality of the selected transmission signal for quality measurement and a transmission signal determination process for determining a transmission signal to be transmitted based on the quality measured in the quality measurement process are performed. And

  According to the present invention, it is possible to monitor the quality of a transmission signal while suppressing an increase in circuit scale.

FIG. 2 is a block diagram illustrating a connection example of the transmission quality monitoring system according to the first embodiment. It is a block diagram showing an example of composition of a quality monitoring part. It is a block diagram showing an example of composition of a quality monitoring part. It is a block diagram showing an example of composition of a quality monitoring part. 5 is a flowchart illustrating an operation of the transmission quality monitoring system according to the first embodiment. It is a block diagram showing an example of composition of signal monitoring device 1 of a 2nd embodiment.

Embodiment 1 FIG.
A transmission quality monitoring system 300 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a connection example of the transmission quality monitoring system 300 according to the first embodiment of the present invention.

  In this example, a case where the quality of a transmission signal in digital terrestrial broadcasting is monitored will be described as an example. However, the present invention may be configured to monitor the quality of another signal.

  As shown in FIG. 1, a transmission quality monitoring system 300 according to the first embodiment is mounted on a transmitter 10. As shown in FIG. 1, the transmitter 10 includes a transmission quality monitoring system 300, a first transmission signal generation unit 100, a second transmission signal generation unit 200, and an output coaxial device 400, and includes an antenna 500 Is connected.

  The first transmission signal generation unit 100 and the second transmission signal generation unit 200 each receive data for transmission signal generation. Then, the first transmission signal generation section 100 and the second transmission signal generation section 200 respectively generate transmission signals based on the input data. Note that the transmission signal generated by the first transmission signal generation unit 100 is referred to as a first transmission signal. In addition, the transmission signal generated by the second transmission signal generation unit 200 is referred to as a second transmission signal.

  Then, the first transmission signal generation unit 100 inputs the generated first transmission signal to the output coaxial device 400. Further, the second transmission signal generation unit 200 inputs the generated second transmission signal to the output coaxial device 400.

  The first transmission signal and the second transmission signal are input to the transmission quality monitoring system 300 via the output coaxial device 400. The transmission quality monitoring system 300 generates selection instruction information indicating which transmission signal to transmit based on the input first transmission signal and second transmission signal. Then, the transmission quality monitoring system 300 inputs the generated selection instruction information to the output coaxial device 400.

  The output coaxial device 400 inputs any one of the input first transmission signal and the second transmission signal to the antenna 500 based on the input selection instruction information. The first transmission signal or the second transmission signal input to the antenna 500 is converted into an electromagnetic wave and emitted (transmitted).

  In addition, the output coaxial device 400 performs a predetermined filtering process described later on the input first transmission signal and second input signal. Then, the output coaxial device 400 inputs the first transmission signal and the second transmission signal that have been subjected to the predetermined filtering to the transmission quality monitoring system 300.

  In this example, it is assumed that data for generating a transmission signal used for terrestrial digital television broadcasting is input to the first transmission signal generation unit 100 and the second transmission signal generation unit 200. More specifically, for example, the output coaxial device 400 transmits a transmission signal used for terrestrial digital television broadcasting including three layers, A-layer, B-layer, and C-layer, each having a different frequency band. It is assumed that input is made to the antenna 500.

  Next, the configuration of the first transmission signal generation unit 100 will be described with reference to FIG. As shown in FIG. 1, first transmission signal generation section 100 includes modulation section 110 and amplification section 120.

  Modulating section 110 performs a modulation process on a carrier having a predetermined frequency based on the data for transmission signal generation input to first transmission signal generation section 100 to generate a first transmission signal. Specifically, first, for example, the modulation unit 110 adds H.264 to the data for generating the transmission signal. By performing an encoding process based on H.264, a signal for a one-segment partial reception service (also referred to as a mobile reception service; hereinafter, also referred to as one-segment) for mobile phones and mobile terminals (hereinafter, a signal for one-segment) is generated. Further, the modulation unit 110 performs, for example, an encoding process based on MPEG (Moving Picture Experts Group) -2 on data for generating a transmission signal to generate a 2K signal. Note that “2K” is a general term for an image having a screen resolution of about 2000 × 1000, and a 2K signal is a signal for displaying such an image on a receiver. Then, modulation section 110 performs a modulation process according to each of the one-segment signal and the 2K signal that have been subjected to the encoding process. The modulation process is, for example, a digital modulation process. More specifically, it is an OFDM (Orthogonal Frequency Division Multiplexing) modulation process. Therefore, in this example, the first transmission signal is an OFDM signal. Then, modulation section 110 inputs the generated first transmission signal to amplification section 120. It should be noted that a signal in the frequency band of the A layer is configured based on the signal for one segment, and a signal in the frequency band of the B layer and a signal in the frequency band of the C layer are configured based on the 2K signal.

  The modulation unit 110 performs a process of adding a Reed-Solomon code (for example, RS (204, 188)), which is an error correction code, to the generated one-segment signal and the 2K signal. The error correction code added to the one-segment signal and the 2K signal is not limited to the Reed-Solomon code, and may be another code.

  Modulating section 110 performs a predetermined energy spreading process on the data to which an error correction code has been added. Specifically, for example, the modulation unit 110 generates a predetermined PRBS (Pseudo-Random Binary Sequence: pseudo-random code sequence) generated using, for example, an M (Maximum Length) sequence 15th-order PN (Pseudo-Noise) signal or the like. And a bit string obtained by removing the synchronization byte in the input data and calculating a bitwise exclusive OR. Then, modulation section 110 sets each calculation result as a result of performing energy diffusion processing on the input data.

  The modulation unit 110 converts the data subjected to the energy diffusion processing into data in units of bytes, and performs byte interleaving processing on the converted data in units of bytes to make the amounts of delay different from each other.

  The modulation unit 110 performs, for example, a predetermined convolutional encoding process on the bit stream based on the one-segment signal and the bit stream based on the 2K signal, which have been subjected to the byte interleaving process. Specifically, the modulating unit 110 uses the original code having, for example, a constraint length k = 7 and a coding rate of 1/2 as a mother code in the bit stream, and performs puncturing at a coding rate set for each layer. The encoding process of the chard convolutional code is performed.

  Modulating section 110 performs bit interleaving processing according to mapping performed later on the bit stream that has been subjected to the encoding processing. Specifically, for example, it is assumed that a bit stream based on the encoded one-segment signal is subjected to QPSK (Quadrature Phase Shift Keying) mapping processing. Therefore, the modulation unit 110 performs a bit interleave process of inserting, for example, a 120-bit delay element into the bit stream based on the one-segment signal. It is also assumed that the bit stream based on the encoded 2K signal is subjected to 64 QAM (Quadrature Amplitude Modulation) mapping processing. Therefore, the modulation unit 110 performs a bit interleave process of inserting, for example, a delay element of 24-120 bits into the bit stream based on the 2K signal.

  The modulation unit 110 performs, for example, a mapping process on the bit stream subjected to the bit interleaving process. Specifically, for example, the modulation unit 110 performs QPSK mapping processing on a bit stream based on the one-segment signal on which bit interleaving processing has been performed, and generates an OFDM signal. Further, the modulation unit 110 performs mapping processing such as 64QAM on the bit stream based on the 2K signal that has been subjected to the bit interleaving processing, and generates an OFDM signal.

  When generating each OFDM signal, modulation section 110 causes each symbol in each carrier of the OFDM signal to include, for example, TMCC information indicating the applied mapping processing.

  The modulation unit 110 may, for example, disperse the symbol data after the modulation (mapping processing) in time and improve the anti-fading performance in a modulation symbol unit (I and Q axis units) by a predetermined time in the OFDM signal. Interleave processing is performed.

  Note that the frequency band of the OFDM signal is divided into, for example, 13 segments, and the modulation unit 110 causes the first transmission signal to change (rotate) the frequency of a carrier (carrier) in each segment, for example. And a frequency interleave process of exchanging frequency bands to be used between segments. Then, modulation section 110 causes the first transmission signal to include information indicating the content of the performed frequency interleaving process.

  The amplifier 120 amplifies the input first transmission signal at a predetermined amplification factor. Then, the amplification unit 120 inputs the amplified first transmission signal to the output coaxial device 400.

  Second transmission signal generation section 200 includes modulation section 210 and amplification section 220 corresponding to modulation section 110 and amplification section 120 in first transmission signal generation section 100 shown in FIG.

  Modulating section 210 and amplifying section 220 perform processing similar to that of corresponding modulating section 110 and amplifying section 120 to generate a second transmission signal. Then, the amplifier 220 inputs the amplified second transmission signal to the output coaxial device 400.

  Next, the configuration of the transmission quality monitoring system 300 will be described with reference to FIG. As shown in FIG. 1, the transmission quality monitoring system 300 according to the first embodiment of the present invention includes a signal switching unit 310 and a quality monitoring unit 320.

  The signal transmission unit 310 receives a first transmission signal and a second transmission signal. Then, signal switching section 310 inputs one of the first transmission signal and the second transmission signal to quality monitoring section 320. The signal switching unit 310 converts the transmission signal input to the quality monitoring unit 320 into a first transmission signal and a second transmission signal at predetermined time intervals or in response to an instruction from an operator. Switch between and between. Therefore, the first transmission signal and the second transmission signal are alternately input to the quality monitoring unit 320.

  To the quality monitoring unit 320, the first transmission signal and the second transmission signal are alternately input. Then, the quality monitoring unit 320 demodulates and decodes the input transmission signal (that is, one of the first transmission signal and the second transmission signal), and decodes the quality of the input transmission signal. Is measured. Therefore, the quality monitoring unit 320 measures the quality of the first transmission signal and the quality of the second transmission signal alternately.

  In this example, the quality monitoring unit 320 is described as measuring the MER (Modulation Error Ratio (modulation error ratio)) and the BER (Bit Error Rate (bit error rate)) as the quality of the transmission signal. , May be configured to measure other indices.

  The quality monitoring unit 320 determines a transmission signal to be output based on the measured quality of the first transmission signal and the quality of the second transmission signal. Then, the quality monitoring unit 320 generates selection instruction information according to the determination result and inputs the information to the output coaxial device 400.

  The configuration of the output coaxial device 400 will be described with reference to FIG. The output coaxial device 400 includes a first band-pass filter 410, a second band-pass filter 420, and a switch (transmitting means) 430.

  The first transmission signal input to the output coaxial device 400 by the first transmission signal generation unit 100 is input to the first bandpass filter 410. In the first band-pass filter 410, a predetermined filtering process for passing a signal in a predetermined frequency band is applied to the input signal, for example.

  Then, the first transmission signal that has been subjected to the predetermined filtering processing by first bandpass filter 410 is input to switch 430 and transmission quality monitoring system 300.

  The second transmission signal input to the output coaxial device 400 by the second transmission signal generation unit 200 is input to the second bandpass filter 420. In the second band-pass filter 420, a predetermined filtering process for passing a signal in a predetermined frequency band is applied to the input signal, for example. The predetermined filtering process performed in the second band-pass filter 420 is, for example, the same process as the predetermined filtering process performed in the first band-pass filter 410.

  Then, the second transmission signal that has been subjected to the predetermined filtering processing by second bandpass filter 420 is input to switch 430 and transmission quality monitoring system 300.

  The switch 430 transmits a transmission signal to be output based on the selection instruction information input to the output coaxial device 400 by the transmission quality monitoring system 300 to the first transmission signal input via the band-pass filters 410 and 420. Switching between the trust signal and the second transmission signal.

  Next, the configuration of the quality monitoring unit 320 will be described more specifically. 2 to 4 are block diagrams illustrating a configuration example of the quality monitoring unit 320. As shown in FIGS. 2 to 4, the quality monitoring unit 320 includes a quadrature demodulation processing unit 321, a synchronous reproduction unit 322, an FFT processing unit 323, an equalization processing unit 324, a frequency deinterleave processing unit 325, and a time deinterleave processing unit 326. , A hierarchical division unit 327, a demapping processing unit 328-a to c, a bit deinterleave processing unit 329-a to c, a depuncturing processing unit 330-a to c, a Viterbi decoding processing unit 331-a to c, a byte. The deinterleave processing units 332-ac, the energy despreading units 333-ac, the RS decoding processing units 334-ac, the BER measurement units 335-ac, the MER measurement unit 336, and the determination unit 337 Including.

  One of the first transmission signal and the second transmission signal is input to the orthogonal demodulation processing unit 321 by the signal switching unit 310. Note that the first transmission signal and the second transmission signal may be collectively referred to as a transmission signal.

  The orthogonal demodulation processing unit 321 performs a predetermined orthogonal demodulation process on the input transmission signal. Specifically, the quadrature demodulation processing unit 321 mixes the input transmission signal and the mutually orthogonal demodulation signal, respectively, and outputs an I (In-phase) component signal and a Q (Quadrature) component signal. And get

  Then, those signals, which are transmission signals after the quadrature demodulation processing, are input to the synchronous reproduction section 322 and the FFT processing section 323, respectively.

  The synchronous reproduction unit 322 performs a mode (in this example, according to the number of carriers in OFDM) based on the signal input to the quadrature demodulation processing unit 321, the signal subjected to the FFT processing by the FFT processing unit 323, and the frame synchronization signal. The OFDM symbol synchronization and the FFT sample frequency are reproduced according to mode 3) and the guard interval length. Specifically, for example, the synchronization reproducing unit 322 specifies (reproduces) a timing for synchronizing OFDM symbols and an FFT sample frequency based on signals input from each unit. Note that the frame synchronization signal is extracted from the signal subjected to the FFT processing by the FFT processing unit 323.

  The FFT processing unit 323 performs FFT processing on the signal input by the quadrature demodulation processing unit 321 based on the information reproduced by the synchronous reproduction unit 322, and converts the signal in the time domain input by the quadrature demodulation processing unit 321 in the frequency domain. Convert to a signal. Then, the FFT processing unit 323 inputs the converted frequency domain signal to the equalization processing unit 324.

  The equalization processing unit 324 performs a predetermined distortion compensation process on the input frequency domain signal. Then, equalization processing section 324 inputs a frequency domain signal that has been subjected to predetermined distortion compensation processing to frequency deinterleave processing section 325 and MER measurement section 336.

  The frequency deinterleave processing unit 325 determines the frequency of each carrier changed in the frequency interleave process performed by the modulation unit 110 based on information indicating the content of the frequency interleave process included in the frequency domain signal. The frequency deinterleaving process for restoring the frequency band exchanged with another exchanged segment is performed on the frequency domain signal converted by the FFT processing unit 323.

  The time deinterleave processing unit 326 performs a time deinterleave process of returning symbol data temporally dispersed by the time interleave process performed by the modulation unit 110 to the original temporal order. It is applied to the signal that has been subjected to the interleave processing.

  The hierarchical division unit 327 divides the signal subjected to the time deinterleaving processing by the time deinterleave processing unit 326 into signals corresponding to each layer. Specifically, for example, in the signal subjected to the time deinterleaving processing by the time deinterleaving processing section 326, the layer dividing section 327 transmits the signal of the carrier in the frequency band corresponding to the A layer to the demapping processing section 328-a. The signal of the carrier in the frequency band corresponding to the B layer is input to the demapping processing unit 328-b, and the signal of the carrier in the frequency band corresponding to the C layer is input to the demapping processing unit 328-c.

  The demapping processing units 328-a to 328-c perform the processing in the modulation unit 110 based on the TMCC information included in the input signal (in this example, included in each symbol of each carrier of the OFDM signal). A demapping process corresponding to the performed mapping process is performed on the signal subjected to the time deinterleaving process. In this example, QPSK mapping processing is performed on the signal of the carrier in the frequency band corresponding to the layer A. Therefore, the demapping processing unit 328-a performs demapping processing according to QPSK on the signal input by the hierarchical division unit 327, and extracts bit information (bit stream). Further, in this example, 64 QAM mapping processing is performed on the carrier signal of the frequency band corresponding to the B layer. Therefore, the demapping processing unit 328-b performs demapping processing on the signals input by the hierarchical division unit 327 in accordance with the mapping processing, and extracts bit information (bit stream). In this example, 64 QAM mapping processing is performed on the carrier signal in the frequency band corresponding to the C layer. Therefore, the demapping processing unit 328-c performs demapping processing on the signals input by the hierarchical division unit 327 in accordance with the mapping processing, and extracts bit information (bit stream).

  The bit deinterleave processing units 329-a to 329c perform bit deinterleave processing according to the bit interleave processing performed by the modulation unit 110 on the bit streams extracted by the demapping processing units 328-a to 328c. More specifically, in the present example, the bit stream based on the one-segment signal is subjected to a bit interleaving process in which a delay element of, for example, 120 bits is inserted in the modulation unit 110. Therefore, the bit deinterleave processing unit 329-a performs, for example, a bit deinterleave process of erasing, for example, a 120-bit delay element from the bit stream extracted by the demapping processing unit 328-a. Further, in this example, the modulation unit 110 performs bit interleaving processing for inserting, for example, a delay element of 24 to 120 bits into the bit stream based on the 2K signal. Therefore, the bit deinterleave processing units 329-b and 329c perform, for example, a bit deinterleave process of erasing the delay element from the bit stream extracted by the demapping processing units 328-b and 328c.

  The depuncturing processing sections 330-a to 330-c perform bit interpolation of the convolutional code according to a predetermined convolutional coding process performed by the modulation section 110. Specifically, the depuncturing processing unit 330-a performs bit interpolation of a convolutional code according to, for example, the coding rate of the A-th layer. In addition, the depuncturing processing unit 330-b performs bit interpolation of a convolutional code according to, for example, the coding rate of the B layer. The depuncturing processing unit 330-c performs bit interpolation of a convolutional code according to, for example, the coding rate of the C layer.

  The Viterbi decoding processing units 331-a to 331-c perform decoding processing on the bit streams whose bits have been interpolated by the depuncturing processing units 330-a to 330-c. Then, the Viterbi decoding processing units 331-a to 331-c input the decoded bit streams to the byte deinterleaving processing units 332-ac. Specifically, the Viterbi decoding processing units 331-a to 331-c perform decoding processing on the bit stream based on, for example, the Viterbi algorithm. The bit stream may be subjected to a decoding process based on another algorithm.

  The byte deinterleave processing units 332-a to 332-c convert the input bit data (bit stream) into byte data. Then, the byte deinterleave processing units 332-a to 332c perform, for example, byte deinterleave processing for resetting a delay amount set by performing the byte interleave processing by the modulation unit 110 on the data.

  The energy despreading units 333-a to 333 c convert the byte-unit data subjected to the byte deinterleaving process by the byte deinterleaving units 332-a to 332 c into a bit-unit bit stream. Apply energy despreading to the stream. Specifically, for example, the energy despreading processing units 333-a to 333-c each perform a bit sequence on the bit stream of the bit stream excluding the synchronization byte and the predetermined PRBS used by the modulation unit 110 for the energy spreading process. Calculate the exclusive OR of the units. Then, the energy despreading processing units 333-ac input the data of the respective calculation results to the RS decoding units 334-ac as results of performing the energy despreading process.

  The RS decoding units 334-a to 334-c input data based on Reed-Solomon codes (for example, RS (204, 188)), which are error correction codes added by the modulation unit 110. The decoding processing for detecting and correcting the error of is performed. Then, the RS decoding units 334-a to 334-c count the number of error bits after the decoding process.

  The RS decoding units 334-a to 334-c respectively generate bit number information indicating the number of bits input by the energy despreading units 333-ac and the number of error bits counted, and the BER measurement units 335-a to 335-c. c.

  The BER measuring units 335-ac calculate the BER based on the bit number information respectively input by the RS decoding units 334-ac. Specifically, the BER measuring units 335-a to 335c divide the count of error bits indicated by the bit count information by the input bit count to calculate the quotient BER.

  The MER measurement unit 336 calculates a modulation error ratio based on the frequency domain signal input by the equalization processing unit 324. Here, the frequency domain signal input to the equalization processing unit 324 has been subjected to mapping processing by the modulation unit 110. Therefore, for example, when the signal input by the equalization processing unit 324 is represented by being arranged on a complex plane including the I axis and the Q axis, the MER measurement unit 336 determines the magnitude of the error from the ideal arrangement. calculate.

  When the input transmission signal is switched, it is calculated that the MER measurement result is degraded from the actual quality of the transmission signal. Therefore, when the input transmission signal is switched, the MER measurement unit 336 holds the previous measurement result until a predetermined time elapses. Then, the MER measuring unit 336 newly measures the MER when a predetermined time has elapsed since the input transmission signal was switched. Note that the synchronization reproduction unit 322 is configured to generate a clock synchronization signal according to the synchronization timing of the OFDM symbol, and the MER measurement unit 336 determines that both the clock synchronization signal and the frame synchronization signal generated by the FFT processing unit 323 are used. The MER measurement may be started at the timing when the MER is enabled.

  The determination unit 337 determines a transmission signal to be output based on the BER measurement result by the BER measurement units 335-ac and the MER measurement result by the MER measurement unit 336. Then, the determination unit 337 generates selection instruction information corresponding to the determined transmission signal and inputs the selection instruction information to the output coaxial device 400.

  The modulation units 110 and 210 and the quality monitoring unit 320 are realized by, for example, a CPU (Central Processing Unit) or a plurality of circuits that execute processing according to program control.

  Next, the operation of the transmission quality monitoring system 300 according to the first embodiment of the present invention will be described. FIG. 5 is a flowchart illustrating an operation of the transmission quality monitoring system 300 according to the first embodiment of the present invention.

  First, the signal switching unit 310 sequentially selects one of the input first transmission signal and the second transmission signal (step S101), and inputs the selected transmission signal to the quality monitoring unit 320. I do.

  In this example, it is assumed that the first transmission signal is selected in the previous process of step S101. It is assumed that the second transmission signal is selected in the process of step S101 this time. Then, this time, the second transmission signal is input to the quality monitoring unit 320.

  The quality monitoring unit 320 demodulates (Step S102) and decodes (Step S103) the input transmission signal (in this example, the first transmission signal last time and the second transmission signal this time), and The MER of the input transmission signal is measured (step S104) and the BER is measured (step S105).

  Therefore, in the previous process of step S104, the MER of the first transmission signal is measured. In the process of step S104, the MER of the second transmission signal is measured.

  Also, in the previous process of step S105, the BER of the first transmission signal is measured. In the process of step S105, the BER of the second transmission signal is measured.

  Note that the demodulation processing in step S102 is performed, for example, by the quadrature demodulation processing unit 321. The decoding processing in step S103 is performed by, for example, the Viterbi decoding processing units 331-a to 331-c and the RS decoding processing units 334-ac.

  Then, the determination unit 337 of the quality monitoring unit 320 outputs based on the processing result of the previous step S104, the processing result of the current step S104, the processing result of the previous step S105, and the processing result of the current step S105. A transmission signal is determined (step S106).

  The determination unit 337 of the quality monitoring unit 320 generates selection instruction information corresponding to the transmission signal determined in the process of step S106, and inputs the information to the output coaxial device 400 (step S107).

  Then, the transmission signal determined in the process of step S106 is input from the output coaxial device 400 to the antenna 500 and transmitted.

  Then, the transmission quality monitoring system 300 repeats the processing of steps S101 to S107 at predetermined time intervals. Then, the transmission signals of the measurement target in the processing of steps S104 and S105 are sequentially switched at predetermined time intervals in the processing of step S101, and the measurement target in the processing of step S106 is the quality of the first transmission signal and the second transmission signal. And the quality of the signal for transmission.

  Here, the process of step S106 will be described. Based on the value of the BER, it is possible to determine whether or not an appropriate video output is possible in the receiver. Therefore, in the process of step S106, the determination unit 337 determines, for example, the BER having the largest value among the current measurement results of the BER measurement units 335-ac, that is, the BER of the BER according to the worst quality. Let the value be the result of this measurement. This is because it is desirable that a video signal can be appropriately output from the receiver for any of the transmission signals in any hierarchy. Similarly, in the process of the previous step S106, the determination unit 337 determines, for example, the BER having the largest value among the previous measurement results of the BER measurement units 335-ac, that is, the BER corresponding to the worst quality. Is the previous measurement result. Then, the determining unit 337 compares, for example, the BER of the first transmission signal and the BER of the second transmission signal, that is, compares the BER of the previous step S104 with the BER of the current step S104. Are compared, a transmission signal having a smaller BER value is determined as a transmission signal to be output.

  By the way, in this example, the first transmission signal and the second transmission signal are subjected to error correction processing by the RS decoding unit 334. Therefore, the BER of the first transmission signal and the BER of the second transmission signal have constant values within a range in which an error corresponding to the quality deterioration can be corrected. Therefore, the determining unit 337 of the quality monitoring unit 320 determines, for example, that the BER of the first transmission signal and the BER of the second transmission signal have the same value, that is, the processing result of the previous step S105 and the current When the processing result of step S105 is the same, the processing result of the previous step S104 is compared with the processing result of the current step S104, and a transmission signal having a smaller MER value is output. Suppose it is determined to be a signal.

  The criterion for determining the output signal for transmission in the process of step S106 is not limited to these, and may be based on another criterion.

  According to the present embodiment, among the transmission signals generated by the plurality of transmission signal generation units 100 and 200, the transmission signal whose quality is to be monitored is switched at predetermined time intervals. Therefore, the quality of each transmission signal generated by the plurality of transmission signal generation units 100 and 200 can be monitored by the transmission quality monitoring system 300 which is a smaller number of quality measuring means.

  Therefore, it is possible to monitor the quality of each transmission signal generated by the plurality of transmission signal generation units 100 and 200 without increasing the size of the transmitter 10 or increasing power consumption.

  In this embodiment, two transmission signal generation units (transmission signal generation units 100 and 200) and one quality monitoring unit 320 are prepared, and the signal switching unit 310 One of the transmission signals generated by the section is selected and input to the quality monitoring section 320. However, three or more transmission signal generation units may be prepared, and two or more quality monitoring units may be prepared. The signal switching unit is configured to select a number of transmission signals corresponding to the number of the quality monitoring units from among the plurality of transmission signals generated by the transmission signal generation units for quality monitoring. Is also good.

Embodiment 2. FIG.
Next, a signal monitoring device 1 according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram illustrating a configuration example of the signal monitoring device 1 according to the second embodiment of the present invention.

  As shown in FIG. 6, the signal monitoring device 1 according to the second embodiment of the present invention includes a signal selection unit (signal selection unit) 31, a quality measurement unit (quality measurement unit) 32, and a transmission signal determination unit (transmission Credit signal determining means) 37.

  The signal selection unit 31 corresponds to, for example, the signal switching unit 310 illustrated in FIG. The quality measuring unit 32 corresponds to, for example, the MER measuring unit 336 shown in FIG. 2 and the BER measuring units 335-ac shown in FIG. The transmission signal determining unit 37 corresponds to, for example, the determining unit 337 illustrated in FIG.

  The signal selection unit 31 includes a plurality of transmission signals (for example, the first transmission signal generation unit 100 and the second transmission signal generation unit 200 illustrated in FIG. 1) input from a plurality of transmission signal generation units. For example, among the first transmission signal and the second transmission signal), a transmission signal for quality measurement is selected.

  The quality measuring unit 32 measures the quality of the transmission signal for quality measurement selected by the signal selecting unit 31.

  Then, the transmission signal determination unit 37 determines a transmission signal to be transmitted based on the quality measured by the quality measurement unit 32.

  According to the present embodiment, since the transmission signal for quality measurement is selected from among the transmission signals generated by the plurality of transmission signal generation units and the quality is measured, the number of transmission signals is reduced. The quality measuring unit 32 can monitor the transmission signal.

  Therefore, the quality of a plurality of transmission signals can be monitored without increasing the size of the transmitter and increasing the power consumption.

REFERENCE SIGNS LIST 1 signal monitoring device 31 signal selection unit 32 quality measurement unit 37 transmission signal determination unit 100 first transmission signal generation unit 110, 210 modulation unit 120, 220 amplification unit 200 second transmission signal generation unit 300 transmission quality monitoring System 310 Signal switching unit 320 Quality monitoring unit 321 Quadrature demodulation processing unit 322 Synchronous reproduction unit 323 FFT processing unit 324 Equalization processing unit 325 Frequency deinterleave processing unit 326 Time deinterleave processing unit 328-a, 328-b, 328-c Demapping processing units 329-a, 329-b, 329-c Bit deinterleaving processing units 330-a, 330-b, 330-c Depuncturing processing units 331-a, 331-b, 331-c Viterbi decoding processing units 332 -A, 332-b, 332-c Byte deinterleave processing unit 333 a, 333-b, 333-c Energy despreading processing unit 334-a, 334-b, 334-c RS decoding processing unit 335-a, 335-b, 335-c BER measuring unit 336 MER measuring unit 337 determining unit 400 output coaxial device 410, 420 bandpass filter 430 switcher 500 antenna

Claims (8)

Among a plurality of transmission signals input from the plurality of transmission signal generation means, a signal selection means for selecting a transmission signal for quality measurement,
Quality measurement means for measuring the quality of the transmission signal for quality measurement selected by the signal selection means,
A signal monitoring device comprising: a transmission signal determination unit that determines a transmission signal to be transmitted based on the quality measured by the quality measurement unit. The signal monitoring device according to claim 1, wherein the signal selection unit switches a transmission signal to be selected at a predetermined time interval. The signal monitoring device according to claim 1, wherein the quality measurement unit measures a modulation error ratio and a bit error rate. 4. The transmission signal determination unit, when the bit error rates of the plurality of transmission signals are the same, determines a transmission signal having a smaller modulation error ratio as a transmission signal to be transmitted. 5. Signal monitoring equipment. The quality measuring means, when switching the transmission signal selected by the signal selecting means from the transmission signal for quality measurement to another transmission signal, after the elapse of a predetermined time, the other transmission The signal monitoring device according to claim 3 or 4, wherein measurement of a modulation error ratio is started for the signal. A signal monitoring device according to any one of claims 1 to 5,
A transmission device comprising: at least one of the plurality of transmission signal generation units and a transmission unit that transmits a transmission signal determined to be transmitted by the transmission signal determination unit. Of the plurality of transmission signals input from the plurality of transmission signal generation means, select a transmission signal for quality measurement,
Measure the quality of the selected transmission signal for quality measurement,
A signal monitoring method comprising: determining a transmission signal to be transmitted based on measured quality. On the computer,
Among a plurality of transmission signals input from a plurality of transmission signal generation means, a signal selection process of selecting a transmission signal for quality measurement,
Quality measurement processing for measuring the quality of the transmission signal for the quality measurement selected in the signal selection processing,
A signal monitoring program for executing transmission signal determination processing for determining a transmission signal to be transmitted based on the quality measured in the quality measurement processing.

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