JP2010251987A - Signal monitoring method and multipath equalization device - Google Patents

Signal monitoring method and multipath equalization device Download PDF

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JP2010251987A
JP2010251987A JP2009098303A JP2009098303A JP2010251987A JP 2010251987 A JP2010251987 A JP 2010251987A JP 2009098303 A JP2009098303 A JP 2009098303A JP 2009098303 A JP2009098303 A JP 2009098303A JP 2010251987 A JP2010251987 A JP 2010251987A
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bpsk
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Yasushi Murakami
康 村上
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Toshiba Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a signal quality-monitoring method and a multipath equalization device, which can self-diagnose a signal quality after equalization process with a simple circuit. <P>SOLUTION: BPSK signal is extracted by a BPSK extracting part 191 out of the I/Q signals having been equalized by an equalizing part 15, and Q signal is extracted out of the BPSK signal by a Q signal extracting part 192. A determining part 193 determines whether the value of Q signal exceeds a preset threshold value or not, and if it exceeds, the signal after equalization process is determined to be abnormal. Thus, the quality of signal after equalization process can be monitored only by measuring amplitude of the Q signal of BPSK signal, with no complex calculation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、例えば地上デジタル放送システムにおいて、OFDM(Orthogonal Frequency Division Multiplexing:直交周波数分割多重)方式の放送波信号に含まれる信号歪みを補償するマルチパス等化装置及び、この装置に用いられる信号品質監視方法に関する。   The present invention relates to, for example, a multipath equalization apparatus that compensates for signal distortion included in an OFDM (Orthogonal Frequency Division Multiplexing) broadcast wave signal in a terrestrial digital broadcasting system, and a signal quality used in the apparatus. It relates to the monitoring method.

地上デジタル放送システムでは、放送サービスエリアの拡大および難視聴地域の解消を目的として、多数の中継装置を所定のエリアに分散配置し、各中継装置にてOFDM方式による放送波信号を多段中継する方式が採用されている。この種のシステムにおける中継装置には、マルチパス遅延波による信号歪を補償するためにマルチパス等化装置が備えられる場合がある(例えば、特許文献1参照)。   In the terrestrial digital broadcasting system, a large number of relay devices are distributed in a predetermined area for the purpose of expanding the broadcast service area and eliminating difficult viewing areas, and each relay device relays broadcast wave signals in multiple stages using the OFDM method. Is adopted. A relay device in this type of system may be provided with a multipath equalizer to compensate for signal distortion caused by a multipath delay wave (see, for example, Patent Document 1).

従来の中継装置に備えられたマルチパス等化装置は、マルチパス等化装置の前段でアナログ−デジタル変換された放送波信号を受け取り、I/Q信号に直交復調し、ガードインターバルを除去する。マルチパス等化装置は、ガードインターバルを除去したI/Q信号にFFT(Fast Fourier Transform)処理を施し、FFT処理後のI/Q信号に、伝搬路推定により算出した伝搬路の逆特性を掛け合わせることで等化を行う。そして、等化されたI/Q信号は、判定等化(硬判定)にて判定され、IFFT(Inverse Fast Fourier Transform)処理が行われ、ガードインターバルが装荷されたのち、直交変調される。   A multipath equalizer provided in a conventional relay apparatus receives a broadcast wave signal that has been analog-to-digital converted at a preceding stage of the multipath equalizer, and performs quadrature demodulation on the I / Q signal to remove the guard interval. The multipath equalizer performs an FFT (Fast Fourier Transform) process on the I / Q signal from which the guard interval is removed, and multiplies the I / Q signal after the FFT process by the inverse characteristic of the propagation path calculated by propagation path estimation. Perform equalization by combining. The equalized I / Q signal is determined by decision equalization (hard decision), subjected to IFFT (Inverse Fast Fourier Transform) processing, loaded with a guard interval, and then orthogonally modulated.

ところで、従来のマルチパス等化装置では、外部にBER(Bit Error Ratio)計、CN(Carrier to Noise)計又はMER(Magnitude of Error Ratio)計等を接続し、信号の等化処理後の信号品質を外部から監視する場合がある。しかしながら、このようなマルチパス等化装置では、装置自身による自己診断を行うことは困難である。   By the way, in the conventional multipath equalizer, a BER (Bit Error Ratio) meter, a CN (Carrier to Noise) meter, a MER (Magnitude of Error Ratio) meter or the like is connected to the outside, and the signal after the signal equalization processing is performed. Quality may be monitored externally. However, with such a multipath equalizer, it is difficult to perform self-diagnosis by the device itself.

また、従来のマルチパス等化装置では、マルチパス等化装置の内部にMER測定部及び閾値判定部を設置し、信号の等化処理後の信号品質をマルチパス等化装置自身で監視する場合がある。しかしながら、MERを測定するには、所定の期間にわたる観測データに基づいて計算する必要があるため、計算が複雑になり回路規模が大きくなる。また、所定の期間分の観測データを保存しなければならないため、大きなメモリが必要になるという問題がある。さらに、OFDM方式の放送波信号が複数階層構造となっている場合には、MER測定部及び閾値判定部を階層毎に設置する必要があり、マルチパス等化装置の大型化の要因となるという問題がある。   In the conventional multipath equalizer, a MER measurement unit and a threshold determination unit are installed inside the multipath equalizer, and the signal quality after signal equalization processing is monitored by the multipath equalizer itself. There is. However, in order to measure MER, it is necessary to calculate based on observation data over a predetermined period, so that the calculation becomes complicated and the circuit scale increases. Moreover, since observation data for a predetermined period must be stored, there is a problem that a large memory is required. Furthermore, when the OFDM broadcast wave signal has a multi-layer structure, it is necessary to install a MER measurement unit and a threshold determination unit for each layer, which is a factor in increasing the size of the multipath equalizer. There's a problem.

特開2006−311385号公報JP 2006-311385 A

以上のように、従来のマルチパス等化装置では、装置自身で放送波信号の等化処理後の信号品質を監視しようとする場合、等化処理後の信号に対する計算量が複雑になるため、回路規模の大型化の要因となっていた。   As described above, in the conventional multipath equalizer, when the device itself monitors the signal quality after the equalization processing of the broadcast wave signal, the calculation amount for the signal after the equalization processing becomes complicated. This was a factor in increasing the circuit scale.

この発明は上記事情によりなされたもので、その目的は、等化処理後の信号品質を簡単な回路で自己診断することが可能な信号監視方法及びマルチパス等化装置を提供することにある。   The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a signal monitoring method and a multipath equalization apparatus capable of self-diagnosis of signal quality after equalization processing with a simple circuit.

上記目的を達成するため、本発明に係る信号監視方法は、OFDM(Orthogonal Frequency Division Multiplexing)方式による受信信号に含まれる信号歪みを補償するマルチパス等化装置に用いられる信号品質監視方法であって、前記信号歪みの等化処理が行われた受信信号からBPSK(Binary Phase Shift Keying)信号を抽出し、前記抽出したBPSK信号のQ信号を抽出し、前記BPSK信号のQ信号の値が予め設定された閾値を超えるか否かを判断し、前記Q信号の値が前記閾値を超える場合、等化処理後の信号に異常があると判定することを特徴とする。   In order to achieve the above object, a signal monitoring method according to the present invention is a signal quality monitoring method used in a multipath equalizer for compensating for signal distortion included in a received signal by an OFDM (Orthogonal Frequency Division Multiplexing) method. BPSK (Binary Phase Shift Keying) signal is extracted from the received signal subjected to the signal distortion equalization processing, the Q signal of the extracted BPSK signal is extracted, and the value of the Q signal of the BPSK signal is preset. It is determined whether the signal exceeds the threshold value, and when the value of the Q signal exceeds the threshold value, it is determined that the signal after the equalization processing is abnormal.

また、本発明に係るマルチパス等化装置は、OFDM(Orthogonal Frequency Division Multiplexing)方式による受信信号に含まれる信号歪みを補償するマルチパス等化装置において、前記受信信号に対して等化処理を行う等化手段と、前記等化処理が行われた信号からBPSK(Binary Phase Shift Keying)信号を抽出するBPSK信号抽出部と、前記抽出したBPSK信号のQ信号を抽出するQ信号抽出部と、前記BPSK信号のQ信号の値が予め設定された閾値を超えるか否かを判断し、前記閾値を超える場合、等化処理後の信号に異常があると判定する判定部とを具備する。   The multipath equalizer according to the present invention performs equalization processing on the received signal in the multipath equalizer that compensates for signal distortion included in the received signal by an OFDM (Orthogonal Frequency Division Multiplexing) scheme. Equalization means, a BPSK signal extraction unit that extracts a Binary Phase Shift Keying (BPSK) signal from the equalized signal, a Q signal extraction unit that extracts a Q signal of the extracted BPSK signal, A determination unit that determines whether or not the value of the Q signal of the BPSK signal exceeds a preset threshold value, and determines that there is an abnormality in the signal after equalization processing when the value exceeds the threshold value;

上記構成による信号監視方法及びマルチパス等化装置では、等化手段で等化処理が施された信号から、BPSK信号抽出部によりBPSK信号を抽出し、Q信号抽出部でこのBPSK信号からQ信号を抽出する。そして、判定部でQ信号の値が予め設定した閾値を超えるか否かを判断し、超える場合には、等化処理後の信号に異常があると判定する。これにより、複雑な計算をせずとも、BPSK信号のQ信号の振幅を測定するのみで、等化処理後の信号の品質を確認することが可能となる。   In the signal monitoring method and multipath equalization apparatus configured as described above, the BPSK signal extraction unit extracts the BPSK signal from the signal subjected to equalization processing by the equalization means, and the Q signal extraction unit extracts the Q signal from the BPSK signal. To extract. Then, the determination unit determines whether or not the value of the Q signal exceeds a preset threshold value. If it exceeds, it is determined that the signal after the equalization processing is abnormal. Thereby, it is possible to confirm the quality of the signal after the equalization processing only by measuring the amplitude of the Q signal of the BPSK signal without performing complicated calculation.

この発明によれば、等化処理後の信号品質を簡単な回路で自己診断することが可能な信号監視方法及びマルチパス等化装置を提供することができる。   According to the present invention, it is possible to provide a signal monitoring method and a multipath equalizer capable of performing self-diagnosis of signal quality after equalization processing with a simple circuit.

本発明の一実施形態に係るマルチパス等化装置の機能構成を示すブロック図である。It is a block diagram which shows the function structure of the multipath equalization apparatus which concerns on one Embodiment of this invention. 図1のFFT部から伝搬路推定部及び等化部へ出力されるI/Q信号の信号配置の例を示す模式図である。FIG. 2 is a schematic diagram illustrating an example of signal arrangement of I / Q signals output from the FFT unit of FIG. 1 to a propagation path estimation unit and an equalization unit. 図1の信号品質監視部が等化処理後の信号品質を監視する際のフローチャートである。It is a flowchart at the time of the signal quality monitoring part of FIG. 1 monitoring the signal quality after an equalization process. BPSK信号と64QAM変調方式により変調された情報信号のコンスタレーションを示す模式図である。It is a schematic diagram which shows the constellation of the information signal modulated by the BPSK signal and the 64QAM modulation system.

以下、図面を参照しながら本発明に係るマルチパス等化装置の実施の形態について詳細に説明する。図1は、本発明の一実施形態に係るマルチパス等化装置の機能構成を示すブロック図である。本実施形態におけるマルチパス等化装置は、例えば、地上デジタル放送システムで用いられる中継装置に使用される。   Hereinafter, embodiments of a multipath equalization apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a functional configuration of a multipath equalizer according to an embodiment of the present invention. The multipath equalization apparatus in this embodiment is used for a relay apparatus used in, for example, a terrestrial digital broadcasting system.

地上デジタル放送システムにおけるOFDM方式の放送波信号は、図1に示すマルチパス等化装置の前段に設置されるアンテナ(図示せず)で受信され、周波数変換部(図示せず)で中間周波数帯に周波数変換され、アナログ−デジタル変換部(図示せず)でデジタル信号に変換されたのち、マルチパス等化装置へ供給される。   An OFDM broadcast wave signal in the terrestrial digital broadcasting system is received by an antenna (not shown) installed in the front stage of the multipath equalizer shown in FIG. 1, and is transmitted to an intermediate frequency band by a frequency converter (not shown). Frequency is converted into a digital signal by an analog-digital converter (not shown), and then supplied to a multipath equalizer.

図1において、デジタル信号に変換された放送波信号は、直交復調部(Q_DEM)11で直交復調されてI/Q信号となり、ガードインターバル除去部12でガードインターバルが除去され、FFT(Fast Fourier Transform)部13でFFT処理される。FFT処理されたI/Q信号は、等化部15及び伝搬路推定部16へ出力される。直交復調部11には自動周波数制御部(AFC)14が接続されており、AFC14は、直交復調後のI/Q信号の周波数をモニタして直交復調部11で生成されるI信号とQ信号との間の周波数のずれを補償する。   In FIG. 1, a broadcast wave signal converted into a digital signal is quadrature demodulated by an orthogonal demodulator (Q_DEM) 11 to become an I / Q signal, a guard interval is removed by a guard interval remover 12, and an FFT (Fast Fourier Transform) is performed. ) Part 13 performs FFT processing. The I / Q signal subjected to the FFT processing is output to the equalization unit 15 and the propagation path estimation unit 16. An automatic frequency control unit (AFC) 14 is connected to the quadrature demodulation unit 11, and the AFC 14 monitors the frequency of the I / Q signal after quadrature demodulation and generates the I signal and the Q signal generated by the quadrature demodulation unit 11. To compensate for the frequency shift between.

伝搬路推定部16は、既知のパイロット信号等に基づいて、FFT処理されたI/Q信号から伝搬路を推定する。逆特性算出部17は、伝搬路推定部16で推定された伝搬路による歪を補正するため、推定された伝搬路の逆特性を算出する。等化部15は、FFT処理されたI/Q信号に逆特性算出部17で算出された逆特性を掛け合わせてマルチパスの等化処理を行い、等化処理後のI/Q信号を判定等化部18及び信号品質監視部19へ出力する。I/Q信号は、判定等化部18で硬判定され、IFFT(Inverse Fast Fourier Transform)部110でIFFT処理が行われ、ガードインターバル装荷部111でガードインターバルが装荷されたのち、直交変調部(Q_MOD)112で直交変調される。   The propagation path estimation unit 16 estimates a propagation path from the FFT-processed I / Q signal based on a known pilot signal or the like. The inverse characteristic calculation unit 17 calculates the inverse characteristic of the estimated propagation path in order to correct the distortion caused by the propagation path estimated by the propagation path estimation unit 16. The equalizing unit 15 multiplies the FFT processed I / Q signal by the inverse characteristic calculated by the inverse characteristic calculating unit 17 to perform multipath equalization processing, and determines the I / Q signal after the equalization processing The data is output to the equalization unit 18 and the signal quality monitoring unit 19. The I / Q signal is subjected to a hard decision by the decision equalization unit 18, an IFFT process is performed by an IFFT (Inverse Fast Fourier Transform) unit 110, a guard interval is loaded by a guard interval loading unit 111, and then an orthogonal modulation unit ( Q_MOD) 112 is orthogonally modulated.

信号品質監視部19は、BPSK(Binary Phase Shift Keying)抽出部191、Q信号抽出部192及び判定部193を備え、等化部15から供給されるI/Q信号の品質を監視する。   The signal quality monitoring unit 19 includes a BPSK (Binary Phase Shift Keying) extraction unit 191, a Q signal extraction unit 192, and a determination unit 193, and monitors the quality of the I / Q signal supplied from the equalization unit 15.

BPSK抽出部191は、等化処理後のI/Q信号からBPSK信号を抽出し、Q信号抽出部192へ出力する。Q信号抽出部192は、BPSK抽出部191で抽出されたBPSK信号からQ信号を抽出する。判定部193は、Q信号抽出部192で抽出されたQ信号の値と予め設定された閾値とを比較し、等化処理後の信号に異常があるか否かを判定する。判定部193は、Q信号の値が閾値を超えている場合は、信号に異常が発生したと判定して外部へアラームを発報する。また、判定部193は、Q信号の値が閾値を超えていない場合は、信号は正常であると判定する。   The BPSK extraction unit 191 extracts the BPSK signal from the equalized I / Q signal and outputs the BPSK signal to the Q signal extraction unit 192. The Q signal extraction unit 192 extracts a Q signal from the BPSK signal extracted by the BPSK extraction unit 191. The determination unit 193 compares the value of the Q signal extracted by the Q signal extraction unit 192 with a preset threshold value, and determines whether or not the equalized signal is abnormal. When the value of the Q signal exceeds the threshold value, the determination unit 193 determines that an abnormality has occurred in the signal and issues an alarm to the outside. The determination unit 193 determines that the signal is normal when the value of the Q signal does not exceed the threshold value.

次に、上記構成における動作を説明する。   Next, operation in the above configuration will be described.

図2は、FFT部13から伝搬路推定部16及び等化部15へ出力されるI/Q信号の信号配置の例を示す模式図である。図2に示す信号フォーマット例において、情報信号S1は、映像や音声などの情報データを伝送するものであり、例えば64QAMで変調される。付加情報(TMCC:Transmission and Multiplex Configuration Control)信号S2は、例えば、変調方式やインタリーブなどの伝送パラメータ情報や、付加情報を伝送するものであり、BPSK変調方式により特定のキャリア(周波数スロット)にて伝送される。連続パイロット(CP:Continual Pilot)信号S3は、OFDM信号の終端を示すものであり、BPSK変調方式により特定のキャリア(周波数スロット)にて伝送される。分散パイロット(SP:Scattered Pilot)信号S4は、周波数及び時間方向に分散してBPSK変調方式により伝送されるものであり、伝搬路推定部16における伝搬路推定等に用いられる。SP信号S4は、例えば周波数方向に1/3、及び時間方向に1/4の割合で挿入される。   FIG. 2 is a schematic diagram illustrating an example of the signal arrangement of the I / Q signal output from the FFT unit 13 to the propagation path estimation unit 16 and the equalization unit 15. In the signal format example shown in FIG. 2, the information signal S1 transmits information data such as video and audio, and is modulated by, for example, 64QAM. An additional information (TMCC: Transmission and Multiplex Configuration Control) signal S2 is used to transmit transmission parameter information such as a modulation scheme and interleaving, and additional information, for example, in a specific carrier (frequency slot) by the BPSK modulation scheme. Is transmitted. A continuous pilot (CP) signal S3 indicates the end of the OFDM signal and is transmitted on a specific carrier (frequency slot) by the BPSK modulation method. A distributed pilot (SP) signal S4 is distributed in the frequency and time directions and transmitted by the BPSK modulation method, and is used for propagation path estimation and the like in the propagation path estimation unit 16. The SP signal S4 is inserted, for example, at a rate of 1/3 in the frequency direction and 1/4 in the time direction.

伝搬路推定部16は、図2に示されるSP信号S4を用いて、全時間及び全周波数における伝搬路を推定する。等化部15は、推定した伝搬路に基づいて逆特性算出部17で算出される逆特性を、FFT部13からのI/Q信号に掛け合わせて等化処理を行う。   The propagation path estimation unit 16 estimates the propagation path at all times and all frequencies using the SP signal S4 shown in FIG. The equalization unit 15 performs equalization processing by multiplying the I / Q signal from the FFT unit 13 by the inverse characteristic calculated by the inverse characteristic calculation unit 17 based on the estimated propagation path.

図3は、本発明の一実施形態に係るマルチパス等化装置における信号品質監視部19が等化処理後の信号品質を監視する際のフローチャートを示す。信号品質監視部19は、図2に示すように特定周波数に連続的に配置されBPSK変調方式により伝送されるTMCC信号S2、CP信号S3又はSP信号S4をBPSK信号として、BPSK抽出部191で抽出する(ステップ31)。信号品質監視部19は、Q信号抽出部192でBPSK信号のQ信号を抽出する(ステップ32)。   FIG. 3 shows a flowchart when the signal quality monitoring unit 19 in the multipath equalizer according to the embodiment of the present invention monitors the signal quality after the equalization processing. As shown in FIG. 2, the signal quality monitoring unit 19 extracts TMCC signal S2, CP signal S3 or SP signal S4, which is continuously arranged at a specific frequency and transmitted by the BPSK modulation method, as a BPSK signal by BPSK extraction unit 191. (Step 31). In the signal quality monitoring unit 19, the Q signal extraction unit 192 extracts the Q signal of the BPSK signal (step 32).

続いて、信号品質監視部19は、判定部193でBPSK信号のQ信号の振幅が閾値以上である否かを判断する(ステップ33)。図4は、BPSK信号と64QAM変調方式により変調された情報信号のコンスタレーションを示す模式図である。BPSK信号は、情報信号よりも4/3だけ振幅が大きい。BPSK信号は、理想的にはI信号のみ存在し、Q信号は“0”である。つまり、BPSK信号のQ信号が“0”でない場合には、マルチパス等化装置自身又は受信したOFDM信号になんらかの異常が発生したおそれがあることになる。本実施形態では、情報信号のQ信号の最小値を上記閾値として設定する。判定部193は、BPSK信号のQ信号の振幅の絶対値が情報信号のQ信号の最小値以上であると判定した場合(ステップ33のYes)、信号に異常があるとしてアラームを発報し(ステップ34)、処理を終了する。   Subsequently, the signal quality monitoring unit 19 determines whether or not the amplitude of the Q signal of the BPSK signal is greater than or equal to a threshold value by the determination unit 193 (step 33). FIG. 4 is a schematic diagram showing a constellation of an information signal modulated by a BPSK signal and a 64QAM modulation method. The BPSK signal is 4/3 larger in amplitude than the information signal. The BPSK signal ideally includes only the I signal, and the Q signal is “0”. That is, when the Q signal of the BPSK signal is not “0”, there is a possibility that some abnormality has occurred in the multipath equalizer itself or the received OFDM signal. In the present embodiment, the minimum value of the Q signal of the information signal is set as the threshold value. If the determination unit 193 determines that the absolute value of the Q signal amplitude of the BPSK signal is greater than or equal to the minimum value of the Q signal of the information signal (Yes in step 33), the determination unit 193 issues an alarm that the signal is abnormal ( Step 34), the process ends.

BPSK信号のQ信号の振幅が情報信号のQ信号の最小値以上となった場合、例えば、図4に示すBPSK信号のコンスタレーションが滲んだ状況及び、図4に示すBPSK信号のコンスタレーションが回転した状況等が推測される。BPSK信号のコンスタレーションの滲みは、CNの劣化が要因である。コンスタレーションが滲む場合、隣接する情報信号のコンスタレーションが混ざるため、コンスタレーションの判定間違いが発生し、正常な信号を後段へ伝送することが困難となる。また、BPSK信号のコンスタレーションの回転は、AFC14の動作異常が要因である。コンスタレーションが回転する場合、所定の位置に情報信号のコンスタレーションが存在しないため、コンスタレーションの判定間違いが発生し、正常な信号を後段へ伝送することが困難となる。   When the amplitude of the Q signal of the BPSK signal is greater than or equal to the minimum value of the Q signal of the information signal, for example, the situation where the constellation of the BPSK signal shown in FIG. 4 is blurred and the constellation of the BPSK signal shown in FIG. The situation etc. which were done are guessed. The constellation blur of the BPSK signal is caused by CN deterioration. When the constellation is blurred, the constellations of adjacent information signals are mixed, so that a constellation determination error occurs and it is difficult to transmit a normal signal to the subsequent stage. The rotation of the constellation of the BPSK signal is caused by an abnormal operation of the AFC 14. When the constellation rotates, there is no constellation of the information signal at a predetermined position. Therefore, a constellation determination error occurs, and it becomes difficult to transmit a normal signal to the subsequent stage.

一方、判定部193は、BPSK信号のQ信号の振幅の絶対値が情報信号のQ信号の最小値未満である場合(ステップ33のNo)、コンスタレーションの判定間違いは発生しないと考えられるため、信号は正常であるとして処理を終了する。   On the other hand, if the absolute value of the amplitude of the Q signal of the BPSK signal is less than the minimum value of the Q signal of the information signal (No in step 33), the determination unit 193 is considered not to cause a determination error in the constellation. The processing is terminated assuming that the signal is normal.

以上のように、上記一実施形態では、等化処理後のI/Q信号からBPSK信号のQ信号のみを抽出する。そして、このQ信号の振幅が予め設定した閾値を超えるか否かを判断し、超える場合には等化処理に異常があると判定するようにしている。これにより、複雑な計算をせずとも、BPSK信号のQ信号の振幅を測定するのみで、等化処理後の信号に異常があることを検知することが可能となる。   As described above, in the above embodiment, only the Q signal of the BPSK signal is extracted from the equalized I / Q signal. Then, it is determined whether or not the amplitude of the Q signal exceeds a preset threshold, and if it exceeds, it is determined that there is an abnormality in the equalization processing. As a result, it is possible to detect that there is an abnormality in the signal after the equalization processing only by measuring the amplitude of the Q signal of the BPSK signal without performing complicated calculations.

したがって、本発明に係るマルチパス等化装置によれば、等化処理後の信号品質を簡単な回路で自己診断することができる。   Therefore, according to the multipath equalizer according to the present invention, the signal quality after the equalization process can be self-diagnosed with a simple circuit.

なお、この発明は上記実施形態に限定されるものではない。例えば、上記一実施形態では、情報信号が64QAM変調方式により変調されて伝送される例について説明したが、情報信号の変調方式は、64QAMに限定されるわけではなく、16QAM、QPSK、256QAM等であっても同様に実施可能である。   The present invention is not limited to the above embodiment. For example, in the above-described embodiment, an example in which an information signal is modulated and transmitted by the 64QAM modulation method has been described. However, the modulation method of the information signal is not limited to 64QAM, and may be 16QAM, QPSK, 256QAM, or the like. Even if it exists, it can implement similarly.

また、上記一実施形態では、判定部193における閾値が情報信号のQ信号の最小値に設定される場合について説明したが、閾値はこの値に限定される訳ではない。   In the above embodiment, the case where the threshold value in the determination unit 193 is set to the minimum value of the Q signal of the information signal has been described, but the threshold value is not limited to this value.

また、上記一実施形態では、判定部193が信号に異常があると判定した場合に外部へアラームを発報する例について説明したが、判定部193が信号に異常があると判定した場合にはNG信号を外部へ出力し、信号が正常であると判定した場合にはOK信号を外部へ出力する場合であっても同様に実施可能である。   In the above-described embodiment, the example in which the determination unit 193 determines that the signal is abnormal has been described. However, when the determination unit 193 determines that the signal is abnormal, If the NG signal is output to the outside and it is determined that the signal is normal, the operation can be similarly performed even when the OK signal is output to the outside.

さらに、この発明は上記実施形態そのままに限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また、上記実施形態に開示されている複数の構成要素の適宜な組み合わせにより、種々の発明を形成できる。例えば、実施形態に示される全構成要素から幾つかの構成要素を削除してもよい。   Furthermore, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

11…Q_DEM
12…GI除去部
13…FFT部
14…AFC
15…等化部
16…伝搬路推定部
17…逆特性算出部
18…判定等化部
19…信号品質監視部
191…BPSK抽出部
192…Q信号抽出部
193…判定部
110…IFFT部
111…GI装荷部
112…Q_MOD
11 ... Q_DEM
12 ... GI removal unit 13 ... FFT unit 14 ... AFC
DESCRIPTION OF SYMBOLS 15 ... Equalization part 16 ... Propagation path estimation part 17 ... Inverse characteristic calculation part 18 ... Determination equalization part 19 ... Signal quality monitoring part 191 ... BPSK extraction part 192 ... Q signal extraction part 193 ... Determination part 110 ... IFFT part 111 ... GI loading part 112 ... Q_MOD

Claims (7)

OFDM(Orthogonal Frequency Division Multiplexing)方式による受信信号に含まれる信号歪みを補償するマルチパス等化装置に用いられる信号品質監視方法であって、
前記信号歪みの等化処理が行われた受信信号からBPSK(Binary Phase Shift Keying)信号を抽出し、
前記抽出したBPSK信号のQ信号を抽出し、
前記BPSK信号のQ信号の値が予め設定された閾値を超えるか否かを判断し、
前記Q信号の値が前記閾値を超える場合、等化処理後の信号に異常があると判定することを特徴とする信号品質監視方法。
A signal quality monitoring method used in a multipath equalizer that compensates for signal distortion included in a received signal by an OFDM (Orthogonal Frequency Division Multiplexing) scheme,
Extracting a BPSK (Binary Phase Shift Keying) signal from the received signal subjected to the signal distortion equalization process,
Extracting the Q signal of the extracted BPSK signal;
Determining whether the value of the Q signal of the BPSK signal exceeds a preset threshold;
A signal quality monitoring method, wherein when the value of the Q signal exceeds the threshold value, it is determined that the signal after equalization processing is abnormal.
前記BPSK信号は、前記受信信号に含まれるSP(Scattered Pilot)信号又はTMCC(Transmission and Multiplex Configuration Control)信号であることを特徴とする請求項1記載の信号品質監視方法。 2. The signal quality monitoring method according to claim 1, wherein the BPSK signal is an SP (Scattered Pilot) signal or a TMCC (Transmission and Multiplex Configuration Control) signal included in the received signal. 前記受信信号における情報信号が所定の位相変調方式により変調されている場合、
前記閾値は、前記情報信号のQ信号の最小値であることを特徴とする請求項1記載の信号品質監視方法。
When the information signal in the received signal is modulated by a predetermined phase modulation method,
2. The signal quality monitoring method according to claim 1, wherein the threshold value is a minimum value of a Q signal of the information signal.
OFDM(Orthogonal Frequency Division Multiplexing)方式による受信信号に含まれる信号歪みを補償するマルチパス等化装置において、
前記受信信号に対して等化処理を行う等化手段と、
前記等化処理が行われた信号からBPSK(Binary Phase Shift Keying)信号を抽出するBPSK信号抽出部と、
前記抽出したBPSK信号のQ信号を抽出するQ信号抽出部と、
前記BPSK信号のQ信号の値が予め設定された閾値を超えるか否かを判断し、前記閾値を超える場合、等化処理後の信号に異常があると判定する判定部と
を具備することを特徴とするマルチパス等化装置。
In a multipath equalizer that compensates for signal distortion included in a received signal by an OFDM (Orthogonal Frequency Division Multiplexing) scheme,
Equalization means for performing equalization on the received signal;
A BPSK signal extraction unit for extracting a BPSK (Binary Phase Shift Keying) signal from the equalized signal;
A Q signal extraction unit for extracting a Q signal of the extracted BPSK signal;
A determination unit that determines whether or not a value of a Q signal of the BPSK signal exceeds a preset threshold value, and determines that there is an abnormality in the signal after equalization processing when the value exceeds the threshold value. A multipath equalizing device that is characterized.
前記BPSK信号は、前記受信信号に含まれるSP(Scattered Pilot)信号又はTMCC(Transmission and Multiplex Configuration Control)信号であることを特徴とする請求項4記載のマルチパス等化装置。 5. The multipath equalizer according to claim 4, wherein the BPSK signal is an SP (Scattered Pilot) signal or a TMCC (Transmission and Multiplex Configuration Control) signal included in the received signal. 前記受信信号における情報信号が所定の位相変調方式により変調されている場合、
前記閾値は、前記情報信号のQ信号の最小値であることを特徴とする請求項4記載のマルチパス等化装置。
When the information signal in the received signal is modulated by a predetermined phase modulation method,
5. The multipath equalizer according to claim 4, wherein the threshold is a minimum value of a Q signal of the information signal.
前記等化手段は、
前記受信信号を直交復調してI/Q信号を生成する直交復調部と、
前記直交復調部で生成される前記I/Q信号の周波数ずれを補償する周波数補償部と、
前記I/Q信号に含まれるガードインターバルを除去するガードインターバル除去部と、
前記ガードインターバルを除去したI/Q信号に対してFFT(Fast Fourier Transform)処理を行うFFT処理部と、
前記FFT処理を施したI/Q信号に対して等化処理を行う等化部と、
前記等化処理を施したI/Q信号に対してIFFT(Inverse Fast Fourier Transform)処理を行うIFFT処理部と、
前記IFFT処理を施したI/Q信号に対してガードインターバルを装荷するガードインターバル装荷部と、
前記ガードインターバルが装荷されたI/Q信号を直交変調する直交変調部と
を備えることを特徴とする請求項4記載のマルチパス等化装置。
The equalizing means includes
An orthogonal demodulator for generating an I / Q signal by orthogonally demodulating the received signal;
A frequency compensation unit that compensates for a frequency shift of the I / Q signal generated by the orthogonal demodulation unit;
A guard interval removing unit that removes a guard interval included in the I / Q signal;
An FFT processing unit for performing FFT (Fast Fourier Transform) processing on the I / Q signal from which the guard interval is removed;
An equalization unit that performs an equalization process on the I / Q signal subjected to the FFT process;
An IFFT processing unit for performing IFFT (Inverse Fast Fourier Transform) processing on the equalized I / Q signal;
A guard interval loading unit for loading a guard interval to the I / Q signal subjected to the IFFT processing;
5. The multipath equalization apparatus according to claim 4, further comprising: an orthogonal modulation unit that orthogonally modulates the I / Q signal loaded with the guard interval.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2330064A2 (en) 2009-12-04 2011-06-08 Ricoh Company, Ltd. Sheet conveying device and image forming apparatus incorporating same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2330064A2 (en) 2009-12-04 2011-06-08 Ricoh Company, Ltd. Sheet conveying device and image forming apparatus incorporating same

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