JP2016046690A - Transmitter - Google Patents
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Abstract
Description
本発明は、デジタル信号を送信する送信装置の技術に関し、特に、伝送路の歪成分の逆特性を予め付加することで、伝送路通過後に理想信号点に近づけることを可能とする送信装置に関する。 The present invention relates to a technique of a transmission apparatus that transmits a digital signal, and more particularly to a transmission apparatus that can be brought close to an ideal signal point after passing through a transmission path by adding in advance a reverse characteristic of a distortion component of the transmission path.
現在運用されている各種規格のデジタル放送のうち、衛星放送を例にすると、複数の放送衛星事業者による独立したトランスポートストリーム（ＴＳ）を多重した信号を、放送衛星に備えた衛星中継器を介することにより伝送する。衛星デジタル放送で採用されている規格としては、ＩＳＤＢ−Ｓ，ＤＶＢ−Ｓ２などがある。以下、送信装置はこれらの規格に適合した一般化したものとして説明する。 Of digital broadcasting of various standards currently in operation, taking satellite broadcasting as an example, a satellite repeater equipped with broadcasting satellites can be used to multiplex signals that are independent transport streams (TS) from multiple broadcasting satellite operators. To be transmitted through. Standards adopted in satellite digital broadcasting include ISDB-S and DVB-S2. In the following description, it is assumed that the transmission apparatus is generalized in conformity with these standards.
図４は、衛星放送における衛星中継器を用いた伝送システムの構成を示すブロック図である。地球局側に設置された送信装置１から映像・音声・データ放送などを多重した放送波信号が実衛星２にアップリンクされ、実衛星２を経由した放送波信号は、各家庭の受信装置３‐１，３‐１，…，３‐ｎ（ｎは１以上の自然数）へダウンリンクされる。実衛星２の衛星中継器は、入力マルチプレクサ（ＩＭＵＸ）フィルタ２１、進行波管増幅器（ＴＷＴＡ）２２、出力マルチプレクサ（ＯＭＵＸ）フィルタ２３等で構成される。この衛星中継器で受信した放送波信号をＩＭＵＸフィルタ２１にて１チャンネル分ごとの帯域抽出を行い、ＴＷＴＡ２２において利得制御を行った後、ＯＭＵＸフィルタ２３で不要周波数成分を抑圧し、後続の合成器（図示せず）により全チャンネル分の放送波信号として合成し、受信装置３‐ｎへ放送波信号を送信する。 FIG. 4 is a block diagram showing a configuration of a transmission system using a satellite repeater in satellite broadcasting. A broadcast wave signal obtained by multiplexing video / audio / data broadcasts from the transmitter 1 installed on the earth station side is uplinked to the real satellite 2, and the broadcast wave signal passing through the real satellite 2 is received by the receiver 3 of each home. -1,3-1,..., 3-n (n is a natural number of 1 or more). The satellite repeater of the actual satellite 2 includes an input multiplexer (IMUX) filter 21, a traveling wave tube amplifier (TWTA) 22, an output multiplexer (OMUX) filter 23, and the like. The broadcast wave signal received by this satellite repeater is band-extracted for each channel by the IMUX filter 21, gain control is performed by the TWTA 22, unnecessary frequency components are suppressed by the OMUX filter 23, and the subsequent synthesizer (Not shown) are combined as broadcast wave signals for all channels and transmitted to the receiving device 3-n.
このような衛星中継器を通過後、ＴＷＴＡ２２の非線形歪などにより、受信装置３‐ｎ側の信号点配置は同じ情報ビットであったとしても所望の信号点からずれが発生し、シンボル間干渉により信号誤りが発生しやすくなることが想定される。このため、衛星中継器等による非線形歪を事前に送信装置１の変調器側で補正する技法が知られている（例えば、特許文献１参照）。 After passing through such a satellite repeater, due to non-linear distortion of the TWTA 22, even if the signal point arrangement on the receiving device 3-n side is the same information bit, a deviation from a desired signal point occurs, and due to intersymbol interference It is assumed that signal errors are likely to occur. For this reason, a technique is known in which nonlinear distortion due to a satellite repeater or the like is corrected in advance on the modulator side of the transmission apparatus 1 (see, for example, Patent Document 1).
図５は、特許文献１の技法による従来の送信装置１における衛星伝送路の歪補正を備えた変調器のみを示すブロック図である。この変調器は、所定の符号化を施したデータ信号（以下、単に「デジタル信号」とも称する）に対して、シリアルのビット列をパラレルに変換するシリアル／パラレル変換（Ｓ／Ｐ）部１１と、変調方式毎にマッピングするマッピング部１２と、歪補正を行う歪補正部１３と、変調方式に応じた直交変調を施す直交変調部１４とを備える。 FIG. 5 is a block diagram showing only the modulator provided with the distortion correction of the satellite transmission path in the conventional transmitter 1 according to the technique of Patent Document 1. In FIG. The modulator includes a serial / parallel conversion (S / P) unit 11 that converts a serial bit string into parallel with respect to a data signal (hereinafter, also simply referred to as “digital signal”) subjected to predetermined encoding, A mapping unit 12 that performs mapping for each modulation method, a distortion correction unit 13 that performs distortion correction, and an orthogonal modulation unit 14 that performs orthogonal modulation according to the modulation method are provided.
歪補正部１３は、マッピング部１２でマッピングされた信号の１シンボル毎に処理を行い、実衛星２の伝送路の特性を模擬した疑似伝送路部１３１と、マッピング部１２においてマッピングされた理想的な信号点配置信号（以下、「理想信号点」と称する）を遅延時間Ｄだけ遅延させる遅延部１３２と、理想信号点と疑似伝送路部１３２を通過した歪信号との差分を求めることで誤差ベクトルを求める第１ベクトル加算部１３３と、理想信号点に誤差ベクトルを加算する第２ベクトル加算部１３４とを備える。ここで、遅延部１３２における遅延時間Ｄは、理想信号点の１シンボルが疑似伝送路部１３１を通過するのに必要な時間と等しく設定される。 The distortion correction unit 13 performs processing for each symbol of the signal mapped by the mapping unit 12, and the pseudo transmission path unit 131 that simulates the characteristics of the transmission path of the real satellite 2 and the ideal mapped by the mapping unit 12. Error is obtained by obtaining a difference between a delay unit 132 that delays a simple signal point arrangement signal (hereinafter referred to as an “ideal signal point”) by a delay time D, and a distortion signal that has passed through the pseudo transmission line unit 132. A first vector adding unit 133 for obtaining a vector and a second vector adding unit 134 for adding an error vector to the ideal signal point are provided. Here, the delay time D in the delay unit 132 is set equal to the time required for one symbol of the ideal signal point to pass through the pseudo transmission line unit 131.
また、疑似伝送路部１３１は、実衛星２の伝送路の特性を模擬するべく、実衛星２が備えるＩＭＵＸフィルタ２１、ＴＷＴＡ２２及びＯＭＵＸフィルタ２３にそれぞれ対応する、位相及び振幅の周波数特性に近似した特性を有するＩＭＵＸフィルタ１３１１、ＴＷＴＡ１３１２及びＯＭＵＸフィルタ１３１３を備える。 Further, the pseudo transmission path unit 131 approximates the frequency characteristics of the phase and amplitude corresponding to the IMUX filter 21, the TWTA 22 and the OMUX filter 23 included in the real satellite 2 in order to simulate the characteristics of the transmission path of the real satellite 2. An IMUX filter 1311, a TWTA 1312, and an OMUX filter 1313 having characteristics are provided.
このように構成された歪補正部１３において求められた信号点座標は、直交変調部１４へ入力され、変調信号を生成する。生成された変調信号は、実衛星２に向けてアップリンクされる。 The signal point coordinates obtained by the distortion correction unit 13 configured as described above are input to the quadrature modulation unit 14 to generate a modulation signal. The generated modulation signal is uplinked toward the real satellite 2.
尚、ここでの変調方式とは、π／２シフトＢＰＳＫ（Binary Phase-Shift Keying）を含むＢＰＳＫ、π／４シフトＱＰＳＫ（Quadrature Phase Shift Keying）を含むＱＰＳＫ、８ＰＳＫ（Phase Shift Keying）、１６ＡＰＳＫ（Amplitude phase shift keying）、３２ＡＰＳＫ、６４ＡＰＳＫ、１２８ＡＰＳＫ、２５６ＡＰＳＫなどを含み、マッピング部１２はこれらの変調方式に対応したマッパを用いることができる。 The modulation schemes here are BPSK including π / 2 shift BPSK (Binary Phase-Shift Keying), QPSK including π / 4 shift QPSK (Quadrature Phase Shift Keying), 8PSK (Phase Shift Keying), 16APSK ( Amplitude phase shift keying), 32APSK, 64APSK, 128APSK, 256APSK, etc., and the mapping unit 12 can use a mapper corresponding to these modulation methods.
実衛星２内の衛星中継器における歪みについて説明する。ＩＭＵＸフィルタ２１は、衛星中継器にて受信したアップリンク信号から各チャンネルの周波数に対応した放送波信号を抽出する帯域通過フィルタであり、群遅延歪みが発生する。ＴＷＴＡ２２は、ＩＭＵＸフィルタ２１にて抽出された各チャンネルの放送波信号に対して電力増幅を行うが、図６に示すような非線形特性により、入力パワー（Amplitude：振幅）対出力パワー（Amplitude：振幅）の比で表されるＡＭ／ＡＭ歪み、及び入力パワー（Amplitude：振幅）対出力位相（Phase）の比で表されるＡＭ／ＰＭ歪みが発生する。ＯＭＵＸフィルタ２３は、ＴＷＴＡ２２において増幅した放送波信号に対し不要な周波数成分を抑圧する帯域通過フィルタであり、群遅延歪みが発生する。 The distortion in the satellite repeater in the actual satellite 2 will be described. The IMUX filter 21 is a band pass filter that extracts a broadcast wave signal corresponding to the frequency of each channel from the uplink signal received by the satellite repeater, and generates group delay distortion. The TWTA 22 performs power amplification on the broadcast wave signal of each channel extracted by the IMUX filter 21. Due to the nonlinear characteristic as shown in FIG. 6, the input power (Amplitude) versus the output power (Amplitude: amplitude). ) And AM / PM distortion expressed by the ratio of input power (Amplitude) to output phase (Phase). The OMUX filter 23 is a band-pass filter that suppresses unnecessary frequency components for the broadcast wave signal amplified in the TWTA 22, and generates group delay distortion.
ＴＷＴＡ２２の電力増幅処理は、入力レベルと出力レベルの間の関係が比例関係となることが望ましいが、入力レベルが上がるにつれて、出力レベルの利得が小さくなり、ある入力レベルを超えると、出力レベルが低下する非線形特性を示す。この出力レベルが低下し始める直前の動作点を、一般に、出力飽和点と云い、ＴＷＴＡ２２における電力効率が最も良くなる。 In the power amplification processing of the TWTA 22, it is desirable that the relationship between the input level and the output level is a proportional relationship. However, as the input level increases, the gain of the output level decreases. It shows a non-linear characteristic that decreases. The operating point immediately before the output level starts to decrease is generally called the output saturation point, and the power efficiency in the TWTA 22 is the best.
このため、衛星放送においては、π／２シフトＢＰＳＫを含むＢＰＳＫやπ／４シフトＱＰＳＫを含むＱＰＳＫ、８ＰＳＫといったＰＳＫ変調を利用する場合、ＴＷＴＡ２２は出力飽和点で動作するよう、ＴＷＴＡ２２に前置される減衰器（図示せず）によって入力レベルが調整される。また、１６ＡＰＳＫや３２ＡＰＳＫ、６４ＡＰＳＫ、１２８ＡＰＳＫ、２５６ＡＰＳＫといったＡＰＳＫ変調の場合、振幅方向の変動に影響を受けやすいため、ＴＷＴＡ２２の出力飽和点付近では所要Ｃ／Ｎの劣化が大きくなるため、出力レベルを減衰器（図示せず）により出力飽和点より下げた状態（「出力バックオフ」とも称される）で運用される。 Therefore, in satellite broadcasting, when using PSK modulation such as BPSK including π / 2 shift BPSK, QPSK including π / 4 shift QPSK, and 8PSK, TWTA 22 is placed in front of TWTA 22 so as to operate at an output saturation point. The input level is adjusted by an attenuator (not shown). Also, in the case of APSK modulation such as 16APSK, 32APSK, 64APSK, 128APSK, and 256APSK, it is easily affected by fluctuations in the amplitude direction, and therefore the required C / N deterioration becomes large near the output saturation point of TWTA22, so the output level is attenuated. It is operated in a state (also referred to as “output backoff”) lower than the output saturation point by a device (not shown).
前述した特許文献１の技法による送信装置１における歪補正では、疑似伝送路部１３１における電力増幅器（ＴＷＴＡ１３１２）等の非線形特性により、送信装置１の変調器内で、歪補正後の信号に過大なピーク電力が発生することがあり、不要なスプリアスの発生や実伝送路の各機器の動作に悪影響が出る場合がある。 In the distortion correction in the transmission apparatus 1 by the technique of Patent Document 1 described above, the distortion-corrected signal is excessive in the modulator of the transmission apparatus 1 due to nonlinear characteristics such as a power amplifier (TWTA 1312) in the pseudo transmission line unit 131. Peak power may be generated, which may cause unnecessary spurious and adversely affect the operation of each device on the actual transmission path.
例えば、図７に、特許文献１の技法の歪補正による信号点の推移の一例を示す。図７に示すように、例えば振幅位相変調の最外周の信号点について説明するに、マッピング部１２から出力されるシンボルの信号点Ｓ１（理想信号点）が、疑似伝送路部１３１の通過後に信号点Ｓ２となるとき、この信号点Ｓ１と信号点Ｓ２の差分の振幅・位相値が誤差ベクトルとなり、ベクトル加算部１３３から出力される。ベクトル加算部１３４は、信号点Ｓ１（理想信号点）に誤差ベクトルを加算することで、歪補正後の信号点Ｓ３を直交変調部１４に出力する。このとき、図７に示すように、歪補正後の信号点Ｓ３が直交変調部１４で実信号化され、過大なピーク電力となり、不要なスプリアスが発生することや実伝送路の各機器の動作に悪影響が出る場合がある。 For example, FIG. 7 shows an example of signal point transition by distortion correction according to the technique of Patent Document 1. As illustrated in FIG. 7, for example, the outermost signal point of amplitude phase modulation is described. The signal point S1 (ideal signal point) of the symbol output from the mapping unit 12 is a signal after passing through the pseudo transmission line unit 131. At the point S2, the amplitude / phase value of the difference between the signal point S1 and the signal point S2 becomes an error vector and is output from the vector addition unit 133. The vector adding unit 134 adds the error vector to the signal point S1 (ideal signal point), and outputs the signal point S3 after distortion correction to the orthogonal modulation unit 14. At this time, as shown in FIG. 7, the signal point S3 after distortion correction is converted into a real signal by the quadrature modulation unit 14, resulting in excessive peak power, generation of unnecessary spurious noise, and operation of each device on the actual transmission path. May be adversely affected.
このため、送信装置１の変調器として、歪補正後の過大なピーク電力の発生を抑制しつつ、実衛星２の衛星中継器等による歪を補正することにより、受信装置３‐ｎ側での信号点配置のずれ幅を小さくし、これにより所要Ｃ／Ｎ（Carrier／Noise）の劣化を低減する技法が望まれる。 For this reason, as a modulator of the transmission apparatus 1, by correcting the distortion caused by the satellite repeater of the actual satellite 2 while suppressing the generation of excessive peak power after distortion correction, the reception apparatus 3-n side There is a demand for a technique for reducing the deviation width of the signal point arrangement and thereby reducing the deterioration of required C / N (Carrier / Noise).
本発明の目的は、上述の問題に鑑みて、所定の伝送路を介して受信装置に向けてデジタル信号を送信するために、該デジタル信号を所定の変調方式で変調する送信装置を提供することにある。 In view of the above problems, an object of the present invention is to provide a transmission device that modulates a digital signal with a predetermined modulation method in order to transmit the digital signal to a reception device via a predetermined transmission path. It is in.
本発明の送信装置では、マッピング後のシンボルについて、ＱＰＳＫや８ＰＳＫなどの位相変調の信号点であるか、１６ＡＰＳＫや３２ＡＰＳＫなどの振幅位相変調の信号点であるかを判別し、振幅位相変調の信号点であれば最外周の信号点であるか内周の信号点であるかを判定し、位相変調の信号点及び振幅位相変調の最外周の信号点に対しては、理想信号点と実衛星等の実伝送路を模擬した信号点との間で、理想信号点の振幅値を維持して位相差を検出し位相補正をシンボル単位で行い、振幅位相変調の内周の信号点に対しては、理想信号点と実衛星等の実伝送路を模擬した信号点との間で、理想信号点に対する振幅差及び位相差を検出し、振幅及び位相補正をシンボル単位で行い、変調するように構成される。これにより、歪補正後の過大なピーク電力の発生を抑制しつつ、受信装置側での信号点配置のずれ幅を小さくし、所要Ｃ／Ｎの劣化を低減する。 In the transmitting apparatus of the present invention, it is determined whether the mapped symbol is a phase modulation signal point such as QPSK or 8PSK, or an amplitude phase modulation signal point such as 16APSK or 32APSK, and the amplitude phase modulation signal If it is a point, it is determined whether the signal point is the outermost signal point or the innermost signal point. The phase difference is detected by maintaining the amplitude value of the ideal signal point with the signal point that simulates the actual transmission path, etc., and phase correction is performed in symbol units. Detects an amplitude difference and a phase difference with respect to an ideal signal point between an ideal signal point and a signal point that simulates an actual transmission path such as a real satellite, and performs amplitude and phase correction on a symbol-by-symbol basis. Composed. Thereby, while suppressing the occurrence of excessive peak power after distortion correction, the shift width of the signal point arrangement on the receiving apparatus side is reduced, and the required C / N deterioration is reduced.
即ち、本発明の送信装置は、所定の伝送路を介して受信装置に向けてデジタル信号を送信するために、該デジタル信号を所定の変調方式で変調する送信装置であって、デジタル信号のマッピング後の理想信号点が、位相変調の信号点であるか振幅位相変調の信号点であるかを判別し、前記振幅位相変調の信号点であれば最外周の信号点であるか内周の信号点であるかを判定する信号点配置判定手段と、前記伝送路上の対象機器の特性に対応する特性を有する擬似伝送器と、前記信号点配置判定手段による判定を基に、前記位相変調の信号点及び前記振幅位相変調の最外周の信号点に対する補正と、前記振幅位相変調の内周の信号点に対する補正とを区別して、デジタル信号のマッピング後の理想信号点について該擬似伝送器を介して得られる信号点と前記理想信号点とのずれを補正する誤差ベクトルを求め、当該マッピング後の理想信号点を前記誤差ベクトルで補正した信号点に変換するベクトル演算手段と、当該信号点のマッピング後の信号点を前記誤差ベクトルで補正するためにタイミング調整するタイミング調整手段と、前記誤差ベクトルで補正した信号点で直交変調する直交変調手段と、を備えることを特徴とする。 That is, the transmitting apparatus of the present invention is a transmitting apparatus that modulates a digital signal with a predetermined modulation method in order to transmit the digital signal to the receiving apparatus via a predetermined transmission path, and for mapping the digital signal. Determine whether the subsequent ideal signal point is a phase modulation signal point or an amplitude phase modulation signal point, and if it is the amplitude phase modulation signal point, it is the outermost signal point or the inner signal Based on the determination by the signal point arrangement determining means for determining whether the signal is a point, the pseudo-transmitter having characteristics corresponding to the characteristics of the target device on the transmission line, and the determination by the signal point arrangement determining means, the phase modulation signal A point and the correction for the outermost signal point of the amplitude phase modulation are distinguished from the correction for the inner periphery signal point of the amplitude phase modulation, and the ideal signal point after mapping of the digital signal is passed through the pseudo-transmitter. can get A vector calculation means for obtaining an error vector for correcting a deviation between the signal point and the ideal signal point, converting the mapped ideal signal point into a signal point corrected with the error vector, and a signal after mapping the signal point Timing adjustment means for adjusting timing to correct a point with the error vector, and orthogonal modulation means for orthogonal modulation with a signal point corrected with the error vector are provided.
また、本発明の送信装置において、前記ベクトル演算手段は、前記信号点配置判定手段による判定を基に、前記位相変調の信号点及び前記振幅位相変調の最外周の信号点に対しては、前記理想信号点と前記擬似伝送器を介して得られる信号点との間で、前記理想信号点の振幅値を維持して位相差を検出し位相補正を行い、前記振幅位相変調の内周の信号点に対しては、前記理想信号点と前記擬似伝送器を介して得られる信号点との間で、前記理想信号点に対する振幅差及び位相差を検出し、振幅及び位相補正を行うことを特徴とする。 Further, in the transmission apparatus of the present invention, the vector calculation means may determine the phase modulation signal point and the amplitude / phase modulation outermost signal point based on the determination by the signal point arrangement determination means. Between the ideal signal point and the signal point obtained via the pseudo-transmitter, the amplitude value of the ideal signal point is maintained to detect a phase difference and perform phase correction, and the inner signal of the amplitude phase modulation For a point, an amplitude difference and a phase difference with respect to the ideal signal point are detected between the ideal signal point and a signal point obtained via the pseudo transmitter, and amplitude and phase correction is performed. And
また、本発明の送信装置において、前記擬似伝送器は、前記対象機器における予め定められた入力フィルタ、増幅器、及び出力フィルタの特性を近似した値の設定値を有することを特徴とする。 In the transmitter according to the present invention, the pseudo transmitter has a set value that approximates characteristics of a predetermined input filter, amplifier, and output filter in the target device.
また、本発明の送信装置において、前記対象機器は、位相及び振幅の周波数特性及び非線形特性のうち１つ以上の既知の特性を有する中継器、電気機器、光学機器、又はこれらの組み合わせを含むことを特徴とする。 Also, in the transmission device of the present invention, the target device includes a repeater, an electrical device, an optical device, or a combination thereof having one or more known characteristics of the frequency characteristics and nonlinear characteristics of phase and amplitude. It is characterized by.
本発明によれば、送信装置内で、歪補正後の過大なピーク電力の発生を抑制しつつ、受信装置側での信号点配置のずれ幅を小さくし、所要Ｃ／Ｎの劣化を低減することが可能となる。 According to the present invention, the generation of excessive peak power after distortion correction is suppressed in the transmission device, the signal point arrangement shift width on the reception device side is reduced, and the required C / N deterioration is reduced. It becomes possible.
以下、図面を参照して、本発明による一実施形態の送信装置１について説明する。図１に、本発明による一実施形態の送信装置１における変調器の概略構成を示すブロック図である。尚、図１は、図５と同様な構成要素には同一の参照番号を付している。 Hereinafter, a transmission apparatus 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a modulator in a transmission apparatus 1 according to an embodiment of the present invention. In FIG. 1, the same components as those in FIG. 5 are denoted by the same reference numerals.
本発明による一実施形態の送信装置１は、各種規格に準拠した一般化した送信装置であり、図４に示す実衛星２における衛星中継器を介する伝送システムに適応可能な装置である。本実施形態の送信装置１は、既存の放送衛星に対して放送波信号を送信することができる。従って、本実施形態の送信装置１は、実衛星２の衛星中継器を介して受信装置３‐ｎに向けてデジタル信号を送信するために、デジタル信号を所定の変調方式で変調する送信装置１として構成される。 A transmission apparatus 1 according to an embodiment of the present invention is a generalized transmission apparatus that conforms to various standards, and is an apparatus that can be applied to a transmission system via a satellite repeater in a real satellite 2 shown in FIG. The transmission apparatus 1 of this embodiment can transmit a broadcast wave signal to an existing broadcast satellite. Therefore, in order to transmit the digital signal to the receiving device 3-n via the satellite repeater of the real satellite 2, the transmitting device 1 of the present embodiment modulates the digital signal with a predetermined modulation method. Configured as
本実施形態の送信装置１における変調器は、送信するデジタル信号（所定の符号化を施した変調前の信号）に対して、シリアルのビット列をパラレルに変換するシリアル／パラレル変換（Ｓ／Ｐ）部１１と、所定の変調方式毎にマッピングするマッピング部１２と、歪補正部１３ａと、各々の所定の変調方式に応じた直交変調を施す直交変調部１４とを備える。ここで、シリアル／パラレル変換（Ｓ／Ｐ）部１１、マッピング部１２、及び直交変調部１４は、図５に示した従来の送信装置１のものと同様に機能し、その更なる詳細な説明は省略する。即ち、本実施形態の送信装置１における変調器は、図５に示した従来の送信装置１の変調器と比較して、歪補正部１３の代わりに、歪補正部１３ａが設けられている点で相違しており、この歪補正部１３ａについて主に説明する。 The modulator in the transmission apparatus 1 of this embodiment is a serial / parallel conversion (S / P) that converts a serial bit string into parallel with respect to a digital signal to be transmitted (a signal before modulation subjected to predetermined encoding). Unit 11, mapping unit 12 that performs mapping for each predetermined modulation method, distortion correction unit 13 a, and orthogonal modulation unit 14 that performs orthogonal modulation according to each predetermined modulation method. Here, the serial / parallel conversion (S / P) unit 11, the mapping unit 12, and the quadrature modulation unit 14 function in the same manner as that of the conventional transmission apparatus 1 shown in FIG. Is omitted. That is, the modulator in the transmission apparatus 1 of the present embodiment is provided with a distortion correction unit 13a instead of the distortion correction unit 13 as compared with the modulator of the conventional transmission apparatus 1 shown in FIG. The distortion correction unit 13a will be mainly described.
歪補正部１３ａは、疑似伝送路部１３１と、遅延部１３２と、ベクトル加算・位相差検出部１３３ａと、ベクトル加算・位相補正部１３４ａと、信号点配置判定部１３５とを備える。 The distortion correction unit 13a includes a pseudo transmission line unit 131, a delay unit 132, a vector addition / phase difference detection unit 133a, a vector addition / phase correction unit 134a, and a signal point arrangement determination unit 135.
疑似伝送路部１３１は、歪補正部１３ａに入力されるマッピング後の理想信号点のデジタル信号（シンボル）について、実衛星２の伝送路の特性を模擬するべく、実衛星２が備えるＩＭＵＸフィルタ２１、ＴＷＴＡ２２、及びＯＭＵＸフィルタ２３にそれぞれ対応する、位相及び振幅の周波数特性に近似した特性を有するＩＭＵＸフィルタ１３１１、飽和抑圧型の進行波管増幅器（ＴＷＴＡ）１３１２、及びＯＭＵＸフィルタ１３１３を備える。 The pseudo transmission path unit 131 uses the IMUX filter 21 included in the real satellite 2 to simulate the characteristics of the transmission path of the real satellite 2 with respect to the digital signal (symbol) of the ideal signal point after mapping input to the distortion correction unit 13a. , TWTA 22, and OMUX filter 23, each having an IMUX filter 1311 having characteristics approximate to the frequency characteristics of the phase and amplitude, a saturation suppression traveling wave tube amplifier (TWTA) 1312, and an OMUX filter 1313.
より具体的には、疑似伝送路部１３１は、歪補正部１３ａに入力されるマッピング後の理想信号点のデジタル信号（シンボル）について、実衛星２によって生じうる信号点のずれを模擬した信号点の同相（Ｉ）成分と直角位相（Ｑ）成分で表されるＩＱ信号を生成し、ベクトル加算・位相差検出部１３３ａに出力する。 More specifically, the pseudo transmission line unit 131 simulates a signal point shift that can be caused by the actual satellite 2 with respect to the digital signal (symbol) of the ideal signal point after mapping input to the distortion correction unit 13a. An IQ signal represented by an in-phase (I) component and a quadrature (Q) component is generated and output to the vector addition / phase difference detection unit 133a.
遅延部１３２は、マッピング部１２においてマッピングされた理想信号点を遅延時間Ｄだけ遅延させる。ここで、遅延部１３２における遅延時間Ｄは、理想信号点の１シンボルが疑似伝送路部１３１を通過するのに必要な時間と等しく設定される。 The delay unit 132 delays the ideal signal point mapped by the mapping unit 12 by a delay time D. Here, the delay time D in the delay unit 132 is set equal to the time required for one symbol of the ideal signal point to pass through the pseudo transmission line unit 131.
信号点配置判定部１３５は、歪補正部１３ａに入力されるマッピング後の理想信号点のデジタル信号（シンボル）について、ＱＰＳＫや８ＰＳＫなどの位相変調の信号点であるか、１６ＡＰＳＫや３２ＡＰＳＫなどの振幅位相変調の信号点であるかを判別し、振幅位相変調の信号点であれば最外周の信号点であるか内周の信号点であるかを判定し、判定結果をベクトル加算・位相差検出部１３３ａ及びベクトル加算・位相補正部１３４ａに出力する。 The signal point arrangement determination unit 135 is a phase modulation signal point such as QPSK or 8PSK, or an amplitude such as 16APSK or 32APSK, regarding the digital signal (symbol) of the ideal signal point after mapping input to the distortion correction unit 13a. Determine whether it is a phase modulation signal point, if it is an amplitude phase modulation signal point, determine whether it is an outermost signal point or an inner signal point, and add the result of the determination to the vector addition / phase difference detection Output to the unit 133a and the vector addition / phase correction unit 134a.
より具体的には、信号点配置判定部１３５は、歪補正部１３ａに入力されるシンボルのＩＱ信号の信号点が、位相変調の信号点であるか、振幅位相変調の最外周の信号点であるか、振幅位相変調の内周の信号点であるかを判定して、位相変調の信号点及び振幅位相変調の最外周の信号点に対する歪補正と、振幅位相変調の内周の信号点に対する歪補正とを区別して実行させるべく、ベクトル加算・位相差検出部１３３ａ及びベクトル加算・位相補正部１３４ａを制御する。 More specifically, the signal point arrangement determination unit 135 determines whether the signal point of the IQ signal of the symbol input to the distortion correction unit 13a is a phase modulation signal point or an outermost signal point of amplitude phase modulation. It is determined whether there is a signal point on the inner circumference of amplitude phase modulation, distortion correction for the signal point of phase modulation and the outermost signal point of amplitude phase modulation, and the signal point on the inner circumference of amplitude phase modulation In order to distinguish and execute the distortion correction, the vector addition / phase difference detection unit 133a and the vector addition / phase correction unit 134a are controlled.
ベクトル加算・位相差検出部１３３ａは、信号点配置判定部１３５の判定結果に基づいて制御され、遅延部１３２を経て理想信号点のシンボルのＩＱ信号を入力するとともに、疑似伝送路部１３１から得られる実衛星２によって生じうる信号点のずれを模擬した信号点のＩＱ信号を入力し、信号点配置判定部１３５の判定結果に応じた動作を行う。 The vector addition / phase difference detection unit 133a is controlled based on the determination result of the signal point arrangement determination unit 135, receives an IQ signal of the symbol of the ideal signal point through the delay unit 132, and obtains it from the pseudo transmission path unit 131. An IQ signal at a signal point simulating a signal point shift that may be caused by the actual satellite 2 is input, and an operation according to the determination result of the signal point arrangement determination unit 135 is performed.
より具体的には、ベクトル加算・位相差検出部１３３ａは、位相変調の信号点及び振幅位相変調の最外周の信号点に対しては、理想信号点と当該模擬した信号点との間で、理想信号点の振幅値を維持した位相差を検出し、この位相差に対応するＩＱ信号を補正ベクトルとして生成し、ベクトル加算・位相補正部１３４ａに出力する。 More specifically, the vector addition / phase difference detection unit 133a has a phase modulation signal point and an amplitude / phase modulation outermost signal point between the ideal signal point and the simulated signal point, A phase difference maintaining the amplitude value of the ideal signal point is detected, an IQ signal corresponding to the phase difference is generated as a correction vector, and output to the vector addition / phase correction unit 134a.
また、ベクトル加算・位相差検出部１３３ａは、振幅位相変調の内周の信号点に対しては、理想信号点と当該模擬した信号点との間で、理想信号点に対する振幅差及び位相差を検出し、この振幅差及び位相差に対応するＩＱ信号を補正ベクトルとして生成し、ベクトル加算・位相補正部１３４ａに出力する。 Further, the vector addition / phase difference detection unit 133a calculates an amplitude difference and a phase difference with respect to the ideal signal point between the ideal signal point and the simulated signal point with respect to the inner peripheral signal point of the amplitude phase modulation. An IQ signal corresponding to the amplitude difference and the phase difference is generated as a correction vector, and is output to the vector addition / phase correction unit 134a.
ベクトル加算・位相補正部１３４ａは、信号点配置判定部１３５の判定結果に基づいて制御され、遅延部１３２を経て理想信号点のシンボルのＩＱ信号を入力するとともに、ベクトル加算・位相差検出部１３３ａから得られる補正ベクトルのＩＱ信号を入力し、ベクトル加算を行って（理想信号点のシンボルのＩＱ信号から補正ベクトルのＩＱ信号を減算して）、直交変調部１４に出力する。 The vector addition / phase correction unit 134a is controlled based on the determination result of the signal point arrangement determination unit 135, and receives the IQ signal of the symbol of the ideal signal point via the delay unit 132, and the vector addition / phase difference detection unit 133a. The correction vector IQ signal obtained from (1) is input, vector addition is performed (the IQ signal of the correction vector is subtracted from the IQ signal of the symbol of the ideal signal point), and output to the quadrature modulation unit 14.
直交変調部１４は、歪補正部１３ａによって補正した信号点で、所定の変調方式に応じて直交変調し、変調波を生成する。ここで云う所定の変調方式には、π／２シフトＢＰＳＫを含むＢＰＳＫ、π／４シフトＱＰＳＫを含むＱＰＳＫ、８ＰＳＫ、１６ＡＰＳＫ、３２ＡＰＳＫ、６４ＡＰＳＫ、１２８ＡＰＳＫ若しくは２５６ＡＰＳＫを含む。 The quadrature modulation unit 14 performs quadrature modulation according to a predetermined modulation method at the signal point corrected by the distortion correction unit 13a to generate a modulated wave. The predetermined modulation schemes herein include BPSK including π / 2 shift BPSK, QPSK including π / 4 shift QPSK, 8PSK, 16APSK, 32APSK, 64APSK, 128APSK, or 256APSK.
以上のように、ベクトル加算・位相差検出部１３３ａ及びベクトル加算・位相補正部１３４ａは、位相変調の信号点及び振幅位相変調の最外周の信号点に対しては、理想信号点と実衛星等の実伝送路を模擬した信号点との間で、理想信号点の振幅値を維持した位相補正をシンボル単位で行うこととなり、振幅位相変調の内周の信号点に対しては、理想信号点と実衛星等の実伝送路を模擬した信号点との間で、理想信号点に対する振幅及び位相補正をシンボル単位で行うこととなる。尚、位相補正は、マッピング１２経過後の信号点と疑似伝送路経過後の信号点との間の位相差に相当する位相角をマッピング１２経過後の信号点から逆補正することにより行う。振幅及び位相補正は、この位相補正に加えて、マッピング１２経過後の信号点と疑似伝送路経過後の信号点との間の振幅差を補正する。 As described above, the vector addition / phase difference detection unit 133a and the vector addition / phase correction unit 134a have an ideal signal point, an actual satellite, and the like for the phase modulation signal point and the amplitude / phase modulation outermost signal point. Phase correction that maintains the amplitude value of the ideal signal point is performed in symbol units with the signal point that simulates the actual transmission path of the signal. And the signal point simulating an actual transmission path such as a real satellite, the amplitude and phase correction for the ideal signal point is performed in symbol units. The phase correction is performed by reversely correcting the phase angle corresponding to the phase difference between the signal point after the lapse of the mapping 12 and the signal point after the lapse of the pseudo transmission path from the signal point after the lapse of the mapping 12. In addition to this phase correction, the amplitude and phase correction corrects an amplitude difference between a signal point after the mapping 12 and a signal point after the pseudo transmission path.
例えば、従来の歪補正を示す信号点の推移を表わす図７と対比して、図２に、本発明に係る位相変調の信号点及び振幅位相変調の最外周の信号点に関する歪補正による信号点の推移の一例を示す。図２に示すように、例えば振幅位相変調の最外周の信号点について説明するに、マッピング部１２から出力されるシンボルの信号点Ｓ１（理想信号点）が、疑似伝送路部１３１の通過後に信号点Ｓ２となるとき、この信号点Ｓ１と信号点Ｓ２の差分の振幅・位相値が誤差ベクトルとなり、ベクトル加算・位相差検出部１３３ａから出力される。ベクトル加算・位相補正部１３４ａは、信号点Ｓ１（理想信号点）に誤差ベクトルを加算することで、歪補正後の信号点Ｓ３を直交変調部１４に出力する。このとき、図２に示すように、歪補正後の信号点Ｓ３が最外周の最大振幅に沿って（理想信号点の振幅値を維持して）位相補正されるため、歪補正後の信号点Ｓ３が直交変調部１４で実信号化されたときに、過大なピーク電力とならず、不要なスプリアスの発生や実伝送路の各機器の動作に対する悪影響を回避することができる。 For example, in contrast to FIG. 7 showing the transition of signal points indicating conventional distortion correction, FIG. 2 shows signal points by distortion correction related to signal points for phase modulation and outermost signal points for amplitude phase modulation according to the present invention. An example of the transition of is shown. As illustrated in FIG. 2, for example, the outermost signal point of amplitude phase modulation will be described. The signal point S1 (ideal signal point) of the symbol output from the mapping unit 12 is a signal after passing through the pseudo transmission line unit 131. At the point S2, the amplitude / phase value of the difference between the signal point S1 and the signal point S2 becomes an error vector and is output from the vector addition / phase difference detection unit 133a. The vector addition / phase correction unit 134a outputs the signal point S3 after distortion correction to the quadrature modulation unit 14 by adding an error vector to the signal point S1 (ideal signal point). At this time, as shown in FIG. 2, since the signal point S3 after distortion correction is phase-corrected along the maximum amplitude of the outermost circumference (maintaining the amplitude value of the ideal signal point), the signal point after distortion correction When S3 is converted into a real signal by the quadrature modulation unit 14, excessive peak power is not generated, and adverse effects on generation of unnecessary spurious and operation of each device on the actual transmission path can be avoided.
尚、本発明に係る歪補正は、振幅位相変調の内周の信号点に対しては、理想信号点と実衛星等の実伝送路を模擬した信号点との間で、理想信号点に対する振幅及び位相補正をシンボル単位で行うため、図７と同様な動作となる。 It should be noted that the distortion correction according to the present invention is such that, for the signal point on the inner periphery of amplitude phase modulation, the amplitude relative to the ideal signal point is between the ideal signal point and a signal point simulating a real transmission line such as a real satellite. Since the phase correction is performed in symbol units, the operation is the same as that in FIG.
また、図３に、本発明に係る位相変調の信号点及び振幅位相変調の最外周の信号点に関する歪補正による信号点の推移の一例を示す。図３に示すように、例えば振幅位相変調の最外周の信号点について説明するに、マッピング部１２から出力されるシンボルの信号点Ｓ１（理想信号点）が、疑似伝送路部１３１の通過後に信号点Ｓ２となるとき、信号点Ｓ２が、理想信号点の最大振幅を超えるような場合も想定されるが、この場合も、この信号点Ｓ１と信号点Ｓ２の差分の振幅・位相値が誤差ベクトルとなり、ベクトル加算・位相差検出部１３３ａから出力される。ベクトル加算・位相補正部１３４ａは、信号点Ｓ１（理想信号点）に誤差ベクトルを加算することで、歪補正後の信号点Ｓ３を直交変調部１４に出力する。このとき、図３に示すように、歪補正後の信号点Ｓ３が最外周の最大振幅に沿って（理想信号点の振幅値を維持して）位相補正されるため、歪補正後の信号点Ｓ３が直交変調部１４で実信号化されたときに、過大なピーク電力とならず、不要なスプリアスの発生や実伝送路の各機器の動作に対する悪影響を回避することができる。 FIG. 3 shows an example of transition of signal points due to distortion correction related to signal points for phase modulation and outermost signal points for amplitude phase modulation according to the present invention. As shown in FIG. 3, for example, the outermost signal point of amplitude phase modulation is described. The signal point S1 (ideal signal point) of the symbol output from the mapping unit 12 is a signal after passing through the pseudo transmission line unit 131. It is assumed that the signal point S2 exceeds the maximum amplitude of the ideal signal point when the point S2 is reached. In this case also, the amplitude / phase value of the difference between the signal point S1 and the signal point S2 is an error vector. And is output from the vector addition / phase difference detection unit 133a. The vector addition / phase correction unit 134a outputs the signal point S3 after distortion correction to the quadrature modulation unit 14 by adding an error vector to the signal point S1 (ideal signal point). At this time, as shown in FIG. 3, since the signal point S3 after distortion correction is phase-corrected along the maximum amplitude of the outermost circumference (maintaining the amplitude value of the ideal signal point), the signal point after distortion correction When S3 is converted into a real signal by the quadrature modulation unit 14, excessive peak power is not generated, and adverse effects on generation of unnecessary spurious and operation of each device on the actual transmission path can be avoided.
したがって、本発明に係る歪補正では、位相変調の信号点及び振幅位相変調の最外周の信号点については位相に関する補正を行い、振幅位相変調の内周の信号点については振幅及び位相に関する補正を行うことで、ＴＷＴＡ１３１２の飽和動作点より高い電力に相当する誤差ベクトルが生成されても、歪補正後の信号におけるピーク電力を抑圧することができる。 Therefore, in the distortion correction according to the present invention, the phase modulation signal point and the outermost signal point of the amplitude phase modulation are corrected with respect to the phase, and the inner periphery signal point of the amplitude phase modulation is corrected with respect to the amplitude and phase. By performing, even if an error vector corresponding to a power higher than the saturation operating point of the TWTA 1312 is generated, the peak power in the signal after distortion correction can be suppressed.
上述の実施形態は代表的な例として説明したが、本発明の趣旨及び範囲内で、多くの変形及び置換することができることは当業者に明らかである。例えば、上述の実施形態では、実伝送路として実衛星２の衛星中継器を対象とする例について説明したが、実伝送路として、地上波用の送信側増幅器、位相及び振幅の周波数特性及び非線形特性のうち１つ以上の既知の特性を有する中継器、電気機器、光学機器、又はこれらの組み合わせに適用することができるため、これらを総括して「対象機器」と称する。尚、実伝送路は、送信側の信号変調後から受信側の信号復調までの信号経路を云う。 Although the above embodiment has been described as a representative example, it will be apparent to those skilled in the art that many variations and substitutions can be made within the spirit and scope of the invention. For example, in the above-described embodiment, the example in which the satellite repeater of the real satellite 2 is targeted as the actual transmission path has been described. However, as the actual transmission path, the terrestrial transmission side amplifier, the frequency characteristics of the phase and amplitude, and the nonlinearity Since the present invention can be applied to a repeater, an electric device, an optical device, or a combination thereof having one or more known properties, these are collectively referred to as “target devices”. The actual transmission path is a signal path from signal modulation on the transmission side to signal demodulation on the reception side.
また、このような対象機器は、実伝送路上の対象機器の特性を近似した特性（即ち、実伝送路上の対象機器の特性に対応する特性）を有する任意の機器で、疑似伝送路部１３１を構成できるため、これらを総括して「擬似伝送器」と称する。また、「近似した特性」（即ち、「対応する特性」）とは、「等価な特性」を含む。すなわち、本発明の本質は、中継器や伝送路で生じる歪を、送信装置において予め予測し、その歪成分を減じてから送信することによって伝送特性の改善を図るものであって、伝送特性の劣化要因となる中継器若しくは伝送路の構成要素はどのようなものであってもよい。とりわけ、本発明は、振幅位相変調の信号伝送に効果を発揮することは上述の実施形態の例で説明したとおりである。 Further, such a target device is an arbitrary device having a characteristic approximating the characteristic of the target device on the actual transmission path (that is, a characteristic corresponding to the characteristic of the target apparatus on the actual transmission path), and the pseudo transmission path unit 131 is provided. Since they can be configured, these are collectively referred to as a “pseudo-transmitter”. The “approximate characteristics” (that is, “corresponding characteristics”) includes “equivalent characteristics”. That is, the essence of the present invention is to predict the distortion generated in the repeater or the transmission path in advance in the transmission apparatus, and to reduce the distortion component before transmitting, thereby improving the transmission characteristic. Any component of the repeater or the transmission path that causes deterioration may be used. In particular, the present invention is effective for signal transmission of amplitude / phase modulation as described in the above-described embodiments.
また、デジタル変調された信号を更に電気／光変換して光ファイバーで伝送し、光／電気変換してデジタル変調された信号を復元し、デジタル復調するような場合には、電気／光変換器、光／電気変換器の非線形特性が問題になる場合がある。このような場合、擬似伝送路部１３１を、ＩＭＵＸフィルタ１３１１、ＴＷＴＡ１３１２、及びＯＭＵＸフィルタ１３１３で構成する代わりに、電気／光変換器、光／電気変換器で構成し、その特性を実際に用いられる電気／光変換器、光／電気変換器の非線形特性とすることで、電気／光変換器、光／電気変換器の非線形特性による劣化を抑圧することができる。 Further, in the case where the digitally modulated signal is further subjected to electrical / optical conversion and transmitted through an optical fiber, and the optically / electrically converted signal is restored and digitally demodulated, an electrical / optical converter, Non-linear characteristics of the optical / electrical converter may be a problem. In such a case, the pseudo transmission line unit 131 is configured by an electrical / optical converter and an optical / electrical converter instead of the IMUX filter 1311, the TWTA 1312, and the OMUX filter 1313, and the characteristics can be actually used. By setting the nonlinear characteristics of the electrical / optical converter and the optical / electrical converter, it is possible to suppress deterioration due to the nonlinear characteristics of the electrical / optical converter and the optical / electrical converter.
従って、本発明は、衛星デジタル放送、地上デジタル放送、それ以外の実伝送路にも適用が可能であり、例えば、通信衛星経由及び／又は中継器経由で映像信号を撮影現場からスタジオまで伝送する素材伝送用には変調方式に１６ＱＡＭ（quadrature amplitude modulation）変調や３２ＱＡＭ変調などが利用される。この場合、マッピング部１２を１６ＱＡＭや３２ＱＡＭ変調に対応したものとする。 Therefore, the present invention can be applied to satellite digital broadcasting, terrestrial digital broadcasting, and other actual transmission paths. For example, a video signal is transmitted from a shooting site to a studio via a communication satellite and / or via a repeater. For material transmission, 16QAM (quadrature amplitude modulation) modulation, 32QAM modulation, or the like is used as a modulation method. In this case, the mapping unit 12 is assumed to be compatible with 16QAM or 32QAM modulation.
本発明によれば、送信装置内で、歪補正後の過大なピーク電力の発生を抑制しつつ、受信装置側での信号点配置のずれ幅を小さくし、所要Ｃ／Ｎの劣化を低減することが可能となるので、実伝送路の歪補正を要する送信装置の用途に有用である。 According to the present invention, the generation of excessive peak power after distortion correction is suppressed in the transmission device, the signal point arrangement shift width on the reception device side is reduced, and the required C / N deterioration is reduced. Therefore, it is useful for the use of a transmission apparatus that requires distortion correction of an actual transmission path.
１ 送信装置
２ 実衛星
３‐１，３-２，３-ｎ 受信装置
１１ シリアル／パラレル変換（Ｓ／Ｐ）部
１２ マッピング部
１３，１３ａ 歪補正部
１４ 直交変調部
２１ 実伝送路の入力マルチプレクサ（ＩＭＵＸ）フィルタ
２２ 実伝送路の進行波管増幅器（ＴＷＴＡ）
２３ 実伝送路の出力マルチプレクサ（ＯＭＵＸ）フィルタ
１３１ 疑似伝送路部
１３２ 遅延部
１３３ 第１のベクトル加算部
１３３ａ ベクトル加算・位相差検出部
１３４ 第２のベクトル加算部
１３４ａ ベクトル加算・位相補正部
１３５ 信号点配置判定部
１３１１ 疑似伝送路部の入力マルチプレクサ（ＩＭＵＸ）フィルタ
１３１２ 疑似伝送路部の進行波管増幅器（ＴＷＴＡ）
１３１３ 疑似伝送路部の出力マルチプレクサ（ＯＭＵＸ）フィルタ
DESCRIPTION OF SYMBOLS 1 Transmitting device 2 Real satellite 3-1, 3-2, 3-n Receiving device 11 Serial / parallel conversion (S / P) unit 12 Mapping unit 13, 13a Distortion correction unit 14 Orthogonal modulation unit 21 Input multiplexer of actual transmission path (IMUX) filter 22 Traveling-wave tube amplifier (TWTA) in actual transmission path
23 Output multiplexer (OMUX) filter for actual transmission path 131 Pseudo transmission path section 132 Delay section 133 First vector addition section 133a Vector addition / phase difference detection section 134 Second vector addition section 134a Vector addition / phase correction section 135 Signal Point placement determination unit 1311 Input multiplexer (IMUX) filter 1312 of pseudo transmission path unit 1312 Traveling wave tube amplifier (TWTA) of pseudo transmission path unit
1313 Pseudo Transmission Line Output Multiplexer (OMUX) Filter
Claims (4)
デジタル信号のマッピング後の理想信号点が、位相変調の信号点であるか振幅位相変調の信号点であるかを判別し、前記振幅位相変調の信号点であれば最外周の信号点であるか内周の信号点であるかを判定する信号点配置判定手段と、
前記伝送路上の対象機器の特性に対応する特性を有する擬似伝送器と、
前記信号点配置判定手段による判定を基に、前記位相変調の信号点及び前記振幅位相変調の最外周の信号点に対する補正と、前記振幅位相変調の内周の信号点に対する補正とを区別して、デジタル信号のマッピング後の理想信号点について該擬似伝送器を介して得られる信号点と前記理想信号点とのずれを補正する誤差ベクトルを求め、当該マッピング後の理想信号点を前記誤差ベクトルで補正した信号点に変換するベクトル演算手段と、
当該信号点のマッピング後の信号点を前記誤差ベクトルで補正するためにタイミング調整するタイミング調整手段と、
前記誤差ベクトルで補正した信号点で直交変調する直交変調手段と、
を備えることを特徴とする送信装置。 In order to transmit a digital signal to a receiving device via a predetermined transmission path, the transmitting device modulates the digital signal with a predetermined modulation method,
Determine whether the ideal signal point after mapping the digital signal is a phase modulation signal point or an amplitude phase modulation signal point, and if it is the amplitude phase modulation signal point, is it the outermost signal point? Signal point arrangement determining means for determining whether the signal point is on the inner circumference;
A pseudo transmitter having characteristics corresponding to the characteristics of the target device on the transmission path;
Based on the determination by the signal point arrangement determination unit, the correction for the signal point of the phase modulation and the signal point of the outermost periphery of the amplitude phase modulation and the correction of the signal point of the inner periphery of the amplitude phase modulation are distinguished, An error vector for correcting the deviation between the ideal signal point obtained by mapping the digital signal and the ideal signal point via the pseudo transmitter is obtained, and the ideal signal point after mapping is corrected with the error vector. Vector calculation means for converting the signal points into
Timing adjustment means for adjusting timing in order to correct the signal point after mapping of the signal point with the error vector;
Orthogonal modulation means for performing orthogonal modulation with a signal point corrected by the error vector;
A transmission device comprising:
前記信号点配置判定手段による判定を基に、前記位相変調の信号点及び前記振幅位相変調の最外周の信号点に対しては、前記理想信号点と前記擬似伝送器を介して得られる信号点との間で、前記理想信号点の振幅値を維持して位相差を検出し位相補正を行い、前記振幅位相変調の内周の信号点に対しては、前記理想信号点と前記擬似伝送器を介して得られる信号点との間で、前記理想信号点に対する振幅差及び位相差を検出し、振幅及び位相補正を行うことを特徴とする、請求項１に記載の送信装置。 The vector calculation means includes
Based on the determination by the signal point arrangement determination means, the signal point obtained via the ideal signal point and the pseudo transmitter for the signal point of the phase modulation and the signal point of the outermost periphery of the amplitude phase modulation The phase difference is detected and the phase is corrected while maintaining the amplitude value of the ideal signal point between the ideal signal point and the pseudo transmitter for the inner peripheral signal point of the amplitude phase modulation. The transmitter according to claim 1, wherein an amplitude difference and a phase difference with respect to the ideal signal point are detected with respect to a signal point obtained via a signal, and amplitude and phase correction is performed.
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