ADAPTIVE EQUALIZATION CIRCUIT, ADAPTIVE EQUALIZATION METHOD, AND RECEIVING DEVICE

• Main Authors: TAKAKURA TOMOHIRO, TAKEYA TSUTOMU, YOSHIDA MITSUTERU, TAKEI KAZUTO
• Format: Patent
• Language: English; Japanese
• Published: 05.06.2024
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; MULTIPLEX COMMUNICATION; RESONATORS; TRANSMISSION

To detect equivalence convergence with high accuracy for a wide range of modulation schemes and stably perform adaptive equalization processing.SOLUTION: When a polarization separation monitor 3 detects that a correlation value between a first polarization signal and a second polarization signal exceeds a predetermined value, a control circuit 4 causes a filter tap coefficient update circuit 2 to re-perform initial convergence of a tap coefficient. The polarization separation monitor 3 determines which of four quadrants on an IQ plane the first and second polarization signals belong to, calculates a correlation value from results of the determination, and compares the correlation value with the predetermined value. When the first and second polarization signals have on-axis data located on an I axis or a Q axis on the IQ plane, a sign determination circuit 7 extracts the on-axis data, and maps positive data on the I-axis, negative data on the I-axis, positive data on the Q-axis, and negative data on the Q-axis of the on-axis data to one of values representing the four quadrants on the IQ plane, respectively, without duplication with each other.SELECTED DRAWING: Figure 2 【課題】広い種類の変調方式に対して同値収束を高精度に検出し、適応等化処理を安定的に行う。【解決手段】第１の偏波信号と第２の偏波信号との相関値が所定値を超えたことを偏波分離モニタ３が検出した場合、制御回路４がフィルタタップ係数更新回路２にタップ係数の初期収束を再実行させる。偏波分離モニタ３は、第１の偏波信号と第２の偏波信号がＩＱ平面上の４つの象限のうちどの象限に属するかを判定し、その判定結果から相関値を計算し、相関値を所定値と比較する。第１の偏波信号と第２の偏波信号にＩＱ平面のＩ軸又はＱ軸上に位置する軸上データが存在する場合、符号判定回路７は、軸上データを抽出し、軸上データのうちＩ軸上の正側のデータ、Ｉ軸上の負側のデータ、Ｑ軸上の正側のデータ、Ｑ軸上の負側のデータをそれぞれＩＱ平面上の４つの象限を示す値のうち一つの値に互いに重複なく対応付ける。【選択図】図２