| 摘要 |
PROBLEM TO BE SOLVED: To prevent a distortion compensating amplifier which performs predistortion compensation processing on an amplified signal from decreasing in performance, when a DPD bandwidth is close to a signal bandwidth. SOLUTION: An LUT 101 stores a plurality of distortion compensation coefficients (h) used for the predistortion compensation processing. A multiplication unit 103 generates a correction value for distortion compensation coefficients h<SB>-N/2</SB>to h<SB>-1</SB>, and h<SB>1</SB>to h<SB>N/2</SB>other than a distortion compensation coefficient h<SB>0</SB>, on the basis of a correction valueΔh calculated on the basis of a transmission signal S(t), before the predistortion compensation processing and the amplified signal after the predistortion compensation processing by using the distortion coefficient h<SB>0</SB>. An addition unit 102 adds the correction valueΔh to the distortion compensation coefficient h<SB>0</SB>, adds the correction value generated by the multiplication unit 103 to the distortion compensation coefficients h<SB>-N/2</SB>to h<SB>-1</SB>, and h<SB>1</SB>to h<SB>N/2</SB>respectively, and updates the distortion compensation coefficients h<SB>-N/2</SB>to h<SB>N/2</SB>of the LUT 101 by using the obtained addition results. COPYRIGHT: (C)2009,JPO&INPIT
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