| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a distortion compensation circuit capable of improving the performance of distortion compensation in an optional frequency band. <P>SOLUTION: In the distortion compensation circuit, a feedback signal from an amplifier 3 is digital-converted by an ADC5, an output from the ADC5 passes through an FIR filter 12 having passing characteristics of a specific band including a frequency band to be used to a quadrature demodulator 13, and is orthogonal-demodulated. An LUT coefficient is calculated by an LUT coefficient calculation part 14, an envelope curve value is calculated by an envelope curve calculation part 15, the LUT coefficient for the envelope curve value is read-out from a look up table in an LUT coefficient setting part 16 and is output to multipliers 17a, 17b, and multipliers 17a, 17b multiply a transmission signal by the LUT coefficient to compensate the distortion. <P>COPYRIGHT: (C)2012,JPO&INPIT |
