| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a distortion compensation quadrature modulator capable of updating distortion compensation coefficients most appropriately at all times when operated. <P>SOLUTION: An apparatus includes: an affine transformer 2 that subjects input complex IF signals I(t) and Q(t) to affine transformation according to affine transformation coefficients, and outputs compensated signals a(t) and b(t); a quadrature modulator 3 that applies quadrature modulation on a local oscillation signal according to the compensated signals, and outputs a modulated signal (RF transmission signal); a quadrature detector 6 that removes a carrier component from the modulated signal and outputs complex feedback signals I'(t) and Q'(t); and a control portion 7 that extracts linear distortion remaining in the complex feedback signals I'(t) and Q'(t) as a plurality of distortion coefficients (DC offsets of the I-phase and the Q-phase, an IQ gain ratio, and a derivation in orthogonality), and updates the current affine transformation coefficients in accordance with updating equations including the distortion coefficients to set updated affine transformation coefficients again in the affine transformation means. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
