| 摘要 |
PROBLEM TO BE SOLVED: To compensate distortion caused by a PA(power amplifier) 36 and to attain miniaturization and power-saving. SOLUTION: In the digital radio equipment where a distortion compensation processing section 26 compensates distortion of base band modulation signals I1, Q1, D/A converter sections 30, 32 (frequency fs1) convert the signals into analog signals, the PA 36 amplifies them, the amplified signal is transmitted, a part of the output of the PA 36 is fed back and demodulated, distortion component caused in the PA 36 is detected to calculate a compensation coefficient for cancellation of the distortion component, a frequency conversion section 40 converts the feedback signal into a 1st IF signal with a frequency F1, a 1st A/D converter 76 applies under sampling (frequency fs2) to the 1st IF signal, a demodulation section 70 demodulates signals I4, Q4 through digital orthogonal demodulation processing, and LPFs 72, 74 obtain distortion component detection signals I5, Q5 from the I4, Q4. The digital wireless equipment is provided with a signal generating section 80 that uses a common reference oscillating source 90 to generate the sampling clocks with the frequencies fs1, fs2, a carrier fed to an analog orthogonal modulation section 34, and the oscillated frequency signal led to the 1st frequency conversion section 40. |
