| 摘要 |
PROBLEM TO BE SOLVED: To highly efficiently perform a lowly distorted base band processing at a low cost in AM/PM conversion, even in the case of digital modulation for which a difference between average power and peak power is large. SOLUTION: A phase shifter 3 and a detector 9 are added to a conventional linearizer type transmission amplifier. The detector 9 detects a part of output signals of a high output amplifier 4, converts the amplitude of modulated wave components to a voltage level and feeds back the voltage level to the phase shifter 3. Then, the phase shifter 3 performs phase correction, corresponding to the fed-back voltage level to RF signals sent from an orthogonal transformer 2 and transmits them to the high output amplifier 4. Thus, when the RF signals of low distortion are outputted from the orthogonal transformer 2 and inputted to the phase shifter 3, optimum phase correction is performed to the RF signals of the low distortion by the phase shifter 3, and optimum transmission signals (RF signals) are transmitted to a transmission antenna 5 by the high output amplifier 4. |
