| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power amplifier which has high efficiency and low distortion, and is applicable to a system of a wide band signal, in the electric power amplifier which combines a DPD and secondary harmonic wave insertion. SOLUTION: The electric power amplifier includes: a push-pull amplifier; a secondary harmonic wave generating circuit for generating a secondary harmonic wave which compensate the fifth order distortion generated in the push-pull amplifier, and a digital pre-distortion circuit for compensating the three dimensional distortion. The push-pull amplifier includes: first and second amplifier circuits for amplifying a basic wave and the secondary harmonic wave after synthesizing; a variable phase shifter for causing the secondary harmonic wave in the other amplifier circuit to short-circuit after adjusting a phase of the secondary harmonic wave within signals output from the first and second amplifier circuits; and a synthesizer for synthesizing basic waves within the signals output from the first and second amplifier circuits by a reversed phase. Hence, the electric power amplifier compensates fifth order distortion and enables a broadband without giving an influence on three dimensional distortion by the secondary harmonic wave insertion. COPYRIGHT: (C)2011,JPO&INPIT
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