| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an amplifier having high power efficiency and low output distortion exceeding a conventional Doherty-type amplifier. <P>SOLUTION: The amplifier composites the output of a plurality of amplification circuits as output. The amplifier comprises a first amplification circuit for operating an amplification element in an AB class in the plurality of amplification circuits; a second amplification circuit for operating the amplification element in a class B or C in the plurality of amplification circuits; a first transmission line that is connected to the output of the first amplification circuit, and has an electric length other thanλ/4; and a second transmission line that is connected to the output of the second amplification circuit and has an arbitrary electric length, and a composite end for compositing the output of the first transmission line and that of the second one. At least one of the first and second transmission lines has a phase shifter. The first amplification circuit has a first preamplifier operated in a class AB, and the second amplification circuit has a second preamplifier using one of classes A-C as an operating point. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
