| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplifier capable of varying a gain without changing a distortion rate of AC input. SOLUTION: The invention relates to an amplifier having a transistor M1, to which AC input is inputted, and inductance LL connected to a drain terminal side of the transistor M1. The amplifier has an impedance control circuit for controlling impedance of at least one of a first connecting line connecting a reference potential and a source terminal side of the transistor M1 and a second connecting line connecting a positive power supply potential and the drain terminal side of the transistor M1. The impedance control circuit is disposed at least between the reference potential and a source terminal of the transistor M1 or between the positive power supply potential and a drain terminal of the transistor M1, wherein a plurality of inductance elements and impedance control elements constituted of switches connected in series to the inductance elements, are connected in parallel. COPYRIGHT: (C)2009,JPO&INPIT
|
