AMPLIFIER AND RADIO FREQUENCY WAVE TUNER

摘要

PROBLEM TO BE SOLVED: To solve the problem of a conventional system that the input impedance of an amplifier itself will become small if it is made small while noise occurs in proportion to the magnitude of the input impedance of the amplifier. SOLUTION: An LNA used as the input stage of a radio frequency wave tuner is equipped with an amplifying stage (1) for inversion and a transconductance stage (6). The amplifying stage (1) is connected to the input part (3) of the amplifier through an input resistor (2) and the output part of the amplifying stage (1) through a feedback resistor (4). The transconductance stage (6) lets a current substantially proportionate to the output voltage (Vout) of the amplifying stage (1) flow to the input resistor (2). COPYRIGHT: (C)2004,JPO