| 摘要 |
A linear amplifier using a low frequency 2nd intermodulation feed-forwarding method to offset the 3rd intermodulation component of a fundamental signal is provided. This linear amplifier includes a transistor for amplifying the power of the fundamental signal, a first filter unit, one end of which is connected to the gate of the transistor, for filtering a 2nd order intermodulation signal from the fundamental signal, a low frequency amplifier connected to the other end of the first filter unit, for amplifying the 2nd order intermodulation signal with a predetermined voltage gain, and a second filter unit connected in series between the output port of the low frequency amplifier and the drain output port of the transistor, for filtering the amplified 2nd intermodulation signal and feeding the same to the output port of the transistor. This linear amplifier feeds the low frequency 2nd order intermodulation component of a fundamental signal forward to the output port of a power amplification transistor, thereby maintaining the stable characteristics of a circuit adopting a feed-forwarding method and favorably offsetting a 3rd intermodulation component that is adjacent to the frequency of the fundamental signal.
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