LINEAR AMPLIFIER USING FORWARD FEEDBACK OF LOW-FREQUENCY TWO-ORDER INTERMODULATION COMPONENT

摘要

PURPOSE: A linear amplifier using forward feedback of a low-frequency two-order intermodulation component to forward-feed back the low-frequency two-order intermodulation component of a fundamental signal to the output port of a power amplifying transistor to maintain stabilized characteristics of the circuit and to attenuate the third-order intermodulation component adjacent to the frequency of the fundamental signal. CONSTITUTION: A linear amplifier using forward feedback of a low-frequency two-order intermodulation component includes a MOS transistor(30) for amplifying the power of a fundamental signal, the first filter(36) for passing the two-order intermodulation component of the fundamental signal, and a low-frequency amplifier(38) for amplifying the two-order intermodulation signal with a predetermined voltage gain. The linear amplifier also has the second filter(37) for filtering the amplified two-order intermodulation signal to forward-feed back the filtered signal to the output port of the MOS transistor, and an output impedance matching unit(34) for matching the impedance with an external load.