Impedance matching circuit and impedance matching system employing the impedance matching circuit

摘要

An exemplary impedance matching circuit (20) includes a signal processing circuit (22) and a variable resistance unit (24). The signal processing unit is configured for identifying a frequency of a signal from an external transmission line (23), generating an identification signal according to the frequency. The variable resistance unit is configured for selecting a resistance matched with an actual impedance of the transmission line.