Patent ID: 8614585

Claim:
An impedance correction device coupled to a circuit under test, the impedance correction device comprising: a step signal generator, generating a step signal; a reference impedance, having one end coupled to the step signal generator and the other end coupled to the circuit under test; a detection unit coupled to the other end of the reference impedance and the circuit under test, detecting the step signal passing through the reference impedance and a measurement signal of the step signal after passing through the circuit under test; an impedance calculation unit coupled to the detection unit and the reference impedance, calculating a characteristic impedance value of the circuit under test according to an impedance value of the reference impedance, the step signal, and the measurement signal; a correction impedance, connected in parallel with the circuit under test; an impedance setting unit coupled to the impedance calculation unit and the correction impedance, adjusting an impedance value of the correction impedance to match the characteristic impedance value, when the characteristic impedance value is different from the impedance value of the reference impedance, when the reference impedance is adjustable, the impedance setting unit adjusts the impedance value of the correction impedance to match the characteristic impedance value according to a difference between the characteristic impedance value and the impedance value of the reference impedance, or when the reference impedance is set to a fixed impedance value, the impedance setting unit adjusts the impedance value according to a comparison table; and a driving unit having a voltage source and coupled to the impedance setting unit, wherein the correction impedance coupled to the voltage source.