Method and device for obtaining essential parameter of circuit

The invention discloses a method and a device for acquiring basic parameter of a circuitry. The method contains the steps as follows: a digital signal processor DSP controls a signal generator SG to generate test signals of a frequency 1 and a frequency 2; sampling unit respectively samples the sampling voltages under the frequency 1 and the frequency 2, and then provides the sampling voltages tothe DSP; the DSP obtains the vector ratios under the sampling voltages of the first frequency and the second frequency, thus the DSP obtains a Z parameter and then obtains the basic parameter of a circuitry. The method and the device provided by the invention can obtain the basic parameter of a circuitry, so as to realize the frequency responding measurement of the circuitry.