本文設計概念是使用超外差降頻的方式得到被動元件的量測電壓與電流訊號，取代直接降頻方式避免I/Q Imbalance及DC Offset問題，且搭配低調整範圍訊號源，避免頻率合成器直接輸出1MHz to 3000MHz，使壓控振盪器調整範圍比例為1:3000讓電路設計複雜度提高。最後使用繞線鐵氧體磁芯與傳輸線阻抗概念設計感應電流電路，讓系統的量測頻寬提高。;The concept of design what uses method of the superheterodyne to obtain the signal of measurement voltage and current of passive components. It substitutes to method of direct-conversion to avoid the issues of I/Q imbalance and DC offset. And, it combines low tuning range (ratio) signal source to avoid the frequency synthesizer producing 1MHz to 3000MHz with direct, that tuning range ratio of voltage controlled oscillator be 1:3000. That will increase complexity to design a circuit. Finally, to use wire wound ferrite core combines the concept impedance of transmission line to create a sensing circuit that increases measurement band width for system.
