The history of Kerwin–Huelsman–Newcomb (KHN) second-order filter is reviewed. A generation method of the KHN filter from passive RLC filter is presented. Two alternative forms of the KHN circuit using operational amplifier are reviewed. The effect of finite gain-bandwidth of the op amps is considered and expressions of the actual ω0 and Q are given. Two KHN circuits with inherently stable Q factor are also included. Two new partially compensated inverted KHN circuits are introduced. Active compensation methods to improve the KHN and the inverted KHN circuit performance for high Q designs are summarized. Spice simulation results are given. The progress of the KHN realizations using the current conveyor is also summarized briefly.
Analysis of Leakage Loss in Silicon Photonics with Finite Gain Compensation