The design of log-domain filters based on the operational simulation of LC ladders

A technique for the design of log-domain filters is introduced which is based on the operational simulation of LC ladders. The method is used to design a fifth-order Chebyshev and elliptic filter. HSPICE simulation results and experimental results are shown with emphasis on frequency behavior and linearity. The filters showed good correlation between the original filter specifications and the measured frequency response. They proved to be easily tunable and could be operated up to 1 MHz or one tenth of the f/sub T/ of the slowest transistor. Total harmonic distortion and intermodulation distortion was measured with results up to -47 and -55 dB, respectively.