LC ladder-based synthesis of log-domain bandpass filters

The design method of log-domain filters based on LC ladder synthesis is extended to cover a class of filter topologies which were not realizable otherwise. As an example, bandpass filters are considered. Known log-domain sub-circuits are combined together to realize a more versatile multiple-input log-domain integrator circuit. The realization of a second-order bandpass filter is discussed. A large signal analysis of the circuit shows how the gain, cutoff frequency, and Q-factor can be electronically and independently tuned. Experimental results are presented