A compact All-NPN fully-differential ladder log-companding filter

This paper presents compact structure of the ladder-based upon fully-differential Log-companding filter in [14]. The proposed filter structure is based on the exponential-state-space integrators with compatible input and output voltage levels. Based upon the proposed structure, the derivation of the all NPN-only 3
^rd
-order fully-differential Log-companding Chebyshev low-pass filter is demonstrated. Simulation results of the demonstrated filters are given.