This paper initially modifies an original Tow-Thomas (T-T) filter and presents the nodal admittance matrix (NAM) of the T-T filter with orthogonal control of fo and Q. Furthermore, in accordance with the nullor-mirror models of the second generation current-controlled conveyor (CCCII), two different topological classes of the T-T filter, class A and class B filters, are acquired by bracket notation method. The class A filter, employing five single-output CCCIIs, has 128 equivalent realizations, the class B filter, employing three single-output CCCIIs and one dual-output CCCII, has also 128 equivalent realizations. 256 different forms of the current-mode and trans-resistance-mode T-T filters are synthesized in all. The synthesized circuits are easy to be integrated and fo and Q can be orthogonally tuned by tuning bias currents of the CCCs. The hand analysis and computer simulation are included to support the generation method.

Keywords: Tow-Thomas (T-T) filter, Second generation current-controlled conveyor (CCCII), Bracket notation method, Systematic synthesis