CMOS Analog Filter Design
Shown above is a 5th order continuous-time Gm-Opamp-C filter intended to test algorithms for the digital adaptation of analog filters. All 5 poles and zeros are digitally programmable. An orthonormal ladder structure is used to optimize dynamic range scaling over a wide range of operating conditions. Constant capacitances are combined with digitally controlled transconductances to provide programmability.
Filters for high speed communication applications are needed for equalization, echo cancellation, and crosstalk cancellation. Traditional filter architectures and circuit topologies may not be suitable for the GHz range. Investigations are required at the system, circuit, and device levels.