F&H filter: A novel ultra-low power discretetime filter
Vıtor M. Grade Tavares, José Carlos Príncipe, J.G. Harris · Electronics Letters · 1999
A new technique for designing filters with long time constants in the discrete time domain is presented. The F&H (filter and hold) methodology halts the state of a continuous time filter every T seconds resulting in a filter implementation with time constants that can be controlled in three distinct ways: by the sampling period T, the duty cycle k = τ/T or the time constant of the continuous time filter prototype. The final filter can be constructed from a typical Gm-C technique with very low power consumption.