CALF: a CORDIC adaptive lattice filter

CALF is a CORDIC processor implementation of the adaptive lattice filter. Unlike previously reported results which simply use the CORDIC processor to implement the lattice algorithm formulated for conventional multiply-and-accumulate type arithmetic units, a novel adaptive normalized lattice algorithm which directly updates the rotation angles rather than the reflection coefficients is reported. Thus, this angle updating lattice algorithm is derived specifically for implementation with a VLSI CORDIC processor. Moreover, this algorithm was further modified to a sign-sign algorithm to take advantage of the fact that the CORDIC processors only rotate a finite number of distinct rotation angles. Computer simulation results showed good converging properties even at rather coarsely quantized angles