Design of Complex FIR Filters With Reduced Group Delay Error Using Semidefinite Programming

This letter proposes an improved method for designing complex finite impulse response (FIR) filters with reduced group delays using semidefinite programming. A key step in the proposed method is to directly impose a group delay constraint, which is formulated as a linear matrix inequality constraint with some reasonable approximations. The main advantage of the proposed design method is the significant reduction in group delay error at the expense of the slight increase in magnitude error. The effectiveness of the proposed design method is illustrated with an example