The Weighted Least Squares (WLS) principle is popular in filter design due to its flexibility, where it can output equiripple filters with appropriate target function and weighted function. Therefore, this research studies the influence of the target function in linear phase Finite-Impulse-Response (FIR) filter design by comparing different target functions in WLS iterations. Compared with the traditional one, simulations show that the proposed target function can obtain more accurate stopband start frequencies which will be useful if the stopband start frequency must be precise in applications.
Jingyu Hua, Zheng Gao, Wankun Kuang, Zhijiang Xu and Chengfeng Ruan, 2012. Comparative Study of Target Function Definition in Linear Phase FIR Filter Design. Information Technology Journal, 11: 734-740.