Low-Complexity Structure for Implementing Even-Order Minimax Variable-Bandpass Filter
Deng Tian-Bo · 2018
The bandwidths of a digital band-pass filter (BPF) can be tuned through adopting an extra parameter called bandwidth-tuning parameter into its transfer function (mathematical model). Such a BPF with tunable bandwidths is called variable-BPF. This paper suggests an efficient approach to the low-complexity implementation of a variable-BPF. The variable-BPF is designed on the basis of the minimax criterion and its coefficients are polynomial functions of the bandwidth-tuning parameter. This improved approach represents all the variable coefficients as unequal-order polynomials. By employing unequal-orders instead of identically the same order as reported in the previous work, unnecessary high orders can be further lowered. As a consequence, the utilization of unequal-order polynomials can further reduce the implementation complexity of the designed variable-BPF, which leads to a low-cost filter implementation as well as fast filtering operations. A comparative implementation example is given to show the complexity reduction along with the achieved comparable variable-BPF accuracy.