Wave active filter: a state-of-the-art review with odd and even order filter implementation

Abstract

This scientific literature survey aims to provide a detailed overview of Wave Active Filter (WAF), including sequential growth of the higher-order filter design using voltage mode and current mode design. This survey paper elaborates on a step-by-step procedure for the wave variable approach for filter design with mathematical analysis. In addition, this work specifically focuses on developing WAF designs using different active blocks. Higher-order WAF designs using modern active blocks are well recorded in this survey paper for better visualization. In literature, third-order and fourth-order WAF implementations are mainly enriched. Hence, an OTA-based WAF is designed for lower- to higher-order filters, demonstrating their efficacy for multifunctional applications such as Wave Active Low Pass Filter (WALPF), Wave Active High Pass Filter (WAHPF), and Wave Active Bandpass Filter (WABPF) using OTA. Besides the theoretical foundations, simulation, and experimental test results are also performed to validate the workability of the OTA-based WAF. The frequency responses of WALPF, WAHPF, and WABPF are demonstrated for the second to sixth orders. The functionality of the OTA-based WAF is verified through frequency spectrum analysis and Monte Carlo simulations. This paper ultimately offers an extensive review of the WAF design process, including mathematical analysis and practical realizations. It provides insights into WAF theory, its benefits, limitations, and potential for future advancements in high-order filters.