Software-Defined Analog Filters: A Paradigm Shift in Radio Filter Performance and Capability
- Magazine Article
Among the most abundant components in all wireless system designs, analog RF filters are used to block interference from various internal and external sources. Limited spectrum divided among an ever-increasing number of users is further driving the need for these ubiquitous but in some ways anachronistic devices. Currently, interference is quite common among cellular base stations, satellite systems, radar installations, and other types of access and backhaul communications systems. Traditional filters are unable to cope with the requirements; in many cases, most often due to insufficient guard bandf. For example, in some international locales, LTE base stations and satellite receivers share the L-band frequencies. At around 3.5 GHz, 5G operators, CBRS radios, and military radars are trying to co-exist. To address this in-band interference, a new, tunable filtering technology is entering the marketplace, uniquely blending the best of both analog and digital technologies.