Design of Sharp Cutoff Filters with Low Quality Factors.

摘要

Electronic filters are used to pass a band of frequencies while rejecting other frequencies. For example, tuning an FM radio is in effect tuning a filter that passes the signal from the desired FM station and blocks the signal from the undesired stations. Advances in technology call for filters with increasingly sharp cutoffs, and these filters are also increasing difficult to manufacture. This difficulty arises from the fact that as the order of the filter is increased, the quality factor Q of each filter section is required to be correspondingly higher. A high Q filter can only be built by using components that closely approximate ideal components, which is often too expensive or not practical. This report presents a method of designing and building filters from low Q components that closely approximate the high Q models. (rh)