A low frequency active filter with plug-in tuning impedances.
P Zalud, Mandalahi Haldigian Indra, I Krekule · PubMed · 1975
A new approach to the construction of low frequency (1 Hz -- 20 kHz) active filters, based on the application of a pair of IC operational amplifiers forming a separate module and a plug-in unit containing RC tuning circuits, is described. The electronic circuits and the design of the filters are presented with all details.