The state variable active filter (SVAF) is an active filter you don’t see mentioned much today; however, it’s been a valuable asset for us old analog types in the past. This became especially true ...

Filters are used in many applications to remove unwanted frequency components from incoming signals, enhance incoming signals, or both. In portable and non-portable medical applications, for example, ...

The usual schematic of a state-variable filter with two inverting integrators is well known. Curiously, the input signal is almost always connected to the minus input of U1. Figure 1 is an example ...