(under subclass 167) Subject matter having an impedance path containing a plurality of filter impedance units connected in series relation between an input and an output terminal, the filter also having a shunt connection containing an impedance connected to the junction of the series filter impedance units and to the other side of the line between the input and output terminals, an impedance path being connected to different ones of the series impedance units at points other than the junction between the units.
(1) Note. The last named impedance path is therefore in parallel with at least a portion of the series connected filter impedance units in the input circuit and the output circuit. The last named impedance path may include an inductive coupling.
(2) Note. Examples of filter networks included and excluded are:
[figure] [figure] [figure]
SEE OR SEARCH CLASS
142, in particular for bridge-type oscillators utilizing a double T bridge of the RC or RL element type.