Inductive electrical signal filter with reduced impedance

Abstract

A translating circuit couples an electrical signal filter to a signal path conveying signals to be filtered. The translating circuit exhibits unity current gain and a voltage gain other than unity between the signal path and the filter, and applies signals from the signal path to the filter. By setting the scale factor (e.g., attenuation) of the translating circuit, the impedance of the filter can be set to any desired level without affecting the operating parameters of the signal path. In the case of an inductive filter, the translating circuit permits the filter to be designed with a lower impedance, and a smaller value inductor less susceptible to picking up interference signals likely to adversely affect signals in the signal path, without requiring a corresponding adjustment in the operating parameters of the signal path.