Signal conditioning apparatus

Abstract

A signal conditioning system that receives inputs from at least one pair of conductors connected to its input. Each such input is processed by an input filter and presented to a buffer amplifier. Each such input filter and buffer amplifier refers to and is powered by independent power sources whose power return reference potentials are independently determined by the potential of the corresponding input signal potential reference conductor for the signal frequencies of interest. The outputs of all such buffer amplifiers, the power return reference potentials, and the power return reference potential of the conditioning circuit output are all appropriately added or subtracted in the next circuit stage. This circuit stage consists of an amplifier buffer having low output impedance which is powered by another independent power source whose power return reference potential is independently determined by the potential of the output signal reference conductor. The output of this circuit stage is connected to an output inductor circuit which in turn drives the output signal conductor. The output includes a filter, and is designed to decouple unstable loading conditions while rejecting external influences on the output signal. The invention also includes means that connect the reference potential of the destination of the output conductors to the system power ground potential. The present invention provides a relatively inexpensive and efficient way of reducing or eliminating interference caused by coax cabling in audio, power and video amplifiers, for example.