Patent ID: 9647756
Date: 2017-05-09
CPC Classifications: H04B

Claim:
1. A Cable Television (CATV) node circuit comprising: a forward pathway having a fiber optic input, the forward pathway having a forward pathway output, wherein the forward pathway passes a forward signal to the forward pathway output in a first frequency range; a return pathway coupled to the forward pathway, the return pathway having a fiber optic output, wherein the return pathway passes a return signal to the fiber optic output in a second frequency range, wherein the first frequency range is higher than the second frequency range; and a cancellation circuit coupled to the forward pathway and the return pathway, wherein the cancellation circuit separates and isolates the forward signal from the return signal, wherein the cancellation circuit comprises: a plurality of directional couplers to separate and isolate the forward signal from the return signal; a Resistor-Capacitor (RC) circuit coupled to one of the plurality of directional couplers; an Inductor-Capacitor (LC) circuit coupled to another of the plurality of directional couplers to adjust a phase of the return signal; and a phase reversal transformer coupled to a third of the plurality of directional couplers, the phase reversal transformer inverting the phase of the forward signals 180° out of phase and back into the return pathway via the third of the plurality of directional couplers.