Patent ID: 7292449
Filing Date: 2007-11-06
Classification: H05K

Abstract:
1. A digital apparatus using a multi-conductor cable having virtual ground returns for reduction of electromagnetic radiated emissions, comprising: a main circuit module; a peripheral circuit module; a cable with two ends connecting at one of the two ends to the main circuit module and connecting at another of the two ends to the peripheral circuit module, the cable having at least three single-wire conductors extending between the two ends with insulation there between, wherein the cable is configured to couple high speed and low-speed signals between the main and peripheral circuit modules on a respective one of the at least three conductors, at least another of the at least three conductors being a ground return; and a plurality of capacitors, wherein the respective one of the at least three conductors that is configured to couple the low-speed signals between the main and peripheral circuit modules are connected at the one of the two ends of the cable to one side of a first capacitor of the plurality of capacitors and connected at the another of the two ends to one side of a second capacitor of the plurality of capacitors including another side of the first and second capacitors being connected to the ground return at the each of the two ends of the cable, the first and second capacitors bridging the respective one of the at least three conductors that couples the high speed signals between the main and peripheral circuit modules at the each of the two ends of the cable, wherein the plurality of capacitors has a total connected capacitance on the each of the two ends of the cable during use corresponding to a low impedance relative to the frequencies of the high speed signals and a high impedance relative to the frequencies of the low-speed signals.