Coaxial Data Communication With Reduced EMI

摘要

Data communication having improved electromagnetic interference (EMI) rejection when communicating through a coaxial cable is provided by using differential transmission and/or reception through a common-mode choke and a dissipative element resulting in extremely low radiated emissions and high immunity to external radiation interference in a low-cost way.

主权项

1. A transmission circuit using two coaxial cables each having a center conductor and a shield, comprising:
an integrated circuit comprising a differential driver having first and second outputs, and a differential receiver having first and second inputs; a first common mode choke coupled between the first output of the differential driver and a center conductor of the coaxial cable, and between the second output of the differential driver and the shield of one of the coaxial cables, wherein the shield is directly connected with a first ground node; a first terminating impedance coupled between the second output of the first differential driver and a second ground node; a second common mode choke coupled between the first input of the differential receiver and the center conductor of the other coaxial cable, and between the second input of the differential receiver and the shield of the other coaxial cable; second terminating impedances coupled between the first and second inputs of the differential receiver and the second ground node; and a dissipative element coupled between the shield of the other coaxial cable and the first ground node.