Circuit Specifications for Radio-Noise Reduction Vehicle-mounted Communication Network: Specification Development using Inverse Calculation

EM noise emission in the radio bands from the communication harness of vehicle-mounted LAN is evaluated by performing an actual measurement test complying with CISPR25. This report provides a method used to define the specifications for the transmitter circuit and receiver circuit required to satisfy the AM noise limit in the test. The noise propagation is analyzed in common and differential modes and an inverse calculation is applied to obtain the specifications. Radio noise from the communication harness will be able to pass the test by designing the transmitter and receiver to meet the specifications developed using this method.