To reduce the amount of high-frequency noise generated in automotive electronics, we have compiled circuit board design techniques that are based on the physical properties of high-frequency signals into a set of circuit board design guidelines.These guidelines were created according to a fundamental approach toward noise reduction, which dictates that high-frequency noise generated as a result of electronic circuit operation must not be allowed to propagate widely through the printed circuit board, and noise radiation sources that resonate with the noise frequency and act as antennas must not be created.To check the noise reduction effect of the circuit board design guidelines, we used them to redesign the printed circuit board of an information-processing electronic control unit that normally has a large number of FM bandwidth noise suppression parts mounted therein. Using this test ECU, we examined the noise reduction effect resulting from using the redesigned printed circuit board.As a result, we were able to confirm that an information-processing electronic control unit using the printed circuit board that was designed in accordance with the design guidelines exhibited a noise reduction effect of up to approximately 10 dBμV/m in the high-frequency bandwidths at and above the FM bandwidth.
Article of Honda R&D Technical Review Vol.26 No.1 (58 - 63)