Optimized Emission Power Spectral Envelope for Efficient EMI Graded Screening in Digital Modulation Systems

The interference margin (IM) has been used for decades to evaluate the interference margin of a system and predict its electromagnetic sensitivity. However, the rapid growth of digital modulation technologies challenges traditional analog models. This paper addresses this by discussing the IM correction for digital modulation of Binary Amplitude Shift Keying(2ASK), Binary Phase Shift Keying(2PSK), andBinary Frequency Shift Keying(2FSK) based on a graded screening model. Considering binary digital modulation's frequency - and energy - domain features, it proposes a frequency screening step method to calculate the IM correction factor from the transmission power spectral envelope. Simulations on communication receivers using these modulations validate the method. When comparing predicted IM with actual test results, the prediction accuracy is greater than 85. 49% within the 3dB error and 91. 84% within the 6dB error. Thus, it can be used effectively for the prediction of electromagnetic interference in basic digital modulation scenarios.