Practical considerations for electromagnetic interference suppression rate with spread spectrum clocking

Electromagnetic interference (EMI) is one of the critical design issues affecting the performance of consumer electronic devices, especially for wireless devices and applications. EMI can easily degrade the performance of systems through undesirable spectral components and by interference from the system itself. Therefore, there are a lot of techniques addressing this issue such as differential signaling, shielding, and spread spectrum clocking (SSC). Specifically, SSC is getting more attention since it directly addresses EMI issues at its source. In this paper, SSC generation and its EMI suppression rate are discussed, and two practical considerations are introduced to improve the measurement accuracy.