Abstract: The Spread-Spectrum-Clock Generation（SSCG） technique is the latest technology to decrease electromagnetic radiation of the electronic system.In recent years，internationally it has been successfully used on computer peripherals and the electronic equipment which take the microprocessor as the core.This paper uses programmable SSCG chip made by MAXIM Corporation to replace the main clock in PCI-expansion equipment of the computer，and comparative test confirms that SSCG can decrease the electromagnetic radiation in the source by using experiment’s method.

Key words: Spread-Spectrum-Clock Generation（SSCG）, Electro Magnetic Interference（EMI）, Electro Magnetic Compatibility（EMC）

摘要： 扩展频谱时钟技术是一种用来降低电子系统电磁辐射的最新技术，近年来在国外已被成功地用于以微处理器为核心的电子设备以及外设。采用理论与实验相结合的方法，在计算机的PCI扩展设备上采用MAXIM公司提供的可编程扩展频谱时钟芯片替代设备主时钟，进行了比较测试，用实验的手段验证了使用扩展频谱时钟降低电磁辐射水平的抑源方法。

关键词: 扩展频谱时钟, 电磁干扰, 电磁兼容