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WEBENCH® Design Center

How to measure Total Jitter (TJ) (Rev. B)


Today, the jitter specification, TJ, is used in more and more systems, at the same time the jitter requirements get lower and lower. Clock generators or jitter cleaners like the CDCM6208 meet those tough jitter specifications for most systems (for example, TMS320TCI66xx DSP-based systems; see Hardware Design Guide for KeyStone I Devices (SPRABI2). The other side of the coin is that the measurement equipment has to be feasible to measure the low-noise clock generators. Therefore, the measurement equipment has to have a lower noise floor than the device under test. This can be achieved by minimizing the noise sources within the measurement equipment. This application report describes the recommended measurement techniques for TJ. It includes the description of the techniques to minimize the noise sources of the measurement equipment. The CDCM6208 characterization setup is used as an example throughout the application report.