| 摘要 |
<p>A method for performing signal quality analysis on digital signals uses simultaneous dual threshold data acquisition. Using this method, the data need not be repetitive and, because the reference data and the variable data are acquired simultaneously, the logic analyzer continues to trigger and further measurements can be made after significant noise has been encountered. One threshold is designated the reference threshold and used to perform triggering and acquisition of reference data, while the other threshold is designated the variable threshold and used to acquire data for the noise margin analysis. At each increment of variable level, the data acquired by the reference acquisition and the data acquired using the variable threshold level is compared to see at what point in time and on what signal lines noise begins to affect the quality of the data. These data comparisons should be tolerant of minor timing variations that arise from the interaction of normal rise and fall times and the varying threshold level, and yet be sensitive to more significant changes in the data that arise from the effects of noise, marginal signal width or amplitude, or excessive rise and fall times.</p> |
