Recently engineers of EDALITY have completed another Signal Integrity (SI) analysis assignment. As it happens often, we managed to improve the quality of high-speed interface before it became a real hardware problem.
By means of SI analysis, we identified the poor signal parameters with the help of so-called eye-diagram (or eye-pattern). We had to precisely fine-tune the PCB traces and slightly change passive circuitry of the CAD project to allow the future electronic device working full speed.
It has to be added, that if the measured signals have a low quality (it may be poorly not synchronized with the master clock, can have too much noise or fade away, switching states too slowly with a low slope, have overshoot or undershoot, by a professional this can be easily identified with the help of an eye-diagram.
The change of eye-diagram shape, looking like an eye closure in the left part of the image above means a significant alteration of the valuable signal. A fully open eye pattern shown at the right corresponds to minimal signal distortion.