The same module and oscilloscopes adjusted by different people can produce two eye diagrams, one good and one bad. Interpretation must have a fixed sequence: first look at the template margin, then look at the amplitude parameters, and finally remove the jitter, then the conclusion will be tenable.

First set the receiving filter and template

Compliance aperture requires the addition of specified baseline filtering on the receiving side. Bandwidth settings, probe and fixture loads will all change the eye shape. The template test looks at the minimum distance between the opening area and the template boundary. A positive margin is just the bottom line. A single close to zero means a high risk at the end of the batch. It is recommended to record the worst single price at the same time during random testing. Only reporting the average value will smooth out the dispersion.

Amplitude parameters: eye height, extinction ratio and overshoot

• Low eye height often comes from insufficient bandwidth or high insertion loss at the opposite end.
• If the extinction ratio is too large, it will compress the eye height and cause dispersion sensitivity problems. You need to pay special attention to long-distance links.
• Overshoot and undershoot reflect the matching of driver and termination. Overshoot will press the template boundary.
• The upper and lower asymmetry of the eye diagram mostly comes from the difference in rise and fall times, which manifests as level offset on the video link.

The total amount and source of jitter should be looked at separately.

The total amount is read as two numbers: RMS and peak-to-peak, and the source is divided into random jitter and deterministic jitter. Random jitter is affected by temperature and bias, while deterministic jitter often comes from inter-symbol interference, power supply ripple, or serialization patterns. The latter can be improved by changing the power supply and wiring. Video signals are sensitive to timing.1-way 3G-SDI audio and video optical transceiverThe jitter margin of this type of link is too small, and flash points or unstable synchronization will appear on the screen first, which will be noticed earlier than the error count; for radio and television scenarios, please refer toRadio, television and large-screen audio and video optical fiber transmission solutionsAcceptance recording method.

Eye diagram and bit error are two sides of the same coin: the eye shape determines the anti-noise margin, and the bit error determines whether the business is affected. Both factory sampling tests are kept on file, so there is a benchmark for comparison on site. If you need to review the interpretation caliber, please call 0755-83179002. EB-LINK technical support can arrange for testing.