RX Margin Analysis

Versal Adaptive SoC GTY and GTYP Transceivers Architecture Manual (AM002)

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1.3 English

As line rates and channel attenuation increase, the receiver equalizers are more often enabled to overcome channel attenuation. This poses a challenge to system bring-up because the quality of the link cannot be determined by measuring the far-end eye opening at the receiver pins. At high line rates, the received eye measured on the printed circuit board can appear to be completely closed even though the internal eye after the receiver equalizer is open.

The GTY and GTYP transceiver RX eye scan provides a mechanism to measure and visualize the receiver eye margin after the equalizer. Additional use modes enable several other methods to determine and diagnose the effects of equalization settings.

Figure 1. Offset Sample and Data Sample to Calculate BER as a Function of Offset—the Statistical Eye