# SNDR with the PCIe Gen6 Standard

Signal to Noise and Distortion Ratio (SNDR) is calculated using the measured P-max, Sigma-e (σe), and Sigma-n (σn) values in the following equation:

With the PCIe Gen6 standard, SNDR is calculated using both even and odd pulse fit vectors as shown in the following equation:

Where PE(k) and PO(k) are (subsampled versions of) the even and odd pulse fit vectors. In other words, the numerator here, divided by 2, is a replacement for Pmax2, or an "Effective" Pmax2.

## See Also

- Determining Sigma-n According to the PCIe Gen6 Standard