Abstract:
Characteristics of the channel has a major effect on the signal integrity. The channel distortion is increased with high-rate
data transmission. Feed-Forward Equalizer (FFE) at transmitter side is one of the methods that can be used to compensate the effect of
the channel. PCIe-Gen3, 4, and 5 standards specify some constraints on the FFE settings and assign some preset values that can be used
based on the effect of FFE on time-domain. In this paper, detailed analysis for the FFE in frequency domain is presented. New preset
values are recommended to achieve enhancement on the behavior over different channels. Short and long channel models are created
based on the PCIe standard specifications to check the suggested preset values with worst channels. Continuous-Time Linear Equalizer
(CTLE) also is modeled to check the effect of FFE with different CTLE boost values. The eye-measurements based on the new preset
values is enhanced by 10% with respect to the default preset values in PCIe specifications for short and long channel. Mapping the
preset value in the frequency domain helps fine tuning process for FFE settings by facilitating more guidance to get the best FFE settings.