Dec 14, 2015 · It was only enabled through ECN: Separate Refclk Independent SSC (SRIS) Architecture in 2013 which became part of the 3.1 base specifications released in Nov 2013. The Data Clocked Refclk architecture is the simplest, as …

PCIe addresses the EMI problem by modulating the reference clock with a "spread spectrum" modulation. This technique is known as Spread Spectrum Clocking, or SSC. SSC clocking reduces the EMI level by spreading the radiated energy over a range of frequencies thereby reducing the peak emissions at the PCIe clock center frequency.

Jul 18, 2023 · Separate Clock Architecture，收发端采用独立的参考时钟，根据有无 SSC 可进一步分为 SRNS ( Separate Refclk with No SSC) 及 SRIS (Separate Refclk with Independent SSC)。 对于收发端采用独立参考时钟的方案，其收发端独立使用不同的参考时钟源，无需单独传递时钟，对布局布线的要求更宽松。 SRNS 允许 ±300 ppm (600ppm)，而 SRIS 允许 ±2800 ppm (5600 ppm，其中SSC允许 5000ppm，TX/RX允许 600 ppm）。 若 PCIe 设备开启了 SRIS，其发 …

Aug 29, 2022 · The PCIe standard supports multiple clocking architectures that include Common Clock, Data Clock, Separate Reference Independent Spread (SRIS), and Separate Reference No Spread (SRNS).

PCIe also employs differential HCSL or LP-HCSL clocks instead of the PCI LVCMOS clocks, allowing for better noise immunity, and Spread Spectrum Clocking (SSC) for reduction of electromagnetic interference (EMI).

Separate Reference Clock with Independent SSC (SRIS) The current PCI - SIG “PCI Express* External Cabling Specification” (www.pcisig.com) defines the reference clock as part of the signals delivered through the cable.

Aug 17, 2019 · This video outlines the Separate Reference Clock with Independent Spread (SRIS) architectures for PCI Express systems, explaining performance requirements and implementation challenges.

The Common Clock architecture results in the lowest cost while simply and robustly implementing Spread Spectrum Clocking (SSC), which is described in Section Spread Spectrum Clocking. Figure 2. Physical Implementation of Common Clock Architecture. Figure 2 above shows a physical implementation of the common clock architecture.

Nov 10, 2022 · Separate Clock Architecture，收发端采用独立的参考时钟，根据有无 SSC 可进一步分为 SRNS ( Separate Refclk with No SSC) 及 SRIS (Separate Refclk with Independent SSC)。 对于收发端采用独立参考时钟的方案，其收发端独立使用不同的参考时钟源，无需单独传递时钟，对布局布线的要求更宽松。 SRNS 允许 ±300 ppm (600ppm)，而 SRIS 允许 ±2800 ppm (5600 ppm，其中SSC允许 5000ppm，TX/RX允许 600 ppm）。 若 PCIe 设备开启了 SRIS， …

SRIS allows 5600 ppm (5000 ssc + 600 ppm) difference for separate REFCLK utilizing independent SSC. Separate Refclk architecture utilizes the different Refclk for both components (Root-Complex/ Endpoint/Switch) and so it introduces difference in clock between the PCIe Components as shown below: