What is PAM4?
Four-level pulse amplitude modulation, sending 2 bits per symbol. It doubles the bit rate at the same symbol rate but reduces noise margin.
Field: I/O Interfaces & Buses
PAM4 in the explanations
PAM4 uses four levels to represent 00, 01, 10 and 11, sending 2 bits per symbol.
What is a characteristic of PAM4 (four-level pulse amplitud…With the same voltage swing, two-level NRZ has the full swing between 0 and 1, but four-level PAM4 leaves only about one third of it between adjacent levels.
Why does forward error correction (FEC) become more importa…As per-lane speeds rise, the same bandwidth needs fewer lanes; for example, a single 100 Gb/s PAM4 lane can carry 100-gigabit traffic.
High-speed links such as 100-gigabit Ethernet are sometimes…
Questions that mention PAM4 (3)
- What is a characteristic of PAM4 (four-level pulse amplitude modulation), adopted in PCI Express 6.0?
- Why does forward error correction (FEC) become more important with PAM4 than with NRZ?
- High-speed links such as 100-gigabit Ethernet are sometimes built by bundling, for example, four 25 Gb/s lanes. Which describes this approach?
Related terms
PCI Express NRZ ECC (error-correcting code) SerDes 128b/130b encoding 8b/10b encoding AXI Bit error rate (BER) Characteristic impedance Clock and data recovery (CDR)