fundamental frequency of NRZ signal

[senmeis]

Hi,

a 28 Gbps NRZ signal has the fundamental frequency of 14 GHz. Does it mean the digital data is evaluated at every rising and falling edge?

 

[FvM]

Rising and falling edge of which clock? If you imagine a 14 GHz clock, yes. The term "fundamental" refers to the spectral content of the data stream, not specifically a clock.

 

[dick_freebird]

The clock at such speeds is almost certainly "recovered" from the data stream by local PLL and to make that reliable, a "transition density" is made a spec (like 8b/10b or Manchester) for data stream formatting.

28GBPS wants a 28Ghz clock.