clock and data recovery (FC, ON) (CDR)

Clock and data recovery ( CDR) is used in digital transmission systems, such as optical networks, to regenerate distorted data signals with the lowest possible bit error rate.

In all transmission media - wireless, fiber optic, cable - amplitude distortions and temporal variations known as jitter occur during transmission. With Clock and Data Recovery, the recovered clock signal has extremely low jitter. The recovery itself can be done by narrowband notch filters, by phase-locked loops( PLL) or by voltage controlled oscillators( VCO).