| 摘要 |
A method is provided for tracking large static or low-frequency frequency offset, such as SSC, in clock recovery of data communication or phase-locked loops based on a dual frequency-locked loop and phase-locked loop architecture. Instant PFD outputs are filtered to separate the phase errors due static/low-frequency frequency offset from the other phase mis-alignment. The static/low-frequency instant errors are used to drive a frequency-locked loop to track out static/low-frequency frequency offset completely. The phase-locked loop only needs to track the instant phase alignment other than the static/low-frequency frequency offset. Its gain or loop bandwidth does not need to be high so that the intrinsic jitter due to high gain or loop bandwidth can be avoided. |
