Systems and methods for performing parallel digital phase-locked-loop
View Patent ↗A parallel phase locked loop (PLL) system includes a first chain of a plurality of pre-locking PLLs that operates from a free-run state to a locked state; and a second chain of a plurality of PLLs to work from the locked-state to recover signal output.
1. A parallel phase locked loop (PLL) system, comprising:
a first chain of a plurality of pre-locking PLLs that operates from a free-run state to a locked state; and
a second chain of a plurality of PLLs to work from the locked-state to recover signal output,
wherein the PLL comprises a decision directed PLL (DDPLL) comprising an internal state with a frequency offset, the internal state comprises a voltage controlled oscillator (VCO) output for a phase rotation, and the VCO compensates a phase output using a subtractor, wherein the subtractor output is coupled to a decision block and an error calculation block to determine an error, wherein the error is processed by a low-pass-filter to get a frequency offset, and the frequency offset together with adjusted error are added as a VCO updating value.
2. The system of claim 1 , wherein the first and second chains each contain multiple PLLs.
3. The system of claim 2 , wherein each PLL inside one chain passes internal states to a subsequent PLL after processing of one segment.
4. The system of claim 2 , wherein each of the first and second chains has matching number of PLLs.
5. The system of claim 1 , wherein the first chain has more PLLs than the second chain.
6. The system of claim 1 , wherein the first chain has fewer PLLs than the second chain.
7. The system of claim 1 , wherein the PLLs operate in parallel, wherein after processing of one segment in a particular block, each PLL immediately processes another segment in a subsequent next block.
8. The system of claim 1 , wherein the first and second chains process different number of samples in one block.
9. The system of claim 1 , wherein the first and second chains process matching number of samples in one block.
10. The system of claim 1 , wherein the first chain has a frequency offset initialized to a previous processing value.
11. The system of claim 1 , wherein the internal state of one DDPLL is passed to a subsequent DDPLL.
12. The system of claim 1 , wherein the first chain is initialized to a predetermined value.