State-preserving intermittently-locked loop (SPILL) frequency synthesizer for portable radio

A novel phase-locked loop concept, SPILL, suitable for intermittent-operation frequency synthesizers used in UHF portable radio sets, is proposed. The SPILL uses digital circuit techniques which preserve frequency and phase during power-off periods, to perform fast acquisition at the beginning of the power-on period. Both theoretical analysis and experiments confirm acceptable acquisition performance. A 1.6-GHz SPILL frequency synthesizer achieves two-orders-of-magnitude improvement in acquisition time. This frequency synthesizer is effective in reducing the power consumption of land mobile communication systems and many kinds of communication systems using radio equipment with high-band frequency synthesizers, such as portable TVs, cordless phones, paging systems, satellite communications, and terrestrial microwave communications.<>