| 摘要 |
Systems, circuits, and techniques for the calibration and fast tuning of VCOs in PLLs are provided. Information for coarse tuning before normal operation are calculated and stored. These systems and techniques decrease significantly the time needed for a PLL to transition from one frequency to another. These techniques involve: determining a digital code Dc, to coarse tune to a calibration frequency, Fc; dividing the operating frequency band of the PLL into a plurality of sub-bands; determining and storing the information needed to generate the offsets for each sub-band. In tuning to a desired frequency, these systems and techniques involve: determining the sub-band corresponding to the desired frequency, F, generating the offset for that sub-band, calculating the digital code for coarse tuning the VCO to the desired sub-band, coarse tuning to a frequency within the desired sub-band, and fine tuning to the desired frequency.
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