题目/Title：20-Mb/s GFSK Modulator Based on 3.6-GHz Hybrid PLL With 3-b DCO Nonlinearity Calibration and Independent Delay Mismatch Control

作者/Author：
                        Xiaoyong Li,Sitao Lv,Woogeun Rhee,Wen Jia,Zhihua Wang

期刊/Journal：IEEE Transactions on Microwave Theory and Techniques

年份/Issue Date：2017Jul.

卷（期）及页码/Volume（No.）&pages：Vol.65, No.7, pp. 2387 - 2398

摘要/Abstract：
A hybrid two-point modulator which mitigates the nonlinearity problem of a digitally controlled oscillator (DCO) and provides a fine delay mismatch calibration is proposed for high data rate applications. A DCO with a separate high-pass modulation path in which only 3 b are used for a capacitor array is designed for flexible gain partition and simple nonlinearity calibration. A nonuniform multilevel quantizer and a finite-impulse response filter are employed to improve modulation quality and reduce quantization noise for high data rate. In the low-pass modulation, a fractional-N divider based on a phase rotator and an additional high-frequency 螖危 modulator enables fine delay time control between two modulation paths. Delay mismatch calibration circuit based on a time-to-digital converter is designed to calculate the optimum delay time automatically. A prototype 3.6-GHz two-point modulator is implemented in 65-nm CMOS. The modulator performs 20-Mb/s GFSK with the error vector magnitude performance of 3.7%, consuming 10.6 mW from a 1-V supply.