A Fully Integrated Fractional-N Frequency Synthesizer for Wireless Communications

Fully integrated;Wireless communications;FIR digital filter;PLL;Fractional-N frequency synthesizer

Son, Han-Woong ; Electrical and Computer Engineering

University:Georgia Institute of Technology

Department:Electrical and Computer Engineering

关键词: Fully integrated;    Wireless communications;    FIR digital filter;    PLL;    Fractional-N frequency synthesizer;   

Others  :  https://smartech.gatech.edu/bitstream/1853/5254/1/son_han-woong_200405_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

A fully integrated, fast-locking fractional-N frequency synthesizer is proposed and demonstrated in this work. In this design, to eliminate the need for large, inaccurate capacitors and resistors in a loop filter, an analog continuous-time loop filter whose performance is sensitive to process and temperature variations and aging has been replaced with a programmable digital Finite Impulse Response (FIR) filter. In addition, using the adaptive loop gain control proportional to the frequency difference, the frequency-locking time has been reduced. Also, the phase noise and spurs have been reduced by a Multi-stAge noise SHaping (MASH) controlled Fractional Frequency Detector (FFD) that generates a digital output corresponding directly to the frequency difference. The proposed frequency synthesizer provides many benefits in terms of high integration ability, technological robustness, fast locking time, low noise level, and multimode flexibility.To prove performance of the proposed frequency synthesizer, the frequency synthesizers analysis, design, and simulation have been carried out at both the system and the circuit levels.Then, the performance was also verified after fabrication and packaging.