Title :
A fractional-N synthesizer for multi-mode positioning system with constant loop bandwidth
Author :
Feng, Yan ; Chen, Guican
Author_Institution :
Dept. of Microelectron., Xian Jiaotong Univ., Xian, China
Abstract :
A fractional-N frequency synthesizer with constant loop bandwidth is presented. This synthesizer can be applied to the multi-mode positioning receiver with seven modes in three positioning systems. In all seven modes it has constant loop bandwidth and can work stably by using the improved adjusting method in charge pump biasing current and the linear varactor in VCO (voltage-controlled oscillator). Simulations show that this synthesizer meets the requirements of high performance receiver. For each mode, the in-band and out-of-band phase noises are not lager than -95dBC/Hz and -119dBC/Hz@1MHz, respectively. The variation of normalized IcpKvco/wvco in seven modes is in the range of -8% and 7%. The setting time is less than 21μs. The total power consumption is 15.34mW at 1.8V voltage supply.
Keywords :
charge pump circuits; frequency synthesizers; phase noise; receivers; varactors; voltage-controlled oscillators; VCO; charge pump biasing current; constant loop bandwidth; fractional-N frequency synthesizer; high performance receiver; linear varactor; multimode positioning receiver; multimode positioning system; phase noise; voltage-controlled oscillator; Bandwidth; Frequency synthesizers; Iterative closest point algorithm; Receivers; Synthesizers; Varactors; Voltage-controlled oscillators; Fractional-N synthesizer; GPS; constant loop bandwidth; multi-mode; phase noise;
Conference_Titel :
Electron Devices and Solid-State Circuits (EDSSC), 2011 International Conference of
Conference_Location :
Tianjin
Print_ISBN :
978-1-4577-1998-1
Electronic_ISBN :
Pending
DOI :
10.1109/EDSSC.2011.6117626
