A GMSK Modulator by Using a Fractional-N Frequency Synthesizer

• Main Authors: Ming-Home Tasi, 蔡明宏
• Other Authors: Tai-Cheng Lee
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/53897460261387127480

碩士 === 國立臺灣大學 === 電子工程學研究所 === 93 === In GSM communication system, the modulation of the modulated signals are GMSK. It is a kind of modulation way of continuiing phase, a kind of GFSK modulation way. In this work, we set up a complete behavior model of phase modulator in Simulink environment. In this chip, we use a sigma-delta fractional-N frequency synthesizer to implement partial RF circuit of the phase modulator. A phase frequency detector, a charge pump ,a multi-modulus divider and a voltage-controlled oscillator are fabricated with 0.35μm 2P4M CMOS technology and are operated over 1.8 GHz. The sigma-delta modulator is implemented by Simu-link and the pattern generator.