Articles by Wael A. Al-Qaq and JianHua Gu, Ansoft Inc.; William J. Martin and Jeffrey L. Cutcher, Motorola Inc.

New Behavioral Models Facilitate Fast and Accurate Simulation of Sigma-delta Fractional-N Synthesizers Using Ansoft Designerâ„¢

By offering extremely low phase noise combined with fast acquisition times, Sigma-delta fractional-N synthesizers are ideally suited to meet the requirements for the emerging 2.5 and 3G digital wireless services, including General Packet Radio Service ...
Fractional-N synthesizers are highly desirable in communication systems because of their high frequency resolution output. This resolution is made possible by dithering the divide value using the output of a sigma-delta modulator. A typical sigma-delta fractional-N frequency synthesizer is shown in Figure 1 . The tri-state phase frequency detector...
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