A wide-range and fast-locking frequency synthesizer for Wimax and WLAN applications

This paper is to present a wide-ranged operation frequency synthesizer. With the use of the technology of multi-phase switching of each band produced by the divider, the best band can be automatically determined within a single reference cycle and the technology can be applied simultaneously to the transmission receivers of Wimax and WLAN specifications. In the VCO design, we use the multi-band VCO design method to achieve low slope and improve the VCO of process variation. In addition, we will improve the traditional method of comparing and selecting the band. By using the method of distinguishing whether the frequency is ahead or behind and the algorithm of rapid band switching, the way to determining the band in a single reference cycle can be reached so as to achieve the wide-ranged operation of the frequency synthesizer.