2.4GHz频率合成器可编程分频器设计与实现

Design and Implementation of Programmable Divider for 2.4 GHz Frequency Synthesizer

介绍了一种应用于802.11b的频率合成器中的可编程分频器.采用级联的异步2分频电路配合相位开关技术,消除了在2.4GHz的高频下分频比改变时产生的毛刺.通过检查初始相位特征信号,解决了由相位开关技术产生的初始相位不确定性问题.仿真结果表明,电路具有很好的稳定性,解决了频率合成器的速度瓶颈;把预分频器调节到合适的直流电平上,可以降低整个电路的功耗.另外,这种除法器有较大的分频比范围,能够应用于不同的设计.

A programmable divider of frequency synthesizer applied to the 802.11b protocol is presented. Asynchronous ÷ 2 dividers in cascade accompanied with phase switching technology are used to eliminate the glitch when divide ratio changes at 2.4 GHz. The uncertainty problem of the initial phase due to the phase switching technology is solved by checking the characteristic signals of the initial phase. The results of simulation show that the circuit has good stability and breaks the speed limitation of frequency synthesizer; the power dissipation of the whole circuit can be reduced by adjusting the prescaler in appropriate DC level. In addition, this kind of divider has large-scale divide ratio and can be applied to different designs.