AL-band frequency sourcebased on sigma-delta fractional-N phase locked loop (PLL) technologyis designed for RF transceiver, utilizingPLL chip integrated with a voltage controlled oscillator (VCO). This frequency source solves the contradiction between high frequency resolution and low phase noise. By the control of the micro-controller, the frequency source can generate any frequency range from 1268MHz to 1360MHz.Experiment results show thatthe L-band frequency source has excellent phase noise and spurioussuppression. Meanwhile,it is easy to debugging,high integration,good consistency.%采用片内集成压控振荡器(VCO)的锁相环芯片LMX2531,设计了一种用于射频收发机前端的L频段频率源.利用小数分频技术克服了整数分频锁相环所固有的高频率分辨率与相位噪声之间的矛盾,同时满足了高频率分辨率与比较好的相位噪声.利用单片机通用IO口对锁相环芯片进行逻辑控制,该频率源可实现1268~1360 MHz频率范围内任意步进频点的合成,并具有2分频输出控制功能.实际测试结果表明,该信号源具有优良的相位噪声和杂散抑制,具有易调试、集成度高、一致性好等优点.
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