用于无线卫星通信网络系统的抑噪分频频率综合器设计

Noise Suppression Frequency Synthesizer Design for Wireless Satellite Communication Network System

为改善传统综合器在噪声影响下分频效果差的问题,设计了用于无线卫星通信网络系统的抑噪分频频率综合器;根据抑噪分频频率综合器总体架构,设计压控振荡器,并选用MAOC-114850芯片作为压控振荡器核心芯片,依据LC压控振荡器原理电路,将压控可变电抗元件插入输入频率原件中,控制输入控制电压和振动频率,通过改变电容器的充电速率,使产生的电流源在电压控制之内;选用MB506直插/DIP8超高频预分频器芯片作为预分频器的核心芯片,经过多次4分频操作定制数字电路;根据环路滤波器的片上集成设计要求,采用三阶无源环路滤波器,改善电阻与电容间的相位裕度,抑噪制声;增加控制模块,限定压控振荡器的最小振荡频率范围,根据晶振参考频率确定跳频间隔,并将结果保存到分频频率综合器中,由此完成抑噪分频频率综合器设计;实验结果表明,该综合器最高分频效率可达到98%,为无线卫星通信网络系统稳定运行提供保障。

In order to improve the problem of poor frequency division of traditional synthesizer under the influence of noise,a noise suppression frequency synthesizer for wireless satellite communication network system is designed.According to the overall architecture of the noise suppression frequency synthesizer,the voltage controlled oscillator is designed,and the MAOC-114850 chip is selected as the core of the voltage controlled oscillator.According to the LC voltage controlled oscillator principle circuit,the voltage controlled variable reactance component is inserted into the input.In the frequency original,the input control voltage and the vibration frequency are controlled,and the generated current source is within the voltage control by changing the charging rate of the capacitor.The MB506 in-line/DIP8 UHF prescaler chip is selected as the core chip of the prescaler,and the digital circuit is customized after many times of frequency division.According to the on-chip integrated design requirements of the loop filter,a third-order passive loop filter is used to improve the phase margin between the resistor and the capacitor,and to suppress noise.The control module is added to define the minimum oscillation frequency range of the voltage controlled oscillator,the frequency hopping interval is determined according to the crystal reference frequency,and the result is saved to the frequency division frequency synthesizer,thereby completing the noise suppression frequency division synthesizer design.The experimental results show that the maximum frequency division efficiency of the synthesizer can reach 98%,which provides guarantee for the stable operation of the wireless satellite communication network system.