宽带低杂散捷变频率源的设计

发布时间：2018-03-05 12:09

本文选题：锁相环　切入点：低杂散　出处：《东南大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着电子设备和通信系统的发展,频率源作为无线设备中的关键部件,其重要性越来越突出,也对频率源的带宽、杂散和相应速度提出了越来越高的要求。因此,频率合成技术也受到了越来越多的关注。在不同频率合成技术中,锁相频率合成可以很好的选择所需频率的信号,抑制杂散分量,并且锁相合成技术产生的谐波分量相对较少,不用大量使用滤波器滤除不需要的成分,对器件模块化、集成化、小型化十分有利。本文研制了基于锁相环的宽带低杂散捷变频率源,论文的主要工作是:1)分析频率源指标对通信系统性能的影响、确定了频率源的指标要求以及指标的主要优化方向。2)确定了宽带低杂散捷变频率源的总体方案。针对低杂散要求,采用双锁相环结构,第一级锁相环作为第二级锁相环的可变参考以抑制整数边界杂散;针对低相位噪声要求,采用低相位噪声参考、适当带宽的环路滤波器、优化的锁相环系统的电荷泵电流等配置参数、单独设计的供电;针对捷变要求,采用ADC采样校准、DAC预置VCO调谐电压的方式;针对宽带要求,采用了双平衡混频器混频的方式以扩展频段,采用滤波器组分频段滤波以保证在宽的频带内都有良好的谐波抑制,采用增益模块和数字步径衰减器分频段组合使用、以保证在宽的频带内都有高的输出功率动态范围。3)完成了宽带低杂散捷变频率源的原理图设计、性能仿真分析和PCB版图设计。讨论了电路设计中一些细节,给出了具体电路实现方式,设计了布板布局以及屏蔽结构来避免串扰杂散,评估了系统中的关键元件,使用相关软件完成了配套算法、编写了驱动代码。4)完成了宽带低杂散捷变频率源焊接、调试和测试工作,实现了系统的预订功能,实测技术指标满足要求。本文研制的宽带低杂散捷变频率源具有低成本、性价比高的特点,可作为信号源供高校学生或中小公司使用,也可以作为接收机、发射机的本振模块使用,具有广泛的应用前景。
[Abstract]:With the development of electronic equipment and communication system, frequency source, as the key component of wireless equipment, is becoming more and more important, and the bandwidth, stray and corresponding speed of frequency source are becoming more and more important. In the different frequency synthesis technology, the phase-locked frequency synthesis can select the signal of the desired frequency well, suppress the stray component, and the phase locked synthesis technology produces relatively few harmonic components. It is beneficial to modularize, integrate and miniaturize the device without using a large number of filters to filter unnecessary components. In this paper, a broadband low spurious variable frequency source based on PLL is developed. The main work of this paper is to analyze the influence of frequency source index on the performance of communication system, and to determine the index requirement of frequency source and the main optimization direction of frequency source. 2) to determine the overall scheme of broadband low spurious variable frequency source. Double phase locked loop (DPLL) structure is adopted, the first stage PLL is used as the variable reference of the second stage PLL to suppress the integer boundary stray, and the low phase noise reference filter with appropriate bandwidth is used for the low phase noise requirement. The configuration parameters of the optimized PLL system, such as charge pump current and so on, are separately designed to supply power; according to the requirements of agility, ADC sampling is used to calibrate the pre-set VCO tuning voltage of VCO; The dual balanced mixer mixer is used to expand the frequency band, the filter component band filter is adopted to ensure good harmonic suppression in a wide frequency band, and the gain module and digital path attenuator are used in combination. The schematic design, performance simulation analysis and PCB layout design of wideband low spurious agile frequency source are completed in order to ensure that there is a high output power dynamic range in wide band. Some details of circuit design are discussed. The realization of the circuit is given, the layout of the layout and the shielding structure are designed to avoid crosstalk and stray, the key components of the system are evaluated, and the relevant software is used to complete the matching algorithm. The driver code .4) has completed the welding, debugging and testing work of the broadband low stray agile frequency source, and realized the reservation function of the system. The measured technical specifications meet the requirements. The broadband low stray agile frequency source developed in this paper has low cost. The high performance-to-price ratio can be used as a signal source for college students or small and medium-sized companies, as well as as a receiver and transmitter local oscillator module, which has a wide application prospect.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN74;TN911.8

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