稳定频率源与时频传输技术研究

发布时间：2018-03-31 11:15

本文选题：光电振荡器　切入点：频率传输　出处：《北京邮电大学》2015年博士论文

【摘要】：高精度航天测控和雷达探测应用的发展既对高频、高性能频率源提出了新的需求,又面临宽带频率信号高稳定传递和时间信号高精度同步的挑战。研究高稳定光电振荡器(OEO)的频率漂移补偿技术和基于光纤的高精度时间、频率传递理论与技术,具有重要的科学价值和应用前景。为满足高频、高性能频率源的需求,论文提出了一种面向高稳定可调谐OEO的频率漂移补偿技术,首次实现了宽带连续可调谐OEO的主动频率漂移补偿。通过注入一个低频外部参考信号提取OEO环路时延抖动信息,并反馈控制OEO光源的波长,对时延抖动进行补偿,实现OEO的稳定。该技术具有补偿范围大的特点,且与OEO的工作频率无关,能够稳定宽带可调谐OEO。实验中,输出稳定信号的范围为2.4GHz到10GHz。OEO工作在2.4GHz振荡频率时,1000s稳定度在补偿后达到了5×10-9,比不补偿时改善超过两个数量级,补偿前后,在偏离载波10kHz处的相位噪声都低于-120dBc/Hz。同时保证了OEO的短期稳定性和长期稳定性。为解决传统窄带频率传输方案中时延补偿范围不足和覆盖范围不足的缺点,提出了两种解决方案,包括a)大动态补偿范围的稳定频率传输技术,使用相位共轭补偿方法,不需要传统可调器件,突破了传统补偿方式的补偿范围限制,实现了2.8GHz频率信号从远端天线至中心处理站10km光纤链路的超大补偿范围的稳定传输；b)多点传输的稳定频率传输技术,实现了“点到多点”的从中心处理站到各远端天线的稳定频率传输,在30km光纤链路上任一点恢复出的信号相位抖动小于2ps,极大的扩展了光纤频率传输的覆盖范围,有效地降低系统的复杂性和成本。为了解决未来分布式天线阵列对系统提出的宽带信号传输和时频同步问题,提出了两种解决方案,包括a)宽带的稳定频率传输技术,利用光纤对不同波长光载波具有不同色散的原理,通过中心处理站传输一个校准射频信号以补偿光纤链路的相位抖动,在一套传输系统中实现了1.205GHz和2.46GHz的多个频率信号从远端天线至中心处理站10km光纤链路的稳定传输,极大的简化了天线的功能；b)时间频率同时传输技术,为克服时间信号高精度同步的挑战,论文提出了时间信号和频率信号采用同一光载波传输的方案,首次实现了时间同步和频率标准传递的协同控制,充分利用频率传输时延抖动小的优势,提高时钟同步的精度,实现高稳定时间频率信号的同时传输。将时间信号调制到2GHz频率信号上与1.21GHz频率参考信号同时传输,在50km的光纤链路中时间信号传输的时间偏差在1s平均时达到了40ps,在1000s平均时减小至2.3ps。频率参考信号的1s稳定度达到了2.8×10-13,1000s的稳定度达到了2×10-15。同时实现了时间和频率信号的光纤稳定传输。
[Abstract]:The development of high precision space TT & C and radar detection applications has put forward new requirements for high frequency and high performance frequency sources. It also faces the challenge of high stable transmission of wideband frequency signal and high precision synchronization of time signal. This paper studies the frequency drift compensation technology of high stability optoelectronic oscillator (OEO) and the theory and technology of high precision time and frequency transfer based on optical fiber. In order to meet the needs of high frequency and high performance frequency sources, a frequency drift compensation technique for high stable tunable OEO is proposed. The active frequency drift compensation of broadband continuously tunable OEO is realized for the first time. The delay jitter information of OEO loop is extracted by injecting a low frequency external reference signal, and the wavelength of OEO light source is controlled by feedback to compensate the delay jitter. This technique has the characteristics of wide compensation range, independent of the working frequency of OEO, and can stabilize the broadband tunable OEO. The output stability signal ranges from 2.4GHz to 10GHz.OEO at the 2.4GHz oscillation frequency, and the stability of 1000s reaches 5 脳 10 ~ (-9) after compensation, which is more than two orders of magnitude better than that without compensation, before and after compensation. The phase noise at deviation from carrier 10kHz is lower than -120dBc / Hz. at the same time, the short and long term stability of OEO is guaranteed. In order to solve the shortcomings of delay compensation range and coverage in traditional narrowband frequency transmission scheme, Two solutions are proposed, including the stable frequency transmission technology with a large dynamic compensation range. The phase conjugation compensation method is used without the need of traditional tunable devices, which breaks through the limitation of the compensation range of the traditional compensation method. The stable frequency transmission technology of 2.8GHz frequency signal from remote antenna to 10km fiber link of central processing station is realized. The stable frequency transmission from the central processing station to the remote antenna is realized. The signal phase jitter recovered at any point in the 30km fiber link is less than 2 pss. which greatly expands the coverage of the fiber frequency transmission. In order to solve the problem of wideband signal transmission and time-frequency synchronization proposed by distributed antenna array in the future, two solutions are proposed, including a) broadband stable frequency transmission technology. Based on the principle that the fiber has different dispersion to different wavelength optical carriers, a calibrated RF signal is transmitted through the central processing station to compensate for the phase jitter in the fiber link. In a transmission system, the stable transmission of multiple frequency signals of 1.205GHz and 2.46GHz from the remote antenna to the central processing station 10km fiber link is realized, which greatly simplifies the technology of simultaneous time and frequency transmission of the antenna. In order to overcome the challenge of high precision time signal synchronization, a scheme of time signal and frequency signal transmission using the same optical carrier is proposed in this paper, and the cooperative control of time synchronization and frequency standard transmission is realized for the first time. In order to improve the precision of clock synchronization and realize the simultaneous transmission of high stable time-frequency signal, the time signal is modulated to the 2GHz frequency signal and transmitted simultaneously with the 1.21GHz frequency reference signal. In the optical fiber link of 50km, the time deviation of time signal transmission reaches 40 psat 1s average, and decreases to 2.3psat 1000s average. The 1s stability of frequency reference signal reaches 2.8 脳 10-131000s and 2 脳 10-15s. The time and frequency are realized at the same time. The signal is transmitted steadily by optical fiber.
【学位授予单位】：北京邮电大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN753.2

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