基于啁啾脉冲的宽带射频信道化接收技术研究

In military warfare, real-time reconnaissance and alerting of enemy situations forced high-performance electronic equipment to develop toward real-time broadband integration. It is required to reduce hardware resource redundancy while dynamically configuring hardware resources and maximizing information detection and processing capabilities. In the high-density and complex signal environments, the real-time reception of large instantaneous broadband RF signals has become a core enabling technology for many applications such as radar, electronic warfare or electromagnetic spectrum monitoring and communication navigation. Limited by the electronic bottleneck of microwave circuit system bandwidth, loss, spectrum leakage and sampling rate, traditional electronic technology can no longer meet the real-time receiving and processing requirements of broadband RF. The photonic based broadband RF channelization maps signals onto the optical carrier, and performs multi-narrowband parallel RF channelizing in the optical domain, which not only avoids the electronic bandwidth bottleneck, but also alleviates the subsequent sampling pressure. It has shown great application potential in many military microwave systems. This project carries out the expected research content of broadband RF channelization reception from the theoretical, simulation and experimental levels. We conduct research on the generation mechanism of chirped pulse, its mixing characteristics and the broadband RF channelization receiving mechanism based on it. The nonlinear distortion generation mechanism of the RF link and the nonlinear suppression method is proposed. The overall theoretical framework of photon-assisted broadband RF channelization reception is constructed. We proposed an RF channelization receiving scheme with a large instantaneous bandwidth, high resolution, large dynamic range and no need for fine spectrum to realize the integration problem of real-time refinement control, radio frequency detection and extraction of optical RF bandwidth. The project will eventually design the prototype at the same time. This project will verify the channelizing reception in the DC-18GHz bandwidth by experiment. The image rejection ratio will be greater than 25dB, and the system dynamic range greater than 90dB·Hz2/3, which provides a technical approach for the transmission, reception and processing of UWB signals in the future.

军事战争中，对敌情的实时侦察和警戒迫使高性能电子装备向着实时宽带一体化的趋势发展，要求在降低设备资源冗余度的同时，还可以动态配置硬件资源，将系统的信息探测处理能力发挥到最大。在高密集度和复杂度的信号环境下，无论是雷达、电子战还是电磁频谱监测、通信导航等众多应用需求的核心使能技术是大瞬时宽带射频信号的实时感知接收。受限于微波电路系统的带宽、损耗、频谱泄漏、采样率等诸多电子瓶颈，单一的电子技术已无法满足宽带射频的实时接收处理需求。基于微波光子学的射频信道化技术将射频信号搬移到光载波上，在光域上对宽带射频进行多窄带并行的信道化处理，不但避开了电子带宽瓶颈，而且缓解了后续采样压力，在众多军用微波系统中展现出巨大的应用潜力。本项目从理论、仿真、实验三个层面展开宽带射频信道化接收的预期研究内容，研究啁啾脉冲的产生机制以及啁啾脉冲的混频特性；研究基于啁啾脉冲的宽带射频信道化接收机制；研究光载射频链路的非线性失真产生机制并提出非线性抑制手段；构建光子辅助的宽带射频信道化接收的整体理论框架，提出一种具备大瞬时带宽、高分辨率、大动态范围且无需精细光谱控制的射频信道化接收方案，解决光载射频带宽的实时精细化控制、射频探测和提取的一体化问题。本项目通过实验验证最终将实现DC-18GHz带宽范围内射频信号的多信道接收，信道带内平坦度小于±1dB，镜像抑制比大于25dB，系统动态范围大于90dB·Hz2/3。为未来超宽带信号的传输、接收和处理提供可行性技术途径。

随着高性能电子装备向着实时宽带一体化的趋势发展，高性能军用射频系统要具备大瞬时侦察带宽、高分辨率、大动态范围以及能够对同时到达的多频点、多形式信号进行无畸变的侦察接收以及实时处理的能力。传统微波电路系统的诸多电子瓶颈越来越无法忽视，严重影响系统性能的提升。光子信道化接收技术是将宽带射频信号转换到光上进行多信道窄带分离，然后通过多本振对信道阵列混频、数字接收，从而实现宽谱信号实时全概率感知。.本项目针对目前信道化接收面临的问题和挑战，从宽带射频信号的实时高精度感知和链路非线性抑制两方面入手，探索新的信道化途径以实现超宽带、大动态范围、一体化的射频传输、处理和接收。本项目主要研究了啁啾脉冲的拍频特性，提出了两种基于啁啾脉冲的宽带射频信道化实时感知技术。一种是利用锁模激光器经过色散介质产生连续啁啾脉冲，实验中实现了DC-20GHz范围内200个信道划分。一种是基于Talbot效应，采用频移反馈激光器来提供啁啾脉冲，实验中产生了500MHz重频的离散啁啾脉冲，实现了500MHz接收范围内，5个带宽为100MHz的信道。同时针对非线性失真问题，研究了基于后数字处理的非线性失真补偿技术，并通过实验测试了该算法对非线性的抑制效果，有效提升了8dB的动态范围，三阶无杂散动态范围90 dB·Hz2/3以上，有效提升了个信道的动态范围。.本项目射频光子信道化接收从如何实现宽带、多制式射频信号的实时高精度接收以及如何抑制链路的各种非线性失真的两大研究方向入手，提出一种具备大瞬时侦察带宽、高分辨率、大动态范围宽带射频信道化接收方案，简化单一射频系统结构，降低系统成本，在宽带射频信号的信道化接受处理方面实现创新性突破，为电子对抗和雷达系统信号接收提供可行性技术途径。本课题工作涉及微波和光子学两个领域，研究内容对两个领域都具有重要的理论意义。