Instantaneous frequency analysis of broadband LFM signals by photonics-assisted equivalent frequency sampling
We propose a photonics-assisted equivalent frequency sampling (EFS) method to analyze the instantaneous frequency of broadband linearly frequency modulated (LFM) microwave signals. The proposed EFS method is implemented by a photonic scanning receiver, which is operated with a frequency scanning rate slightly different from the repetition rate of the LFM signals. Compared with the broadband LFM signal analysis based on temporal sampling, the proposed method avoids the use of high-speed analog to digital converters, and the instantaneous frequency acquisition realized by frequency-to-time mapping is also simplified since real-time Fourier transformation is not required. Feasibility of the proposed method is verified through an experiment, in which frequency analysis of
基金项目：This work was supported by the National Natural Science Foundation of China (No. 61871214), the Natural Science Foundation of Jiangsu Province (No. BK20180066), and the Six Talent Peaks Project in Jiangsu Province (No. DZXX-005).
张方正：Key Laboratory of Radar Imaging and Microwave Photonics, Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
潘时龙：Key Laboratory of Radar Imaging and Microwave Photonics, Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
备注：This work was supported by the National Natural Science Foundation of China (No. 61871214), the Natural Science Foundation of Jiangsu Province (No. BK20180066), and the Six Talent Peaks Project in Jiangsu Province (No. DZXX-005).
【1】P. W. EastP. W. East. Fifty years of instantaneous frequency measurement. IET Radar Sonar Navigat. 6, (2012).
【2】F. Zhang, Q. Guo, Z. Wang, P. Zhou, G. Zhang, J. Sun and S. Pan. Photonics-based broadband radar for high-resolution and real-time inverse synthetic aperture imaging. Opt. Express. 25, (2017).
【3】F. Zhang, Q. Guo, Y. Zhang, Y. Yao, P. Zhou, D. Zhu and S. Pan. Photonics-based real-time and high-resolution ISAR imaging of non-cooperative target. Chin. Opt. Lett. 15, (2017).
【4】Y. Zhao, Y. H. Hu, and H. Wang. Enhanced random equivalent sampling based on compressed sensing. IEEE Trans. Instru. Meas. 61, (2012).
【5】X. Zou, W. Li, W. Pan, L. Yan and J. Yao. Photonic-assisted microwave channelizer with improved channel characteristics based on spectrum controlled stimulated Brillouin scattering. IEEE Trans. Microw. Theory Techn. 61, (2013).
【6】X. Zou, B. Lu, W. Pan, L. Yan, A. St?hr and J. Yao. Photonics for microwave measurements. Laser Photon. Rev. 10, (2016).
【7】H. Chi, X. H. Zou and J. P. Yao. An approach to the measurement of microwave frequency based on optical power monitoring. IEEE Photon. Technol. Lett. 20, (2008).
【8】T. A. Nguyen, E. H. W. Chan and R. A. Minasian. Instantaneous high-resolution multiple-frequency measurement system based on frequency-to-time mapping technique. Opt. Lett. 39, (2014).
【9】J. Shi, F. Zhang, D. Ben and S. Pan. Photonics-based broadband microwave instantaneous frequency measurement by frequency-to-phase-slope mapping. IEEE Trans. Microw. Theory Techn. 67, (2018).
【10】J. Shi, F. Zhang, X. Ye, Y. Yang, D. Ben and S. Pan. Photonics-based dual-functional system for simultaneous high-resolution radar imaging and fast frequency measurement. Opt. Lett. 44, (2019).
【11】J. Shi, F. Zhang, D. Ben and S. Pan. Photonic-assisted single system for microwave frequency and phase noise measurement. Chin. Opt. Lett. 18, (2020).
【12】W. Wang, R. Davis, T. Jung, R. Lodenkamper, L. Lembo, J. Brock and M. Wu. Characterization of a coherent optical RF channelizer based on a diffraction grating. IEEE Trans. Microw. Theory Tech. 49, (2001).
【13】J. Azana and L. R. Chen. Experimental demonstration of real-time Fourier transformation using linearly chirped fibre Bragg gratings. Electron. Lett. 35, (1999).
【14】H. Guillet de Chatellus, L. Romero Cortes and J. Azana. Optical real-time Fourier transformation with kilohertz resolutions. Optica. 3, (2016).
【15】J. Shi, F. Zhang, D. Ben and S. Pan. Simultaneous radar detection and frequency measurement by broadband microwave photonic processing. J. Lightwave Technol. 38, (2020).
【16】Y. Zhou, F. Zhang, J. Shi and S. Pan. Deep neural network-assisted high-accuracy microwave instantaneous frequency measurement with a photonic scanning receiver. Opt. Lett. 45, (2020).
Yuewen Zhou, Fangzheng Zhang, Shilong Pan, "Instantaneous frequency analysis of broadband LFM signals by photonics-assisted equivalent frequency sampling," Chinese Optics Letters 19(1), 013901 (2021)