Konatham Saikrishna Reddy, Maram Reza, Romero Cortés Luis, Chang Jun Ho, Rusch Leslie, LaRochelle Sophie, Guillet de Chatellus Hugues, Azaña José
Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications (INRS-EMT), 800 de la Gauchetière Ouest, Suite 6900, H5A 1K6, Montréal, Québec, Canada.
Fonex Data Systems Inc., Montréal, Québec, H4S 1P6, Canada.
Nat Commun. 2020 Jul 3;11(1):3309. doi: 10.1038/s41467-020-17119-2.
Real-time tracking of a waveform frequency content is essential for detection and analysis of fast rare events in communications, radar, radio astronomy, spectroscopy, sensing etc. This requires a method that can provide real-time spectrum analysis (RT-SA) of high-speed waveforms in a continuous and gap-free fashion. Digital signal processing is inefficient to perform RT-SA over instantaneous frequency bandwidths above the sub-GHz range and/or to track spectral changes faster than a few microseconds. Analog dispersion-induced frequency-to-time mapping enables RT-SA of short isolated pulse-like signals but cannot be extended to continuous waveforms. Here, we propose a universal analog processing approach for time-mapping a gap-free spectrogram -the prime method for dynamic frequency analysis- of an incoming arbitrary waveform, based on a simple sampling and dispersive delay scheme. In experiments, the spectrograms of GHz-bandwidth microwave signals are captured at a speed of ~5×10 Fourier transforms per second, allowing to intercept nanosecond-duration frequency transients in real time. This method opens new opportunities for dynamic frequency analysis and processing of high-speed waveforms.
实时跟踪波形频率成分对于通信、雷达、射电天文学、光谱学、传感等领域中快速罕见事件的检测和分析至关重要。这需要一种能够以连续且无间隙的方式对高速波形进行实时频谱分析（RT-SA）的方法。在高于亚吉赫兹范围的瞬时频率带宽上执行RT-SA，和/或跟踪比几微秒更快的频谱变化时，数字信号处理效率低下。模拟色散诱导的频率到时间映射能够对短的孤立脉冲状信号进行RT-SA，但无法扩展到连续波形。在此，我们基于一种简单的采样和色散延迟方案，提出了一种通用的模拟处理方法，用于对输入的任意波形进行无间隙频谱图的时间映射（动态频率分析的主要方法）。在实验中，以每秒约5×10次傅里叶变换的速度捕获了吉赫兹带宽微波信号的频谱图，从而能够实时截获纳秒持续时间的频率瞬变。该方法为高速波形的动态频率分析和处理开辟了新机遇。
