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 ~5×10⁹ 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.

波形频率内容的实时跟踪对于检测和分析通讯，雷达，射电天文学，光谱学，传感等中的快速稀有事件至关重要。这需要一种能够提供实时频谱分析（RT-SA）的方法。连续且无间隙的高速波形。数字信号处理无法在低于GHz的频率范围内的瞬时频率带宽上执行RT-SA和/或跟踪频谱变化的速度低于几微秒。模拟色散引起的频率-时间映射可实现短隔离脉冲状信号的RT-SA，但无法扩展为连续波形。在这里，我们提出了一种通用模拟处理方法，用于对无间隙频谱图进行时间映射-动态频率分析的主要方法-输入任意波形，基于简单的采样和色散延迟方案。在实验中，以〜5×10的速度捕获GHz带宽微波信号的频谱图每秒^9次傅立叶变换，可实时截获纳秒级的频率瞬变。这种方法为动态频率分析和高速波形处理打开了新的机会。