Real-time gap-free dynamic waveform spectral analysis with nanosecond resolutions through analog signal processing.
Nat Commun 2020;
11:3309. [PMID:
32620871 PMCID:
PMC7335167 DOI:
10.1038/s41467-020-17119-2]
[Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 06/09/2020] [Indexed: 11/23/2022] Open
Abstract
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.
Real-time dynamic Fourier analysis of high-speed signals is difficult using either digital or analog schemes. Here, the authors present a universal analog approach that can track the changing frequency spectrum of waveforms in a real-time fashion at the nanosecond level, continuously and with no gaps.
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