Schematic of
single-event noise discrimination using the spectral cloning receiver.
Image credit:
Photonics Systems Group at UC San Diego.
(December 12, 2015) Electrical
engineers at the University of California, San Diego developed a receiver that
can detect a weak, fast, randomly occurring signal. The study, published in the
Dec. 11 issue of Science, lays the groundwork for a new class of highly
sensitive communication receivers and scientific instruments that can extract
faint, non-repetitive signals from noise. The advance has applications in
secure communication, electronic warfare, signal intelligence, remote sensing,
astronomy and spectroscopy.
The research is motivated by a long-standing need to capture
random, singly-occurring phenomena in nature and in communications. An example
of these includes the spontaneous decay of a molecule, an event that emits a
single noisy signal and therefore eludes detection by conventional methods.
Because a standard detector must repeat measurements of the event multiple
times to confirm its existence, it prevents, in principle, the capture of a random,
non-repetitive event. Another limitation is that the capture of a fast event
requires an equally fast detector.
To overcome the limitations of conventional detection
methods, UC San Diego researchers developed a spectral-cloning receiver that
works by replicating the received noisy signal to generate multiple spectral
(colored) copies, and then combines these copies to reveal the existence of the
signal within the noise.