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posted by martyb on Saturday May 23 2020, @06:01AM   Printer-friendly
from the it's-all-in-the-timing dept.

Arthur T Knackerbracket has found the following story:

Researchers at the National Institute of Standards and Technology (NIST) have used state-of-the-art atomic clocks, advanced light detectors, and a measurement tool called a frequency comb to boost the stability of microwave signals 100-fold. This marks a giant step toward better electronics to enable more accurate time dissemination, improved navigation, more reliable communications and higher-resolution imaging for radar and astronomy. Improving the microwave signal's consistency over a specific time period helps ensure reliable operation of a device or system.

[...] In their setup, the researchers used the "ticking" of two of NIST's ytterbium lattice clocks to generate light pulses, as well as frequency combs serving as gears to translate the higher-frequency optical pulses accurately into lower-frequency microwave signals. Advanced photodiodes converted light pulses into electrical currents, which in turn generated a 10 gigahertz (GHz, or a billion cycles per second) microwave signal that tracked the clocks' ticking exactly, with an error of just one part in a quintillion (1 followed by 18 zeros).This performance level is on par with that of both optical clocks and 100 times more stable than the best microwave sources.

[...] Optical waves have shorter, faster cycles than microwaves do, so they have different shapes. In converting stable optical waves to microwaves, the researchers tracked the phase—the exact timing of the waves—to ensure they were identical, and not shifted relative to one another. The experiment tracked phase changes with a resolution corresponding to just one millionth of a cycle.

"This is a field where just doubling microwave stability can take years or decades to achieve," group leader Chris Oates said. "A hundred times better is almost unfathomable."

[...] Ultra-stable electronic signals could support widespread applications, including future calibration of electronic clocks, such as electric devices powered by oscillating quartz crystals. This is an important consideration for the redefinition of the international time standard, the SI second, now based on the microwave frequencies absorbed by the cesium atoms in conventional clocks. In the coming years, the international scientific community is expected to select a new time standard based on optical frequencies that other atoms, such as ytterbium, absorb. Super-stable signals could also make wireless communications systems more reliable.

Journal Reference
Takuma Nakamura, Josue Davila-Rodriguez, Holly Leopardi, et al. Coherent optical clock down-conversion for microwave frequencies with 10−18 instability [$], Science (DOI: 10.1126/science.abb2473)


Original Submission

 
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  • (Score: 0) by Anonymous Coward on Saturday May 23 2020, @01:44PM

    by Anonymous Coward on Saturday May 23 2020, @01:44PM (#998138)

    >> Actually, would this improve GPS resolution?

    It would, except that 5G is going to interfere with GPS so you will only know where your 4kTV dinner is to the nearest 15km or so.