Small, low-noise oscillator may help in surveillance

Applications could include homeland security (e.g., surveillance of radio traffic for anomalous signals, or high-resolution digital imaging radar on unmanned aircraft), telecommunications (e.g., maintaining separation between frequencies in high-bandwidth networks), and perhaps even consumer devices (e.g., satellite television downlinks).

A patent was issued recently* for the NIST oscillator, which is about the size of a roll of 35 mm camera film. NIST researchers have built five prototypes on test fixtures, which offer several-orders-of-magnitude reductions in various types of self-generated signal interference, or noise, compared to typical commercial oscillators, resulting in improved frequency stability, according to David Howe, one of the inventors. In addition, the simple design reduces costs and improves reliability, while consuming less power than other oscillators of comparable signal purity. The small size could be an advantage on some surveillance platforms.

Microwave oscillators are used as reference or clock signals in many high-precision technologies. Through control of temperature and other variables, the oscillators produce a desired signal at one narrowly defined frequency while suppressing random, electronically induced "noise" generated by components. In the best microwave oscillators, the signal typically is amplified inside a metal cavity containing a solid insulating material that internally sustains microwaves and radio waves with minimal loss, especially at cryogenic temperatures, an expensive and complex design. By contrast, the NIST oscillator uses an ultra-stiff ceramic manifold that supports a single frequency with either a vacuum or air as the insulating medium.

The NIST device operates at high signal power (many watts) without the noise penalty found in the conventional design just described. The technique maintains such a stable frequency that it can overcome or compensate for self-generated noise produced by components such as amplifiers that sustain oscillation. NIST researchers continue to work on improvements, hoping to make the technology more tolerant of vibrations such as those from aircraft, field radars, and even sub-audible vibrations in buildings.

Source: NIST

‘High Q’ Nanowires May be Practical Oscillators
Nanowires grown at the National Institute of Standards and Technology (NIST) have a mechanical “quality factor” at least 10 times higher than reported values for other nanoscale devices such as carbon nanotubes, and comparable to that of commercial quartz crystals. Because a high Q factor indicates a capacity for stable vibrations, the nanowires might be used as oscillators in nano-electromechanical systems for future nano-sensors and communications devices.
'Radio Wave Cooling' Offers New Twist on Laser Cooling
Visible and ultraviolet laser light has been used for years to cool trapped atoms—and more recently larger objects—by reducing the extent of their thermal motion. Now, applying a different form of radiation for a similar purpose, physicists at the National Institute of Standards and Technology have used radio waves to dampen the motion of a miniature mechanical oscillator containing more than a quadrillion atoms, a cooling technique that may open a new window into the quantum world using smaller and simpler equipment.
Nano-Signals Get a Boost from Magnetic Spin Waves
Researchers have figured out how nanoscale microwave transmitters gain greater signal power than the sum of their parts—a finding that will help in the design of nano-oscillator arrays for possible use as transmitters and receivers in cell phones, radar systems, or computer chips.
Like fireflies and pendulum clocks, nano-oscillators synchronize their behavior
Like the flashing of fireflies and ticking of pendulum clocks, the signals emitted by multiple nanoscale oscillators can naturally synchronize under certain conditions, greatly amplifying their output power and stabilizing their signal pattern, according to scientists at the Commerce Department's National Institute of Standards and Technology.
Chip-scale atomic clock
The heart of a minuscule atomic clock---believed to be 100 times smaller than any other atomic clock---has been demonstrated by scientists at the Commerce Department's National Institute of Standards and Technology (NIST), opening the door to atomically precise timekeeping in portable, battery-powered devices for secure wireless communications, more precise navigation and other applications.
Scientists create first dense gas of ultracold 'polar' molecules
Scientists at JILA, a joint institute of the National Institute of Standards and Technology (NIST)and the University of Colorado at Boulder, have applied their expertise in ultracold atoms and lasers to produce the first high-density gas of ultracold molecules—two different atoms bonded together—that are both stable and capable of strong interactions.
New Technique Reveals Hidden Properties of Ultracold Atomic Gases
(PhysOrg.com) -- Physicists at JILA, a joint institute of the National Institute of Standards and Technology and the University of Colorado at Boulder, have demonstrated a powerful new technique that reveals hidden properties of ultracold atomic gases.
NIST assists in solar stake-out to improve space weather forecasts
The sun is about to undergo unremitting scrutiny. About six times each minute of every hour for at least five years, a soon-to-be launched NASA satellite will measure the sun's quirky—and sometimes stormy—output of extreme ultraviolet (EUV) light. To ensure that this solar stake-out yields data useful for understanding the weather in space and its earthly consequences, researchers at the National Institute of Standards and Technology are helping a NASA team prepare for annual rocket-borne check-ups of key instruments aboard the Solar Dynamics Observatory (SDO).

Small, low-noise oscillator may help in surveillance

Related stories:

News discussion: