Interesting Oscillator Developments at NIST
Scientists at the National Institute of Standards and Technology (NIST) have reported a breakthrough in their research in improving oscillators. Last week NIST said its researchers had developed a new microwave oscillator that "is smaller, simpler, and produces clearer signals at a single frequency than comparable devices." Oscillators are required for generating RF signals and, in all but the simplest applications, for receiving them.
The NIST oscillator is about the size of a 35mm slide film canister. NIST researchers have built five of them and they offer a reduction of several orders of magnitude in various types of self-generated interference.
Electronically induced noise is a major problem for oscillators. Conventional oscillators reduce noise by putting the oscillator inside a metal cavity containing a solid insulating material and using cryogenic cooling. However, this is an expensive and complex design. NIST said its oscillator uses an ultra-stiff ceramic manifold that supports a single frequency with either a vacuum or air as the insulating medium.
NIST said the device can operate at multi-watt power levels without the noise penalty of conventional designs. "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 are continuing to improve the design and hope to make the technology more tolerant of vibrations such as those present on aircraft, field radars and even the sub-sonic vibrations present in buildings.
For additional information, you may be able to pick up some hints from the paper that D.A. Howe, one of the researchers, presented with the NIST team at the 36th Annual Precise Time and Time Interval (PTTI) Meeting, "Ultra-Low-Noise Cavity-Stabilized Microwave Reference Oscillator Using an Air-Dielectric Resonator". While researching this article I found an interesting NIST Web site on oscillators, Properties of Oscillator Signals and Measurement Methods.
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