The Technique Development of OCXO in China

Wei Zhou, Jinglu Ma, Liansheng Jiang, Lina Bai, Zongqiang Xuan

Abstract:	Recent years the technique level of OCXOs are enhanced and the production and application quantities also increase obviously in China. Because of the request for higher specifications, lower cost, and more quantity to OCXOs, many technologies have to be developed to suit to the market. This paper introduces the main technique development of OCXOs in China including the results in production and research developed by factories, institutes and universities. Recent years the production of OCXOs becomes industrialized from conventional laboratory production. Some measurement techniques, production and aging equipment, test systems are developed. In the middle class OCXOs, to lower the cost vacuum packaged resistance weld crystals are used instead of cold weld crystals and glass packaged crystals, and 10-9/day aging can be obtained in big quantity production. The most precision crystals are AT cut. The glass packaged precision SC cut crystals have been made since more than twenty years ago, and now some companies are paying attention to build new production line to make cold weld SC cut crystals. For lower cost, smaller size, higher precision, wider temperature range, and mass production, some circuit design techniques were developed. One chip integrated OCXO circuits are used in middle class OCXOs. It includes oscillation, buffer amplifier, and the main temperature control circuit together. By using it OCXO with SC cut crystal 1 10 10- × /day aging and 9 3 10- ± × frequency – temperature performance can be obtained, and OCXO with AT cut crystal 9 3 10- × /day aging and 8 1 10- ± × frequency – temperature performance can be obtained. As a level representation, ultra-stable OCXO was also developed. Although BVA precision crystals cannot be made in China, through a long-period research the special quartz crystal frequency standard has been accomplished. It can show 5×10-12/day aging, 3×10-13/s stability and -148dB/Hz phase noise at 100 Hz offset.
Published in:	Proceedings of the 37th Annual Precise Time and Time Interval Systems and Applications Meeting August 29 - 31, 2005 Vancouver, Canada
Pages:	812 - 815
Cite this article:	Zhou, Wei, Ma, Jinglu, Jiang, Liansheng, Bai, Lina, Xuan, Zongqiang, "The Technique Development of OCXO in China," Proceedings of the 37th Annual Precise Time and Time Interval Systems and Applications Meeting, Vancouver, Canada, August 2005, pp. 812-815.
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