The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 27, 2003
Filed:
Sep. 27, 2001
Ken Atsumi, Sapporo, JP;
Hideyuki Matsuura, Sapporo, JP;
Yoshifumi Nakajima, Sapporo, JP;
Yoshito Koyama, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A rubidium atom oscillator is not influenced by a circumference noise or the like, and is excellent in the short-term stability and the phase noise characteristic. A crystal oscillator oscillates a fixed frequency as an atomic resonance frequency. A direct digital synthesizer inputs an output of the crystal oscillator as a system clock and also inputs tuned data corresponding to an error signal generated according to a resonance frequency so as to carry out a variable control of an output frequency. A frequency synthesizer synthesizes and multiplies an output of the direct digital synthesizer and applies a phase modulation with a low-frequency signal. An atomic resonator inputs an output of the frequency synthesizer and detects an error signal with respect to a resonance frequency of rubidium atoms. A tuned-data generating circuit inputs the error signal from the atomic resonator so as to generate the tuned data corresponding to the error signal. The output frequency of the direct digital synthesizer is output from the rubidium atom oscillator.