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Abstract
Recently established time and frequency standard system in Korea and its maintenance are described. For international synchronization, we primarily rely upon the annual visit of USNO portable clock. LORAN-C, VLF, LF and HF are also received as back-up sources.
We have at present three commercial caesium-beam frequency standards: two are installed at K-SRI and the third one at KBS (Korean Broadcasting System) in Seoul. The time announcement which is nationally broadcasted through the KBS network is now derived from this caesium beam standard. The announcement consists of four tones: one on-hour tone of 880 Hz preceded by three forecast tones of 440 Hz starting at 3 seconds to the hour. The time tones are monitored at K-SRI.
We developed a special clock with an AM/FM receiver which can utilize the tones for automatic reset. This clock will be described briefly in this paper. We will also discuss the possibility of using the instrument for frequency calibration.