Title :
Experiments with numerically controlled atomic clocks
Author :
Eskelinen, P. ; Matola, M.
Author_Institution :
Lappeenranta Univ. of Technol., Finland
fDate :
10/1/1997 12:00:00 AM
Abstract :
Long term timing stability of present atomic clocks can be considerably improved by simple numerical algorithms which correct both the inherent frequency bias and the effects of supply voltage variations and outside temperature. Rubidium units are demonstrated to operate with less than 100 ns errors per week or any sensible longer interval corresponding to relative uncertainties of 10-13. Often a linear subtraction of frequency offset which can be realized by a microprocessor controlled digital delay line is sufficient. A cesium clock could be run at 10-15 level, but reliable and reasonable real-time measurement techniques do not yet exist
Keywords :
atomic clocks; computerised instrumentation; computerised numerical control; frequency dividers; jitter; phase locked oscillators; physical instrumentation control; voltage-controlled oscillators; Rb; TTL; VCO; apparent jitter; control software; frequency offset; inherent frequency bias; linear subtraction; long term timing stability; microprocessor controlled digital delay line; numerical algorithms; numerically controlled atomic clocks; outside temperature effects; programmable dividers; relative uncertainties; supply voltage variation effects; Atomic clocks; Delay lines; Digital control; Frequency; Measurement techniques; Microprocessors; Stability; Temperature sensors; Timing; Voltage;
Journal_Title :
Aerospace and Electronic Systems Magazine, IEEE
