Disciplined oscillator system with frequency control and accumulated time control

摘要

A disciplined oscillator system having a standard oscillator which is automatically corrected for both frequency errors and time error accumulation to a constant frequency signal which is derived from the WWVB carrier frequency and the WWVB TIME CODE to maintain overall frequency accuracy within one part in 109 notwithstanding oscillator aging and in spite of jitter and distortion due to propagation delays and noise which may cause loss of, or time jitter in, the WWVB signals. Frequency errors are detected through the use of a counter (24) having a measurement accuracy greater than one part in 1010. An error detector (26) derives correction signals by averaging a plurality of frequency variances obtained in successive measurement cycles. Timing errors are corrected by dividers (34, 40) controlled by a timing discriminator (36) which responds to timing variance between signals from the standard oscillator and from the WWVB reference which are phase locked to those TIME CODE signals which are substantially free of noise and jitter. The timing correction is inhibited after the standard oscillator is corrected. Frequency correction is applied continuously.