| 摘要 |
PURPOSE:To suppress a daily variation and a jitter which occur due to the propagation of a long wave standard radio wave, and also, to prevent the interruption of a reference frequency signal to be caused by the deterioration of radio wave propagation, by interlocking a loose coupling oscillator to a phase tracking type receiver of the long wave standard radio wave. CONSTITUTION:A demodulation signal output 1a from a long wave standard radio wave receiver 1 having an antenna 2, and the output of a voltage control type crystal oscillator 28 are inputted to a digital phase comparator 23 through frequency dividers 21, 22, respectively. A digital filter 25 average and proportionally integrates a phase difference signal 23a, and controls the voltage controlled type crystal oscillator 28, and a loose coupling oscillation output 29 is inputted to an external reference signal input terminal 1b of the long wave standard radio wave receiver 1. Also, a frequency value of the phase difference signal 23a to an input radio wave is stored in a microprocessor 26, and when the demodulation signal output is not generated due to the deterioration of radio wave propagation or the stop wave, the voltage controlled crystal oscillator 28 is operated in a free-running state by using the stored frequency as an initial value. |
