| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent timing of output signals from varying rapidly on output switching at current and spare sides in redundant reference frequency generation systems. <P>SOLUTION: In a current-side reference frequency generator 51, a 1PPS signal generated by a GPS receiver 21a of an own apparatus is supplied to a PLL circuit 22a. In a spare-side reference frequency generator 52, a 1 Hz signal output from a PLL circuit 22a of the current-side reference frequency generator 51 is supplied to a PLL circuit 22b via a first transmission path. The 1 Hz signal input to the spare side is returned to the current side via a second transmission path having the amount of delay equal to that of the first transmission path. The current-side reference frequency generator 51 outputs a signal for correction, based on a time difference between a 1 Hz signal from the PLL circuit 22a of an own apparatus and a 1 Hz signal output to the spare side for returning. A spare-side reference frequency generator 52 adjusts the phase of the output signal of the PLL circuit 22b, based on the signal for correction. <P>COPYRIGHT: (C)2010,JPO&INPIT |
