The utility model provides a punctual system master clock signal keeps ware, data acquisition unit with activestandby clock correction, master clock and third party's clock clock correction, be equipped with the clock and compare data transmission to data processing unit with third party's clock clock correction and punctual clock ensemble, data processing element calculate obtains the master clock volume of controlling and is equipped with the clock volume of controlling, detects the atomic clock abnormal conditions simultaneously, control is sent the master clock volume of controlling and is equipped with the clock volume of controlling to the phase place fine setting appearance of activestandby clock with display element, sends the hold instruction to the phase -locked loop circuit during master clock trouble to switch to being equipped with the clock, power combiner has input behind master clock and the output signal parallel connection that is equipped with the clock sample voltage storage control function's phase -locked loop to regard the output of phase -locked loop as output signal. The utility model discloses can real -time detection master clock trouble, realize the continuity and the uniformity of high accuracy master clock time frequency signal's output.