A New Clock for Improving the Accuracy of Local Frequency and Time Standards

In line with the continually advancing ma turity of the electronics field as a whole, the portion of the field concerned with frequency control has made significant forward strides in recent years. As a result, high-precision fre quency standards employing quartz resonators presently achieve stabilities of a part in 109 per day or better, while atomic standards ex hibit accuracies of one or two parts in 1010. In order to operate a frequency standard at or near presently attainable accuracies, it is necessary to minimize the error that may occur in comparing the standard with the primary signal against which the standard will be cali brated. In precision work such comparison error should be minimized, not only so that the uncertainty in the standard will be re duced, but also so that the drift characteristic that all quartz standards exhibit to a greater or lesser degree can be determined and moni tored with maximum accuracy. As an indica tion of the degree to which it may be desirable to reduce comparison error, it should be noted that the accuracy of WWV carrier and time signals is currently 2 parts in 10'°.