HANDBOOK OF MICROWAVE MEASUREMENTS COMPLETELY REVISED AND ENLARGED

摘要

The present unit of time, although defined. is not yet in use. The tune currently used is known as Universal Time (UT 2). R is based on the average sidereal rotational speed9 of the earth. During one year of observation this scale has been established by the Naval Observatory with an ac-curacy of about one in 109. This then sets the upper limit of accuracy obtainable in the measurement of high frequency oscillations. Accuracies of this order over intervals of a few days are being achieved by devices in the fields of communication and navigation and in certain types of scientific work.