Early atomic time scales consisted of quartz clocks with frequencies calibrated by a single atomic clock; the atomic clocks were not operated continuously.
ˈɜːli ɐtˈɑːmɪk tˈaɪm skˈeɪlz kənsˈɪstᵻd ʌv kwˈɔːɹts klˈɑːks wɪð fɹˈiːkwənsiz kˈælɪbɹˌeɪɾᵻd baɪ ɐ sˈɪŋɡəl ɐtˈɑːmɪk klˈɑːk; ðɪ ɐtˈɑːmɪk klˈɑːks wɜː nˌɑːt ˈɑːpɚɹˌeɪɾᵻd kəntˈɪnjuːəsli.