The Hewlett-Packard Model 5061A Cesium Beam Frequency Standard is a compact, self-contained frequency standard which uses a cesium beam tube resonator to stabilize the output frequency of a quartz crystal oscillator. Solid-state components and the closed-loop, self-checking control circuit provide an accuracy of ± 1 part in lO00000000000. Output frequencies are 5 MHz, 1 MHz, 100 kHz, and 100 kHz signal for applications such as use with a HP Model 115BR/CR Frequency Divider and Digital Clock. Atomic or UT2 (UTC) time reference is available with the 5061A. The time scale is easily changed by setting a four thumbwheel switch and a slide switch.