Citation
Abstract
A new frequency standard has been demonstrated with the aid of a double phaselocked loop (PLL) receiver. A superconducting cavity-maser oscillator (SCMQ) and a hydrogen maser are combined to show the medium-term performance of the hydrogen maser together with improved short-term performance made possible by the SCMO. The receiver, which generates a 100-MHz signal with reduced noise, is phase-locked to (and may be used in place of) the 100-MHz hydrogen-maser output. The maser signal, 2.69xxx-GHz SCMO output, and a 100-MHz quartzcrystal oscillator are optimally combined by the receiver. A measured two-source fractional frequency stability of 2 x 10-14 was obtained for a meastiring time of rT = 1 sec, and 1 x 10715 at r = 1,000 sec. The 1I-sec value is approximately 10 times lower than that for hydrogen masers, while the 1,000-sec value is identical to hydrogen-maser performance. The design is based on phase-noise models for the hydrogen maser, the SCMO, and quartz-crystal oscillators for offset frequencies down to 1 x 107-® Hz.
Details
- Volume
- 42-107
- Published
- November 15, 1991
- Pages
- 1–11
- File Size
- 390.8 KB