Note: Precise phase and frequency comparator based on direct phase-time measurements

0441135 - ÚFE 2015 RIV US eng J - Journal Article
Prochazka, I. - Pánek, Petr - Kodet, J.
Note: Precise phase and frequency comparator based on direct phase-time measurements.
Review of Scientific Instruments. Roč. 85, č. 12 (2014), s. 126110. ISSN 0034-6748. E-ISSN 1089-7623
Institutional support: RVO:67985882
Keywords : Clocks * Oscillators * Stability
Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Impact factor: 1.614, year: 2014

We are reporting on the design, performance, and application results of a phase and frequency comparator based on the direct phase-time measurement using a high performance event timer. The advantages of this approach are the simple implementation, a broad frequency range, and the clear interpretation of the measured results. Primarily we analyzed the background instability of the instrument in a common-clock test when a 200 MHz clock signal was connected to both inputs and the noise bandwidth was kept at 5 Hz by a preprocessing of the measured data. The results show that the Allan deviation of the background instability follows 4 x 10(-14)/tau for a wide range of averaging intervals from 0.1 s up to 10(4) s. These results are better than background instability of commercially available state-of-the-art instruments based on the phase difference multiplication. Finally the instrument was used for comparison of two H-masers. This experiment proofed that one of possible applications is a comparison of low-noise highly stable frequency sources and measurement of their frequency stability in the time-domain. The noise background of the instrument was negligible for averaging intervals longer than 100 ms
Permanent Link: http://hdl.handle.net/11104/0244189