Novus NR2310D-ROG, Руководство пользователя

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USERS GUIDE NR2310D-ROG
REVISION N
DATE
031121
Page #: 8 www.novuspower.com
The Time Base
The heart of the system is the reference. Novus offers OCXO and Rubidium
based references. Because of the relatively poor phase noise performance of
Rubidium, many of our customers select a Rubidium with a cleanup OCXO to
achieve high stability and low phase noise. Following is a plot of the phase
noise of a Rubidium reference and a Rubidium reference followed by a clean-
up OCXO.
Our Rubidium references offer a stability of < ±1 ppb/year compared to a
typical OCXO ±50 ppb/year. The Rubidium source consists of a
voltagecontrolled crystal oscillator (VCXO) which is locked to a highly stable
atomic transition in the ground state of the 85Rb isotope.
Novus uses several vendors for the OCXO. The OCXO selected is based on
required phase noise, stability, and cost. There are other secondary
considerations such as size, power consumption, etc.
In addition to standard OCXO devices, Novus also uses double oven OCXOs
as an alternative to a single oven OCXO. As can be imagined, a double oven