The core timing accuracy of our reference products makes them the ideal back-bone for timing critical measurements. The Time-Check measures Allan- Deviation on timing modules such as crystals, atomic sources against our ultra-low noise GNSS stabilized Rubidium reference. The NR9000 dual time base is an outstanding addition to any lab that must answer the question posed by an auditor _” How do you know your frequency reference is working properly?” With a completely redundant time base driving and internal frequency counter- you are measuring the reference performance continuously and can log that data via the internet for as long as required.