An automatic multichannel generalized system for frequency measurement

Abstract

Monitoring the performance of the primary frequency sources continuously through comparing it versus the transfer standards and the calibration of the secondary frequency sources periodically versus the primary ones are of the main missions assigned to any time and frequency laboratory either it was a calibration laboratory or a national metrological laboratory. An automatic Generalized System (GS) for monitoring/calibrating any frequency source that has a Relative Frequency Offset (RFO) greater than 1 × 10-14Hz/Hz has been built. This GS is able to use either of two measurement methods according to the accuracy of the frequency source being measured. A graphical programming language, which is Labview, was used in writing the software required for both hardware control and data logging. So, the software can be easily reconfigured for any upgrading plans. Also a flexible arrangement for the hardware setup was used such that two measurement systems are merged in one system. So, according to the user needs the right hardware setup can be chosen. The results obtained by this GS were verified through comparing them to those generated by one of the commercial turnkey solutions.

Keywords

• Generalized system
• time interval measurement
• phase comparison method
• direct frequency measurement method
• calibration system