Title :
A hybrid digital/analog servo for the NIST-7 frequency standard
Author :
Lowe, J.P. ; Lee, W.D. ; Walls, F.L. ; Drullinger, R.E.
Author_Institution :
Time & Frequency Div., Nat. Inst. of Stand. & Technol., Boulder, CO, USA
Abstract :
This paper describes a hybrid (analog/digital) approach to the servo electronics for the NIST-7 cesium-beam frequency standard. A digital servo system has been added to the existing analog system to enhance the capabilities of both servos. The analog servo allows a 5 MHz oscillator to be frequency locked directly to the atomic transition frequency. The digital servo reduces the frequency perturbations due to changes in the ambient magnetic field. Also, the existence of separate servo systems allows independent measurements of systematic errors. Design specifications are given and stability measurement results are presented
Keywords :
Zeeman effect; atomic beams; atomic clocks; caesium; digital control; frequency measurement; frequency stability; measurement standards; physical instrumentation control; servomechanisms; 5 MHz; 5 MHz oscillator; Cs; NIST-7 cesium-beam; NIST-7 frequency standard; atomic transition frequency; frequency locked oscillator; frequency standard; hybrid digital/analog servo; servo electronics; stability measurement; systematic errors; Clocks; Distortion measurement; Fluctuations; Frequency conversion; Frequency synthesizers; Magnetic field measurement; Magnetic shielding; Masers; Phase noise; Servomechanisms;
Conference_Titel :
Frequency Control Symposium, 1994. 48th., Proceedings of the 1994 IEEE International
Conference_Location :
Boston, MA
Print_ISBN :
0-7803-1945-1
DOI :
10.1109/FREQ.1994.398264
