ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
We present a comparative study of existing low-frequency noise reduction techniques for dc superconducting quantum interference devices (SQUIDS). These methods are essential to applications involving high-Tc SQUIDS because they dramatically reduce the 1/f noise to useful low-frequency noise levels. We propose a formal presentation of the problem and explain mathematically the working principles of these noise reductions methods, particularly for fluctuations arising from the critical current of the junctions. An increase in the white noise level is generally observed when a sinusoidal lock-in detection is used for these methods and we give here a mathematical explanation for this peculiar effect. Finally, noise measurements made on high-Tc grain boundary dc SQUIDS are presented; the experimental results are in close agreement with theory. © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1146812
