DocumentCode :
3795775
Title :
Impact of noise of linearity of SQUID feedback loops at high slew rate
Author :
H. Matz
Author_Institution :
Inst. fuer Elektrotech. Grundlagen der Inf., Karlsruhe Univ., Germany
Volume :
3
Issue :
3
fYear :
1993
Firstpage :
3054
Lastpage :
3058
Abstract :
A simplified digital DC SQUID (superconducting quantum interference device) system has been simulated to determine the degree of linearity in a digital flux-locked-loop (FLL), with 12-b D/A converter. The influence of comparator noise and quantization noise on the feedback loops corresponding to single- and two-pole integrators is investigated as a function of the normalized slew rate s/sub N/=s/s/sub max/. A simple approximation describing the attainable linearity up to a specific slew rate range is suggested. Measurements with and without a DC SQUID magnetometer in a digital FLL system yielded a satisfying agreement with simulations in the range 0.3
Keywords :
"Linearity","Feedback loop","Superconducting device noise","Frequency locked loops","Delay","Magnetic fields","Nonlinear distortion","Quantization","SQUID magnetometers","Magnetic field measurement"
Journal_Title :
IEEE Transactions on Applied Superconductivity
Publisher :
ieee
ISSN :
1051-8223
Type :
jour
DOI :
10.1109/77.234841
Filename :
234841
Link To Document :
