Digital spatial filter made from a SQUID array

Author

Bruno, A.C. ; Espy, M.A. ; Clark, D.D. ; Matlashov, A.N. ; Kraus, R.H., Jr.

Author_Institution

Dept. of Phys., Pontificia Univ. Catolica do Rio de Janeiro, Brazil

Volume

13

Issue

2

fYear

2003

fDate

6/1/2003 12:00:00 AM

Firstpage

779

Lastpage

782

Abstract

A linear array of high transition temperature SQUID, has been configured to work as digital spatial filters. The SQUID filters can be configured to obtain a desired spatial frequency response. We describe their design using a technique known as Frequency Sampling, which consists of specifying a discrete spatial frequency response for the SQUID array spatial filter. We then apply that sequence to the inverse Discrete Fourier Transform to get the spatial domain gain of each SQUID and the baseline. Several designs for spatial band-pass filters are proposed and checked experimentally. The results show that while keeping or even increasing the noise rejection obtained with conventional gradiometers, the SQUID filters preserve the original signal characteristics of the source.

Keywords

SQUID magnetometers; band-pass filters; digital filters; discrete Fourier transforms; high-temperature superconductors; spatial filters; superconducting arrays; superconducting device noise; superconducting filters; band-pass filter; digital spatial filter; frequency response; frequency sampling; high-T_c SQUID gradiometer; inverse discrete Fourier transform; linear array; noise rejection; Band pass filters; Coils; Digital filters; Discrete Fourier transforms; Frequency response; Magnetic field measurement; SQUIDs; Sampling methods; Spatial filters; Temperature;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2003.814041

Filename

1211719