Electricity: measuring and testing – Magnetic – Magnetometers
Patent
1992-10-28
1995-04-11
Snow, Walter E.
Electricity: measuring and testing
Magnetic
Magnetometers
505846, G01R 33035
Patent
active
054062012
ABSTRACT:
A magnetic field detecting circuit has a relaxation oscillator SQUID. An oscillator circuit includes a coil and a resistor connected together in series. The oscillator circuit produces an output signal having an oscillating frequency dependent on an applied DC bias current. A magnetic field input circuit is magnetically coupled with the coil of the oscillator circuit for applying a magnetic field. A Josephson device is connected in parallel with the oscillator circuit for converting the magnetic field to an electric signal for varying the oscillating frequency dependent on the magnetic field. The magnetic field is detected by detecting a variation of the oscillating frequency. The sensitivity of the magnetic field detecting circuit is improved by magnetically coupling an RF-SQUID with an input coil to form the magnetic field input circuit. To provide a multi-channel magnetic field detecting circuit, a plurality of oscillator circuits are connected in series with each other, and a respective Josephson device is connected in parallel with each corresponding oscillator circuit. A plurality of magnetic field input circuits are each magnetically coupled with the coil of a respective oscillator circuit, and a plurality of control lines are magnetically coupled with each respective Josephson device to vary the critical current of the Josephson device to thereby control the oscillation frequency of each oscillator circuit.
REFERENCES:
patent: 4689559 (1987-08-01), Hastings et al.
patent: 5045788 (1991-09-01), Hayashi et al.
Applied Physics A. Solids and Surfaces, vol. A47, No. 3, Nov. 1988, Berlin, Germany, pp. 285-289, M. Muck et al., "A Frequency-Modulated Read-Out System for DC SQUIDS".
Japanese Journal of Applied Physics, vol. 28, No. 3, Mar. 1989, Tokyo, Japan pp. 456-458, H. Furukawa et al., "Multichannel DC SQUID System".
IEEE Transactions on Magnetics, vol. MAG 15, No. 1, Jan. 1978, New York, US, pp. 474-477, J. N. Hollenhorst et al., "High Sensitivity Microwave SQUID".
Patent Abstracts of Japan, vol. 9, No. 308 (P-410) (2031) Dec. 4, 1985.
IBM Technical Disclosure Bulletin, vol. 32, No. 12, May, 1990, New York, US, pp. 93-94, "High Magnetic Field Resolution RF SQUID".
Chiba Norio
Kiryu Shogo
Shimizu Nobuhiro
Adams Bruce L.
Agency Industrial Science and Technology
Seiko Instruments Inc.
Snow Walter E.
Wilks Van C.
LandOfFree
Magnetic field detecting circuit having a relaxation oscillator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Magnetic field detecting circuit having a relaxation oscillator , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic field detecting circuit having a relaxation oscillator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1541141