PULSE-OUTPUT TYPE SQUID

Japanese Patent JP3103866

B2

PURPOSE: To make it possible to discriminate a signal corresponding to noises from a signal corresponding to the change in external magnetic field and to prevent the decrease in sensitivity by imparting an offset to the magnetic field, providing two or more operating points on the curve of a threshold value, detecting the amount of the output pulses from the operating points, and performing operation processing.
CONSTITUTION: The bias AC from a bias current source 1 and the magnetic-field modulating wave from a magnetic-field modulating wave source 3 are applied on a SQUID 2, respectively. Generated pulses are amplified and discriminated. The pulses generated at operating points A and B are outputted into pulse generators 7 and 7'. Then, the pulses are made to pass integrators 8 and 8'. Voltages, which offset the outputs of the integrators 8 and 8', are imparted with variable voltage sources 9 and 9'. The voltage transition probability of the SQUID 2 corresponds to 1/4 of the bias frequency at each operating point. Adders 10, 10' and 12 are operated, and the outputs corresponding to the applied magnetic field are obtained. Then, the negative feedback is applied on a coil 4 through a switch 13, an integrator 14, an adder 15 and the like. The negative feedback is applied on the bias current by an adder 21' through a switch 20. Thus the noise component can be alleviated.

Yuji Iwata
Hisao Hayakawa
Yoshiaki Takai
Akira Fujimaki

JP33803691A

October 30, 2000

November 28, 1991

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Aisin Seiki Co., Ltd.
Nagoya University

G01R33/035; H01L39/22; (IPC1-7): G01R33/035

JP63149914A
JP63290979A
JP6421378A
JP6421379A
JP1307681A
JP2257076A
JP320684A
JP3197887A
JP3238378A

Hideaki Kuwahara

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