FLUX-LOCKED LOOP CIRCUIT, FLUX-LOCKED LOOP METHOD, AND SQUID MEASURING APPARATUS FOR ENLARGING OPERATIONAL RANGE WITHOUT USING ADDITIONAL CURRENT SOURCE

摘要

PURPOSE: A flux-locked loop circuit, a flux-locked loop method, and a squid measuring apparatus are provided to form always a same state of a FLL(Flux Locked Loop) by resetting an integer at a FLL point apart from a start FLL point. ;CONSTITUTION: A flux-locked loop circuit(160) comprises a preamplification unit, an integration unit, an operating range enlargement unit, and a feedback circuit unit. The preamplification unit amplifies an output signal of SQUID. The integration unit integrates an output signal of the preamplification unit and outputs the integrated signal. The operating range enlargement unit initializes the integration unit by comparing the output signal of the integration unit with a positive or a negative reference reset voltage. The feedback circuit unit provided the current to remove a difference between the external flux and the flux corresponding to the multiple of the integer of the reset voltage according to the output signal of the integration unit.;COPYRIGHT KIPO 2011