Readout circuit based on SQUID (Superconducting Quantum Interference Device) offset voltage reversal and method for inhibiting low-frequency noises

• Main Authors: ZHANG GUOFENG, RONG LIANGLIANG, XIE XIAOMING, DONG HUI, WANG YONGLIANG, WANG HUIWU, JIANG MIANHENG
• Format: Patent
• Language: Chinese; English
• Published: 25.04.2012
• Subjects: MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

The invention relates to a readout circuit based on SQUID (Superconducting Quantum Interference Device) offset voltage reversal and a method for inhibiting low-frequency noise. The readout circuit is characterized in that the offset reversal is realized by an offset reversal circuit in order to inhibit the generation of the low-frequency noises; and particularly, the readout circuit comprises an SBC(SQUID Boottrap Circuit)-structured SQUID low temperature part and an offset reversal readout circuit part. The main process of the method comprises the steps of: (1) regulating an input offset voltage in an amplifier; (2) loading an alternating-current square-wave offset voltage; (3) regulating a flux phase and compensating direct-current flux; (4) eliminating carrier waves; and (5) outputting in an integral feedback manner. The circuit related by the invention is simpler in structure and convenient for multi-channel integration, and can be widely applied to low-frequency measurements such as biomagnetism and geop