| 摘要 |
<p>PURPOSE:To remarkably reduce RF noise from a high-sensitivity digital SQUID fluxmeter used for measuring very small magnetic fluxes and, at the same time, to improve the S/N of the fluxmeter. CONSTITUTION:A magnetic flux transformer 1 constitutes a SQUID fluxmeter provided with a magnetic flux sensor using an SQUID, current source which supplies a bias current to the SQUID, and feedback circuit which linearizes the output of the SQUID and incorporates a detection circuit 3 which catches a very small magnetic field and input coil 2 which transmits the very small magnetic field to the SQUID. In addition, the transformer 1 has an earth point at the point where the inductance of the coil 2 can be divided into two equal parts.</p> |
