【摘要】 本文阐述了为提高 ７７Ｋ超导量子干涉器（ｓｕｐｅｒｃｏｎｄｕｃｔｉｎｇ ｑｕａｎｔｕｍ ｉｎｔｅｒｆｅｒｅｎｃｅ ｄｅｖｉｃｅ简称ＳＱＵＩＤ）磁强计的磁场灵敏度，选择 ＳＱＵＩＤ载波电流频率在甚高频（简称 ＶＨＦ）频段的优点，并介绍了在 ＳＱＵＩＤ磁强计电路中采用频率合成及锁相技术来实现电路低噪声的工作原理，使磁测有比较高的信噪比。该磁强计在地球物理勘查的弱磁测量上将得到广泛的应用。更多还原

【Abstract】 This paper describes the advantages of selection of carrier current frequency for SQUID in very high frequency (VHF) bands in order to improve magnetic sensitivity of 77K superconducting quantum interference device (SQUID) magnetometer. An introduction to the working principle of composite frequency and frequency locked loop technology for realization circuit low--noise in SQUID magnetometer was presented. Thus it makes magnetic measurement have higher signal to noise ratio. The magnetometer can be extensively applied to electromagnetic survey in weak magnetic territories.更多还原