引言用“直流置换法”确定广播录音磁带的基准磁平,其优点之一是直流带磁通的测量在理论上和实践上都很成熟。而测量直流带磁通大都采用经典的冲击检流计法,虽然它的线路简单易行,但就冲击检流计本身,它的磁通灵敏度太低了。因为据IEC标准规定,广播录音磁带的基准磁 INTRODUCTION One of the advantages of using dc-displacement method to determine the reference magnetic level of broadcast tapes is that the DC flux measurement is mature both theoretically and practically. The measurement of the DC flux with the majority of the classic impact galvanometer method, although its simple line, but the impact galvanometer itself, its flux sensitivity is too low. Because according to the IEC standard, the reference magnetic tape of a broadcast recording tape