| 摘要 |
<p>PURPOSE:To reduce effects of background light on the result of measurement and thereby to conduct reliable measurements by a method wherein a signal component of the same angular frequency with that of an alternating-current magnetic field acting on a Faraday element is taken out of an output signal of a light-sensing unit and the relative ratio between them is determined. CONSTITUTION:An identical angular frequency component detector 30 is constructed of an electric filter, a phase detecting circuit, etc. and supplies a divider 34 with a signal component Eomega of the same angular frequency omega with that of an alternating-current magnetic field H to be measured, on the basis of an electric signal E. The divider 34 divides a signal component E2omega from a double angular frequency component detector 32 by the signal component Eomega from the identical angular frequency component detector 30 and outputs a division signal ET (= E2omega/Eomega) thus obtained. Accordingly, effects of background light on the result of measurement is greatly reduced, and reliable measurements can be performed constantly.</p> |
