Measuring device for magnetic flux by means of a counter used digital - fll - system of the hysteresis - characteristic lines type for a squid

摘要

In a SQUID magnetometer, high resolution, a high slew rate, and a high dynamic range are achieved without using expensive circuit components having a large number of processing bits and enabling a high speed processing operation. A digital FLL circuit using a double counter system is provided. This circuit utilizes two or more counters, for example, a change range counter in a digital FLL for carrying out a processing operation at a high speed and a reproducing counter in a control/measuring computer. In addition, in the present invention, hysteresis characteristics having a 1PhiSUB0 /SUBpositive margin is used. That is, a change of a state of a magnetic flux is counted by means of a counter. At the time of this change, control is made so as to track a different channel between cases in which a magnetic flux increases and decreases, thereby stabilizing the control.