On the basis of frequency analysis of magnetooptic signals, a new meth
od to measure microsized spots is described. The method not only has h
igh measuring accuracy and the ability of real-time measurement, but i
t is also simple. In this paper, several mathematical models to examin
e measuring error are developed. By theoretical analysis, for detectio
n frequency of 0.6 MHz and spot radius of 0.5-mu-m, the relative error
is within 0.032%.