Rotating coil method for the measurement of deflecting magnetic fields in cathode ray tube

Abstract

A fast and reliable method for measuring and analyzing the magnetic fields of the deflecting yoke (DY) in a cathode ray tube (CRT) is presented. The measurement is based on the rotating coil method and uses a set of coils to measure the axial distribution of DY magnetic fields. The output voltage of each coil is integrated and then Fourier transformed to obtain the multipole error components. The magnetic vector and scalar potentials are calculated from the measured data using a theory of complex magnetic potential. The results of the rotating coil measurement are compared with those of the conventional Hall probe mapping method. Both results agree reasonably well, indicating that the rotating coil method can be applied for efficient measurement of a complicated DY magnetic field; the required time for measurement is very short and on-line analysis of multipole error fields is possible. (C) 2000 Elsevier Science B.V. All rights reserved.