METHOD AND DEVICE FOR MEASURING MAGNETIC PROPERTIES OF SHEET MATERIAL Russian patent published in 2001 - IPC

FIELD: measuring magnetic properties of materials including bank notes. SUBSTANCE: method depends on conversion of sheet material magnetic characteristics into electric signals by means of measuring head followed by amplifying head-generated signals within definite range so that signals arriving from sheet material sections having low density of magnetic particles are amplified to greater extent than signals of higher amplitude coming from sheet material where density of magnetic particles is high. To this end signal range is divided into three sections where signals are amplified to respective constant value. Both extreme sections are equally amplified and intermediate section is amplified to higher degree. Prior to being amplified, electric signal should be better shifted through constant value so that zero point of signal range be in center of intermediate section. EFFECT: improved validity of signals both at low and high density of magnetic particles in sheet material. 22 cl, 18 dwg