| 摘要 |
PURPOSE:To detect a position impossible to measure by correcting the same, by providing not only a plurality of detection sensors but also a peak holding circuit and a switching circuit. CONSTITUTION:The first and second magnetic field sensors 10, 11 are fixed at the symmetric positions spaced apart by 180 deg. from each other and a ring- shaped magnetic circuit is rotated in the direction shown by an arrow. When the position of the first sensor 10 present at the interface of the N- and S-poles of a permanent magnet 2 is set to 0 deg., the first sensor 10 has an insensitive band at 0 deg. and the second sensor 11 has an insensitive band at 180 deg.. The output terminals of two sensors 10, 11 are connected to a peak holding circuit 14 through a change-over switch 13 and a switch driving circuit 12 holds the output of the first sensor 10 as a sample when the output of the first sensor 10 is increasing and the output of the second sensor 11 becomes zero and adds the output of the second sensor 11 thereto to obtain the final output. The release of the holding of the peak and the change-over to the first sensor 10 are performed when the output of the first sensor 10 becomes zero.
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