Abstract: A rotation detector of a motor according to an embodiment includes a first support and a second support, a pair of magnetic field forming units, at least one magnetic field detector, and a first magnetic member and a second magnetic member. The first magnetic member and the second magnetic member are each made of a magnetic material, cover longitudinal-direction both ends of the magnetic field detector facing the first support, respectively, and face each other with a gap interposed therebetween at a longitudinal-direction mid-portion of the magnetic field detector in the longitudinal direction. A dimension of each of the magnetic field forming units in a tangential direction of a circumference is larger than a dimension of the corresponding magnetic field forming unit in a radial direction and is larger than the distance of the gap.

Abstract: A rotation detector provided in a motor unit according to an embodiment includes a first support and a second support, a pair of magnetic field generator, at least one magnetic field detector, and a first magnetic member and a second magnetic member. The pair of magnetic field generator is provided on the first support in a manner facing the second support, and has opposite polarities. The magnetic field detector is formed by winding a coil around a magnetic element whose magnetized direction changes in the longitudinal direction, and is provided on the second support in such a manner that a longitudinal-direction side of the magnetic element faces the first support. Each of the first magnetic member and the second magnetic member is made of a magnetic material, and covers a longitudinal-direction end of the magnetic field detector facing the first support.

Abstract: An encoder signal processing device comprising an A/D converter converting a periodic analog signal, a memory storing position detection error information and a computing unit including a position data calculator which calculates position data from the digital data and an error correcting section which corrects the position data based on the position detection error information. The memory includes a first memory encoding position error data which is included in the position data by the use of the computing unit and storing a correction coefficient. A second memory decoding the position error data on the basis of the correction coefficient by the use of the computing unit and storing correction data for correcting the position data and error-containing position data generated on the basis of the encoded position error data.

Abstract: There is provided a position detecting signal with high accuracy in which a high order distortion error is corrected by the use of a simple processing circuit and method. Two measuring targets which are not illustrated are displaced at a constant velocity, and an analog signals Sa and Sb detected with displacement by the sensor signal detection section are converted into digital data by A/D converter (1). Then, position data ?0 is calculated by position data calculator (2). Next, the position data ?0 is encoded in an error-correction parameter acquiring section (3) and stored in a first memory (4). When a power source is applied, an error-containing position data preparing section (5) decodes by reading out a correction coefficient. An error-correction position table preparing section (6) prepares a decoded data and a correction table of ideal position data and recodes in a second memory (7).