| 摘要 |
PURPOSE:To record a magnetic signal exactly and magnetically and to detect a reference position exactly by opposing magneto-resistance elements to an index track on which constant wavelength signal parts and index parts are alternately continued. CONSTITUTION:The index track on which the constant wavelength signal parts 12 recording repeated magnetic signals having a fixed wavelength lambda and the index parts 13 recording magnetic signals having a fixed wavelength 2lambda are alternately and continuously formed is formed on a magnetic recording medium. The recording medium is a member for detecting a reference position and formed unitedly with a unit executing rotational or straight motion or the like and the index track is formed along its moving direction theta. The current paths MR1, MR2 of each magneto-resistance element 14 are constituted of ferromagnetic magneto-resistance elements, arranged with the pitch lambda in the moving direction theta and connected to both the terminals of a DC power supply 15 in series. An output terminal 16 is connected to the node of the current paths MR1, MR2. Since the constant wavelength signal parts 12 and the index parts 13 are alternately and continuously formed and signal detection can be exactly executed, the reference position can be exactly detected.
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