| 摘要 |
PROBLEM TO BE SOLVED: To provide a three-band position transducer (magnetic encoder) having a small size and improved accuracy. SOLUTION: The three-band position transducer is constituted of coils 10, 12 and 14 each having wavelengthsλ1,λ2, andλ3 all arranged on the scale side, and transmission coils 20, 22 and 24, and reception coils 30, 32, and 34 all arranged in the read head (grid) side. The reception coils 30, 32, and 34 are placed oppositely to the transmission coils 10, 12 and 13. If the transmission coil 20 is driven, the transmission coils 12 and 14 function as the reception coil, generating a directive current. An electromagnetic field is generated from the transmission coil 10 and detected at the reception coil 30. Under a condition ofλ2<λ3<λ1,λ1 is prevented from being incomplete form a lack of some pulses. Three wavelengths are synthesized using a phase difference betweenλ1 andλ2, and a phase difference betweenλ1 andλ3. COPYRIGHT: (C)2003,JPO
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