| 摘要 |
PURPOSE:To measure a tape remainder with a simple constitution by providing a rotor having phase information carriers with different prescribed pitches circularly on reel spindles and detecting both phase information carriers for passing through the intersection of a rotary locus by a single detecting means so as to calculate rotary speeds of both reel spindles. CONSTITUTION:On disks 7 and 8 fitted to the reel spindles 5a and 6a at tape winding and tape feed sides the phase information carriers such as slits 7a and 8a are provided along the circumference by the different prescribed pitches, and passing of these phase information carriers is detected by the single rotation detecting means composed of a phototransistor 10, a light emitting diode 9 installed on the intersection of the rotary locus of both phase information carriers, etc. The rotary speeds of both disks 7 and 8 are calculated from the output of time width available when one slit 7a among outputs of the rotation detecting means passes through and that when the other slit 8a does.
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