| 摘要 |
PURPOSE:To make it possible to increase a response speed by controlling the amplitude of an exciting signal according to the magnitude of the output of a displacement detecting method that detects the displacement of a magnetic head. CONSTITUTION:The tracking circuit is equipped with tape speed detecting circuit 12, head displacement detecting circuit 13, fly-back voltage generating circuit 14, integrator 15, oscillator 16, and error signal generating circuit 17. Magnetic head 5 is fitted at the tip of bimorph plate 7, which is fitted to the rotary drum at one end. Strain gauge 33, fitted on the surface of bimorph plate 7, detects the displacement of bimorph plate 7. Then, the frequency of an exciting signal is selected in the upper side band of the 1st resonance frequency of the electromagnetical converting element and according to the magnitude of the output of the displacing method, the amplitude of the exciting signal is controlled. |
