| 摘要 |
PURPOSE:To realize an electronic camera provided with a center point detecting circuit of a PG yoke with simple constitution by providing a center detecting circuit receiving a detection signal of a PG coil of U-shaped form and extracting its peak and a turning phase control circuit receiving the said output so as to control the turning phase of a magnetic disc. CONSTITUTION:When a PG yoke 21 is moved in the direction of arrow as shown in Fig. A in a PG coil 31 and a magnetic flux entering a front stage (a) of the PG coil 31 is positive as shown in Fig. B, since a negative magnetic flux enters a post-stage (b), a waveform of an electromotive force E generated in the coil is as shown in Fig. C. That is, A generated electromotive force E is maximum when the center of the PG coil 31 and that of the PG yoke 21 are coincident, and the point being a maximum is the center point A of the PG yoke 21. When a center detection circuit 32 is constituted so as to pick up the peak of the generated electromotive force E, a signal representing the center point A of the PG yoke 21 is outputted from the output as shown in Fig. D. |
