| 摘要 |
PURPOSE:To control the position of a piar of rotary heads for a rotary erasing head so as to set it at a correct position, by reproducing a pilot signal recorded by the rotary erasing head with a rotary head on one side, and making the lower edge of a track formed with an erasing head coincide with that of the rotary head by using a reproduced output. CONSTITUTION:The heights of heads H1 and H2 can be adjusted by bimorph plates 25 and 26. The pilot signal from an oscillator 11 is recorded with the rotary erasing head FE through a pulse from a control circuit 12 and a gate circuit 10. The signal is reproduced with the head H1, and is sent to a relative height detection circuit 19. The circuit 19 compares the signal with the signal from the circuit 12, and sends the signal by which a difference between the lower edge of the head H1 and the edge of the pilot signal goes to zero, to an adder circuit 21, and adds it on the lower edge detecting signal of the head H1 from a circuit 20, then, controls the bimorph plate 25 via a driver 23.
|
