JPS5489612A - Magnetic recorder and reproducer - Google Patents

Abstract

PURPOSE:To reduce drum diameter and achieve the miniaturization of the apparatus by specifying the winding angle of a recording medium on a rotary drum and the head disposition angles of 2 sets 4 pieces at specific values and operating the heads through changing over. CONSTITUTION:The period when signal currents are supplied to magnetic heads 1 thru 4 of 2 sets 4 pieces twice those of ordinary ones disposed adjacently at an angle 90 deg. is so defined that during the time when the signal current is supplied to a certain head in this period no signal currents are supplied to other head except at the overlapping if the portion where a magnetic tape (t) is wound to a rotary drum (d) is let to be 270 deg. + alpha deg.. As a result, if the diameter of the drum (d) is let to be D1, the diameter of ordinary one to be D0 and track length to be L, these become L=1/2piD0=3/4piD, D=2/3D0. The number of revolutions f of the drum becomes T=theta/360t, f=1/T 360/270 if the time of 1 field is let to be (t) and the time when the drum rotates by the angle theta to be T, thus as compared to ordinary ones on particularly high speeds are required. Thereby, the rotary drum diameter may be reduced and the apparatus miniaturized.