GB1306848A - System for producing an electrical output signal in correspondence with a magnetic flux generating source - Google Patents

Abstract

1306848 Magnetic transducing systems SONY CORP 3 April 1970 [9 April 1969] 16097/70 Heading G5R A magnetic record having a track in which successive portions vary in lateral position and/or transverse magnetization direction is sensed by a flux-responsive head having at least two gaps 11, 12 parallel to the relative transducing direction and defined by opposed cores 5, 6 and a central core 2 carrying two coils 3, 4 spaced along the magnetic flux path produced in the core 2 during use. The core 2 is saturable and has two limbs 17, 18. The coils 3, 4 receive a 100 kHz supply to set up a bias field ha, hb which is unbalanced when influenced by a flux H produced by a record track transversely magnetized or laterally offset relative to the gaps. The fluxes H and ha, hb combine to vary the relative inductances of the coils 3, 4, possibly by saturation of one limb 18, and produce a differential output at terminals 28a, 28b. The record track may be produced by a movable head to produce e.g. a sinewave (Figs. 7, 8, not shown); by a twin-gap head producing oppositely directed magnetic fields (Fig. 9, not shown); or by a rubber magnet embedded in a helical or V-shaped groove in a drum (Figs. 14-17, not shown). A programmed series of signals may be produced by respective flux-responsive heads (1a ... 1n, Fig. 11, not shown) co-operating with tracks recorded by a manually indexable head (56) on a drum capable of manual rotation, the head (56) and drum having indexing scales (59, 63).