Mechanisch-elektrischer Wandler fuer die Erzeugung oder Abtastung einer rillenfoermigen Tonspur

摘要

974,506. Stereophonic transducers. TELEFUNKEN A.G. Feb. 2, 1961 [Feb. 2, 1960], No. 4059/61. Heading H4J. In a moving coil transducer two groups of coils are disposed symmetrically one on each side of a plane of symmetry perpendicular to a plane parallel to which vibratal movements are executed, and each group of coils comprises a principal coil and an auxiliary coil, the auxiliary coil of each group being connected with the principal coil of the other group. A stereophonic transducer for recording or reproducing gramophone records comprises a bellshaped member 1 (Fig. 2). supporting two saddle-shaped groups of coils 6A, 7A. The lower parts of the groups of coils are located within an annular air gap defined by an outer magnetic ring 13 (Fig. 5), and an inner magnetic core 11. A steady, radial magnetic field is provided across the air gap by a permanent magnet (not shown). The return connecting links of the coils are situated outside the air gap as shown, or pass through apertures in the member 1 and a diametral slot in the core 11. Inside member 1 are located, near a stylus support 2, feedback coils 8, 9 disposed in an annular gap defined by conical faces of an outer magnetic ring 12 and an inner magnetic core 10. The groups of coils 6A, 7A contain principal coils comprising two coils 6, 61 and 7, 71 (Fig. 4), and auxiliary coils 611, 711. Terminals 14, 15, 16 are associated with a left-hand signal channel and terminals 17, 18, 19 are associated with a right-hand signal channel. The feedback coils 8, 9 are provided with auxiliary coils 811, 911 (not.shown). Each auxiliary coil is placed on the side opposite to that on which its principal coil is located. A compensation coil 20, comprising coils 201 and 2011 (not shown) for the left and right-hand channels respectively, compensates for direct inductive coupling between coil groups 6A, 7A and feedback coils 8, 9. Member 1 is supported by two stirrups 3 secured by a flat spring 4 to a casing (not shown) and by a spring rod 5 to such casing. The mounting permits translatory movement of member 1 in the direction of its axis of symmetry and tilting movement about an axis near the spring 4.