Multichannel pickup cartridge

Claim 1

Multichannel pickup cartridge adapted for simultaneous reproduction of multichannel signals from a recorded disk having a groove with two walls each modulated with respect to each other, comprising a cantilever arm carrying at one end thereof a stylus tip adapted to engage said groove, support means for the cantilever arm including a flexible suspension rod which is secured at its one end to the other end of the arm, extends away from said one end of the arm and anchored at its other end, under tension, to a cartridge body, said suspension rod defining a fulcrum for the cantilever arm at a point intermediate said other end of the arm and the anchorage, a damper of elastic material interposed between the other end of the cantilever arm and the support means, the damper being arranged in surrounding relationship with the suspension rod to thereby allow free movement of the cantilever arm about the fulcrum, a pair of axially magnetized magnet armatures mounted on the arm adjacent to the other end thereof so as to extend in a plane perpendicular to the axis of the arm and in a configuration corresponding to the respective modulated walls of the groove, each of said magnet armatures being arranged to lie in a plane which passes through a point nearest to the said fulcrum, said support means permitting the cantilever arm to transmit any oscillatory motion of the stylus tip said magnet armatures, and an electromagnetic generator with two pairs of axially spaced pole pieces, each pair of said pole pieces being arranged parallel to each magnet armature, said pole pieces forming a pair of independent magnetic gaps in which the magnet armatures are movable, respectively, to change independently magnetic flux in the respective gap in response to a motion of the stylus tip.