Recording at least two signal channels in a common groove of a magnetic record carrier

Claim 1

A playback transducer device for a record carrier composed of at least a layer of magnetizable material in which the groove is formed, the groove being provided with a firsT undulation component constituting a spatial representation of a first carrier oscillation modulated by a first information signal and a second undulation component constituting a spatial representation of a second carrier oscillation, whose frequency is different from that of the first oscillation, modulated by a second information signal, comprising, in combination: pickup means arranged to extend into the groove and to be guided in contact with the groove walls as the carrier moves relative to said means, said means including an element made of a magnetic material of at least the paramagnetic type arranged to extend into the groove; sensing coil means inductively coupled with said element for providing a playback signal which varies in accordance with the magnetic flux variations produced in said element as said pickup means moves along the groove, which playback signal is a reproduction of the combined first and second modulated carrier oscillations; and electric filter means having an input connected to said sensing coil means for separating the first and second carrier oscillation components of said playback signal from one another, said filter means having two outputs at each of which a respective one of the playback signal components appears.