Abstract: A magnetic recording medium, such as magnetic tape, a record carrier, or the like, has an audio track recorded thereon; immediately adjacent the audio track is a control track having major low frequency components. To reduce cross talk between the control track and the audio track, the control track is recorded in form of pulse pairs, in which the pulses are essentially square wave pulses and located immediately adjacent each other and have respective opposite polarity, the pulse pairs being spaced from each other by pulse gaps which are long with respect to the duration of individual pulses of the pair; the particular pulse pair arrangement results in a Fourier frequency distribution which has substantial amplitude level in higher frequency ranges which, due to the characteristics of the recording medium, are less subject to cross talk.

Abstract: A slip ring device including a metallic sleeve inside an insulated rotor assembly consisting of conductive rings. A friction fit between the metallic sleeve and metallic supporting shaft drilled in such a manner as to accommodate electrical leads routed out through the center of the shaft. A metallic sleeve supporting the insulated conductive rings positioned by a step in the supporting shaft diameter and not cemented to the supporting shaft so that it can easily be replaced without requiring the main rotor support shaft to be replaced.