System for recording and automatic playback of a musical performance

Abstract

A musical keyboard instrument is disclosed for recording and storing a musical performance and then automatically playing back the performance. As is conventional, a keyboard having a plurality of keys is provided, along with musical tone generators that are associated with the keys. In accordance with the disclosed invention, means are provided for sensing, at a sensing time, those of the keys which are activated. A sequence of frames are generated, each frame including digital information representative of the keys that are activated at a given sensing time. The duration of each frame is a function of the relative locations of the keys activated at a given sensing time, and is therefore a duration which can vary from frame to frame. Each sensing time is determined by the previously completed frame, i.e., when a frame is complete, the statuses of the keys are again sensed so that the next frame can be generated. The sequences of frames are stored on magnetic tape. In a preferred form of the invention, the keys are divided into groups or 'ports', and the digital information for each frame includes identification of the ports that have one or more activated keys and identification of the individual keys that are activated within that port. The rationale of this coding scheme is particularly compatible with the physical characteristics and manual dexterity of a human playing a keyboard instrument. The digital information of each frame is encoded in frequency shift keyed form and frequency shift keyed signals are recorded by generating digitally synthesized sinusoidal signals for application to magnetic tape.