Automatic performance device with tempo follow-up function

Abstract

An automatic performance device is of a type in which the automatic performance is executed in accordance with musical data read out successively. It comprises a fast feed stop control circuit for advancing the progress of the automatic performance when an actual key depression timing is faster than an ideal key depression timing indicated by the read out musical data and for temporarily stopping the progress when the former delays behind the latter. Comparison between the actual key depression timing and the ideal key depression timing is made by comparing the content of a counter counting the tempo pulses which decides the tempo of the automatic performance with note-length information included in the musical data. It further comprises a tempo control circuit for changing a period of the tempo pulses based on a tempo of a performance made by the actual key depression. The detection of the tempo of the performance made by the actual key depression is based on a count value of a counter counting the clock pulses whose period varies with the note-length information and presence or absence of the actual key depression. In order to prevent the period of the tempo pulses from being changed by only one great deviation of the actual key depression timing, the count value is latched at every key depression, the newest count values are kept, and the tempo detection may be made in accordance with the average value of the newest count values.