Electronic musical instrument having legato effect

Abstract

An electronic musical instrument is of a type wherein an envelope to be imparted to a musical tone is stored in a memory as its sampled values and sequentially read out to constitute an envelope shape. A key depression causes the read-out of the memory. The instrument is improved to provide a rich sound effect of legato performance by successively and smoothly shifting the tone of the former key to that of the latter key while maintaining a predetermined constant tone volume. This legato effect can be carried out by successively maintaining the sustain level of the musical tone envelope from the tone of the former key shifted to the latter key. The musical tone envelope is read from the envelope memory by an address which is shifted by a clock pulse. After the key has been depressed, the address continues to be shifted by the clock pulse until it has reached a predetermined value, whereupon the supply of the clock pulse is prohibited to cause the envelope memory to produce a sustain level corresponding to the address. Thereafter, this address is held to maintain the sustain level of tones of subsequently depressed keys regardless of whether the initially depressed key ash been released or not, or whether the subsequently depressed keys are being depressed or have been released. An embodiment in which the legato effect is produced with respect to a pedal keyboard is described.