Percussion generator having snub control

Abstract

A percussion generator for an electronic musical instrument, such as an electronic organ, wherein the percussion generator is responsive to a time division multiplexed serial data stream produced by scanning the keys of the keyboard. A control pulse is produced each time that a new key on the keyboard is depressed, and this pulse, which has a duration equal to or greater than a plurality of scans of the keyboard, is employed to produce a burst of keydown pulses in the data stream. The percussion generator is responsive to the serial data stream and each of the aforementioned control pulses to produce keydown pulses in the appropriate time slots of the data stream in a plurality of successive sequences thereof and then terminate the keydown pulses even though the associated keys remain depressed. A recirculating register dynamically stores those keydown pulses which have been blocked from the demultiplexer as long as the associated keys remain depressed, so that as new keys are depressed and new control pulses generated, the tones associated with the previously depressed keys will not again sound. A snub control is provided so that, in the event a number of keys are pressed in rapid succession as in a glissando, their sustains will not overlap to the point that a blurring of the sound occurs. Snubbing is accomplished by causing the keyers to convert from a long to a short decay state during the occurrence of the aforementioned control pulses.