Multiplex chime generator

Abstract

A multiple pitch generator, in particular a chime generator, incorporated in an electronic organ of the multiplexed variety wherein the keyboard is scanned and a cyclically recurring serial data stream produced wherein keydown pulses appear in time slots corresponding to depressed keys of the keyboard. The chime generator produces a plurality of tones in response to the actuation of a single key of the solo keyboard, for example, wherein the tones are those necessary to closely simulate a chime sound. This is accomplished by sequentially passing the serial data stream containing the keydown pulse through a series of shift registers which insert in the data stream pulses in subsequent time slots corresponding to the next three lowest tones making up the chime. Since a true chime tone also includes a note five notes above the note played, the partial chime data stream is delayed five time slots and this data stream is summed with the initial data stream carrying the original keydown pulse in the time slot for the note played so as to position the additional pulse in its proper location ahead of the pulse for the actuated key. In order to then transpose the pulses in the data stream back to their proper positions for the key played, the latching pulse for the demultiplexer is delayed five time slots.