Plural manual organ having transposer

Abstract

An electronic organ, particularly of the institutional type employing classical voicing, having Swell and Great manuals as well as a full pedalboard wherein the manuals and pedalboard are multiplexed simultaneously to produce a plurality of synchronized serial data streams. Intermanual coupling is accomplished by connecting the data stream from one manual to the footage generation circuit of another manual, and footages are generated for each manual by utilizing tapped shift registers introducing controlled amounts of delay of the keyboard data before demultiplexing thereof. There is a bank of multiplexers for each voice, such as flutes, principals, complex and percussion, which receive the serial data streams from one or more of the footage generators. The demultiplexer-keyers are supplied with tones and function to demultiplex the serial data streams and provide tones selected in accordance with the keydown pulses in the serial data streams to the voicing circuitry. Because the footages are generated by selectively delaying the data streams, each manual is scanned twice and the data is gated off on alternate scans to permit the data streams to be supplemented with the lower frequency footage data. An automatic bass feature permits monophonic bass tones to be played without having to play the pedals, and this is accomplished by coupling into the pedal data stream the lowest data bit originating from the Great manual. Transposition is accomplished by transposing the demultiplex latch command ahead or behind in time so that the data stream is latched either early or late by one or more time slots depending on the amount of transposition selected. A fold circuit injects keydown pulses into the data stream in octavely related time slots ahead of those time slots which are transposed outside the available stages of the demultiplexer when the serial to parallel conversion occurs.