Abstract: An organ circuit and method of operation in which a detecting system detects combinations of keys played in the accompaniment portion of the keyboard arrangement of an electronic organ and through associated circuitry causes a respective chord to sound regardless of the particular position of the depressed keys or the particular chord inversion represented by the depressed keys.

Abstract: An electronic organ having at least a portion of the keyboard connected with the corresponding keyers by a multiplexing system consisting of a multiplexer at the keyboard end of the system. A control circuit is interposed between the multiplexer and the demultiplexer and is selectively operable for interrupting the change of data in the demultiplexer and, instead, holding therein the data present in the demultiplexer at the time of actuation of the control circuit. The control circuit is adapted to be made ineffective at the will of the player, or by depressing a key in the aforesaid portion of the keyboard. The arrangement permits a player to hold the keyers pertaining to a group of keys from the portion of the keyboard without holding the keys depressed thereby permitting the player to use both hands elsewhere on the keyboard.

Abstract: A pulse generator especially for an electronic musical instrument in which a "D" type flip-flop is employed with the logic level at the data input thereof being transferred to the output in conformity with the supply to the clock input of a fixed frequency rectangular wave and the supply to the clear input of a rectangular wave having a frequency which is a whole multiple of the fixed frequency. The output at the output terminal of the flip-flop is a pulse having a duty cycle of predetermined length. The pulses at the output terminal are, of course, repetitive and remain at the same duty cycle without variation. By using a plurality of the flip-flops, each having respective inputs to the clock and clear terminals, a desired range of pitches can be generated.

Abstract: An electric organ with logic circuitry incorporated therein which will automatically cause "fill notes" to sound in the solo part of a composition being played with the fill notes being harmonically consistant with the notes being played in the solo part of the composition and with the chords played in the accompaniment part of the composition.