Abstract: A chord recognition system for an electronic musical instrument, namely an electronic organ. A shift register receives data information from the keying lines of selected playing keys. The pattern of the received data is compared against selected normalized chord patterns in a program logic array to determine if the note input sequence is in a known musical relationship such as major, minor, minor sixth, seventh or others. A chord logic circuit receives the information from the programmed logic circuit and further reduces the information to output signals indicating a major, minor, or seventh chord and a pattern found signal. If no chord pattern is detected in the input data sequence, the register shifts the data on its first input line to its last input line and all other data is transferred downward accordingly. A counter sequences at each shift of the data input information. The shifted data is now compared in the programmed logic array as described above.

Abstract: A harmony generating circuit generates high harmony signals in response to coincident lower manual accompaniment signals and upper manual melody signals. Gating circuitry responsive to coincident inputs from accompaniment chords played on the lower manual and melody notes played on the upper manual generate harmony notes on the upper manual which correspond to the accompaniment notes played on the lower manual but are above the melody notes and approximately within one octave of the melody notes.

Abstract: The bass note generation system provides one of several different types or styles of bass-line accompaniment for the organist. A chord pattern detector receives signals on keying lines corresponding to keys depressed by the instrument player and attempts to recognize a normalized chord pattern. A counter tracks the operation of the chord pattern detector and provides an output corresponding to the alphabetic note of any recognized chord. If the chord pattern is recognized, the output of the detector and the output of the counter address a normalized and preprogrammed bassline pattern memory. The digital value of the bass note stored in the memory and the outut of the counter are serially added to transpose the normalized bass note to the appropriate musical key and applied to a decorder-keyer circuit at selected time intervals in a musical measure for providing a precomposed musical bassline output.