Electronic musical instrument with automatic bass performance circuitry

Claim 2

An electronic musical instrument comprising tone generators; a chord keyboard provided with key switches for selectively keying tone signals from said tone generators; a chord detector including first, second and third detector matrixes responsive to operation of said chord keyboard for detecting the root and fifth notes, the third note, and the major sixth or minor seventh note contained in the chord being played on said chord keyboard and delivering control outputs for corresponding bass notes; first, second and third bass selectors responsive to said control outputs from said chord detector matrixes for selectively deriving bass tone signals corresponding to respective notes included in the chord from said tone generators; a chord gate circuit supplied with tone signals from said tone generators through the operation of said chord keyboard; first, second, third and fourth bass gate circuits supplied with each bass tone signal corresponding respectively to the root note, fifth note, third note and major sixth or minor seventh note from said bass selectors; and a rhythm pattern pulse generator coupled to said chord gate circuit for applying timing pulses to said chord gate circuit for opening the same in accordance with a predetermined rhythm pattern and further coupled to the individual base gate circuits for supplying timing pulses to said respective bass gate circuits to open the same in a specific order proper to said chord being played.

Claim 3

The electronic musical instrument according to claim 1 wherein each one of said first, second and third matrixes comprises a plurality of column conductors and a plurality of output conductors crossing said column conductors, said plurality of column conductors of each matrix corresponding to respective notes included in one octave and being connected to respective key switches actuated by the keys of said chord keyboard corresponding to said notes, each one of said column conductors of said first matrix being connect to a source of voltage via a first resistor, each one of the output conductors of said first matrix being connected to two selected output conductors of said second and third matrixes through a pair of diodes connected in series opposition, each one of the output conductors of the first matrix being grounded through a second resistor, the juncture between said diodes which are connected in series opposition being connected to said source of voltage through a third resistor, diodes being connected at two crossing points between one output conductor of said first matrix and said plurality of column conductors, and a diode being connected at a crossing point between each one output conductor of said second and third matrixes and said plurality of column conductors, whereby when keys of said chord keyboard are depressed, said key switches corresponding to said depressed keys are closed so as to produce outputs from predetermined output conductors of said first, second and third matrixes corresponding to respective notes contained in respective chords.

Claim 4

The electronic musical instrument according to claim 1 wherein each one of said bass selectors comprises a plurality of flip-flop circuits, each including a normally conductive first transistor and a normally conductive second transistor, the emitter electrodes of said second transistors being connected to a common feedback impedance element, the base electrode of said first transistor being connected to output terminal of said chord detector matrix, and the collector electrode of said first transistor being connected to said tone generators whereby a bass tone signal is derived from the collector electrode of said first normally conductive transistor oNly when said first transistor is rendered nonconductive in response to the output from said chord detector.

Claim 5

The electronic musical instrument according to claim 1 wherein said rhythm pattern pulse generator includes a pulse distributor for supplying timing pulses to said respective bass gate circuits which comprises first, second and third gate control circuits supplied respectively with pulses of different phases to produce timing pulses for controlling said first and second bass gate circuits, the outputs of said second and third gate control circuits being combined, a fourth gate control circuit responsive to the output from said second chord detector matrix for preventing application of the timing pulse from said second gate control circuit to second bass gate circuit and for supplying said timing pulse to said bass gate circuit, and a fifth gate control circuit responsive to the output from said third chord detector matrix for preventing application of said timing pulse from said second and fourth gate control circuits to said second and third bass gate circuits and for supplying said timing pulse to said fourth bass gate circuit, thereby carrying out bass performance in conformity with the chord being played on said chord keyboard.

Claim 6

The electronic musical instrument according to claim 1 wherein said rhythm pattern pulse generator includes a pulse distributor for supplying timing pulses to said respective bass gate circuits which comprises a plurality of input conductors supplied respectively with pulses of different phases, a plurality of groups of output conductors of the number corresponding to a plurality of rhythms to be played, a plurality of normally nonconductive diodes which are disposed at crossing points between output conductors of said respective groups and said input conductors in accordance with rhythm pattern corresponding to said group of output conductors, and a plurality of rhythm selector switches connected to the respective groups of output conductors for rendering conductive the diodes connected to said output conductors, whereby when one of rhythm selector switches is selectively closed, said timing pulses are supplied to said respective bass gate circuits from said respective output conductors connected to said closed selector switch.

Claim 7

The electronic musical instrument according to claim 1 which further includes a chord memory which memorizes respective notes contained in a chord in response to respective outputs from said chord detector matrixes produced by operation of said chord keyboard and applied continuously the tone signals to said chord gate circuit form said tone generators, thereby carrying out chord performance without necessity of continuously depressing the keys of said chord keyboard.