Automatic accompaniment device of an electronic musical instrument

Claim 2

In an electronic musical instrument having a plurality of key switches wherein actuation of each key switch acts to generate a different single note of a musical scale, and automatic accompanying device therefor, said device comprising: a voltage means, said key switches being connected to said voltage means; chord detector means coupled to said individual key switches for monitoring designated combinations of notes being played to detect the presence of different chords, said chord detecting means comprising a plurality of AND circuits connected to said key switches as chord detecting logics, said chord detector means providing an output indicative of said selected chord; a D.C. voltage generator means coupled to said chord detector means for generating a D.C. voltage having a level representative of said detected chord, said D.C. voltage generator comprising a source of D.C. current, a plurality of relays connected to and energized by said AND circuits and a voltage dividing circuit having a resistor coupled to said source of D.C. current and adapted to produce step-down voltages at intermediate terminals provided on said resistor upon application of a D.C. current thereto, and contacts connected to said terminals, whereby predetermined voltages are selectively obtained by means of said contacts being actuated by said energized relays; a voltage controlled variable frequency oscillator means connected to said contacts of said D.C. voltage generator for generating a bass tone signal proper for the detected chord, said bass tone signal being at a frequency determined by said D.C. voltage; a rhythm pattern pulse generator means for generating pulses of predetermined rhythm patterns, and a tone gate means connected to said oscillator means and said pulse generator means for gating said generated bass tone signal in response to said pulses.

Claim 3

An automatic accompaniment device as claimed in claim 1 in which said voltage controlled variable frequency means comprises a first oscillator and a second oscillator, the first oscillator generating a bass tone signal having a frequency of the root note for the detected chord, the second oscillator operating simultaneously with the first oscillator and generating a base tone signal having a frequency of the fifth note for the detected chord, the first and the second oscillator being connected respectively to a pair of tone gates which gates the signals, applied thereto from the first and the second oscillator, in accordance with the rhythm Pattern pulses from the rhythm pattern pulse generator.

Claim 4

An automatic accompaniment device instrument as claimed in claim 1 in which said variable frequency oscillator means comprises an astable multivibrator and a voltage amplifying circuit connected to said astable multivibrator.

Claim 5

In an electronic musical instrument having a plurality of key switches wherein actuation of each key switch acts to generate a different single note of a musical scale, and automatic accompanying device therefor, said device comprising: a voltage means, said key switches being connected to said voltage means; chord detector means coupled to said individual key switches for monitoring designated combinations of notes being played to detect the presence of different chords, said chord detecting means comprising a plurality of AND circuits connected to said key switches as chord detecting logics, said chord detector means providing an output indicative of said selected chord; a D.C. voltage generator means coupled to said chord detector means for generating a D.C. voltage having a level representative of said detected chord, said D.C. voltage generator comprising a source of D.C. current, a plurality of relays connected to and energized by said AND circuits and a voltage dividing circuit having a resistor coupled to said source of D.C. current and adapted to produce step-down voltages at intermediate terminals provided on said resistor upon application of a D.C. current thereto, and contacts connected to said terminals, whereby predetermined voltages are selectively obtained by means of said contacts being actuated by said energized relays; a voltage controlled variable frequency oscillator means connected to said contacts of said D.C. voltage generator for generating a bass tone signal proper for the detected chord, said bass tone signal being at a frequency determined by said D.C. voltage; a rhythm pattern pulse generator means for generating pulses of predetermined rhythm patterns, and a tone gate means connected to said oscillator means and said pulse generator means for gating said generated bass tone signal in response to said pulses, and wherein said plurality of AND circuits comprises a first and a second AND circuit group, the first AND circuit group being connected to said key switches which correspond to the notes of a chord thereby carrying out logical operation thereof, the second AND circuit group being connected to and operated by the output of the first AND circuit group and the outputs of the rhythm pattern pulse generator, and wherein said plurality of relays are connected to and energized by the second AND circuit group.

Claim 6

In an electronic musical instrument having a plurality of key switches wherein actuation of each key switch acts to generate a different single note of a musical scale, and automatic accompanying device therefor, said device comprising: a voltage means, said key switches being connected to said voltage means; chord detector means coupled to said individual key switches for monitoring designated combinations of notes being played to detect the presence of different chords, said chord detecting means comprising a plurality of AND circuits connected to said key switches as chord detecting logics, said chord detector means providing an output indicative of said selected chord; a D.C. voltage generator means coupled to said chord detector means for generating a D.C. voltage having a level representative of said detected chord, said D.C. voltage generator comprising a source of D.C. current, a plurality of relays connected to and energized by said AND circuits and a voltage dividing circuit having a resistor coupled to said source of D.C. current and adapted to produce step-down voltages at intermediate terminals provided on said resistor upon application of a D.C. current thereto, and contacts connected to said terminals, whereby predetermined voltages are selectively obtained by means of said contacts being actuated by said energized relays; a voltage controlled variable frequency oscillator means connected to said contacts of said D.C. voltage generator for generating a bass tone signal proper for the detected chord, said bass tone signal being at a frequency determined by said D.C. voltage; a rhythm pattern pulse generator means for generating pulses of predetermined rhythm patterns, and a tone gate means connected to said oscillator means and said pulse generator means for gating said generated bass tone signal in response to said pulses, and wherein said plurality of AND circuits comprises a first and a second AND circuit group, the first AND circuit group being connected to said key switches which correspond to the notes of a chord thereby carrying out logical operation thereof, the second AND circuit group being connected to and operated by the output of the first AND circuit group and the outputs of the rhythm pattern pulse generator, and wherein said plurality of relays are connected to and energized by the second AND circuit group.

Claim 7

In an electronic musical instrument having a plurality of key switches wherein actuation of each key switch acts to generate a different single note of a musical scale, and automatic accompanying device therefor, said device comprising: a voltage means, said key switches being connected to said voltage means; chord detector means coupled to said individual key switches for monitoring designated combinations of notes being played to detect the presence of different chords, said chord detecting means comprising a plurality of AND circuits connected to said key switches as chord detecting logics, said chord detector means providing an output indicative of said selected chords; a D.C. voltage generator means coupled to said chord detector means for generating a D.C. voltage having a level representative of said detected chord, said D.C. voltage generator comprising a source of D.C. current, a plurality of relays connected to and energized by said AND circuits, and a voltage dividing circuit having a resistor coupled to said source of D.C. current and adapted to produce step-down voltages at two groups of intermediate terminals provided on said resistor upon application of a D.C. current thereto, and contacts connected to said terminals, whereby predetermined voltageS are selectively obtained by means of said contacts being actuated by said energized relays; a voltage controlled variable frequency oscillator means for generating a bass tone signal proper for the detected chord, said bass tone signal being at a frequency determined by said D.C. voltage; a rhythm pattern pulse generator means for generating pulses of predetermined rhythm patterns, and a tone gate means connected to said oscillator means and said pulse generator means for gating said generated bass tone signal in response to said pulses; and wherein a voltage gate circuit is connected to said rhythm pattern pulse generator and said D.C. voltage generator, said gate circuit providing a gating operation which is carried out in accordance with the rhythm pattern pulses from said rhythm pattern pulse generator to thereby gate said D.C. voltage supplied from said D.C. voltage generator, said gate circuit further providing an output signal which is applied to the voltage controlled variable frequency oscillator means.

Claim 8

In an electronic musical instrument having a plurality of key switches wherein actuation of each key switch acts to generate a different single note of a musical scale, and automatic accompanying device therefor, said device comprising: a voltage means, said key switches being connected to said voltage means; chord detector means coupled to said individual key switches for monitoring designated combinations of notes being played to detect the presence of different chords, said chord detecting means comprising a plurality of AND circuits connected to said key switches as chord detecting logics, said chord detector means providing an output indicative of said selected chords; a D.C. voltage generator means coupled to said chord detector means for generating a D.C. voltage having a level representative of said detected chord, said D.C. voltage generator comprising a source of D.C. current, a plurality of relays connected to and energized by said AND circuits, and a voltage dividing circuit having a resistor coupled to said source of D.C. current and adapted to produce step-down voltages at two groups of intermediate terminals provided on said resistor upon application of a D.C. current thereto, and contacts connected to said terminals, whereby predetermined voltageS are selectively obtained by means of said contacts being actuated by said energized relays; a voltage controlled variable frequency oscillator means for generating a bass tone signal proper for the detected chord, said bass tone signal being at a frequency determined by said D.C. voltage; a rhythm pattern pulse generator means for generating pulses of predetermined rhythm patterns, and a tone gate means connected to said oscillator means and said pulse generator means for gating said generated bass tone signal in response to said pulses; and wherein a voltage gate circuit is connected to said rhythm pattern pulse generator and said D.C. voltage generator, said gate circuit providing a gating operation which is carried out in accordance with the rhythm pattern pulses from said rhythm pattern pulse generator to thereby gate said D.C. voltage supplied from said D.C. voltage generator, said gate circuit further providing an output signal which is applied to the voltage controlled variable frequency oscillator means.