Alternate high-low and root-fifth selection system for electrical musical instruments

Claim 2

In an electrical musical instrument: a plurality of switching elements, each being selectably actuated for keying one of the notes of the musical scale; a plurality of chord logic gates, each coupled to a preselected combination of said switching elements and providing an output signal upon actuation of selected subcombinations thereof representing a particular set of chords having at least a common root note; a plurality of chord tone gating means, each coupled to one of said chord logic gates and being adapted to gate at least one tone signal corresponding to said common root note in response to said output signal.

Claim 3

Apparatus as claimed in claim 1, wherein each of said chord logic gates is associated with a particular set of chords having both a common root and a common fifth note; and each of said chord tone gating means comprises two tone signal gates for separately gating two tone signals corresponding to said common root and fifth notes.

Claim 4

Apparatus as claimed in claim 2, further comprising: three-note detector means comprising: discriminator circuit means coupled to said switching elements for producing a discriminator output signal if and only if switching elements corresponding to three separate notes are actuated, and coincidence circuit means coupled to said discriminator circuit means and each of said chord logic gates for signalling coincidence of said discriminator output signals and one of said output signals from said chord logic gates; and gating circuit means receiving each of said root and fifth tone signals from said chord tone gating means for gating said root and fifth tone signals in response to said coincidence signal.

Claim 5

Apparatus as claimed in claim 3, further comprising: a tone signal preference system coupled to said switching elements for selectively gating high and low tone signals corresponding to the highest and lowest notes keyed by said switching elements; and said gating circuit means further receiving said high and low tone signals for gating the same in absence of said coincidence signal.

Claim 6

Apparatus as claimed in claim 2, wherein each of said chord logic gates is coupled to switching elements representing associated root, major third, minor third, fifth, and seventh notes of a particular set of chords and comprises logic gating means for producing an output if switching elements corresponding to one of the following subcombinations of notes are actuated: a. root, major third, fifth; b. root, minor third, fifth; c. root, major third, seventh; and d. root, minor third, seventh.

Claim 7

Apparatus as claimed in claim 5, wherein said logic gating means comprises: a first transistor having its base electrode coupled to a switching element representing a root note; a first pair of transistors having emitter and collector electrodes connected in common and base electrodes separately connected to switching elements representing major third and minor third notes; and a second pair of transistors having emitter and collector electrodes connected in common and base electrodes separately connected to switching elements representing fifth and seventh notes; said first transistor and said first and second pair of transistors being coupled in series between a source of D.C. bias and ground reference such that coincident operation of said first transistor and at least one transistor in each of said first and second pairs produces an output signal from said chord logic gate.

Claim 8

In an electronic musical instrument: a set of switching elements, each being selectably actuated for keying one of the notes of the musical scale over at least a two-octave range; a set of logic OR gates, each associated with one of the notes of the musical scale and having inputs coupled to octavely related switching elements associated with said note; a plurality of chord logic gates, each coupled to a preselected combination of said OR gates and producing an output signal upon actuation of switching elements associated with selected subcombinations of notes representing a particular set of chords having common root and fifth notes; a plurality of pairs of chord tone gates, each pair coupled to one of said chord logic gates for gating tone signals corresponding to common root and fifth notes in response to said output signal; circuit means coupled to said set of OR gates for developing a D.C. voltage corresponding to the number of OR gates actuated and thereby to the number of different notes being keyed by said switching elements; a three-note detector comprising a discriminator circuit receiving said D.C. voltage and producing a discriminator output signal if and only if three different notes are being keyed and a coincidence circuit coupled to said discriminator circuit and each of said chord logic gates for producing a control signal upon coincidence of said discriminator output signal and an output signal from one of said chord logic gates; a pair of output gate circuits each receiving in common respective root and fifth note tone signals from said chord tone gates and gating said tone signals to a pair of output leads in response to said control signal.

Claim 9

In an electronic musical instrument: a set of switching elements, each being selectably actuated for keying one of the notes of the musical scale over at least a two-octave range; a set of logic OR gates, each associated with one of the notes of the musical scale and having inputs coupled to octavely related switching elements associated with said note; a plurality of chord logic gates, each coupled to a preselected combination of said OR gates and producing an output signal upon actuation of switching elements associated with selected subcombinations of notes representing a particular set of chords having common root and fifth notes; a plurality of pairs of chord tone gates, each pair coupled to one of said chord logic gates for gating tone signals corresponding to common root and fifth notes in response to said output signal; circuit means coupled to said set of OR gates for developing a D.C. voltage corresponding to the number of OR gates actuated and thereby to the number of different notes being keyed by said switching elements; a three-note detector comprising a discriminator circuit receiving said D.C. voltage and producing a discriminator output signal if and only if three different notes are being keyed and a coincidence circuit coupled to said discriminator circuit and each of said chord logic gates for producing a control signal upon coincidence of said discriminator output signal and an output signal from one of said chord logic gates; a pair of output gate circuits each receiving in common respective root and fifth note tone signals from said chord tone gates and gating said tone signals to a pair of output leads in response to said control signal.

Claim 10

Apparatus as claimed in claim 7, wherein said three-note detector further comprises a control cirCuit coupled to said coincidence circuit for producing a second control signal in the absence of said first control signal; and further comprising: a tone signal preference system coupled to said switching elements for selectively gating high and low tone signals corresponding to the highest and lowest notes keyed by said switching elements; and a second pair of output gate circuits each receiving one of said high and low tone signals and gating said tone signals to said pair of output leads in response to said second control signal.

Claim 11

In an electronic musical instrument: a plurality of switching elements, each being selectably actuated for keying one of the notes of the musical scale; a plurality of chord logic gates, each coupled to a preselected combination of said switching elements and providing an output signal upon actuation of selected subcombinations thereof representing a particular set of chords having common root and fifth notes; a plurality of sets of chord tone gates, each coupled to one of said chord logic gates for gating tone signals corresponding to said common root and fifth notes; discriminator circuit means coupled to said switching elements for producing a discriminator output signal if and only if switching elements corresponding to three separate notes are actuated; coincidence circuit means coupled to said discriminator circuit means and each of said chord logic gates for producing a first control signal upon coincidence of said discriminator output signal and one of said output signals from said chord logic gates and a second control signal in the absence of said first control signal; a tone signal preference system coupled to said switching elements for selectively gating high and low tone signals corresponding to the highest and lowest notes keyed by said switching elements; and gating circuit means receiving said root and fifth tone signals and said high and low tone signals and responsive to said first control signal to gate said root and fifth tone signals, respectively, to first and second output leads and responsive to said second control signal to gate said low and high tone signals, respectively, to said first and second output leads.

Claim 12

In an electronic musical instrument: a plurality of switching elements, each being selectably actuated for keying one of the notes of the musical scale; a plurality of chord logic gates, each coupled to a preselected combination of said switching elements and providing an output signal upon actuation of selected subcombinations thereof representing a particular set of chords having common root and fifth notes; a plurality of sets of chord tone gates, each coupled to one of said chord logic gates for gating tone signals corresponding to said common root and fifth notes; discriminator circuit means coupled to said switching elements for producing a discriminator output signal if and only if switching elements corresponding to three separate notes are actuated; coincidence circuit means coupled to said discriminator circuit means and each of said chord logic gates for producing a first control signal upon coincidence of said discriminator output signal and one of said output signals from said chord logic gates and a second control signal in the absence of said first control signal; a tone signal preference system coupled to said switching elements for selectively gating high and low tone signals corresponding to the highest and lowest notes keyed by said switching elements; and gating circuit means receiving said root and fifth tone signals and said high and low tone signals and responsive to said first control signal to gate said root and fifth tone signals, respectively, to first and second output leads and responsive to said second control signal to gate said low and high tone signals, respectively, to said first and second output leads.

Claim 13

Apparatus as claimed in claim 9, wherein said gating circuit means comprises first and second pairs of transistor gates; a first transistor in each pair receiving, respectively, said root and low tone signals at emitter electrodes and said first and second control signals at base electrodes, and having commoned collector electrodes connected to said first output lead; a second transistor in each pair receiving, respectively, said fifth and high tone signals at emitter electrodes and said first and second control signals at base electrodes, and having commoned collectors connected to said second output lead.