Electronic musical instrument simulating chiff, tracker, and dynamic keying

Claim 2

A pair of sigmoid switches for achieving chiff in an electrical musical instrument comprising: a pair of insulated gate field-effect transistors having gate, drain, body and source electrodes and a sigmoid relation between the controlling gate voltage and the controlling drain voltage, means for applying exponential change in voltage to said gate electrode of one of said transistors which varies between a minimum level and a maximum level, means for applying a tone frequency signal to said source electrode of said one of said transistors, means for applying an exponential change in voltage to said gate electrode of the other of said transistors which varies between a minimum level and a maximum level in a manner different from the voltage applied to said gate electrode of said one of said transistors, means for applying a chiff frequency signal to said source electrode of said other of said transistors, and means for combining the output signals being developed at said drain electrodes of said pair of transistors, said combined output signals forming a signal representing a transient tone and a fundamental tone with the transient tone appearing before or during the onset of the fundamental tone.

Claim 3

A dynamic keyer for an electrical musical instrument comprising: a player actuated switch having released and depressed positions, and contacts between said released and depressed positions, tone switch means having a gate input for applying a tone to said electrical musical instrument, a bias voltage, and a capacitive network, said bias voltage being connected through one of said contacts to said capacitive network when said switch is actuated to produce a changing voltage across said capacitive network, said last named voltage being connected through another of said contacts to said gate input so that the voltage applied to said tone switch means is dependent upon the speed of movement of said player actuated switch through said contacts.

Claim 4

A dynamic keyer for an electrical musical instrument comprising: a player actuated switch having released and depressed positions, and contacts between said released and depressed positions, tone switch means having a gate input for applying a tone to said electrical musical instrument, a bias voltage, and a capacitive network, said bias voltage being connected through one of said contacts to said capacitive network when said switch is actuated to produce a changing voltage across said capacitive network, said last named voltage being connected through another of said contacts to said gate input so that the voltage applied to said tone switch means is dependent upon the speed of movement of said player actuated switch through said contacts.

Claim 5

The dynamic keyer of claim 2 wherein said capacitive network comprises: a first RC circuit generating an exponentially changing voltage of one polarity as said player actuated switch is depressed; a second RC circuit for generating an exponentially changing voltage of opposite polarity as said player actuated switch is released; and wherein said switching means comprises a pair of complementary insulated gate field-effect transistors having a gate, drain, body, and source electrode respectively, said source electrodes providing respective input terminals for input currents of opposite polarity, said drain electrodes being interconnected to provide an output terminal for said circuit, oppositely poled rectifying means coupling said respective body electrodes to circuit common; and a means for applying biasing voltages of opposite polarity to said gate electrodes of said transistors to render said transistors alternately conductive from source electrode to drain electrode as said player actuated switch is alternately depreSsed and released, the same polarity being applied to both said gate electrodes at one time, the biasing voltage of one polarity producing an output current at said output terminal of a polarity corresponding to one of said input currents and a biasing voltage of opposite polarity producing an output current at said output terminal of a polarity corresponding to the other of said input currents.

Claim 6

The dynamic keyer of claim 3 wherein said player actuated switch comprises a conductive element electrically connected to said bias voltage so as to provide a constant voltage at said element and a first spring contact means connected to said first RC circuit which is first engaged by said conductive element as said player actuated switch is depressed, a second spring contact means connected to said gate electrodes and subsequently engaged by said conductive element as said player actuated switch is depressed, and a third spring contact means connected to said second RC circuit and engaged last by said element as said player actuated switch is depressed.

Claim 7

The dynamic keyer of claim 4 including another player actuated switch having released, and depressed positions, and contacts between said released and depressed positions, a switch means connected with said other player actuated switch and said first and second RC circuit so as to generate from said RC circuit when said switch means is actuated an exponentially changing voltage of one polarity as said player actuated switch is depressed and to generate from said second RC circuit when said switch means is actuated an exponentially changing voltage of the opposite polarity as said player actuated switch is released.

Claim 8

An electrical musical instrument having the dynamic keying of claim 2 further comprising: a plurality of tone frequency current sources, and a plurality of modulators for modulating said tone frequency currents, said tone switch means being connected between said tone frequency current sources and said modulators and actuated in response to said voltage across said capacitive network.

Claim 9

The electrical musical instrument of claim 6 further comprising: a plurality of chiff frequency current sources coupled to said plurality of modulators, and a plurality of chiff switch means connected between said chiff frequency current sources and said modulators for selectively applying said chiff frequency currents to said modulators, said capacitive circuit being connected to and controlling said switch means to provide tracker keying of said chiff frequency current sources.

Claim 10

The electrical musical instrument of claim 7 wherein said plurality of switch means connected between said tone frequency current sources and said modulators and said plurality of switch means connected between said chiff frequency current sources and said modulators comprise sigmoid switches.

Claim 11

The electrical musical instrument of claim 8 wherein said tone frequency current sigmoid switches comprise metal oxide semiconductor field-effect transistors respectively having gate, drain, body and source electrodes and a sigmoid relation between the controlling gate voltage and the controlled drain voltage.

Claim 12

The electrical musical instrument of claim 9 further comprising a metal oxide semiconductor field-effect transistor associated with each of said tracker keyer means having gate, drain, body and source electrodes, said gate electrodes being connected to said gate electrode of said tone frequency current field-effect transistor and said drain electrode being connected to said gate electrode of said chiff frequency current field-effect transistor so as to ground said gate electrode of said chiff frequency current switch when said tone frequency current switch is fully on to interrupt said chiff frequency current.

Claim 13

An electronic piano voice keyer for an electrical musical instrument comprising: a player actuated switch having released and depressed positions, an active Sigmoid switching device having input, output, and control terminals, a source of tone signals connected to said input terminal, a variable source of control signals connected to said control terminal in response to actuation of said player actuated switch, said source applying a sufficiently small gate control signal to said control terminal when said player actuated switch is in the released position to maintain said active sigmoid switching device below the threshold level and prevent conducting said tone signal from said input terminal to said output terminal, said source applying a first diminishing control signal to said gate terminal when said player actuated switch is initially depressed such that said active sigmoid switching device initially conducts a first diminishing tone signal from said input terminal to said output terminal, said source applying a second diminishing signal which is smaller than and diminishes more slowly than said first signal, to said gate terminal after said player actuated switch has been depressed such that said switching device subsequently conducts a tone signal, which is smaller than and diminishes more slowly than said first tone signal, from said input terminal to said output terminal, said first diminishing tone signal being followed by said second diminishing tone signal simulating the initially rapid and subsequently slow decay of a sustained piano tone, and means responsive to the rate of actuation of said player actuated switch for varying the magnitude of said first diminishing control signal in accordance with said rate.

Claim 14

An electronic piano voice keyer for an electrical musical instrument comprising: a player actuated switch having released and depressed positions, an active Sigmoid switching device having input, output, and control terminals, a source of tone signals connected to said input terminal, a variable source of control signals connected to said control terminal in response to actuation of said player actuated switch, said source applying a sufficiently small gate control signal to said control terminal when said player actuated switch is in the released position to maintain said active sigmoid switching device below the threshold level and prevent conducting said tone signal from said input terminal to said output terminal, said source applying a first diminishing control signal to said gate terminal when said player actuated switch is initially depressed such that said active sigmoid switching device initially conducts a first diminishing tone signal from said input terminal to said output terminal, said source applying a second diminishing signal which is smaller than and diminishes more slowly than said first signal, to said gate terminal after said player actuated switch has been depressed such that said switching device subsequently conducts a tone signal, which is smaller than and diminishes more slowly than said first tone signal, from said input terminal to said output terminal, said first diminishing tone signal being followed by said second diminishing tone signal simulating the initially rapid and subsequently slow decay of a sustained piano tone, and means responsive to the rate of actuation of said player actuated switch for varying the magnitude of said first diminishing control signal in accordance with said rate.

Claim 15

The electronic piano voice keyer of claim 11 wherein said active sigmoid switching device is a metal oxide semiconductor field-effect transistor having source, drain, and gate electrodes comprising said input, output, and control terminals respectively.

Claim 16

The electronic piano voice keyer of claim 12 wherein said variable source of gate control signals comprises: a power supply; a charge retaining network including a chargeable means, a pair of charging circuits having different overall nonlinear resistances, and a switching means coupled to said player actuated switch for connecting said chargeable means to said power supply in response to movement of said player actuated switch to the depressed position, the initial charging current from said power supply applied to one of said charging circuits when said player operated switch is initially depressed providing said first diminishing control signal followed by a subsequent charging current through said other of said charging circuits providing said second diminishing control signal, and a control signal coupling circuit connected to said charge retaining network applying said first diminishing control signal in response to said initial charging current to said control terminal and subsequently applying the second diminishing control signal in response to said subsequent charging current to said control terminal.

Claim 17

The electronic piano voice keyer of claim 13 further comprising another player actuated switch having released and depressed positions, said variable source of gate control signals being responsive to the position of said other player actuated switch, such that gate control signals only apply an initially first diminishing control signal followed by a second diminishing control signal when said other player actuated switch is depressed.

Claim 18

The electronic piano voice keyer of claim 14 further comprising another player actuated switch having released and depressed positions, said variable source of gate control signals being responsive to the position of said other player actuated switch, said variable source of gate control signals only applying a first diminishing control signal followed by a second diminishing control signal when said other player actuated switch is depressed.

Claim 19

The electronic piano voice keyer of claim 15 wherein said charge retaining network comprises a resistance meanS in series with said chargeable element, a regenerative switch in shunt with said resistance means, and another switching means coupled to said other player actuated switch for actuating said regenerative switch by connecting said power supply to said regenerative switch when said other player actuated switch is in the depressed position, said regenerative switch being actuated by depressing said player actuated switch and sustaining the piano tone as long as said other player actuated switch is depressed.

Claim 20

An electrical musical instrument comprising: a player actuated switch having released and depressed positions, and contacts between said released and depressed positions; a main tone frequency current source; a chiff frequency current source; a modulator means for modulating main tone and chiff frequency currents from said main tone frequency current and said chiff frequency current source; a main tone switching means having a sigmoid relation between the voltage on its gate and the tone it switches, for coupling said main tone frequency current source to said modulator means, a bias voltage connected through one of said switch positions to said gate of said switching means in response to movement of said player actuated switch; and a chiff frequency switching means, having a sigmoid relation between the voltage on its gate and the chiff frequency it switches, for coupling said chiff frequency current source to said modulator means, said bias voltage being connected through one of said switch positions to said gate of said chiff frequency switching means in response to movement of said player actuated switch.

Claim 21

An electrical musical instrument comprising: a player actuated switch having released and depressed positions, and contacts between said released and depressed positions; a main tone frequency current source; a chiff frequency current source; a modulator means for modulating main tone and chiff frequency currents from said main tone frequency current and said chiff frequency current source; a main tone switching means having a sigmoid relation between the voltage on its gate and the tone it switches, for coupling said main tone frequency current source to said modulator means, a bias voltage connected through one of said switch positions to said gate of said switching means in response to movement of said player actuated switch; and a chiff frequency switching means, having a sigmoid relation between the voltage on its gate and the chiff frequency it switches, for coupling said chiff frequency current source to said modulator means, said bias voltage being connected through one of said switch positions to said gate of said chiff frequency switching means in response to movement of said player actuated switch.

Claim 22

An electrical musical instrument of claim 17 further comprising: a chiff suppression switching means for decoupling said chiff frequency current source from said modulator means in response to movement of said player actuated switch.

Claim 23

The electrical musical instrument of claim 18 further comprising: a regenerative switch means for continuously actuating said chiff suppression switch means when said player actuated switch reaches the depressed position and moves through said contacts between said released and depressed positions to said release position.

Claim 24

The electrical musical instrument of claim 19 wherein said main tone switching means comprises a first field-effect transistor and an RC network connected between said gate electrode of said first transistor and circuit common, said chiff frequency switching means comprises a second field-effect transistor and an RC network connected between the gate electrode of said second transistor and circuit common, and said chiff suppression switching means comprises a third field-effect transistor having a gate electrode connected to said second RC network and a channel electrode connected to said gate electrode of said first transistor, the substrates of said first transistor, said second transistor, and said third transistor having different biases with respect to the circuit common so as to render the first transistor conductive first, said second transistor conducted second, and said third transistor conducted third as said player actuated switch is moved from the released position through to the contacts between said released and depressed positions to said depressed position.

Claim 25

The electrical musical instrument of claim 20 wherein said gate electrode of said third transistor is connected to said regenerative switch means.