US3699234A

US3699234A - Muscular volt age-controlled tone modifying system for electronic musical instrument

Info

Publication number: US3699234A
Application number: US138619A
Authority: US
Inventors: Takeshi Adachi
Original assignee: Nippon Gakki Co Ltd
Current assignee: Nippon Gakki Co Ltd
Priority date: 1971-04-29
Filing date: 1971-04-29
Publication date: 1972-10-17
Anticipated expiration: 1989-10-17

Abstract

Tone modifying circuits of an electronic musical instrument such as keyers, vibrato circuit, tone coloring circuit, tremolo effect producing circuit, volume circuit and like circuits can be controlled as desired by the player in accordance with the variation of the muscular voltages produced across selected muscles of the player provided with pickup means. To this end, at least one pair of muscular voltage pickup electrodes are attached onto at least one selected portion of the player''s skin under which a very low level muscular voltage is generated upon contraction of the electrode-carrying muscle. These pickup electrodes are connected to muscular voltage processing circuits to eliminate unwanted background noise components and to amplify the picked-up muscular voltage to a desired level. The processed voltage is then supplied to control terminals of the modifying circuits in the form of either pulses or DC potentials. In case a plurality of pickup electrodes are mounted on fingers of the player, various touch-responsive tone controls are possible. By summing various levels of muscular voltages obtained from a number of paired pickup electrodes arranged in different portions of the player''s skin, random control of the modifying circuits can be achieved to provide tonal effects rich in variety.

Description

United States Patent Adachi Oct. 17, 1972 [54] MUSCULAR VOLT AGE-CONTROLLED 3,199,508 8/1965 Roth l28/2.06 TONE MODIFYI SYSTEM FOR 3,426,150 2/1969 Tygart ..128/206 X ELECTRONIC MUSICAL INSTRUMENT [72] lnventor: Takeshi Adachi, Hamamatsu, Japan [73] Assignee: Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu-shi, Japan 22 Filed: April 29, 1971 [21] Appl. No.: 138,619

[30] Foreign Application Priority Data May 6, 1970 Japan ..45/38514 May 6, 1970 Japan ..45/38515 May 28, 1970 Japan ..45/45890 May 28, 1970 Japan ..45/45891 May 28, 1970 Japan ..45/45892 June 6, 1970 Japan ..45/49019 June 10, 1970 Japan ..45/50111 June 13, 1970 Japan ..45/51238 June 24, 1970 Japan ..45/54970 July 7, 1970 Japan ..45/59316 July 16, 1970 Japan ..45/62453 [52] US. Cl. ..84/1.24, 84/l.l2, 84/1.13, 84/l.2l, 84/1.25, 84/1.26, 84/1.27, 84/DIG.

' 7 [51] -Int. Cl. ..'...G10h 1/02 [58] Field ofSearch....3/l.l;128/2.06;84/1.0l, 1.24

[56] References Cited UNITED STATES PATENTS 3,565,058 2/1971 Mansfield ..128/2.06

Primary ExaminerLewis H. Myers Assistant Examiner-U. Weldon Attorney-Cushman, Darby & Cushman [57] ABSTRACT Tone modifying circuits of an electronic musical instrument such as keyers, vibrato circuit, tone coloring circuit, tremolo effect producing circuit, volume circuit and like circuits can be controlled as desired by the player in accordance with the variation of the muscular voltages produced across selected muscles of the player provided with pickup means. To this end, at least one pair of muscular voltage pickup electrodes are attached onto at least one selected portion of the players skin under which a very low level muscular voltage is generated upon contraction of the electrode-carrying muscle. These pickup electrodes are connected to muscular voltage processing circuits to eliminate unwanted background noise components and to amplify the picked-up muscular voltage to a .desired level. The processed voltage is then supplied to control terminals of the modifying circuits in the form of either pulses or DC potentials. in case a plurality of pickup electrodes are mounted on fingers of the player, various touch-responsive tone controls are possible. By summing various levels of muscular voltages obtained from a number of paired pickup electrodes arranged in different portions of the players skin, random control of the modifying circuits can be achieved to provide tonal effects rich in variety.

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MUSCULAR VOLT AGE-CONTROLLED TONE MODIFYING SYSTEM FOR ELECTRONIC MUSICAL INSTRUMENT BACKGROUND OF THE INVENTIO a. Field of the Invention The present invention is concerned generally with an electronic musical instrument provided with tone modifying systems, and more particularly, it relates to an improvement in the tone modifying systems of electronic musical instrument by the provision of tone modifying circuits which are controlled in accordance with the variation of the muscular voltages picked up from selected muscles of the player.

b. Description of the Prior Art Various types of conventional electronic musical instrum'ents, such as electronic organs and the like, are generally provided with tone generators for producing audible frequencies and with means for modifying the waveform or envelope of the produced tone frequencies to provide desired tonal effects. These means are actuated primarilyby manual operation of the player using his fingers, feet and/or knees. Recently, however, an attempt has been made to control tone modifying circuits of an electronic musical instrument by utilizing the muscular voltages which appear across selected muscles of the player upon contraction thereof so as to serve as the control input signals to provide various tonal effects as desired by the player without relying on the afore-mentioned manual operation, which means without depending on manual actuation of the manipulation switches such as tablet switches and knee lever switches, an expression pedal for output volume control, or the like. Apart from such an attempt, various proposals have been made to pick up a muscular voltage which is very weak and delicate and to process this picked-up voltage and to transmit as an instrument control signal the processed voltage to various tone modifying circuits housed in the console of the instrument. However, those muscular voltage-controlled tone modifying systems of the prior art have failed to produce perfect emotional expressions of the music being played and/or to produce various different tonal effects such as random rythms or combined tonal effects because of the incapability of the systems to make effective use of various different magnitudes and envelopes of the muscular voltages. Thus, there has been the demand for the development of improved control systems of the type described for tone modifying purposes, which are free of the inconveniences and drawbacks of the prior art and which insure the production of desired emotional expressions as well as tonal effects either singular or mixed, without requiring any manual operation.

SUMMARY OF THE INVENTION desired bythe player, outstandingly good emotional expressions by the player and/or various kinds of tonal effects of music being played.

Another aspect of the present invention is to provide an improved controlling systems of the type described which permit desired complicated control of the tonal effects without inconveniently complicating the instrument circuitries.

A further aspect of the present invention is to provide an improved control means for controlling the muscular voltage-controlled tone modifying systems of the type described, which are capable of selecting special effects during the playing of the instrument and which are easy for the player to operate.

A still further aspect of the present invention is to provide an improved muscular voltage-controlled tone modifying systems for the instrument, which permit random vibrato effect to be produced as desired.

A yet further aspect of the present invention is to provide an improved muscular voltage-controlled tone modifying circuits, which by the provision of muscular voltage pickup means on the fingers of the player allow the so-called touch-respective tone control to be achieved, upon depression of the playing keys of the instrument.

Another aspect of the present invention is to provide an improved muscular voltage-controlled tone modifying systems which are adapted to be subjected to integrated operation by the weak muscular voltages occurring momentarily to thereby insure the operation of the tone modifying systems.

Still another aspect of the present invention is to provide an improved muscular voltage-controlled tone modifying systems of the type described, which are capable of performing differential control of tone modifying circuits from a plurality of pickup means attached onto different portions of the players skin.

Yet another aspect of the present invention is to provide an improved control systems of the type described having a simple structure, which enable a plurality of tone modifying circuits to be controlled independently with easiness as desired by the player in either analog or digital form without applying any specific manual operation onto the keys, switches, tablets, knee lever, and the like of the instrument.

These and other. objects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of an electronic musical instrument having a system for controlling tone modifying circuits by muscular voltages, embodying the present invention.

FIG. 2 is a schematic block diagram showing an example of a muscular voltage processing circuit used in the present invention.

FIG. 3 is a circuit diagram showing the details of FIG.

FIG. 6 is a circuit view, showing an example of a vari- I able impedance circuit used in the present invention.

FIG.-7 is a diagram showing a modification of a differentially controllable circuit of the present invention.

FIGS. 8A to 8C are waveforms for explaining the operation of FIG. 7.

FIG. 9 is a schematic block diagram showing another example of a muscular voltage processing circuit used in the present invention.

FIGS. 10A to 10F are waveforms developed at several output sides of the blocks in FIG. 9.

FIGS. 11 and 13 are schematic views showing examples of an adaptation circuit cooperating with the circuit of FIG. 9, and a modification thereof, respectively.

FIGS. 12 and 14 are pulse waveforms shown for explaining the operation of FIGS. 11 and 13, respectively.

FIG. 15 is a structural view of an electromagnetically actuated tablet switch, by way of example, which is under control of a muscular voltage appearing across a muscle of the player.

FIGS. 16, 17 and 19 are block diagrams showing several examples for controlling one or more tonemodifying circuits, respectively.

FIGS. 18 and 20 are pulse waveforms shown for explaining the operation of FIGS. 17 and 19 respectively.

FIGS. 21 is a diagram showing a muscular voltagecontrolled tablet switch system utilizing the circuit of FIG. 13.

FIG. 22 is a schematic circuit diagram showing a muscular voltage-controlled tone generator system.

FIG. 23 is a diagram for explaining the operation of the circuit shown in FIG. 22.

FIGS. 24 and 25 are diagrams each showing circuits including an automatic rythm playing device which is adapted to be controlled by muscular voltages.

FIG. 26 is a circuit diagram showing an embodiment of a muscular voltage-controlled tone volume control system in the instrument.

FIG. 27 is a circuit diagram showing another embodiment of a muscular voltage output volume control system.

FIG. 28 is a circuit diagram showing a muscular voltage-controlled tone volume control system for a touchresponsive keyboard performance.

FIG. 29 is a block diagram showing a modification of the volume control system of FIG. 28.

FIG. 30is a circuit block diagram showing a muscular voltage-controlled differentially operable tone output volume control system of the instrument.

FIGS. 31A, 31B and 31C are circuit diagrams of muscular voltage-controlled tone color control circuits of the instrument, respectively.

FIGS. 32A, 32B and 32C are graphs shown for explaining the circuits of FIGS. 31A, 31B and 31C, respectively.

FIG. 33 is a block diagram of an arrangement of a plurality of muscular voltage pickup means and muscular voltage processing circuits for use in providing a muscular voltage of a random waveform as well as of a large amplitude.

FIG. 34 is a waveform chart of a signal which may be obtained at the output of the circuit of FIG. 33.

FIG. 35 is a block diagram of a muscular voltagecontrolled tremolo effect producing circuit arrangement.

FIG. 36 is a circuit diagram showing an example of the details ofthe block diagram of FIG. 35.

FIG. 37 is a view of a speaker system used in the arrangement of FIGS. 35 and 36 for producing a tremolo effect under control of a muscular voltage.

It is to be understood that like references and numerals indicate like parts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 there is shown a perspective view of an electronic musical instrument such as an electronic organ generally indicated at l which comprises as its playing actuators

manual keyboards

2 and 3 in multiple stages, a pedal keyboard 4, an expression control pedal 5, an electromagnetically actuated tablet switches TB, and so forth. A pair of

electrodes

7a and 7b electrically associated with a grounded electrode are adapted to be fixedly mounted on the body of the player at suitable positions of an arm 6 of the player, for example, on the skin surface on the inside of the forearm by means of an electrically conductive paste or electrically conductive bonding tape, so that a muscular voltage produced upon contraction of a muscle of the arm and appearing at the skin on which the electrodes are mounted may be picked up or detected.

The

electrodes

7a and 7b are connected, through lead wires or shielded wires, with a muscular voltage processing circuit E which will be described hereinafter. That is to say, these lead wires are connected with the opposite ends of a primary winding 1, of a coupling transformer L as shown in FIGS. 2 and 3 whose secondary winding 1 is connected to an input side of an amplifier circuit A of which the output is connected subsequently with a non-linear circuit B composed of two diodes having non-linear characteristics which are connected in parallel with and in reverse polarity with each other, for cutting off said background noise components contained in the weak muscular voltage picked up by the electrodes, a bandpass filter F, a rectifier circuit D, an integrator circuit I such as a Miller circuitand a time constant circuit C, whose output is connected to a terminal T. Thus, the block E enclosed by two-dotted chain line represents a muscular voltage processing circuit. In this processing circuit, a muscular voltage having the waveform of FIG. 4A which appears for example, upon bending the arm 6 or the finers thereof may be obtained at the output of the amplifier A. Then, the background noise component of the voltage is cut off through the non-linear circuit B and the bandpass filter having a pass hand between and 500 Hz whereby any minimal variations in the envelope of the voltage are suppressed into a waveform of FIG. 4B, and then it is rectified by a rectifier D into a unidirectional waveform as shown in FIG. 4C, the rectified envelope component being shown in FIG. 4D. The rectified voltage is integrated into a waveform of FIG. 4E and then it is passed through the time constant circuit to be formed into a waveform of FIG. 4F, which has a sustaining varying DC characteristic.

Reference is now made to examples of the manner in which tone modifying circuits of an electronic musical instrument or the like are controlled by means of the above-mentioned muscular voltage processing circuit E continuously in amplitude, phase or frequency.

Referring to FIG. 5, there is illustrated an example of circuits of the type described, in which 0 represents tone generators which are provided corresponding in number to the playing keys arranged in a usual electronic musical instrument.

A tone signal which is generated from each tone generator 0 is keyed by a key-controlled keyer K and is passed through a tone coloring circuit Fi including a filter. The output of the circuit Fi is supplied to a tremolo effect producing circuit M and then it is power-amplified by a power amplifier A and converted to a sound by an electro-acoustic transducer such as a speaker S. Thus, the block G indicates'a complete arrangement of an electronic organ. For the tone generator 0 is also provided a vibrato effect producing circuit V for varying the oscillation frequency of each tone generator. The tremolo effect producing circuit M makes amplitude modulation of the tone signal supplied from the preceding stage, i.e., the tone coloring circuit Fi.

5,, E E represent muscular voltageprocessing circuits of which each is constituted in the same manner as described above in connection with FIGS. 2 i

and 3. That is, at the input side of each of these circuits E E E,, signals from muscular voltage pickup means provided on different positions of the players muscles such as trapezius, biceps of a thigh, biceps, extensor digitiform c'ommunis, sternocleido-mastoid, vastus lateralis and vastus medials in the muscular system of the man are adapted to be supplied.

At the output side of the each circuit, a varying DC signal is provided for controlling the vibrato effect producing circuit V, tone coloring circuit Fi, or tremolo effect producing circuit M, whereby the impedance of each variable impedance element thereof may be varied so that the frequency characteristics of the filter of the tone coloring circuit, the oscillation frequency of the vibrato effect circuit and the amplification of the power amplifier may be varied accordingly upon receipt of the muscular voltages.

For example, the amplifier A may be so arranged as to have a variable impedance element such as an insulated gate-controlled field effect transistor as shown in FIG. 6 for varying its output level to thereby vary the output volume of the speaker S in accordance with the degree of extension or bending of the muscle, utilizing a DC signal having the waveform shown in FIG. 4E or 4F, which varies in level in accordance with the degree of contraction of the muscle. Thus, the use of the variable impedance element of which impedance can be increased or decreased depending on the degree of contraction of the muscle permits the provision of the same effects as thus produced by the conventional expression pedal or knee lever, for example, by bending the arm or fingers onto which the muscular voltage pickup means are mounted, or by applying a force thereto. In particular, in case the pickup means are attached onto the trapezius or the biceps of a thigh, the output volume of the instrument may be adjusted by vertical motion of a shoulder or a leg. Such muscular voltagecontrolled variable impedance element may also be used in the vibrato effect producing circuit V, the tone coloring circuit Fi or the tremolo effect producing circuit M to provide continuously varying effects.

ment, by picking up muscular voltages of at least two different but mutually associated muscles forming a pair or pairs selected from among the various muscles of the players body, and by processing the pick-up muscular voltages. To this end, at least two pairs of

pickup electrodes

7a and 7b are attached to, for instance, the right forearm 6A and the left forearm 6B of the player, respectively. The outputs of these electrodes are connected through transformers L to muscular voltage processing circuits E and E of the type described-above, respectively. Output terminals-T and T of the respective circuit E and E are connected via resistors R and R to gate electrodes (1 and (1 of field effect transistors Q and Q2 (hereunder referred to as FETs), respectively. The drain of PET Q 1 is connected to a power source +Vcc and the source of FET O is grounded, while the source of FETQ and the drain of PET Q are connected to a common connection point q,, and led to an output terminal T,,, thus constituting a muscular voltage controlled differential synthesizer E shown by a two-dot chain line block. The output of the circuit arrangement may be connected to, for example, the control terminal of the tone volume amplifier A of FIG. 5. In the circuit E two unidirectional voltage signals obtained from the processing circuits E and E are differentially synthesized, developing a signal having the waveform shown in FIG. 8A at the output terminal T The synthesized signal is utilized to control various tone modifying circuits as shown in FIG. 5, e.g., for the control of the speaker volume of the instrument as described above, in such a manner as shown in FIG. 8B. For example, by the extension and bending of the right forearm 6A, the tone volume of the speaker may be adjusted through the variation of the impedance of the variable impedance element used for an increase with respect to a predetermined level v of volume, whereas by the extension and bending of the left forearm 6B, the output volume of the speaker S may be adjusted therethrough for a decrease with respect to the above-mentioned level v Thus, expression pedal effects simulating tonal effects may be easily attained.

The differentially operable circuit E, can produce a processed DC potential signal having a desired amplitude envelope characteristic which is suitable for the control of the tone modifying circuits, merely by making a contraction of the related muscles or by imparting a force to the muscle on which the above-mentioned type pickup means are mounted, for a relatively short period of time, for example one second or less. As a result, the fatigue-of the player can be reduced to a great extent during the playing of the instrument. In'

case the processed signal is used as a control signal for controlling the tremolo effect producing circuit M or the vibrato-effect producing circuit V, the tremolo frequency or the vibrato frequency can be varied as desired in a manner as shown in FIG. 8C depending upon the degree of contraction of the muscles. In these cases, the control signal from the circuit E is supplied to an impedance-varying element such as an PET incorporated in a bias circuit or a CR coupling feedback mined period of time in response to the degree of contraction of the related muscles.

As a second embodiment of the present invention, reference is now made to a muscular voltage processing circuit for processing the picked-up muscular voltage into a pulse form, which is of a constant amplitude, to thereby control the keyers of the instrument or to control various kinds of control switches of the instrument.

Referring to FIG. 9, there is illustrated as a muscular voltage processing circuit H a circuit arrangement for producing pulse wave signals on the basis of a muscular voltage which appears across the muscle of the player upon contraction thereof, which comprises a transformer L having a primary winding 1 connected with a muscular voltage pickup means of the abovementioned type and a secondary winding 1 an amplifier A connected with the said secondary winding 1 for amplifying a very feeble muscular voltage picked up by the pickup means, a non-linear circuit B, a bandpass filter F, a rectifier circuit D intended for eliminating background noise components, an integrator circuit 1, a clipper circuit C1 having an output terminal R at its output side, and a differentiator Ed having a terminal T at its output, all of which are made in subsequent cascade connection.

In the operation of the above-mentioned circuit H the amplifier A amplifies a muscular voltage having such a waveform as shown in FIG. A which may be picked up by the muscular voltage pickup means mounted on, for example, an arm, upon stretching or bending of either the arm or the fingers. Then, two diodes connected in parallel and in mutually opposing polarities in the non-linear circuit B cut off the background noise component which is of a relatively low level and which is superposed on the picked-up muscular voltage, producing the waveform of FIG. 108. The resulting waveform voltage is fed to the bandpass filter F whose pass band is between, for example, I20 and 500 Hz, whereby minimal variations in the envelope of the input voltage are eliminated. After the voltage is amplified, it is rectified through the rectifier D, developing a unidirectional voltage as shown in FIG. 10C. The rectified voltage is then integrated by the integrator I into a signal of the waveform of FIG. 10D, and fed to the clipper C1 formed of a saturated type amplifier to provide a square wave signal having a predetermined level as shown in FIG. 10E. The square wave signal may be derived at the terminal T. It is to be noted that the signal may be derived in the form of a pulse signal having such a waveform as that shown in FIG. 10F through the differentiator Ed.

In FIG. 11, there is illustrated an example of the manner for controlling tone-modifying circuits in an electronic musical instrument or the like by making use of the muscular voltage which has been processed in the manner as described in connection with the second embodiment, which is one of the simplest examples. The system of FIG. 11 comprises an output terminal T(T') of a muscular voltage processing circuit [-1, which is capable of producing a pulse signal having the waveform as shown in FIG. 12A and a flip flop circuit 10 adapted to receive the pulse signal at its input side and to make its conducting state and non-conducting state alternately for each receipt of the successive pulse input, thus producing a square waveform signal as shown in FIG. 12B. This flip-flop circuit is connected to tone-modifying circuit, such as tone keyers, an automatic rythm playing device, and starter-stoppers of the rythm device for providing several kinds of tonal effect, which starters-and-stoppers are provided in the form of switching means, respectively. For example, in case the muscular voltage pickup means are mounted on the arm, shoulder or foot of the player, this system permits a first motion of the pickup-carrying portion of the muscle to serve to start the tone modifying circuit or to impart the tonal effects, while a second motion thereof serves to stop the operation of the circuits orto release the application of the tonal effects in the instrument.

Thus, the system provides an increased expression power for the music being played.

'Referring to FIG. 13, there is illustrated another example of a muscular voltage-controlledtone modifying circuit system which produces two-way pulse signals as shown in FIGS. 14A and 14B by the use of separate muscular voltage processing circuits H, each'being connected through an individual transformer L to a corresponding muscular voltage pickup means.

The separate pulse signals of FIGS. 14A and 14B are produced in association with contraction of muscles of the left and

right hands

6A and 6B of the player to which pairs of

electrodes

7a and 7b of the pickup means are attached. These pulse signals are fed to two separate input terminals of an R-S flip-flop circuit F1, respectively, and hence, the flip-flop is rendered in its conducting state and its non-conducting state, alternately, to develop a square pulse shown in FIG. 14C, depending upon the pulse inputs for the flip-flop F], as illustrated in FIG. 14. The output signal of the flip-flop F1 is coupled with the tone modifying circuit 12 in the instrument of the various types described above. The

pickup electrodes

7a and 7b may be attached to selected skin portions of the shoulder or the legs of the player instead of the

arms

6A and 6B.

The advantages of this arrangement are in that even if the pickup means-carrying muscle is successively moved, the state of the flip-flop is not altered except by the application of an initial pulse input thereto. Accordingly, a fail-safe playing is attained with this instrument. In other words, any unexpected erroneous operation by the player can be avoided.

Referring to FIGS. 15 to 21, an embodiment of the present invention is described in which a muscular voltage which is picked up from the skin of the player is processed in a pulse form and is applied to an electromagnetically actuated tablet provided in an electronic musical instrument or like instrument to drive it, for the selective control of the playing effects.

In FIG. 15, the structure of the tablet switch TB is illustrated by way of example, in which numeral indicates a tablet knob, 111 a coil spring for snap action, 112 a rotary shaft, 113 a movable yoke coupled with the tablet knob 110 by, for example, bonding; 114 an iron core, 115 a mount, 118a and 118b coils, 119 a stopper for the movable yoke 113, 120 a contact piece, 121 an actuator rod made of insulating material, and 122 an opening in the mount 115.

Claims

1. In an electronic musical instrument including tone signal modifying circuits, a system for controlling said tone-modifying circuits by mUscular voltages, comprising: pick-up means having at least one pair of electrodes adapted to be mounted on a selected portion of the skin of the player for detecting a muscular voltage appearing across the related muscle upon contraction thereof and producing an electrical output signal which varies as a function of the deleted voltage, at least one muscular voltage processing circuit including amplifier means connected with said pick-up means for receiving and amplifying said output signal voltage, background noise rejector means connected to said amplifier for removing the background noise component from the amplified voltage, and rectifier means connected to said rejector means for providing a unidirectional signal, and at least one voltage-controlled variable circuitry having a control terminal which is connected to the output of said muscular voltage processing circuit and having other terminals which are connected to said tone signal modifying circuits for controlling the modifying characteristic thereof, including means for receiving said unidirectional signal and providing an output voltage which varies as a function of said unidirectional signal.

2. The system according to claim 1, in which the said processing circuit includes a time constant means for delaying the detected muscular voltage to provide a control DC signal proportional to the amplitude characteristic of the picked-up muscular voltage.

3. The system according to claim 1, in which the said receiving and providing means includes a voltage-controlled variable impedance element.

4. The system according to claim 3, in which the said variable impedance element is a transistor.

5. A system according to claim 3 in which said voltage-controlled variable impedance element is a field effect transistor having a gate electrode used as said control terminal.

6. The system according to claim 1, in which said processing circuit includes an integrator circuit, a clipper circuit and a differentiation circuit in series connection, a terminal at the output side of the said clipper circuit for deriving a square waveform signal, and another terminal at the output side of the said differentiator circuit for providing a pulse wave signal, and the said receiving and providing means includes at least a flip-flop, monostable circuit means connected to the said flip-flop, at their input side and paired actuating coils of a electromagnetically actuated tablet at their output side for selectively energizing the coils.

7. The system according to claim 5 in which the said receiving and providing means further includes counter means for controlling the respective plurality of tablets as a function of pulse count.

8. The system according to claim 6, in which the said receiving and providing means includes a ring counter for receiving a signal from the said terminals in front of the flip-flops and a plurality of paired monostable multivibrators, each paired multivibrators being connected to the coils of each of said tablets to effect predetermined control of the said tablets in response to the number of pulses received at the said counter.

9. The system according to claim 1, in which the said receiving and providing means includes means for varying the bias voltage of an oscillative element of each tone generator.

10. The system according to claim 1, in which the said receiving and providing means includes a field effect transistor whose base is connected to the output of the said processing circuit and whose source and drain electrodes are connected in parallel with a resistor forming a feedback time constant circuit of a free-running multivibrator, the said multivibrator constituting a clock pulse generator of an automatic rythm generator, thereby the frequency of the oscillation being varied in response to the muscular voltage input.

11. The system according to claim 1, in which the said receiving and providing means includes a voltage-controlled variable attennator means provided between variOus keyer circuits and an electro-acoustic transducer means.

12. The system according to claim 1, in which the said pickup means are adapted to be mounted on fingers of the player, whereby a touch-responsive muscular voltages may be provided.

13. The system according to claim 1, in which the said receiving and providing means includes a first and a second field effect transistors (FET''s) whose bases are connected to output terminals of the said muscular voltage processing circuit means which are separate from each ather, and the drain of the said first FET and the source of the said second FET are connected at a common point to which an electro-acoustic transducer means is connected through a resistor, and the source of the first FET and the drain of the second FET are connected to the output side of separate keyboad keyer circuits, respectively, between which a potentiometer is connected whose contact point is connected to the common point.

14. The system according to claim 1, in which a voltage summing circuit is provided to a plurality of the said processing circuit means to provide a composite DC signal having a random envelope as a control signal.

15. The system according to claim 1, in which the said adapting means includes a voltage-controlled variable voltage source connected to said processing circuit means, a motor carrying thereon an electro-acoustic transducer means and moving the direction of said transducer, a speed detector for detecting the speed of the motor being moved, a speed to voltage converter circuit receiving information of the speed detector, a voltage comparator circuit comparing the voltage of said variable voltage source with a converted voltage from the voltage convertor, a motor control drive circuit receiving the result of comparison in said comparator, and a power source energizing the motor through said drive circuit.

16. A system according to claim 1, in which said receiving and providing means further includes an oscillator followed by frequency dividers to form tone generators, and said tone signal modifying circuit includes said frequency dividers.

17. The system according to claim 1, in which said muscular voltage processing circuit includes an integrator circuit with its input being connected to the output of said rectifier means, a clipper circuit with its input being connected to the output of said integrator circuit, a differentiation circuit with its input being connected to the output of said clipper circuit, a first terminal connected to the output side of said clipper circuit for deriving a square waveform signal, and a second terminal connected to the output side of said differentiation circuit for providing a pulse wave signal.

18. The system according to claim 17, in which said receiving and providing means includes at least a flip-flop and monostable circuit means connected to said flip-flop at their input side and paired actuating coils of an electromagnetically actuated tablet switch provided at the output side of said monostable circuit means for selectively energizing the coils.