Title:
SYSTEM FOR CONTROLLING TONE-MODIFYING CIRCUITS BY MUSCULAR VOLTAGE IN ELECTRONIC MUSICAL INSTRUMENT
United States Patent 3705948


Abstract:
An electronic musical instrument which is controlled of its tonal effect by utilizing the muscular voltages of the player generated at his will across his muscles, in addition to the control by the usual manual operation of the playing keys. To this end, a pair of muscular voltage pickup electrodes are attached to at least one selected portion of the player's skin under which a muscular voltage appears upon contraction of the related muscle. Between the pickup electrodes and various tone-modifying circuits are provided circuits for processing the picked-up muscular voltage and for producing control signals to the modifying circuits in specific digital or analog form based on this processed voltage, to accomplish the desired tonal effect control. A wireless transmission means may be provided between the player and the instrument to transmit the picked-up voltage or the control signals to the tone-modifying circuits for more convenient and easier control.



Inventors:
TOMISAWA NORIO
Application Number:
05/121969
Publication Date:
12/12/1972
Filing Date:
03/08/1971
Assignee:
NIPPON GAKKI SEIZO KK.
Primary Class:
Other Classes:
84/678, 984/378
International Classes:
G10H5/00; (IPC1-7): G10H1/02
Field of Search:
3/1.1 128
View Patent Images:



Primary Examiner:
Myers, Lewis H.
Assistant Examiner:
Weldon U.
Claims:
I claim

1. In an electronic musical instrument including tone signal modifying circuits each having a control terminal, a system comprising:

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

3. The system according to claim 2, in which are provided between said muscular voltage processing circuit and said control terminal of the tone signal modifying circuit counter means connected with one of said pulse signal deriving means and a plurality of monostable multivibrators each connected to an individual tone signal modifying circuits to thereby control the respective tone signal modifying circuits by pulse count.

4. The system according to claim 2, in which a flip-flop circuit is provided between one of of said pulse signal deriving means and the control terminal of said tone signal modifying circuits.

5. The system according to claim 2, in which are provided between one of said pulse signal deriving means and the control terminals of said tone signal modifying circuits, a ring counter for receiving a signal from said terminals, and a plurality of monostable multivibrators each connected to the individual modifying circuits to effect predetermined sequential control of said modifying circuits in response to the number of pulses being received at said counter.

6. The system according to claim 1, in in which said pick-up means are located on different portions of the player's skin representing different muscles and are connected with individual picked-up voltage processing circuits to provide differential control for said tone signal modifying circuits.

7. The system according to claim 1, in which said muscular voltage processing circuit further includes a time constant circuit connected to said rectifier means to provide a decay signal in accordance with the peak amplitude of said unidirectional signal.

8. The system according to claim 1, further comprising adding means connected at its input to a plurality of said muscular voltage processing circuit having individual input voltages to provide said unidirectional control signal in a large quantity.

9. The system according to claim 1, in which said muscular voltage processing circuit includes a transformer connected with a plurality of paired electrodes in output summing connection.

10. The system according to claim 1, in which said muscular voltage processing circuit includes a plurality of transformers connected with said paired electrodes of a corresponding number in output summing connection.

11. The system according to claim 1, in which said transmission means includes a modulator means for modulating a carrier with the unidirectional signal from said muscular voltage processing circuit and a transmitter means for transmitting the modulated signal in a radio wave, said modulator and said transmitter being adapted to be mounted on the skin of the player, a receiver means for receiving the transmitted signal and a demodulator for demodulating the received signal into a unidirectional signal, said receiver means and said demodulator being located in the console of the instrument and an output terminal of said demodulator being connected to at least one of said control terminals of the tone signal modifying circuits.

12. The system according to claim 5, in which said ring counter is a reversible ring counter.

13. In a method of operating an electronic musical instrument of the type having a plurality of audio tone producing circuits, means for varying an audio characteristic of said tone producing circuits and means for manually operating said circuits to produce audio tones having the steps of:

14. In an electronic musical instrument having a plurality of audio tone producing circuits, means operatively connected to said circuits for causing, when manually operated, said tone producing circuits to produce said tones, electrode means for detecting the muscular voltage produced by at least one muscle on a human body, and means for varying an audio characteristic of the tones produced by at least one of said circuits as a function of said detected muscular voltage, the improvement comprising means for receiving said muscular voltage and producing an electromagnetic wave signal and means for transmitting said electromagnetic wave signal to said varying means through space.

Description:
BACKGROUND OF THE INVENTION

a. Field of the Invention

The present invention is concerned generally with an electronic musical instrument having tone modifying circuits, and more particularly, it relates to a specific system for controlling these tone modifying circuits by a muscular voltage picked up from the instrument player.

B. Description of the Prior Art

There has recently been developed an electronic musical instrument having muscular voltage-controlled tone-modifying circuits as a novel control system which permits the control of various tonal effects by the use of a muscular voltage appearing across a muscle of the player's body upon contraction thereof without depending upon manual actuation of manipulating switches such as tablet switches and knee lever switches, an expression pedal for volume control, and the like. This muscular voltage-controlled tone-modifying arrangement is described in a co-pending application, Ser. No. 115,981, filed Feb. 17, 1971.

Such a control system has an advantage in that the instrument is controlled to produce several tone effects at the will of the player by attaching muscular voltage pickup means to the body of the player. However, no effective control system using the voltage of the player's muscles has yet been developed. More specifically, there have been achieved neither any means suitable for the processing of the picked-up muscular voltage which is very delicate and contains a background noise therein, nor any convenient means for transmitting a control signal derived from the generated muscular voltage to the console of the instrument in which muscular voltage-controlled tone-modifying circuits are housed.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an improved system for controlling tone-modifying circuits by muscular voltages in an electronic musical instrument in which the muscular voltages which are picked up upon contraction of a muscle of the player during the playing of the instrument are usefully and effectively used as control signals of the instrument to improve emotional expression or variety of tonal effects of music being played.

Another object of the present invention is to provide an improved controlling system of the type described which permits the player to selectively attain desired complicated control of the effects in very good response to the player's will.

Another object of the present invention is to provide an improved controlling system of the type described which permits reversible control therefor by the combination of a plurality of muscular voltage pickup means.

A further object of the present invention is to provide an improved controlling system of the type described which has means capable of obtaining a large signal by collecting a number of minimal muscular voltages from various parts of the player's body.

A still further object of the present invention is to provide an improved controlling system of the type described in which a control signal obtained from the picked-up muscular voltage is delivered from the player to the console of the instrument in the form of radio wave transmission or wireless transmission.

Another object of the present invention is to provide an electronic musical instrument which permits electrical remote control, by relying on the technique of telemetry.

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 drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing an electronic musical instrument provided with a system for controlling tone-modifying circuits by muscular voltages, according to an exemplified embodiment of the present invention;

FIG. 2 is an illustration representing a combination of a console of an electronic organ and the player on which a plurality of muscular voltage pickup means and a signal transmitter are mounted;

FIG. 3 is a block diagram showing a muscular voltage processing circuit and a modulator and a transmitter, etc., which are mounted on the body of the player;

FIGS. 4A and 4B are block diagrams showing a receiver and tone signal control circuits or tone signal modifying circuits of the instrument, respectively, which are located in the a console of the instrument;

FIGS. 5A to 5F are waveforms of the signal in a muscular voltage processing circuit and a transmitter of this invention;

FIG. 6 is a block diagram showing an embodiment for providing a pulse signal depending on a muscular voltage;

FIG. 7 is a circuit diagram showing a more concrete example of FIG. 6;

FIGS. 8A and 8B are pulse waveforms which are to be provided from the muscular voltage processing circuit shown in FIG. 6 or FIG. 7;

FIGS. 9 to 11 are block diagrams showing several examples for controlling one or more tone-modifying circuits, respectively;

FIGS. 12 to 14 are pulse waveforms shown to explain the operation of FIGS. 9 to 11, respectively;

FIG. 15 is a block diagram showing another embodiment of the present invention;

FIGS. 16A to 16C are diagrams showing waveforms for explaining the circuit of FIG. 15;

FIG. 17 is a modification of FIG. 11;

FIG. 18 is a block diagram, showing another embodiment of the muscular voltage processing circuit at the output of which is obtained an analog signal having been subjected to wave shaping;

FIG. 19 is a circuit diagram showing a more concrete example of FIG. 18;

FIGS. 20A to 20F are diagrams showing waveforms obtained at several points of blocks of FIG. 18 or FIG. 19;

FIG. 21 is a modification of FIG. 18 which is somewhat similar to FIG. 15;

FIGS. 22a to 22c are waveforms for explaining the operation of FIG. 21;

FIG. 23 is a block diagram of an arrangement of a plurality of muscular voltage pickup means and muscular voltage processing circuits for providing a large amount of muscular voltage;

FIG. 24 is a schematic circuit block diagram showing an example of a muscular voltage-controlled tone effect control system; and

FIGS. 25 to 28 are various modifications of FIG. 23.

It is to be undustood that like reference and numerals indicate like parts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, there is illustrated an electric musical instrument such as a key-actuated electronic organ generally indicated at 1 which comprises -- as its playing actuators -- manual keyboards 2 and 3 arranged in multiple stages, a pedal keyboard 4, an expression pedal 5, and so forth. A pair of electrodes 6a and 6b electrically associated with a grounded electrode 6c are adapted to be securely mounted on the body of the player at appropriate 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, whereby 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.

As shown in FIG. 3, the electrodes 6a and 6b are connected with both end of a primary winding 11 of a transformer L through a shielded wire 7 shown in FIG. 1, which transformer constitutes a part of a muscular voltage processing circuit E1 shown by a two-dot chain line block in FIG. 3, while the secondary winding 12 thereof is connected to an input side of an amplifier circuit Ao of which the output is connected subsequently with a non-linear circuit 8 composed of two diodes having non-linear characteristics which are connected in parallel with and in reverse polarization with each other, for cutting off said background noise contained in the muscular voltage picked up by the electrodes, a bandpass filter 9, a rectifier circuit 10 and and an integrator circuit 11 such as a Miller circuit. In the muscular voltage processing circuit E1 thus formed, the picked-up muscular voltage having the waveform of FIG. 5A may be obtained at the output of the amplifier Ao. The background noise component of the voltage is cut off through the non-linear circuit 8 and the bandpass filter into a waveform of FIG. 5B, and then it is rectified by the rectifier 10 into a unidirectional waveform signal as shown in FIG. 5C. The unidirectional signal is integrated into a pulsated unidirectional signal as shown in FIG. 5D by the integrator 11.

The block D of FIG. 3 shows a transmitter which includes at least one sub-carrier oscillator 121 generating a sub-carrier signal which has a constant amplitude and is relatively low in frequency, for example, 14.5 kHz, as shown in FIG. 5E and a frequency-modulator 131 (see, e.g., Markus, Sourcebook of Electronic Circuits, McGraw-Hill, 1968, Pg. 458) in which the generated subcarrier signal is frequency-modulated with the processed muscular voltage having the waveform of FIG. 5D and applied to a modulation terminal t1 of the modulator, thus producing a modulated signal as shown in FIG. 5F at the output of the modulator. In the same manner, a plurality of such arrangements may be provided. That is to say, other muscular voltage processing circuits E2, ---, En may be provided corresponding in number to the muscular voltage pickup means mounted in different positions of several kinds of muscles of the player, such as the trapezius and the biceps of a thigh, independently. Accordingly, individual output signals of the circuits E2, ---, En based on respective muscular voltage pickup means may be applied at terminals t2, ---, tn as the modulating signals for other frequency modulation circuits composed of modulators 132, ---, 13n and subcarrier oscillators 122, ---, 12n, respectively.

Subcarrier frequencies generated by such oscillators 122, ---, 12n for example, can be set at 10.5 kHz, 7.35 kHz. The respective output terminals of the modulators 132, ---, 13n are arranged so that the modulated subcarrier signals may be mixed with the above-mentioned output signal of the modulator 131. Thus, the mixed subcarrier signals modulated with the muscular voltages are applied to a modulating input terminal of a main modulator circuit 15, and a radio frequency signal generated by a main oscillator 14 as a carrier -- for example, a VHF signal of 100 MHZ having a constant amplitude -- is frequency-modulated by the applied subcarrier signals. Then, the frequency-modulated VHF signal is amplified through an amplifier circuit 16 and emitted from a transmitting antenna means 17. Thus, the block E1 and block D constitute a muscular voltage processing and transmitting circuit assembly B as a whole. This assembly B is mounted in place on the body of the player in a manner as shown in FIG. 2.

On the other hand, in the console 1A of the organ 1 reception antennas 18 are disposed to receive a radio wave emitted from the antenna 17, which are preferably of a dipole type or the Yagi antenna type, as shown in FIGS. 1 and 2. Incoming signals received by the antenna 18 are processed by a receiver means shown in FIG. 4A in various manners. That is to say, the incoming signals are at first amplified by an amplified 19, and are demodulated through a demodulator 20 such as a frequency discriminator and are fed through bandpass filters 211, 212 ---, 21n which are respectively adapted to select subcarrier signals having frequencies corresponding to oscillation frequencies of the subcarrier oscillators, of 14.5 kHz, 10.5 kHz and 7.35 kHz, thus effecting separation of the multiple modulated signals, and then the respective separated signals are subjected to further frequency-demodulation by means of demodulators 221, 222 --- 22n, individually, thus resulting in DC signals having the original waveform shown in FIG. 5D at respective terminals T1, T2, ---, Tn connected at the output sides of the demodulators 221, 222, ---, 22n. The DC signals can vary in level in response to the degree of contraction of muscles on which the muscular voltage pickup means are mounted.

By the use of the DC signals, various controls for tone-modifying circuits (see, e.g., Journal of the Audio Engineering Society, Vol. 13, No. 3, July 1965, pages 200-206) of the electronic musical instrument can be effectively carried out.

For example, as shown in FIG. 4B, either a tone signal per se in the instrument or the control circuit for controlling a tone signal-modifying circuit is subjected to the control by its electrical characteristics such as amplitude, frequency and phase to thereby vary the tone volume, the tone pitch, the tone color or other tonal effects in the instrument.

In FIG. 4B, symbol O represents tone generator circuits which correspond in number to that of keys which are arranged in the instrument.

Individual tone signals generated by a number of said tone generator circuits are keyed by the respective key-operated keying circuits K and then the keyed tone signals are fed to tone coloring circuits F having filters therein. The output signals of the tone coloring circuits are applied to a tremolo effect producing circuit M and are fed through a power amplifier A to an electro-acoustic transducer such as a speaker SP. To the tone generator O is also connected a vibrato effect producing circuit V, i.e., a very low frequency oscillator, whereby individual oscillation frequencies at the oscillators of the tone generator circuits O are varied to provide vibrato effects. The tremolo effect producing circuit M effects amplitude modulation of the input tone signals to produce tremolo effects. To the respective control terminals of these tone modifying circuits are connected output terminals T1, T2, ---, Tn of the receiver of FIG. 4A, which correspond to muscular voltage processing circuits E1, E2, ---, En, by way of a radio transmission system. Since the levels of the DC signals developed at the terminals T1, T2 ---, Tn depend upon the magnitude of the picked-up muscular voltages, i.e., the amount of contraction of the above-mentioned muscles, the signals are used as the control signals to vary the oscillation frequency or oscillation output level of the vibrato effect-producing circuit V by variably changing biasing of oscillative elements and the feedback ratio, to vary the frequency characteristic of the filter in each tone coloring circuit F and also to vary the amplification of the amplifier circuit A, respectively. For example, the amplifier circuit A may be so arranged to have a variable impedance element such as a gate-controlled field effect transistor for variably controlling its output level to vary the output volume of the speaker SP in accordance with the degree of extension or bending of muscle in wireless system. Thus, the use of a variable impedance element of which impedance can be increased or decreased in accordance with the degree of contraction of muscle permits the provision of the same effects as that produced by the conventional expression pedal, for example, by bending the arm or fingers onto which muscular voltage pickup means are attached, or by applying a force thereto. In case the pickup means are mounted on the trapezius or the biceps of a thigh, the output volume of the instrument may be adjusted by an up and down motion of the shoulder or the leg.

The output signals at terminals T1, T2, ---, Tn may be used to control electromagnetically actuated tablets of the instrument through a monostable multivibrator as well as to control the motion of the tremolo effect-producing rotary speaker.

Though in the embodiment, a frequency-modulation transmission system has been employed, phase-modulation type, amplitude-modulation or pulse code modulation type may, of cource, be substituted therefor. The above-mentioned non-linear circuit 8 and the bandpass filter circuit 9 may be dispensed with if necessary, but this does not essentially adversely effect the principal operation of the circuits of this embodiment. Each antenna used in this invention is preferably of a directional type to eliminate any interference noise, and is located preferably inside the console on the upper side thereof to provide high antenna efficiency.

Referring to FIG. 6, there is a shown -- as a muscular voltage processing circuit G -- a circuit arrangement for producing pulse wave signals from a muscular voltage, which comprises a transformer L having a primary winding 11 connected with a muscular voltage pickup means of the above-mentioned type and a secondary winding 12, an amplifier Ao connected with said secondary winding 12, for amplifying a minimal muscular voltage picked up by the pickup means, a non-linear circuit 8, a bandpass filter 9, a rectifier circuit 10 for cutting off the background noise, an integrator circuit 11, a clipper circuit 30 having an output terminal T1 at its output side, and a differentiator 31 having a terminal T', all of which are provided in sequential series connection.

FIG. 7 shows a circuit, in a concrete form, of FIG. 6 only by way of example. In operation, the amplifier Ao amplifies a muscular voltage having such a waveform as the one shown in FIG. 5A 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. Thereafter, semiconductor diodes d1 and d2 which are connected in parallel and in mutually opposing polarities in the non-linear circuit cut off the background noise component, if any, of a relatively low level which is contained in the amplified muscular voltage so as to be processed into such one as is shown in FIG. 5B. The resulting waveform voltage is fed to the bandpass filter 9 having the range of for example 120 up to 500 Hz, whereby minimal variations in the envelope of the input voltage are eliminated, and then it is amplified and rectified by the rectifier 10, thus providing at its output a unidirectional voltage signal as shown in FIG. 5C. This unidirectional voltage signal is integrated by the integrator 11 to develop a signal having the waveform of FIG. 5D. Then, it is fed to the clipper circuit 30 which is formed with a saturated amplifier or Schmitt circuit to provide a pulse signal of a square waveform having a predetermined level as shown in FIG. 8A. This square waveform signal may be derived at the terminal T. It should be understood that the signal may be derived in the form of a pulse signal having such a percussive waveform as shown in FIG. 8B through the differentiator.

Now, referring to FIGS. 9 to 14, there is made a description of several examples of the manner for controlling tone-modifying circuits in an electronic musical instrument or the like by making use of the muscular voltage processed in the manner as described above.

As one of the simplest such examples, a system of FIG. 9 is referred to. This system includes a muscular voltage processing circuit G capable of producing a pulse signal having the waveform as shown in FIG. 12A in such a manner as described in FIG. 6, and a flip-flop circuit 40 adapted to receive the pulse signal at its input side and to become conductive and non-conductive alternately for the successive respective pulse input, as shown by the waveform of FIG. 12B. This flip-flop is connected to tone-modifying circuits, such as an automatic rhythm generator, and starters-stoppers of the rhythm generator for imparting several kinds of tonal effects, which are provided in the form of switching means, respectively. For example, in case the muscular voltage pickup means is mounted on the arm, shoulder or foot of the player, this system permits a first motion of the pickup-mounted portion of muscle to start the tone-modifying circuits or impart the tonal effects, while a second motion thereof to stop the operation of the circuits or release the application of the tonal effects in the instrument. Thus, the system provides a increased expression power for music being played.

FIG. 10 shows a more complex muscular voltage-controlled tone-modifying system, which comprises a muscular voltage processing circuit G of the type described above, a computer or counter circuit 42, a plurality of monostable multivibrators 431, 432, ---, 43n individually connected to the counter 42, and tone-modifying circuits 441, 442, ---44n connected with the above-mentioned multivibrators, respectively. In operation, the counter 42 performs the counting of the number of pulse signals produced from the processing circuit G in accordance with the contraction of the muscle having pickup means mounted thereon, per unit time, and produce several different kinds of signals each being specified to its mating multivibrator, in accordance with the result of the pulse count, whereby the multivibrators 431, 432, ---, 43n may be selectively actuated. When a pulse per unit time (FIG. 13A) is applied to the counter 42, the first monostable multivibrator 431 is actuated to become conductive for a predetermined period of time T (FIG. 13B), and actuates only the first tone-modifying circuit 441, which imparts either a first tonal effect or selectively any other desired tone coloring effect to the music being played, accompanied by an automatic releasing action. When two pulses are applied successively to the counter 42 (FIG. 13C), the second multivibrator 442 alone is actuated, to render only the second tone modifying circuit 442 operative to impart either a second tonal effect or selecting a tone-coloring effect to the music being played, thereafter releasing these actions to return to the initial ordinary state of playing. Similarly, it should be easily understood that an nth multivibrator and its tone-modifying circuit provided on the subsequent stage are operated in the same manner as described above, as seem from the relation shown in FIGS. 13E and 13D.

FIG. 11 shows a modification of FIG. 10, in which a reversible ring counter 45 is provided in place of the counter 42, whereby a number of multivibrators 461, 462 ---, 46n which are connected in parallel with the counter 45 are energized and de-energized sequentially. For example, when a series of pulses shown in FIG. 14A are fed to the counter 45, its corresponding monostable multivibrators are made sequentially operative, rendering themselves conductive, as shown in FIGS. 14B to 14E. These complex actions can be applied individually or/and in combination for controlling the output volume, or/and for changing the tone colors or/and for controlling the tone control signals, thus producing several different kinds of tonal effects, or/and for turning the leaves of the score, or/and controlling the direction of the output speaker. Thus, they can remarkably simplify the pattern of the playing of the instrument as well as permit an excellent colorful playing, to provide delicate complex tonal effects at the will of the player.

Referring now to FIG. 15, there is shown another example of a muscular voltage-controlled tone-modifying circuit system which produces two-way pulse signals as shown in FIGS. 16A and 16B, by the means of separate muscular voltage processing circuits G and G1, each being connected through an individual transformer L to a corresponding muscular voltage pickup means. Separate pulse signals are produced in association with contractions of muscles of the left and the right hands 46A, 46B of the player to which pairs of electrodes 47a and 47b of the pickup means are attached. These pulse signals are fed to two separate input terminals of a flip-flop circuit 40, respectively, and as a result, the flip-flop circuit is rendered to the conducting state and the non-conducting state, alternately in the manner shown in FIG. 16C, in association with the pulse inputs for the flip-flop 40 of FIGS. 16A and 16B. The output of the flip-flop circuit 40 is coupled with the tone-modifying circuit 41 of the instrument. The pickup electrodes 47a and 47b may be attached to selected skin portions of the shoulder or the legs of the player in place of the arms 46A and 46B. The arrangement of FIG. 15 is advantageous in that, even though the muscle on which a pickup means is mounted is successively moved, the state of the flip-flop means is not altered excepting the application thereto of an initial pulse input. Therefore, a failure-free playing can be attained with this instrument. That is to say, any unexpected erroneous operation by the player may be avoided.

The muscular voltage processing circuits G and G1 may be applied to the input terminals of the ring counter 45 of FIG. 11 as shown in FIG. 17, in such a manner that a signal from the circuit G causes the counter to function in a certain form and direction, while another signal from the other circuit G1 causes this counter to act in the reverse direction and form.

FIG. 18 illustrates another example of the system according to the present invention, which provides an analog signal based on a muscular voltage. The system E50 is somewhat similar to that of FIG. 6 in the manner of providing a muscular voltage pickup means composed of pair electrodes 6a, 6b and a grounded electrode 6c, a transformer L, an amplifier A50, a non-linear circuit 58, a bandpass filter 59, and a rectifier 60. However, the former is provided further with a time constant circuit 61 connected with the rectifier circuit 60 and having an output terminal T50. An example of a more concrete circuit arrangement of FIG. 18 is illustrated in FIG. 19.

The operation and function of this circuit will be described with reference to FIGS. 20A to 20F. A muscular voltage which appears across the electrodes-mounted muscle of the arm upon extension or bending thereof generally takes the pattern as indicated in FIG. 20A. This voltage is passed through the amplifier A50 and the non-linear circuit 58 intended for cutting off a low level background noise contained in the voltage, to be processed into the waveform as shown in FIG. 20B. A signal having the waveform shown in FIG. 20C is developed at the output side of the rectifier 60 after passing through the bandpass filter 59 having the pass band characteristic, for example, between 120 and 500 Hz, and then it is applied to the circuit 61 such as a Miller integrator to thereby produe a pulsated DC signal having a delay characteristic waveform of FIG. 20E or FIG. 20F, at the terminal T50.

According to this embodiment, a preferred continuous or analogous signal may be obtained as control signal for the instrument by making use of a muscular voltage which appears across a muscle upon contraction thereof and which is destined to perish in a very short length of time. This signal permits a continuous control for the instrument by means of the time constant circuit. This signal has a DC envelope which is analogous to the peak levels of the picked-up muscular voltage, and is retained for a predetermined period of time from the time of generation of the muscular voltage.

FIG. 21 illustrates a modified muscular voltage processing circuit arrangement intended for performing differential control of the tone-modifying circuits which are provided in an electronic musical instrument, 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 player's body, and by processing the picked-up muscular voltages. The terms "mutually associated pair" or "paired muscles" which are used herein points to such a pair of pairs of muscles that one of the muscles forming a pair may be a muscle of the left forearm and the other may be the counterpart of the right forearm, or one of which may be a muscle of an index finger of the left hand and the other may be the counterpart of the right foot. To attain the aforesaid purpose, at least two pairs of pickup electrodes 57a and 57b are attached to, for example, the right foream 56A and the left forearm 56B of the player, respectively. These respective paired electrodes are connected through transformers L to muscular voltage processing circuits EA and EB, respectively, which are of the type as described in connection with FIG. 18 or FIG. 19. Output terminals TA and TB of the respective circuits EA and EB are connected through resistors R1 and R2 to gate electrodes q1 and q2 of field effect transistors (referred to as FET's) Q1 and Q2, respectively. The drain of FET Q1, is connected to a power source +Vcc and the source of FET Q2 is grounded, while the source of FET Q1 and the drain of FET Q2 are connected to a common connection point qo and led to an output terminal To thus constituting a muscular voltage differential synthesizer E. In such an arrangement, two unidirectional envelope signals obtained from the circuits EA and EB in the manner as from FIG. 18 are differentially synthesized into a signal having the waveform shown in FIG. 22a at the output terminal To. The signal thus obtained is utilized to control the tone-modifying circuits, e.g., for the controlling of the speaker volume of the instrument, as shown in FIG. 22b. That is to say, by the extension and bending of the right forearm 56A, the tone volume of the speaker may be adjusted for an increase with respect to a predetermined level Vo of volume, whereas by the extension and bending of the left forearm 56B, the output volume of the speaker may be adjusted for a decrease with respect to said level Vo. Thus, a tonal effect similar to that produced by the use of the expression pedals may be easily attained.

Furthermore, this arrangement can produce a sustained signal having a desired amplitude envelope for controlling the tone-modifying circuits, merely by a single contraction of the muscle or by a single application of force to the muscle on which the pickup means are mounted, for a relatively short time such as 1 second or less. As a result, the fatigue of the player can be reduced to a great extent. When the sustain signal is used to control a tremolo effect-producing circuit or a vibrato effect-imparting circuit of the instrument, the tremolo frequency or the vibrato frequency can be varied in a manner as shown in FIG. 22c in accordance with the degree of contraction of the muscles.

Turning now to FIGS. 23 to 28, there are illustrated various examples of muscular voltage synthesizing and processing systems for collecting a number of miminal muscular voltages picked up from paired muscules located at two or more different portions of the player's body to effectively provide a muscular voltage signal having a large amplitude.

In FIG. 23, a number of paired electrodes 6a, 6b; 6c, 6d; 6e, 6f are mounted on muscles located at two or more different portions of the player's body in pairs and connected via shielded wires to the primary windings of coupling transformers L1, L2 ---, Ln disposed at the input side of the muscular voltage processing circuits E1, E2 ---, En respectively. At the output side of the respective processing circuits are connected mixing resistors R1, R2, ---, Rn, respectively, and a bank of the resistors are connected in common to led point ro which, in turn, is grounded via a resistor Ro and is also let to a terminal ta. Thus, a block EA constitutes a muscular voltage synthesizing and processing circuit. Each muscular voltage processing circuit can be of the type as described previously. Each signal derived from the terminal ta may be applied to any control terminal of tone-modifying circuits of an electronic musical instrument. An example of such system is illustrated in FIG. 24, in which O represents tone generator circuits which are provided so as to correspond in number to the playing keys arranged in the musical instrument. A tone signal generated from a tone generator O is keyed by a key-controlled keyer circuit K and is passed through a tone coloring circuit F formed with a filter. Such an output signal is fed to a tremolo effect producing circuit M and then to a power amplifier circuit A and therefrom to an electro-acoustic transducer such as a loudspeaker SP. For the tone generator O is also provided a vibrato effect producing circuit V for varying the oscillation frequency of each tone generator by means of, for example, a voltage-controlled variable impedance element. The tremolo effect producing circuit M effects amplitude modulation of the tone signal supplied from the tone coloring circuit F. EA1, EA2, ---, EAn indicate muscular voltage synthesizing and processing circuits of which each is constituted in the same manner as described in connection with FIG. 23. These circuits EA1, EA2, ---, EAn are connected to the above-mentioned vibrato effect producing circuit V, tone coloring circuit F, and tremolo-effect producing circuit M, respectively, 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 muscular voltages.

FIG. 25 illustrates a muscular voltage coupling arrangement EC having a single transformer Lo connected with a muscular voltage processing circuit E.

At the primary of the transformer, a number of primary windings are provided individually, across each of which a pair of muscular voltage pickup electrodes 6a, 6b; 6c, 6d or 6e, 6f are connected, and the center tap of each primary winding is grounded. At the output side of the circuit E is provided an output terminal tc which develops a summed-up muscular voltage. On the other hand, in FIG. 27 which is associated with FIG. 25, a muscular voltage coupling circuit EB has a plurality of transformers L1, L2, ---, Ln which correspond in number to the paired pickup electrodes. Secondary windings of the transformers are connected in series, both ends of which are grounded and connected to the circuit E. The pickup electrode pairs may be connected in parallel to a single primary winding of the transformer L, as shown in FIG. 26. Instead, the paired pickup electrodes may be connected in series with a single primary winding as shown in FIG. 28. Thus, when a series of paired pickup electrodes are mounted on selected portions of the muscles of the player, the above-mentioned muscular voltage collecting arrangements permit a synthesized muscular voltage signal having large DC level variations to be obtained, so that it becomes possible to effect desired control -- in a wide, dynamic range -- of the music being played on the instrument.

As has been described above, the present invention permits various kinds of complex tonal effect controls to be performed in an electronic musical instrument or the like in whatever way as intended by the player by making use of muscular voltages appearing across muscles of the player's body upon contraction thereof.

It will be understood, of course, that various changes, alterations and modifications of the present embodiments can be made without departing from the scope of the invention.