US3652774A

US3652774A - Keying system for electronic musical instruments

Info

Publication number: US3652774A
Application number: US80937A
Authority: US
Inventors: Junji Ohno
Original assignee: Nippon Gakki Co Ltd
Current assignee: Nippon Gakki Co Ltd
Priority date: 1969-10-16
Filing date: 1970-10-15
Publication date: 1972-03-28
Anticipated expiration: 1989-03-28

Abstract

In an electronic musical instrument having playing keys of a keyboard and associated keyer circuits, the effect of doublecontrol can be obtained by the provision of a keying system including first and second keyer controllers provided for each key to control the respective keyers. The first keyer controller is operative for normal key depression stroke prior to the key''s lowest position, while the second keyer controller is responsive to a depressing force applied to the key during its stay at the lowermost end of its stroke.

Description

United States Patent Ohno 1 51 Mar. 28, 1972 .[54] KEYING SYSTEM FOR ELECTRONIC MUSICAL INSTRUMENTS [72] Inventor: Junji Ohno, Hamamatsu, Japan [73] Assigneez' Nippon Gakki Selzo Kabushiki Kaisha,

' Hamamtsu-shi, Shizuoka-ken, Japan 22' Filed: Oct. 15,1970

21 Appl.No.: 80,937

[30] 7 Foreign Application Priority Data Japan...; ..44/82723 Oct. 16, 1969 Oct. 16, 1969 Oct. 16, 1969 Oct. 16, 1969 Oct. 20, 1969 Oct. 20, 1969 Oct. 22, 1969 Oct. 22, 1969 Oct. 24, 1969 Oct. 24, 1969 Oct. 24, 1969 Oct. 24, 1969 Japan .::..44/8505 8 [52] [1.8. CI. ..'.84/l.24, 84/].26, 84/DIG.'7

s11 1m.c|.....; ..G10h1/02 58 Field ofSearch ..s4/1.01, 1.24, 1.26,D1G. 7, 84/121, 1.27

[56] References Cited UNITED STATES PATENTS 3,564,105 2/1971 Amano ..84/1 .01 2,296,125 9/1942 Traub....

2,848,920 8/1958 Lester....

3,463,867 8/1969 Pavig 3,507,970 4/1970 Jones 3,544,695 12/ 1 970 Dijksterhuis ..84/1 .26 3,567,839 3/1971 Dijksterhuis ..84/l.26

Primary Examiner-Thomas J. Kozma Assistant Examiner-Ulysses Weldon Attorney-Cushman, Darby & Cushman [57] ABSTRACT In an electronic musical instrument having playing keys of a keyboard and associated keyer circuits, the effect of doublecontrol can be obtained by the provision of a keying system including first and second keyer controllers provided for each key to control the respective keyers. The first keyer controller is operative for normal key depression stroke prior to the keys lowest position, while the second keyer controller is responsive to a depressing force applied to the key during its stay at the lowermost end of its stroke.

22 Claims, 37 Drawing Figures OUTPUT SIGNAL LEVEL PATENTEDMARZMQYE'V I 3, 52,774

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T FIG. 6d LIJ 3 FIG. 6e m U I z E (D KEY PRESSURE INVENTOR.

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KCONT CKT TONE I (EYER VCC' KEY TIME KEY INVENTOR, DEPRESSED DELEASED i H A 1702,06 vs PATENTEDMAR28 m2 SHEET on HF '10 FIG .80

IET T" K Rzu C2| d LEVEL RESISTANCE VALUE KEY PRESSURE 1 FIG. 8d-' KEY DEPRE SSED RELEASED I INVENTOR. BY \JbVlJi I I aukm A47 70PM V3 PATENTEDMAR28 m2 SHEEI GSUF 10 FIG .90

"TEE: REYEKTS T KP 1 F|G.9c J F|G.9f

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BY Jam 0/010 M I n (mars PATENTfnmARze 1972 3,55 ,77

sum 08 0F 10 FlG.l|o

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DEPRESSED RELEASED DEPRESSED RELEASED KEY TIME KEY DEPRESSED ED INVENTOR.

W?0 7 r erronueyi' KEYING SYSTEM FOR ELECTRONIC MUSICAL INSTRUMENTS BACKGROUND OF THE INVENTION 1. Field of Invention The present invention is concerned with electronic musical instruments, and more particularly it relates to keying system for electronic musical instrument having playing keys, which is capable of making double control of the keyer associated with the key and operable during the depression of this key.

2. Description of the Prior Art In the conventional electronic musical instrument, tonal effects once produced from depression of a key could not be further controlled at all by the operator. That is, once a playing key for keying a keyer provided for each key in associated relation therewith is depressed by the operator, the keyer which is thus actuated can no longer be controlled by any key depressing action. That is to say, according to the instrument of the prior art, it was impossible to make the so-called aftercontrol" which means that the tone envelope produced from a nonnal key depression can be additionally varied in its mode by a further operation of the once-depressed key. For this reason, there was encountered the inconvenience in the past that no desired delicate tonal effects of the music being played could be obtained once a key was depressed.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a novel keying system for an electronic musical instrument, which is capable of making after-control to produce delicate tonal effects according to the desire of the person who plays the instrument.

Another object of the present invention is to provide a novel keying system for the instrument of the type described, said system having first and second keyer control means capable of performing double control, i.e., being operative successively in accordance with a normal and a subsequent further depression of an associated key.

A still another object of the present invention is to provide a novel keying system for the instrument of the type described and capable of producing combined tone envelopes as required.

A further object of the present invention is to provide a novel keying system for the instrument of the type described and capable of combining tone signals different from each other by virtue of an initial controller and a subsequent controller both of which are associated with the same playing key.

Another object of the present invention is to provide a novel keying system for the instrument of the type described and capable of controlling the decay time or amplitude characteristics of a percussive signal and/or an attack signal.

Yet another object of the present invention is to provide a novel keying system for the instrument of the type described and capable of producing the so-called touch-responsive tone envelope effect such that a keyed tone signal has an amplitude in accordance with the intensity of depression of an associated key, as well as the so-called after-control effect such that the keyer is controlled in accordance with a further depression applied to the playing key after normal depression of the same.

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

BRIEF DESCRIPTION OFTHE DRAWINGS FIG. 1 is a somewhat diagrammatic side elevation, partly in section, of a keyboard of an electronic musical instrument, showing an embodiment of the present invention;

FIG. 2 is a schematic block diagram, showing the novel keying system embodying the present invention for use in the instrument; 1

FIG. 3 is a somewhat diagrammatic side elevation, partly in the present invention;

FIGS. 4 and 5 are similar views of the keyboard, showing further embodiments of the present invention, respectively;

FIGS. 6a through 6e illustrate another embodiment of the present invention, in which: FIG. 6a is a schematic block diagram of the novel keying system embodying the present invention;.FIG. 6b is a circuit diagram associated with a playing key and showing an example of FIG. 6a; FIG. 6c is a somewhat diagrammatic side elevation, partly in section, of an essential portion of the keyboard for said example; and FIGS. 6d and 6e are charts for explaining the function of the said keying system;

FIGS. 7a through 7c are illustrations of the novel keying system according to a still further embodiment, in which: FIG. 7a is a schematic block diagram showing this embodiment; FIG. 7b is a circuit diagram associated with a playing key and showing an example of FIG. 7a; and FIG. 7c is a chart for explaining the function of this embodiment;

FIGS. 8a through 8e are illustrations of another embodiment of the present invention, in which: FIG. 8a is a circuit diagram associated with a playing key; FIG. 8b is a somewhat diagrammatic side elevation of an essential portion of the keyboard for this embodiment; and FIGS. 8c to 8e are charts for explaining the function of this embodiment;

FIGS. 9a through 9f are illustrations of still another embodiment of the present invention, in which: FIG. 9a is a schematic block diagram showing this embodiment; FIG. 9b is a circuit diagram showing an example of FIG. 9a; and FIGS. to 9f are charts for explaining the function of this system;

FIG. 10a is a block diagram showing another embodiment of the present invention, and FIG. 10b is a circuit diagram showing an example of FIG. 10a;

FIGS. Ila through lle are illustrations showing a further embodiment of the present invention, in which: FIG. 11a is a schematic block diagram showing this embodiment; FIG. 11b is a circuit diagram associated with a playing key and embodying an example of FIG. 11a; FIG. 11c is a somewhat diagrammatic side elevation of an essential portion of the keyboard for this embodiment; and FIGS. 11d and lle are charts for explaining the function of mainly this embodiment;

FIG. 12a is a circuit .diagram associated with a playing key and showing a still further embodiment of the present invention; FIGS. 12b and 12c are charts for explaining the function of mainly this embodiment;

FIG. 13a is a schematic block diagram of another embodiment of the present invention; FIG. 13b is a circuit diagram associated with a playing key and showing a modification of FIG. 9a; and FIG. is a chart for explaining the function of DESCRIPTION OF THE PREFERRED EMBODIMENTS Description of the present invention will be made on several embodiments by referring to the accompanying drawings.

Referring to FIGS. 1 and 2, there is shown a basic embodiment of the present invention, in which numeral 1 represents one of a pluralityof playing keys contained in the keyboard and spaced with a required distance from a frame 2, each key 1 been pivotally supported by a support 2a extending upright from the rear end of the frame 2. Between the rear end of the key 1 and the frame 2, there is provided a tension spring 3 to normally keep the key in the normal horizontal position. At the bottom surface of the forward portion of the key I, there are provided a shouldered portion 1a for applying a pressure force onto a pressure-sensitive resistance element 5 which will be described later and which is provided therebelow on the forward portion of the frame 2, and a stopper lb provided on the downward extension of the shouldered portion la for limiting the upward movement of the key 1 to thereby normally hold the key in place.

From the bottom face of an intermediate portion of the key 1 behind the shouldered portion 1a, there extends downwardly a lever 1c. A magnet 4 is secured to the lower end of this lever 10. The pressure-sensitive resistance element 5 which may be a piece of electroconductive rubber, a pressuresensitive diode or the like is provided on the upper side of the frame 2 so as to face said shouldered portion In at a predetermined interval therebetween. A coil 6 is wound around a bobbin located on the frame 2 behind the extension of the shouldered portion la to face the magnet 4 at a predetermined interval therebetween. The shouldered portion 1a is arranged so that it is brought into contact with the pressure-sensitive resistance element 5 at substantially the lowermost end position of the keys normal stroke. Further, an actuator 7 for actuating a key-switch which is seen as a block defined by a phantom line in FIG. 1 is mounted, for vertical movement, on the bottom of the key 1 so as to pass through the frame 2.

The coil 6 and the pressure-sensitive resistance element 5 constitute a key speed detecting circuit KS and a key pressure detecting circuit KP, respectively. These circuits are connected to tone keyers S, and S for controllably gating the tone signal. The actual circuit construction of the keyers will be explained in detail hereinlater with respect to an other embodiments. The tone signal is entered at a common input terminal T of the keyers and then is derived at a common output terminal T, as an output signal having various electrical characteristics in response to the speed of the key being depressed which is detected by the coil 6 and to the pressure applied onto the same key detected by the element 5. The terminal T at the input side of the keyers S,. and 8,, is connected to a tone generator circuit (not shown). The key speed detecting circuit KS, the key pressure detecting circuit KP and the keyers S, and 8,, respectively correspond in number to the number of tone generator circuits provided in association with the playing keys in the electronic musical instrument.

In operation, in the state of the instrument where the key 1 is about to be depressed, there is produced no change in the flux in the coil 6 and, accordingly, the actuator is rendered inoperative, retaining the closed state of the normally closed contact (not shown) of the key switch. However, as the key 1 is depressed from the aforesaid inoperative position, the magnet 4 secured to the lever 10 of this key 1 is forced to move downwardly, and approaches, with certain speed, the coil 6 located thereunder. Along with-this, the shouldered portion 1a of the key 1 is brought into contact with the pressure-sensitive resistance element 5, and accordingly the sides of the magnet 4 are positioned to face the coil 6. As the magnet 4 approaches the coil 6 at a given speed, the already established interlinking fluxes around the coil 6 are caused to vary to produce an electromotive force therein. The electromotive force thus generated is then introduced into the tone keyer S as shown in FIG. 2 and this electromotive force is used to key the keyer to control the tone signal generated in the tone generator (not shown). In other words, when the key 1 is depressed strongly or with a substantially great speed, the magnet 4 also travels at a high speed toward the coil 6, and, as a consequence, the electromotive force generated in the coil 6 will have a greater magnitude. In contrast to this, when the key 1 is softly depressed or with a smaller speed to travel closer to the coil 6, the electromotive force generated in the coil 6 will have a much smaller magnitude. The keyer which keys or gates the tone signal generated from the tone generator into creasing amount of the applied pressure. As a consequence, the variation in the resistance value of the element 5 may be utilized to establish the amount of the electrical control of the keyer, e.g., the controlling voltage signal. The control signal thus established based on the variation in the resistance value of the pressure-sensitive element 5 is applied to the keyer circuit S of FIG. 2, so that the level of the tone signal generated by the tone generator may be varied corresponding to said applied pressure to the element 5. Thus, there is derived at the terminal T through both the keyers 5,, and S a keyed tone signal such that the tone signal whose amplitude is variable with the speed of the key depression and the tone signal whose envelope is variable in accordance with the magnitude of the pressing force applied onto the key during its stay at the lowermost end of its stroke are mixed together. Thus, this arrangement not only provides the advantage that the build-up envelope (amplitude) characteristic of the keyed tone signal can be varied in accordance with the normal depression of the key, i.e., the speed of the key depression socalled a touch-responsive control effect" but also it provides the so-called after-control effect as well.

Upon release of the depressed key 1, however, it returns to the normal position by means of the spring 3, and renders the keyer non-operative.

In FIG. 3, there is shown a modification of a keyboard assembly shown in FIG. 1, in which a flexible member 8 having a flexible arm capable of making a deflecting movement is securely provided on the frame 2, on which a strain gauge 9 constituting a pressure-sensitive element is mounted so that the gauge 9 may change its electrical resistance in response with the amount of the deflection produced by said fluxible member 8 as a result of the pressure applied thereto by the shouldered portion la of the key 1 being depressed. This modification of the pressure-sensitive member, i.e., the second control means, provides the same effects of the two types as those described in connection with the arrangement in FIG. 1.

As a substitution of the pressure-sensitive resistance element, theremay be used an arrangement comprising a magneto-sensitive element such as a magneto-sensitive semiconductor device mounted on the frame 2 and a magnet secured to the key 1 so as to face the semiconductor device. A piezoelectric element may be utilized instead. The first control signal generating means comprising the magnet 4 and the coil 6 also may be substituted by a combination of a magneto-sensitive element and a magnet, or by a key switch having, in combination, a fixed contact and a movable contact. It should be understood also that, in FIG. 2, tone signals which are different from each other may be supplied separately to the keyers S and S.

In FIG. 4, there is shown another modification of the second control signal generating means provided in the keyboard asthe terminal T may be triggered so that the keyed output level at the terminal T may be controlled in accordance with the magnitude of the generated electromotive force. Furthermore, the keyer circuit 8,, may be provided with a storing circuit for storing therein the electromotive force generated in the coil upon key depression, whereby the output of the keyer circuit may be maintained at the same keyed level for the period in which the key is being depressed.

On the other hand, during the stay of the key at the lowermost end of its stroke, if this key is depressed further to apply a pressure onto the upper face of the pressure-sensitive resistance element 5 at the pressing portion la, the resistance value of the element 5 decreases in accordance with the insembly, in which a flexible member 15, the pressure-sensitive resistance element 5 such as a strain gauge, a lower limit stopper 18 are arranged substantially in the reverse relation with the arrangement shown in FIG. 3. That is, on the bottom surface of the key 1, there is formed a recess 1d allowing deflection of the flexible member 15 spaced therefrom. The strain gauge 5 is mounted on this flexible member 15. The stopper 18 is positioned on the frame 2 in such a way that it may be brought into contact with the flexible member 15 to produce a deflection of this flexible member 15.

FIG. 5 shows a further embodiment of the keyboard assembly associated with a keying system. The embodiment features that actuation of both the first and second control signal generating means is effected by a single lever 4 having a magnet 4 at its end. Instead of the arrangement of the second control signal generating means shown in FIGS. 1, 3 and 4, a pressure-sensitive resistance element 17 such as an electro-conductive rubber, a pressure-sensitive diode on the like 1 is posi tioned on the central bottom of a hollow bobbin having a coil 6 wounded therearound. The magnet 4 is adapted to be brought into contact with the element 17 by a further depression of the key 1 to apply a pressure onto this element 17 during the stay of the key at the lowermost end of its stroke.

Referring now to FIGS. 6a through 6e, a still further embodiment of the present invention is described, in which in FIG. 6a, KS, and KP represent a key contact circuit and a key pressure detecting circuit, respectively, which will be described later. These circuits KS, and KP are assigned for the control of a tone signal keyer circuit SW in such a way that the tone signal applied to the terminal T, can be controlled in its level in accordance with the key depression and that a resulting keyed tone signal having a variety of envelope (amplitude) characteristics may be derived at the output terminal T, of the keyer circuit.

In FIG. 6b, there is shown a circuit diagram showing the details of the blocks shown in FIG. 6a, in which S represents generally a switch having a movable contact S, and a stationary contact 8,, and is adapted to close the movable contact S, upon depression of any one key K arranged on a keyboard of an electronic musical instrument. The movable contact S, is connected, through a resistor R,, with a field-effect transistor Q (hereinafter referred to simply as an FET) at the gate of the latter, which the stationary contact S, is connected, via a pres sure-sensitive variable resistor R,, with a power source +Vcc. This variable resistor R, has a resistance characteristic to vary its resistance value in response to the pressing force applied to the key K in such a way as shown in FIG. 6d. The juncture d between the switch S and the resistor R, is grounded through parallel-connected capacitor C and resistor R The source of FET Q is connected through a resistor R,, to a juncture e which lies between two bleeder resistors R, and R,, disposed in series between the power source +Vcc and the ground, and has a signal input terminal T,. The point e is grounded via a capacitor C,. The drain of the FET Q is connected via a resistor R,, to the source +Vcc, and has a signal output terminal T,,.

To the input terminal T, is applied a tone signal having a predetermined waveform from a known tone generator (not shown) such as a flip-flop type, while, at the output terminal T, there can be derived a keyed tone signal of a predetermined level by varying the conductivity between the source and the drain of the FET Q so as to correspond to the variation of the gate potential of the F ET Q which takes place depending upon the speed or amount of the key depressed. For the sake of simplicity, each block shown in FIG. 6a is enclosed by one-dot chain line.

The source voltage of the FET Q in the keyer is so set at a required level through the bleeder resistors R and R, that the FET is rendered non-conductive showing an extreme increase in the drain-source impedance when the gate potential is equal to ground or zero voltage. The element R, provided in the key pressure detecting circuit KP is so arranged that, as shown in FIG. 6c, it is adapted to be pressed upon by the shouldered portion k formed at a forward bottom portion of a key K which, in turn, is supported pivotably at a fulcrum 11 at its end, to apply a pressure onto the pressure-responsive element R, which is provided at a corresponding position on a frame 12.

The numbersof each of the circuits K8,, KP and SW which are housed in the console of the electronic musical instrument correspond in number, for example, 61, to the tone signal generators, respectively.

The operation of the above-mentioned embodiment will be described hereunder.

When any one of the keys K is manually depressed, the switch S is first closed to initiate the normal sounding of the tone at a level determined by the normal resistance value of the element R, as on the conventional electronic musical instrument, and, thereafter, if the pressure-responsive resistive element R, is pressed upon at its top surface by means of said surface k of the depressed key K'when the key K stays at its lowermost end of stroke, the resistance of he element R, will decrease in accordance with the amount of the pressure applied to the key as shown by the curve in FIG. 6d, and accordingly there will arise a change in the gate voltage of the FET Q in response to the amount of the pressure on the key, resulting in a variation in the source-drain impedance of the FET Q in compliance with the amount of the pressure applied onto the key. Thus, the input tone signal applied to the input terminal T, at the source side of the FET Q can be derived at the output terminal T a at the drain side of the FET Q. Such a keyed tone signal is permitted to vary its envelope of the output level in many ways in response to the amount of the pressure of the key with respect to time t as shown in FIG. 6e. Therefore, during the stay of the key K at the lowermost end of its stroke, if this key is depressed further, the gate potential of the FET Q will increase, the level of the keyed tone signal will become higher. On the other hand, when the key K is softly depressed during the above-mentioned stay of the key, a keyed tone signal of a normal lower level, i.e., a tone signal level control based on after-control," can be derived. Thus, there is obtained a special playing effect of the instrument.

Then, upon release of the depressed key K, it returns to the initial normal position by virtue of the resiliency of the spring 13, as shown in FIG. 60. Along with this, the pressure applied onto the element R, is released accordingly, and the resistance of the element R, becomes higher again, and then the switch S becomes open. As a result, the gate potential of the FET Q is rendered zero, resulting in the shutting off of the input tone signal applied to the terminal T,, and an output tone signal can no longer be detected.

Though the pressure-responsive variable resistive element whose resistance is decreased in accordance with a pressure applied thereto has been illustrated in this embodiment, the use of an element of the type in which its resistance is increased in accordance with the applied pressure, is of course possible. In which case, the wiring connection as shown in FIG. 6b, the element R, and the resistance element R, must be replaced by each other. Further, the switch S can be omitted in the wiring of FIG. 6b if the element R, used is of the type that its resistance value shows infinity or nearly zero when no pressure is applied.

In FIGS. 7a through there is shown a modification of the embodiment shown in FIGS. 6a through 6e. In this modified embodiment, the key contact circuit KS, and the key pressure detecting circuit KP are connected to the keyers S and S having separate input terminals T,, and T,,, respectively, and the respective outputs of the keyers are connected in common with each other to have a common output terminal T,,,. An example of a circuit diagram showing the details of the abovementioned block circuits is illustrated in FIG. 7b. However, detailed description of the circuit arrangement is omitted for the sake of simplicity. According to this modified embodiment, when one key K is depressed, its associated switches S and 8,, are closed. whereupon, a positive voltage which is produced at a divider circuit composed of resistors R,, and R,, is applied, via a resistor R,,, to a first FET Q11 at its gate, so that the FET Q,, is rendered conductive, and a first tone input signal applied to the terminal T,, which is connected with the source of the FET Q is derived at the terminal T,,. The first tone output signal can be continuously obtained in its predetermined level, depicting a curve A shown in FIG. 7c and independently of the speed of the key depression during the stroke of the key. On the other hand, when the switch 8,, is closed and when a pressure-responsive variable resistance element R, which constitutes a key-pressure detecting circuit KP is given a desired resistance value, by a further pressing action of the key-during its stay at the lowermost end of stroke, the gate voltage at an FET Q is altered to form a source-drain path of the FET 0,,, so that a second tone input signal applied to the input terminal T,, can be derived at the terminal T, connected to the drain of the FET Q,,. Accordingly, it will be understood that separate keyed tone signals developed in dividually from the FETs Q,, and 0,, are mixed together and developed at the terminal T,,. A waveform of this mixed signal is shown in FIG. 70 by way of example, of which curve B indicates variation in the envelope or the level of a tone signal keyed through the FET O This means that the envelope of the keyed signal may be varied with respect to time by a key pressing force at the lowermost end of the key stroke as vided a keyer control circuit forcausing the decay time of said signal to be varied in accordance with the pressure applied to a pressure-sensitive resistance varying element R, by further pressing of the key at its normal lowermost end of stroke. The keying system associated with each key schematically comprises a controlling power source circuit DC, a key pressure detecting circuit KP having the element R,, a key. contact circuit KS and the tone keyer circuit SC having a keying FET Q.

In a keyboard assembly as shown in FIG. 8b, a key K is pivotably supported at its one end on a fulcrum 21, and a frame 22 adapted to be subjected to a pressure of a shouldered portion k formed in the forward bottom portion of the key K is provided with a leaf spring 24 arranged in parallel with the frame 22 via a resilient spacer 23 formed with felt or rubber and provided at the position facing said shouldered portion k.

On one end of the leaf spring 24, there is provided the abovementioned pressure-sensitive resistance varying element R,

which may be either a conductive rubber, a strain gauge or a pressure-sensitive diode, in such a manner as is supported at its top by a support member or frame 25. Accordingly, when the key K is depressed against aresilient force of a restoring spring 26 which is provided between the rear ends of the key K and the frame 25, the shouldered portion k of the key K depresses the resilient spacer 23, so thatthe depressing force exerted by the leaf spring 24 onto the element R substantially absorbed by the resilient'spacer 23 and accordingly the resistance value of this element is increased in accordance with key pressure as shown in FIG. 8c, thus functioning as a key pressure detecting circuit KP. In the circuit of FIG. 8a, it will be noted that as the voltage changed on a capacitor C is ap plied through a resistor R to the gate of an FET Q, its drainsourceimpedance decreases in accordance with its input gate voltage level (as shown by a solid curve in FIG. 8d), and an input tone signal applied to an input terminal T of the keyer circuit can be derived at its output terminal T through the FET 0. At that time, if the key is faintly depressed to establish a smaller resistance inthe element R the positive voltage on I the charged capacitor C is abruptly discharged as shown by a solid curve in FIG. 8d, and as a result, the envelope of the output signal at the output terminal T becomes as shown by the curve A in FIG. 8e, thus providing an attack signal or a percussive signal at the output terminal T On the other hand, during the stay of the key K at its lowermost end of stroke, even if the key is strongly depressed further, this pressing force to the element R is reduced due to the resiliency of the resilient spacer 23, so that the resistance value of the element R, becomes greater as shown in FIG. 8c. As a result, the charge voltage of the capacitor'C cannot bedischarged abruptly so that the' gate of the FET Q is held at a positive voltage. Accordingly, an input tone signal which is applied to the terminal T can be varied as desired during the attenuation of its envelope'in accordance with the magnitude of the depression of key in such a way as indicated by the chain line B, the broken line C or the dotted curve D in FIG. 8e.

Referring to FIGS. 9a through 9f, there is shown another embodiment of the present keying system, in which a keyer circuit for providing a decay tone signal having a predetermined build-up amplitude in dependently of the speed of key depression, there is additionally provideda keyer control circuit capable of causing the envelope of the keyed tone signal to be varied continuously from the time the key is positioned at its lowest level, in accordance with the pressure applied to a pressure-sensitive resistance varying circuit after the normal key depression.

FIG. 9a shows a schematic diagram of this embodiment, in which PC and KP represent an attack pulse generator circuit and a key pressure detecting circuit having the resistance varying element R respectively, whereby keyer circuits S, and S, having keying FETs Q Q and common input and output terminals T T respectively, are individually controlled to key the input tone signals and to develop the keyed signals with a variety of envelopes in accordance with the amounts of key depression. The circuit arrangement is substantially similar to that of FlG.8a except these double keyers.

In operation, when the key is normally depressed to close a switch S, a DC voltage having a predetermined level as shown by a rectangular waveform in FIG. 90 is developed across a resistor 44 by dividing a DC power source'voltage +E through bleeder resistors R and R The developed voltage is differentiated by a circuit composedof a capacitor C and a resistor 45.into positive and negative-'going'pulses as shown in FIG. 9d. Through a diodeD only the positive-going pulse is derived and converted through a capacitor C and a resistor R to such a pulse voltage as shown in FIG. 9e. The pulse thus formed is applied to the gate of an F131" 0 to render it conductive in accordance with the applied pulse, so that an input signal applied to an input terminal T may be derived at an output terminal T in the form of an attack signal as shown by the curve A in FIG. 9f. I

After the normal key depression if the key depressed at the lowermost end of its stroke is depressed further topressonthe pressure-sensitive resistance varying element R ,'the element varies its resistance value in accordance with the pressure applied thereto, so that the input tone signal applied to the other keyer FET 0, is keyed to develop an output signal having a varying envelope or amplitude with respect to timeas shown bythecurveBin FIG. 9f I FIGS. 10a and 10b show a modification of the embodiment illustrated in FIGS. 94 through 9f, in which the two keyer cir- Referring to FIGS. 11a through 11d, there is shown an embodiment of the keying system of the invention, in which in at.

least one keyer'circuit for providing a varying envelope of a keyed signal in response to the speed of normal key depression, i.e., the so-called touch-responsive control effect,"

there is additionally provided another keyer control circuit capable of varying the envelope of 'the keyed tone signal in accordance with the pressure applied to a pressure-sensitive reresponding key for generating an electromotive force and a key pressure detecting circuitKP responsive to the magnitude of the pressure applied by a key to the corresponding pres-.

sure-sensitive resistance varying element R after the normal key depression to vary the resistance value of said element, whereby the tone keyers S and 8,, are controlled so that input tone signals applied to a common input terminal-T may be keyed and derived at a common output terminal T in the form of keyed signals having a varietyof envelopes in accordance with both the key depressing speed and the key pressure.

FIG. 11b illustrates an'example embodying the circuit diagram of the blocks shown in FIG. 11a, in which the two keyer circuits S, and 8,, have an F ET Q and an FET Q tespectively, each of the transistors essentially effecting the keying or gating of an input signal.

FIG. 11c shows a modification of a keyboard assembly, I

In this circuit arrangement, it will be seen that a tone signal keyed at the FET Q may be varied with respect to time in its envelope of the output signal in accordance with the key pressure applied to the element R as shown by the curve p in FIG. 1 1d.

Though this embodiment illustrates one common input terminal T for the keyer circuits S and 8,, each of the keyer circuits may be an individual input terminal so as to receive different tone signals independently of each other. That is, the latter is permitted to additionally control a tone having a different footage as illustrated in FIG. 1 1e as compared with the envelope produced by the arrangement of FIG. 11a as shown in FIG. 1 1d.

Referring to FIGS. 12a through 12c, there is shown still another embodiment similar to that of FIG. 8, in which the key contact detecting circuit of FIG. 8 is replaced by a touchresponsive control circuit, i.e., a key depressing speed detecting circuit KS responsive to the speed of key depression to generate an electromotive force adapted for triggering at least one keyer circuit. This arrangement features that in a keyer circuit for providing a percussive signal or an attack signal whose build-up amplitude is varied in accordance with the speed of key depression, there is provided a keyer control circuit which is capable of varying a decay time of either of said signals in accordance with the magnitude of key pressure applied after the normal key depression.

In the arrangement shown in FIG. 12a, when the key K is quickly depressed and, thereafter, when it is strongly pressed upon at its lowermost end of stroke, the envelope of the keyed output tone signal becomes as shown by the two-dot chain line in FIG. 12b. When the further pressure force applied onto the key at its lowermost level of stroke following the normal speed depression of the same is varied in many ways, there are obtained various kinds of envelopes having different lengths of decay time in the manner as shown by other chain curves in FIG. 12b. Furthermore, in case the normal depression speed of the key and the pressure force applied to the key at its lowermost level of stroke are both small, the resulting envelope of the keyed output signal will be small in amplitude and short in decay time as shown in FIG. 12c.

FIGS. 13a through 13c show a modification of FIG. 9, in

which a detected signal from the key depressing speed detecting circuit KS is applied to a damped pulse shaping circuit to provide a damped pulse whose amplitude is in response to the depressing speed of the key, whereby the so-called touchresponsive, percussive control effects" are obtained.

FIG. 13a shows an essential portion of the modification.

Though the modification of FIG. 13a illustrates one common input terminal connected to both the keyer circuits S, and S it is needless to say that they may have individual input terminals separately from each other.

What is claimed is:

1. In an electronic musical instrument having playing keys for manual depression to a stop position, a keying system for gating tone signals, comprising:

at least one keyer provided for each key in associated relation therewith,

first control means associated'with said key for actuating said keyer during the depressing stroke of said key before said key reaches said stop position, and

second control means associated with said key for controlling such keyer in response to the depressing force applied to said key during its stay 'at said stop position.

2. The keying system according to claim 1, in which said second control means includes a pressure-sensitive resistance element capable of varying an electrical property thereof in response to the magnitude of the pressure applied thereto.

3. The keying system according to claim 2, in which said pressure-sensitive resistance element includes a strain gauge provided on one end of a flexible member provided in either one of a manually movable portion and a fixed portion of a keyboard assembly, said strain gauge being adapted to be subjected to a pressure by a further pressing of the key beyond normal key depression.

4. The keying system according to claim 2, in which said pressure-sensitive resistance means has a piezo-electric member.

5. The keying system according to claim 1, in which said first control means includes means for generating an elec tromotive force in response to the speed of the key depression.

6. The keying system according to claim 5, in which said electromotive force generating means includes a magnet mounted on the key and a coil assembly disposed on a fixed member, said magnet being adapted to be untouchably surrounded by said coil assembly so as to face each other.

7. The keying system according to claim 6, in which a pressure-sensitive resistance element is housed within the coil assembly, said element facing said magnet and is adapted to be subjected to a pressure by the face of the magnet via a corresponding key when the latter is pressed beyond the normal key depression.

8. The keying system according to claim 7, in which said pressure-sensitive resistance element may be oneof a piezoelectric element and a magneto-sensitive element.

9. The keying system according to claim 1, in which said first means is constituted by a key contact circuit for effecting a switching action to the keyer circuit to key an input tone signal at a predetermined level, and said second control means is constituted by a pressure-sensitive resistance varying circuit for varying the resistance value in accordance with a pressure applied thereto to thereby control an amplitude or envelope of the keyed tone signal.

10. The keying system according to claim 9, in which said key contact circuit and said pressure sensitive resistance varying circuit are connected to respective keyer circuits each of whose input is an individual tone signal and whose outputs has a common output terminal.

11. The keying system according to claim 1, in which said first control means functions to provide a percussive envelope of the keyed tone signal and said second control means functions to vary a decay time of said envelope.

12. The keying system according to claim 1, in which said first control means includes an attack pulse generator connected to a first keyer circuit for generating an attack tone signal from the keyer with a predetermined buildup and decay envelope, and said second control means includes a pressuresensitive resistance varying circuit varying the resistance value of a resistive element in accordance with a pressure applied thereto and connected to a second keyer circuit, said resistance varying circuit varying the envelope of a tone signal keyed by said second keyer.

13. The keying system according to claim 12, in which said first and second keyers have a common input terminal and a common output terminal.

14. The keying system according to claim 12, in which said first and second keyers have respective input terminals separate from each other.

15. The keying system according to claim 1, in which said first control means includes a key speed detecting circuit connected to a first keyer circuit and capable of generating an electrical signal in response to the speed of key depression, and second control means includes a pressure-sensitive resistance varying circuit connected to a second keyer circuit and capable of varying the resistance value of a resistive element in accordance with a pressure applied thereto by a key pressing action to thereby vary the envelope of a tone signal keyed by the second keyer circuit.

16. The keying system according to claim 15, in which said first and second keyers have a common input terminal and a common output terminal.

17. The keying system according to claim 15, in which said first and second keyers have respective input tenninals separate from each other.

18. The keying system according to claim 1, in which said first control means functions to provide a percussive envelope of the keyed tone signal having an amplitude in response to the depression speed of the key, and said second control means functions to vary a decay time of said envelope.

19. The keying system according to claim 1, in which said first control means includes an attack pulse generator connected to a first keyer circuit for generating an attack tone signal from the keyer with an amplitude in response to the depression speed of the key; and said second control means includes a pressure-sensitive resistance varying circuit varying the resistance value of a resistive element in accordance with a pressure applied thereto and connected to a second keyer circuit, said resistance varying circuit varying the envelope of a tone signal keyed by said second keyer.

Claims

1. In an electronic musical instrument having playing keys for manual depression to a stop position, a keying system for gating tone signals, comprising: at least one keyer provided for each key in associated relation therewith, first control means associated with said key for actuating said keyer during the depressing stroke of said key before said key reaches said stop position, and second control means associated with said key for controlling such keyer in response to the depressing force applied to said key during its stay at said stop position.

5. The keying system according to claim 1, in which said first control means includes means for generating an electromotive force in response to the speed of the key depression.

8. The keying system according to claim 7, in which said pressure-sensitive resistance element may be one of a piezo-electric element and a magneto-sensitive element.

12. The keying system according to claim 1, in which said first control means includes an attack pulse generator connected to a first keyer circuit for generatinG an attack tone signal from the keyer with a predetermined buildup and decay envelope, and said second control means includes a pressure-sensitive resistance varying circuit varying the resistance value of a resistive element in accordance with a pressure applied thereto and connected to a second keyer circuit, said resistance varying circuit varying the envelope of a tone signal keyed by said second keyer.

17. The keying system according to claim 15, in which said first and second keyers have respective input terminals separate from each other.

20. The keying system according to claim 19, in which said first and second keyers have a common input terminal and a common output terminal.

21. The keying system according to claim 19, in which said first and second keyers have respective input terminals separate from each other.

22. The keying system according to claim 19, in which a pulse shaping circuit is provided between said attack pulse generator and said first keyer circuit.