US3902396A

US3902396A - Electronic musical instrument

Info

Publication number: US3902396A
Application number: US461417A
Authority: US
Inventors: Teruo Hiyoshi
Original assignee: Nippon Gakki Co Ltd
Current assignee: Nippon Gakki Co Ltd
Priority date: 1973-04-19
Filing date: 1974-04-16
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02

Abstract

An electronic musical instrument comprises a plurality of tone signal synthesizing circuits connected to a keyboard section in parallel with each other and means for combining the outputs of said tone signal synthesizing circuits. The tone signal synthesizing circuit comprises a series connection of a voltagecontrolled oscillator, a voltage-controlled filter, and a voltage-controlled amplifier; a first, a second and a third waveform generator for supplying controlling voltage waveforms to the oscillator, the filter and the amplifier, respectively, for controlling the tone pitch, the tone coloring and the envelope of the tone signal; and a waveform controlling circuit for supplying information variables for determining the shapes of the controlling waveforms to the waveform generators. The outputs of the tone signal synthesizing circuits are combined to supply an output tone signal provided with coupler effect. Upon depression of any single key, said plurality of tone signal synthesizing circuits are rendered operative to produce a music sound which is a mixture of a plurality of different tones.

Description

United States Patent 1191 Hiyoshi Sept. 2, 1975 1 1 ELECTRONIC MUSICAL INSTRUMENT [75] Inventor: Teruo l-Iiyoshi, Hamamatsu, Japan [73] Assignee: Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu, Japan 22 Filed: Apr. 16, 1974 21 Appl. No.: 461,417

84/1.13, 1.19, 1.22, 1.24-1.27, DIG. 2, DIG. 9, DIG. 20, 1.17, DIG. 8

3,767,833 10/1973 Noble ct a1. 84/].01 3,786,166 1/1974 Mieda 84/1.0|

3,801,721 4/1974 Bungcr 84/1.l9

3,809,791 5/1974 Uchiyama 84/124 3,818,115 6/1974 Hirano 84/].24

3,828,110 8/1974 Colin 84/1.0l

R27,983 4/1974 Stearns 84/1.01

Primary ExaminerStephen J. Tomsky Assistant ExaminerStanley J. Witkowski Attorney, Agent, or FirmCushman, Darby, & Cushman [5 7 ABSTRACT An electronic musical instrument comprises a plurality of tone signal synthesizing circuits connected to a keyboard section in parallel with each other and means for combining the outputs of said tone signal synthesizing circuits. The tone signal synthesizing circuit comprises a series connection of a voltage-controlled oscillator, a voltage-controlled filter, and a voltagecontrolled amplifier; a first, a second and a third waveform generator for supplying controlling voltage waveforms to the oscillator, the filter and the amplifier, respectively, for controlling the tone pitch, the

[56] References Cited tone coloring and the envelope of the tone signal; and

UNITED STATES PATENTS a waveform controlling circuit for supplying informa- 288 904 H966 Gem 0 84/1 0] tion variables for determining the shapes of the con- 5 H966 84/l:26 trolling waveforms to the waveform generators. The 3:538:804 11 1970 George ..s4/1.01 outputs of the tone Signal synthesizing Circuits are 3,557,295 1/1971 Adachi 84/].19 x ombined to supply an Output tone signal provided 3,570,357 3/1971 Adachi... 84/126 with coupler effect. Upon depression of any single 3.571. 1 3/1971 Ada him 84/1.13 key, said plurality of tone signal synthesizing circuits 3582530 6/197 l--- 84/136 are rendered operative to produce a music sound 3'609203 9/1971 84/10] which is a mixture of a plurality of different tones. 3,614,288 10/1971 Amano 84/].01 X 3,626,078 12/1971 Sekiguchi 84/124 6 Claims, 8 Drawing Figures 20 /3u FIRST VCO VCF VCA ARRAMSEMENT r 4 f r WAVEFURM WAVEFGRM ENVELOPE 5 l" GEN GEN l" CONTROL 1 l 6 7 8 wAvEFoRM CCNTROLLING KEYBOARD CKT SECTION 3b 4b 2 VCO i VCF VGA 1 I I 2b ,3b 4b WAVEFORM WAVEFORM ENVELOPE 5b F GEN F GEN I CONTROL i l 6b WANGEMENT WAVEFORM CONTROLLING CKT PATENTEUSEP 2mm R 902 39s SHEET 2 OF 5 F IG. 2A

ATTACK LEVEL NORMAL LEVEL INITIAL LEVEL CuT-OEF LEVEL KEY DEPRESSED Z QEE SECOND ATTACK FIRST D CA DECAY E Y TIME 38 POWER 3 SUPPLY 39 SCHMITT TRIGGER HIGH INPUT OUTPUT 43 IMPEOANCE CONVERTER BUFFER AMPL N N\ I 53 36 VOLTAGE SIGNAL CONTROLLING VOLTAGE FROM KEY sEC- WAVEFORM TION 1 ELECTRONIC MUSICAL INSTRUMENT BACKGROUND OF THE INVENTION rality of synthesizer circuits to obtain coupler effect by simultaneously producing a plurality of different tones for a single depressed key.

2. D escription'of the Prior Art Conventional electronic musical instrument which is now used is provided with tonesou'rce circuits including oscillators and freque ncy dividers for producing frequency signals corresponding to each of the tone pitches for the depressedkeys of the keyboard. Such a frequency signal is used as the tonesourcesignal. The tone source signal is selectively coupled to one of plural sets of filter circuits with different characteristics to effect tone coloring. Thus, a musical tone signal with a predetermined tone pitch and a predetermined tone color is provided The musical tone signal is then supplied to a sound-producing divice such as a combination of an amplifier and a speaker system to produce the sounds of music being played. y

In such a known electronic musical instrument, how ever, the tone source signal derived corresponding to the operation of a key of the keyboard is a signal with a given frequency'corresponding to the tone pitch for the depressed key of the keyboard and is formed with reference to said frequency from the time the key is depressed to the time this key is released. The tone signal is synthesized by appropriately selecting harmonic components of such'a signal. Accordingly, the performance sound produced'from such a known electronic musical instrument tends to be monotonous and cannot be accepted as being a truly enjoyable and pleasant musical sound, rich in musical-interest. In any natural musical instrument, the tone pitch and the tone color of a musical sound of produced are exposed to subtle variationsfrom the commencement till the termination of the generations of the musicalsound, and thereby fine, exquisite expression of musical sound rich in naturalness is obtained. However, it is very difficult to express effectively the subtle variations in tonepitch and tone color by the conventional electronic musical instrument. a i

The present invention is intended to improve the performance of the known electronic musicalinstrument by eliminating the aforesaid drawbacks of such instrument.

SUMMARY OF THE INVENTION It is. therefore, the object of the present invention to provide an electronic musical instrument of a synthe- Sizer type which comprises a plurality .of synthesizer circuits to obtain coupler effect by simultaneously prodticihg a plurality of different tones for a single depressed key. I According to an embodiment ofthis invention, there is provided an electronic musical instrument comprising: a playing keyboard section including a plurality of keys for producing awoltage signal determining the tone pitch ofa depressed key; at lcast one musical tone signal synthesizing arrangement comprising a plurality of sub-arrangements connected to said playing keyboardsection in parallel with each other, and combining means for combining the outputs of said subarrangements, each of said sub-arrangements including a voltage-controlled variable-frequency oscillator connected to the keyboard section and generating a tone signal corresponding to said voltage signal, a voltagecontrolled frequency-variable filter connected to said voltage-controlled frequency-variable oscillator, a first controlling waveform generator connected to said voltage-controlled frequency-variable oscillator for generating a controlling voltage waveform which controls the frequency of the tone signal generated from said oscillator, a second controlling waveform generator connected to said voltage-controlled frequency-variable filter for generating a controlling voltage waveform which, in turn, controls the cut-off frequency of said filter, a waveform controlling circuit connected to said first and said second waveform generators for supplying information variables for determining the shapes of said controlling waveforms.

BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned and other objects, features and advantages of this invention will become more apparcut, and the invention itself will be best understood, by giving reference to the following description of preferred embodiments of this invention when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram of an embodiment of the electronic musical instrument according to this invention;

FIGS. 2A and 2B show examples of controlling waveforms concerning the embodiment of this invention;

FIG. 3 is a circuit diagram of an example of the voltage-controlled oscillator VCO;

FIG, 4 is a block diagram of the main portion of another embodiment of the electronic musical instrument according to this invention;

FIG. 5 is a circuit diagram of a pitch controlling circuit in the electronic musical instrument;

FIG. 6 is a block diagram of a key assigner of the electronic musical instrument; and

FIG. 7 is a circuit diagram of a concrete example of a key assigner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to clarify the invention disclosed herein, an embodiment according to this invention will be described hereinafter by referring to FIG. 1.

In the arrangement illustrated in FIG. 1, a keyboard section 10 constituting a music-playing section including, for example, a keyboard or the like produces a signal with a given voltage level corresponding to the depressed key. The voltage signal from the keyboard section 10 is coupled, in parallel, to first and second voltagecontrolled variable-

frequency oscillators

2a and 2b (hereinafter abbreviated as VCO) to derive the tone source signals corresponding to the depressed key from each of the VCOs respectively. The tone source signal from the VCO's 2a and 2b are applied to

voltagecontrolled variable filters

3a and 3b (hereinafter abbreviated as VCF) for effecting tone-coloring and then to voltage-controlled variable-

gain amplifiers

4a and 4b (hereinafter abbreviated as VCA) for envelopecontrolling the tonesignal. In the above manner, the musical tone signal producing circuit is formed of the first and second sub-musical tone synthesizer arrangements a and 5h. Numeral 5a represents

members

211, 2a, 3a, 3a, 4a and 4a of FIG. I, and similarly 5h represents the

members

2b, 2b, 3b, 3b. 4b and 4h. The musical tone signals from the first and second submusical tone synthesizer arrangements are synthesized by a resistor 6 so that the resultant tone signal is derived through a sliding terminal of the resistor 6. This synthesized tone signal is then amplified appropriately in an amplifier 7 and is supplied to a speaker system 8 to voice a performance sound therefrom.

Waveform-

generators

2a, 2b, 3a, 3b, 4a, and 4b are provided for the

VCOs

2a and 2b, the

VCFs

3a and 3b, and the VCAs 4a and 412, respectively, to control them with voltage waveforms generated therefrom. These waveform generators 2a 4 h are controlled by the

waveform controlling circuits

6a and 6b, and produce control waveform signals, varying in voltage level with time, in response to the key operation signal derived from the keyboard section I0, i.e. the'trigger signal including key-depressed signal which is generated upon the depression ofa key and key-released signal which is produced upon the release of the key, in accordance with the instructions from the

waveform controlling circuits

6a and 6b the term instructions is used to mean voltage signals representing quantities for determining the transient times and the voltage levels of the controlling waveforms (cf. FIGS. 2A and 28). Details of this part are described in the copending U.S. patent application Ser. No. 457,646 (Hiyoshi et al) which is commonly assigned with the instant application, since the main part of this copending application is to control the transient times and the voltage levels of the controlling waveforms with signal voltages.

FIGS. 2A and 2B show examples of the controlling voltage waveforms obtained from the waveform generators 2a.

2b

4a, 4b. The controlling waveform shown in FIG. 2A is for the tone pitch and the tone color control and is applied to the

VCOs

2a and 2b, and the

VCFs

3a and 3b. The controlling waveform is first triggered by the trigger signal from the keyboard section upon the depression of a key, and then shows a sharp build-up in the attack time starting from the initial level which is lower than the normal level and ending in the attack level which is higher than the normal level, and next decays down to the normal level in the first decay time, sustains this normal level till the key is released, and finally decays down to the initial level in the second decay time after the key is released. When the control waveform signal is coupled to the

VCOs

2a and 2b, the normal level (normal frequency) is set by the voltage signal from the keyboard section 10. The controlling waveform builds up rapidly upon the key depression so that the frequency of the tone source signal, rapidly increases from a frequency somewhat lower than the normal level (normal frequency) to the attack level of a frequency somewhat higher than the normal level. The normal frequency signal can be obtained after the first decay time. At the time of keyreleased, the frequency is decreased from the normal frequency level during the second decay time, and consequently the oscillation signal is cut off. That is, an attacking tone source signal with a frequency somewhat higher than the normal level is obtained at the keydepressed time, and thereafter the frequency is varied as shown by the waveform shown in FIG. 2A. Thus, a tone signal having a tone pitch modified as the waveform shown in FIG. 2A as shown in the figure is provided by simply depressing a key.

Similarly, in the case of the

VCFs

3a and 3b, the cutoff frequency is varied in such a manner as the waveform shown in FIG. 2A. for example, so that higher harmonies are increased especially at the time of the keydepressed, and the cut-off frequency is decreased after the key release, so that the musical sound ceases softly. In this way, the tone coloring is modified.

Here, a polarity reversing control may be provided for the controlling waveforms for the VCOs and the VCFs so that the polarity of the controlling waveform can be reversed.

The control of the

VCAs

4a and 4b is the envelope control of the amplitude of the musical tone signals derived from the

VCFs

3a and 3b by a controlling waveform as shown by the curve shown in FIG. 2B. Namely, the amplitude increases from the normal level and varies after the controlling waveform. In this case, the normal level is the cut-off level.

The

waveform controlling circuits

6a and 6b including resistor circuits or switch circuits are provided for the respective musical tone synthesizer arrangements to set and memorize the information such as the attack level, the initial level, the attack time, the first decay time, the second decay time. and the polarity for controlling the VCOs and the VCAs and the information for controlling the VCAs, such as the sustain level, the attack time. the first decay time, the second decay time, for determining the shape of the controlling waveforms. The waveform controlling circuit is the invention of another U.S. application (Ser. No. 457,646) as described above, before which there has been no pertinent prior art. The information can be switched and modified to generate desired signal waveforms.

FIG. 3 shows an example of the concrete configuration of the VCO, wherein the voltage signal from the keyboard section 10 is applied from a terminal 33 and is read-out through a high input impedance buffer 35 after-being memorized in a capacitor 34. Furthermore, the voltage signal is coupled with the control waveform derived from a terminal 36 and is converted into a current signal by a voltage-controlled converter 37. The current derived from the voltage-current converter 37 changes the voltage of a capacitor 39 which is interconnected between a power supply 38 and the converter circuit 37. The voltage across the capacitor 39 is applied to a Schmitt trigger circuit 41 to trigger the transistor 42 into a conducting state when it reaches a predetermined value. The conducting transistor forms a discharging circuit for the capacitor 39. The charging and discharging of the capacitor 39 are repeated to provide an oscillating output from an output terminal 43, corresponding to the cycle of the charging and discharging. Thus, a tone signal is provided.

In this electronic musical instrument as described above, the musical tone signals are independently produced corresponding to the depression of a key in the musical tone signal producing circuits 5a and 5b, and are extremely rich in variations because the tone pitch and the tone color vary with time. For example. if the information signals in the waveform-controlling

circuits

6a and 6b are set differently with respect to the initial value. etc.. the musical tone signals having different variations in the tone pitch and the tone color will be obtained in the respective tone signal producing circuits, synthesized into a composite tone signal applied to a voicing system to produce coupler effect.

Modified embodiments of the electronic musical instrument according to this invention will be described by referring to FIGS. 4, 5, 6 and 7. v

A key assigner 11 is illustrated in FIGS. 4 and 6 and is disposed between the keyboard section l0'and the musical tone'signal synthesizer arrangement 13a, and

is directly connected to them through the key switches."

This key assigner 11 has, however, the functions of ap plying the voltage signals from the keyboard section to the musical tone producing devices and of distributing these voltage signals to each of the tone signal producing devices in accordance with the order of the key depression, as will be described in conjunction with FIGS. 4, 5, 6 and 7.

Referring now to FIG. 6, for example, it will be noted that to a key assigner 11 consisting of five rows of se lectably connecting circuitries 11a 110 is connected a keyboard section including a resistor network (shown at block for producing a plurality of note namedetermining voltages and key switches 12a 12 associated with the keys (not shown) of the keyboard. Also to this key assigner are connected five musical tone producing devices 13a 13 The key switches 12:! 1211 are selectively turned on as the keys on the keyboard section are depressed, thereby energizing the key assigner to couple the note name-determining voltage to the musical tone signal producing device.

When plural keys, at most five in this embodiment. are rendered to the state of being depressed concurrently, then corresponding number of the connecting circuitries llu 110 of the key assigner 1] are exclusively captivated" accordingly by these depressed keys, one circuitry for one key, in the order of depression. In this way, the selected number of the note namedetermining voltages corresponding to the depressed keys are supplied to the assigned ones of the five musical tone synthesizer arrangements 13:! 130.

Each of the musical tone signal producing devices 13a I30 are provided with voltage-controlled variable frequency oscillators 14a and 14b (hereinafter abbreviated as VCO) provided in the first and second synthesizer sub-arrangements 131 and 132 (these two constituting one set of musical tone synthesizer arrangement 13a shown in FIG. 4) to which the voltage signals from the connecting circuitry llu of the key assigner are supplied to oscillate-the tone source signals with frequencies determined by the voltage of the inputted signal.,Each of the tone source signals is colored into a musical tone signal by the tone coloring circuit comprising voltage-controlled

variable filter

15a or 15b (hereinafter abbreviated as VCF). These colored tone signals are then amplified by voltage-controlled variable gain amplifiers 16a and 1612 (hereinafter abbrevi ated as VCA) and combined to supply an output at an output terminal 17. Accordingly. the musical tone signal producing device 13a or I30 comprises the musical tone signal producing circuits l3] and 132 in the .first and second musical tone sub-synthesizer arrangements as stated above and the voltage waveform signal from each of the

waveform generators

18a, 18b. l9u. 19b, 20a, and'20h for controlling the tone pitch, the tone color and the envelope are connected to the \/'(Os 14a. 14b, the VCFs 15a, 15/2, and the

VCAs

16a, 16b, respectively. The waveform generators 18a, lXb. 19a. 1912.200 and 20/; receive the trigger signal produced by a key upon the key depression or the key release through thecorresponding key assigner for producing the controlling waveforms. The shapes of these controlling waveforms are determined by the information variables supplied from the

waveform controlling circuits

21a and 21!), similar to the embodiment described above. For example, the oscillation frequency of the VCO 14a is controlled by the voltage signal supplied from the depressed key through the key assigner corresponding to the tone pitch of the depressed key and the controlling voltage waveform supplied from the waveform generator 18a, to providea tone source signal with a frequency varying with time following the depression of the key.

Furthermore, the tone-coloring is effected by the VCF 15a in accordance with its cut-off frequency and the tone color is varied with time, in response to the cut-off frequency variation. The envelope of the tone signal is variably controlled by the VCA 1611. In other words, the waveform-controlling circuit 2] provides the details of the control for the tone pitch, the tone color and the sound volume.

Since two waveform-controlling circuits 21a and 21b, in this embodiment, are provided for controlling the musical tone

signal producing circuits

131 and 132, although a similar signal voltage is applied from the key assigners to the

circuits

131 and 132 in the first and second musical tone subsynthesizer arrangements, the musical tone signals obtained become different for different subarrangements. Two kinds of musical tone signals having pitches which are different by a predetermined interval are produced concurrently upon the depression of a key, and are converted to a mixed audible sound. The voltage signals from the pitch control circuits 22:1 and 22b are applied to the VCOs 14a and 14b to control variably the pitch of the tone source signal corresponding to the instructions from pitch setters 21(- and 2111 in the waveform controlling device 21.

According to a more detailed description, for example, when the VCO 1411 includes, as illustrated in FIG. 5, a capacitor 23 for memorizing the voltage signal determining the tone pitch and supplied through the key assigner. a buffer 24 of high input impedance for reading-out the voltage across the capacitor 23, and an oscillator 25 for receiving the voltage signal read out by the buffer 24, the voltage signal from the pitch control circuit 22:: which is composed of a voltage dividing circuit including resistors is superposed on the voltage sig nal read out from the buffer 24. The pitch control circuit 2211 can select or set a coupler tone pitch such as 2, 4 by using the pitch setter 2lc comprising a dial member or the like. The controlling waveform from the waveform generator 18a is also superposed to the output voltage signal. The musical tone signal producing devices 131 and I32 thus provide tone signals in an arbitrarily selected coupler relation which then form a performance sound of very rich musical quality.

lf a key switch 12b is turned on while holding the key switch 121! on," the key assigner llh which has the second priority order following the key assigner llu is captivated and the voltage signal corresponding to the key switch 12b is applied to the musical tone signal producing circuit 13b.

When multiple keys are operated simultaneously, the musical tone signal producing devices 13a are selectively'connected to the connecting circuitries I la 1 la, and the musical tone signal producing devices which are selected produce the desired musical tone signal and supply a desired musical tone through the sound-producing system having a speaker (not shown). Letter D indicates a delay circuit which can be inserted in the trigger signal circuit.

FIG. 7 is a circuit diagram showing the internal details of that portion of the key assigner ll corresponding to the key switch 120 for the simplicity of explanation.

A drive control circuit for relays 30a 30 including

transistors

27, 28 and 29 is provided in each of the connecting circuitries lla to He corresponding to the key switch 120, and the relays 30a to 30e are connected to the collector of the transistor 29 to actuate the relays when the transistor 29 is rendered conductive. The collector of this transistor 29 is connected to the base of the transistor 31 which is provided in all of the connecting circuitries excepting lle to render the transistor 31 non-conductive by lowering the potential of the base of the transistor 31 as a result of the transistor 29 being in its on state. The collector of the transistor 27 and the emitters of the transistors 28 and 29 are grounded, in combination, to the ground line of the connecting circuitry 11a through the key switch 120 in the manner as shown. In the connecting circuitries 11b to 11], the combined lead, in turn, is connected to the collector of the transistor 3] of the connecting circuitries 11a to 1111 in the prior stage. With reference to the connecting circuitry He, the emitters of the transistors 27 to 29 are, in combination, connected to the collector of the transistor 31 in the connecting circuitry 1111. If the key switch 120 is turned on when no other key is depressed, the ground circuit of the transistors 27 to 29 in the connecting circuitry Il a and each of the transistors 27 to 29 is rendered conductive to trigger the relay 30. Accordingly, a contact 32a of the relay 30a is actuated and the voltage signal is derived from an output terminal 33a by the voltage divider circuit including the resistor R corresponding to the key switch 120 and is applied to the musical tone signal producing device 13a. In such condition, the base of the transistor 31 is set at a low potential by rendering the transistor 29 conductive and is set to non-conduction. As a result, the ground circuit of the connecting circuitries l lb to He is not formed, accordingly the signal due to the operation of the key switch 12b is not applied to other musical tone signal producing devices 1312 to 13?.

If another key switch has been already turned on before the key switch 120 is turned on, the connecting circuitry Ila for the turned-on key switch 120 is already put in the selected condition in the same manner as described above, consequently the transistor 27 in the corresponding circuit is driven into the conductive state. Therefore, the potential of the terminal 26a is set at a decreased level with respect to the otherwise normal potential. Accordingly, the transistor 27 in the connecting circuitry llu is not energized, and if the key switch 12(- is turned on, the relay 30a is not energized.

Since the ground circuit of the transistor 31 is formed and the positive bias voltage is applied to the base of the transistor 31 through the relay 3011 by the turningon of the key switch 12c, the transistor 3] is rendered conductive to form the ground circuit of the transistors 27 to 29 in the connecting circuitry 1 lb provided in the next stage. This demonstrates that the key switch 12(- captivates the connecting circuitry [lb and serves to couple the signal voltage corresponding to the key switch l2c from output terminal 33/; to the musical tone signal producing device l3h by the actuationof the contact 32b due to the actuation of the relay 30/).

Thus, when plural key switches are concurrently turned on. the connecting circuitries 11a to He are captivated in accordance with the order of the turningon of the key switches, and the voltage signal corresponding to each of the turned-on key switches can be separately and respectively delivered to the respective musical tone signal producing devices.

According to this invention as described above, the modifications and changes of the musical sound can be adjusted as desired or be variably switched to improve the performance of the electronic musical instrument effectively.

Furthermore, the electronic musical instrument according to this invention including the combination of a monophonic electronic musical instrument can produce desired coupler effect. Moreover, by adopting the aforesaid key assigner, there can be materialized an electronic musical instrument in the poliphonic form.

The musical tone signal producing circuits in the first and second sub-musical tone synthesizer arrangements have been described in conjunction with the embodiments. It is to be noted, however, that the number of the synthesizer arrangements can be increased, and the synthesizing method of the musical tone signals which are derived from each of the synthesizer arrangements canbe arbitrarily altered to obtain finer performance sound.

I claim:

1. An electronic musical instrument comprising,

a playing keyboard section including a plurality of keys for producing a voltage signal determining the tone pitch of a depressed key;

at, least one musical tone signal synthesizing means connected to said keys and comprising a plurality of circuits each connected to said playing keyboard section and each connected in parallel with each other, and combining means connected to the output'of each of said circuits for combining the outputs of said circuits, each of said circuits including a voltage-controlled, variable-frequency oscillator connected to the keyboard section and generating a tone signal corresponding to and responsive to said voltage signal, a voltage-controlled, frequency-variable filter connected to the output of said voltage-controlled, frequency-variable oscillator, a first controlling waveform generator connected to said voltage-controlled, frequency-variable oscillator for generating a controlling voltage waveform which controls the frequency of the tone signal generated from said oscillator, a second controlling waveform generator connected to said voltagecontrolled. frequency-variable filter for generating a controlling voltage waveform which controls the cut-off frequency of said filter, and a waveform controlling circuit connected to said first and said second waveform generators independently of said keyboard section for supplying voltage information to said generators, thereby determining the shapes of said controlling waveforms.

2. An electronic musical instrument as claimed in claim I, in which said combining means is a variable resistor for variably adding the musical tone signals from the respective circuits.

3. An electronic musical instrument according to claim 1.. in which at least one of said circuits further comprises a pitch controller connected to the voltagecontrolled. frequency-variable oscillator for controlling the oscillation frequency of the oscillator in a predetermined manner so as to give a coupler effect to the output of the combining means.

4. An electronic musical instrument according to claim 1, in which each of said circuits further comprises a voltage-controlled amplifier connected to said voltage-controlled filter for imparting an envelope to the tone signal su-plied from said voltage-controlled filter, and a third controlling waveform generator connected to said amplifier for generating a controlling voltage waveform which controls the envelope of the tone signal, and supplying voltage information to said third waveform generator.

5. An electronic musical instrument according to claim 1, in which the number of said musical tone signal synthesizing means is at least two, and the electronic musical instrument further comprises a key assigner connected between said keyboard section and said respective tone signal synthesizing means.

6. An electronic musical instrument comprising:

a playing keyboard section to produce a signal having a tone-pitch-determining voltage signal representing the note pitch of the depressed key of the keyboard; a plurality of voltage-controlled. variablefrequency oscillators to receive in parallel fashion, said signal from the playing keyboard section to produce tone source signals respectively in response thereto, a plurality of voltage-controlled variable filters arranged to receive said respective tone source signals from said oscillators and to convert said tone source signals into musical tone signals by coloring the tone; a sound-producing device to additively convert the tone source signals received from said variable filters into audible sound; a plurality of waveform generators connected correspondingly to the respective oscillators and the respective variable filters to produce control voltages with a given waveform constituted by a voltage waveform varying with time for controlling the tone pitch and the tone color; and a plurality of waveform controlling circuits for controlling the waveform generators respectively independently of each other.

Claims

1. An electronic musical instrument comprising, a playing keyboard section including a plurality of keys for producing a voltage signal determining the tone pitch of a depressed key; at least one musical tone signal synthesizing means connected to said keys and comprising a plurality of circuits each connected to said playing keyboard section and each connected in parallel with each other, and combining means connected to the output of each of said circuits for combining the outputs of said circuits, each of said circuits including a voltage-controlled, variable-frequency oscillator connected to the keyboard section and generating a tone signal corresponding to and responsive to said voltage signal, a voltage-controlled, frequency-variable filter connected to the output of said voltage-controlled, frequency-variable oscillator, a first controlling waveform generator connected to said voltage-controlled, frequencyvariable oscillator for generating a controlling voltage waveform which controls the frequency of the tone signal generated from said oscillator, a second controlling waveform generator connected to said voltage-controlled, frequencyvariable filter for generating a controlling voltage waveform which controls the cut-off frequency of said filter, and a waveform controlling circuit connected to said first and said second waveform generators independently of said keyboard section for supplying voltage information to said generators, thereby determining the shapes of said controlling waveforms.

2. An electronic musical instrument as claimed in claim 1, in which said combining means is a variable resistor for variably adding the musical tone signals from the respective circuits.

3. An electronic musical instrument according to claim 1, in which at least one of said circuits further comprises a pitch controller connected to the voltage-controlled, frequency-variable oscillator for controlling the oscillation frequency of the oscillator in a predetermined manner so as to give a coupler effect to the output of the combining means.

6. An electronic musical instrument comprising: a playing keyboard section to produce a signal having a tone-pitch-determining voltage signal representing the note pitch of the depressed key of the keyboard; a plurality of voltage-controlled, variable-frequency oscillators to receive, in parallel fashion, said signal from the playing keyboard section to produce tone source signals respectively in response thereto, a plurality of voltage-controlled variable filters arranged to receive said respective tone source signals from said oscillators and to convert said tone source signals into musical tone signals by coloring the tone; a sound-producing device to additively convert the tone source signals received from said variable filters into audible sound; a plurality of waveform generators connected correspondingly to the respective oscillators and the respective variable filters to produce control voltages with a given waveform constituted by a voltage waveform varying with time for controlling the tone pitch and the tone color; and a plurality of waveform controlling circuits for controlling the waveform generators respectively independently of each other.