Title:
CIRCUIT FOR RAPID NOTE PASSAGE IN ELECTRONIC MUSICAL INSTRUMENT
United States Patent 3651729
Abstract:
An electronic musical instrument-circuit for a rapid note passage (portamento or arpeggio) comprises an operational device for leading out, when manipulated, a DC signal representing a manipulated position and an AC signal, a capacitor which is connected to be charged with the DC signal, a voltage memory oscillator capable of producing a musical scale tone signale having a frequency determined by the DC voltage at the capacitor, a gate signal shaping circuit which receives the AC signal and produces an envelope curve signal for the musical scale tone signal, and a gate circuit for gating the tone signal in accordance with the envelope signal. The operational device comprises an elongated resistance rod and a plurality of contacts which are spaced from each other and are oppositely spaced apart at a certain distance from the resistance rod but are brought into contact with the resistance rod when manipulated. There is further provided a switch arrangement to selectively connect the plurality of contacts with the capacitor. When all of the contacts are connected with the capacitor, a gliding manipulation of the operational device results in a portamento performance, and when only a few of the contacts are connected with the capacitor, a gliding manipulation of the operational device results in arpeggio performance.
US Patent References:
Electrical musical instrument
Lertes et al. - March 1932 - 1847119
Cathodic coupling oscillator for electronic music instruments
Jenny - July 1951 - 2562429
Electrical musical instrument
Hanert - July 1953 - 2645968
Attachment for automatically playing root tones of chords in bass section of organ
Greif - September 1961 - 3001432
Post signal modulation in electronic musical instruments
Schwartz et al. - January 1968 - 3365993
Electrical musical instrument
Lertes et al. - March 1932 - 1847119
Cathodic coupling oscillator for electronic music instruments
Jenny - July 1951 - 2562429
Electrical musical instrument
Hanert - July 1953 - 2645968
Attachment for automatically playing root tones of chords in bass section of organ
Greif - September 1961 - 3001432
Post signal modulation in electronic musical instruments
Schwartz et al. - January 1968 - 3365993
Application Number:
05/067000
Publication Date:
03/28/1972
Filing Date:
08/26/1970
View Patent Images:
Export Citation:
Assignee:
Nippon Gakki Seizo Kabushiki Kaisha (Hamamatsu-shi, JA)
Primary Class:
Other Classes:
84/DIG.020, 984/310, 84/716
International Classes:
G10H1/04; G10H1/02
Field of Search:
84/1.17,1.24,1.01,DIG.22
US Patent References:
| 3432607 | BASS CONTROL OF ELECTRONIC MUSICAL INSTRUMENTS | March 1969 | Bergman | |
| 3484529 | ELECTRONIC MUSICAL INSTRUMENT | December 1969 | Moore | |
| 3511917 | VOLTAGE SELECTION ARRANGEMENT WHEREIN SAME CONTACTS SWITCH SELECTABLE D.C. PITCH POTENTIAL AND CONSTANT A.C. FOR CONTROL FUNCTION | May 1970 | Mallet | |
| 3548066 | PLURAL MODE AUTOMATIC BASS NOTE SYSTEM FOR MUSICAL CHORDS WITH AUTOMATIC RHYTHM DEVICE | December 1970 | Freeman | |
| 3553336 | ACCENTER TOUCH BAR FOR ELECTRONIC MUSICAL INSTRUMENT | January 1971 | Markowitz et al. | |
| 3198055 | Piano having chord playing means | August 1965 | Von Gunten | |
| 3227027 | Piano having electrically controlled note sustaining means | January 1966 | Von Gunten | |
| 3358070 | Electronic organ arpeggio effect device | December 1967 | Young |
Primary Examiner:
Kozma, Thomas J.
Assistant Examiner:
Witkowski, Stanley J.
Claims:
What is claimed is
1. A portamento circuit in an electronic musical instrument, comprising: an operational device including a resistor and a plurality of contacts spaced apart from each other and oppositely spaced apart at a certain distance from said resistor normally, but brought into contact therewith when depressed for leading out from said resistor a DC voltage representing a depressed position and an AC signal; a DC source across said resistor; a capacitor connected to said contacts for being charged with said DC voltage, a voltage memory oscillator connected to said resistor for providing said AC signal; said voltage memory oscillator being connected to said capacitor for producing a tone signal having a frequency determined by said DC voltage at said capacitor; a gate signal shaping circuit connected to said contacts producing an envelope signal for said tone signal upon receipt of said AC signal; a gate circuit connected to said voltage memory oscillator and said gate signal shaping circuit for gating said tone signal in accordance with said envelope signal; and a multicontact switch device connected between said plurality of contacts and said capacitor.
2. An arpeggio circuit in an electronic musical instrument, comprising: an operational device including a resistor and a plurality of contacts spaced apart from each other and oppositely spaced apart at a certain distance from said resistor normally, but brought into contact therewith when depressed for leading out from said resistor a DC voltage representing a depressed position and an AC signal; a DC source across said resistor; a voltage memory oscillator connected to said resistor for providing an AC signal; a capacitor connected to said contacts for being charged with said DC voltage, said voltage memory oscillator being connected to said capacitor for producing a tone signal having frequency determined by said DC voltage at said capacitor; a gate signal shaping circuit connected to said contacts producing an envelope signal for said tone signal upon receipt of said AC signal; a gate circuit connected to said voltage memory oscillator and said gate signal shaping circuit for gating said tone signal in accordance with said envelope signal; and key switches connected between respective ones of said plurality of contacts and said capacitor, the contacts corresponding to same note names in different octaves being interconnected.
1. A portamento circuit in an electronic musical instrument, comprising: an operational device including a resistor and a plurality of contacts spaced apart from each other and oppositely spaced apart at a certain distance from said resistor normally, but brought into contact therewith when depressed for leading out from said resistor a DC voltage representing a depressed position and an AC signal; a DC source across said resistor; a capacitor connected to said contacts for being charged with said DC voltage, a voltage memory oscillator connected to said resistor for providing said AC signal; said voltage memory oscillator being connected to said capacitor for producing a tone signal having a frequency determined by said DC voltage at said capacitor; a gate signal shaping circuit connected to said contacts producing an envelope signal for said tone signal upon receipt of said AC signal; a gate circuit connected to said voltage memory oscillator and said gate signal shaping circuit for gating said tone signal in accordance with said envelope signal; and a multicontact switch device connected between said plurality of contacts and said capacitor.
2. An arpeggio circuit in an electronic musical instrument, comprising: an operational device including a resistor and a plurality of contacts spaced apart from each other and oppositely spaced apart at a certain distance from said resistor normally, but brought into contact therewith when depressed for leading out from said resistor a DC voltage representing a depressed position and an AC signal; a DC source across said resistor; a voltage memory oscillator connected to said resistor for providing an AC signal; a capacitor connected to said contacts for being charged with said DC voltage, said voltage memory oscillator being connected to said capacitor for producing a tone signal having frequency determined by said DC voltage at said capacitor; a gate signal shaping circuit connected to said contacts producing an envelope signal for said tone signal upon receipt of said AC signal; a gate circuit connected to said voltage memory oscillator and said gate signal shaping circuit for gating said tone signal in accordance with said envelope signal; and key switches connected between respective ones of said plurality of contacts and said capacitor, the contacts corresponding to same note names in different octaves being interconnected.
Description:
BACKGROUND OF THE INVENTION
The present invention relates to a portamento circuit in a monophonic electronic musical instrument, said circuit being constructed so that a portamento-effect as well as an accurate musical scale can be easily produced and a note selection and a gating envelope trigger can be attained by means of the same performance operation, and furthermore it relates to an electronic musical instrument capable of easily attaining arpeggio performance.
In general, an electronic musical instrument, which is constructed so that an oscillation frequency of a single oscillator is varied in accordance with performance operation in order to produce any musical scale tone signal within a desired tone range, cannot perform simultaneously a plurality of tones, so that said electronic musical instrument is called as "a monophonic electronic musical instrument." Such musical instrument described above has been often used as a merely simple and small electronic musical instrument or as one part of an electronic musical instrument of large scale and complexity.
In the musical instrument described above, however, when a performance is to be carried out it is required to operate simultaneously a musical scale note deciding device for varying a frequency of the tone source and a gate control device for gating a tone source signal thereby to form a required envelope, and said requirement has been attained by utilizing a key-board provided with switches of several rows which are cooperated, whereby said key-board is made to carry out both functions of the above-mentioned devices. Consequently, the key-board requires at least two rows of cooperating switches, thus causing a complex and expensive structure of the key-board and accordingly of the musical instrument.
On the other hand, the portamento-effect in an electronic musical instrument can be produced by increasing or decreasing continuously the oscillation frequency and ordinarily said effect has been produced by varying resistance value of a certain variable resistor provided in the oscillator. For this variation of the variable resistor, it is conventional to slide a slide knob along a variable resistor with a finger or to adjust a contact point between a contact and a resistor with a finger, said contact consisting of a flexible conductive film and said contact and resistor being spaced from each other by a certain distance.
In the case of using a slide knob, however, a resistance variation from a desired resistance value cannot be attained by position of a slide knob, so that when the portamento performance is to be performed, the slide knob must be initially returned to the required starting position, thus causing inconvenience of the performance. Of course, in the latter case mentioned above, production of the portamento-effect is relatively easy, but performance of accurate musical scale is very difficult. Furthermore, the so-called arpeggio performance relates generally to a performance in which notes of a chord are successively employed upwardly or downwardly. For instance, the performance corresponds to the case, in which just after sounding of do, mi and sol in a certain octave, do mi and sol in the next higher octave is sounded and similarly notes of the chord in successively higher octaves are successively sounded.
The performance described above has been conventionally achieved by rapidly and successively pushing each of required note keys in the keyboard, but it is very difficult for the beginners to push successively the keys constituting a desired chord of each octave over a wide key range and furthermore, there is a limit in an extremely high speed arpeggio performance.
SUMMARY OF THE INVENTION
Therefore, an essential object of the invention is to provide an electronic musical instrument capable of producing a rapid glide over the notes in a scale such as a substantially smooth portamento-effect, and also producing accurate musical scale tones, said production being attained by using a portamento performance device, in which a plurality of contacts arranged so as to be spaced from each other at a certain distance and a resistor are provided so that said contacts are spaced by a certain distance from said resistor and brought into contact with said resistor when manipulated.
It is another object of the invention to provide an electronic musical instrument provided with a portamento circuit capable of producing musical scale note deciding signals and gate control signals at the same performance operational position.
It is a further object of the invention to provide an electronic musical instrument which can carry out a rapid glide over the selected notes in a scale such as arpeggio performance by using the circuit mentioned above.
It is still another object of the invention to provide an electronic musical instrument provided with a particular arpeggio performance device comprising, as its main constructional element, a particular oscillator adapted to impart a sustaining characteristic to chords, performance operation of said instrument being very simple.
The foregoing objects and other objects as well as the characteristic features of the invention will become more apparent from the following detailed description and the appended claims when read in conjunction with the accompanying drawings, in which like parts are designated by like reference numerals.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a block diagram showing an example of a portamento and arpeggio performance device according to the invention;
FIG. 2 is a detailed circuit diagram showing a gate signal shaping circuit, a voltage memory oscillator, and a gate circuit in FIG. 1; and
FIG. 3 shows graphs showing wave-forms at various parts of the circuit shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a portamento and arpeggio circuit which is capable of producing a continuous musical scale as well as a broken chord (Alberti bass). 1 is a DC source for controlling the oscillation frequency, and 2 is a voltage memory oscillator. The voltage from the DC source 1 and the output from the oscillator 2 are connected to a resistor 8 through capacitors 3, 4 and 5, and resistors 6 and 7 so that they are not interfered with each other. The resistor 8 is rod-shaped. A plurality of contacts 9 is provided at a predetermined distance from the resistor 8, and the contacts are arranged so as to be apart from one another with a certain distance, and further they are normally maintained so as not to make contact. When a contact 9 is depressed during a musical performance, the contact thus depressed is brought into contact with the resistor 8, whereby the required DC voltage and a certain AC signal from the oscillator are obtained at the point thus contacted. The DC component thus obtained becomes a voltage corresponding to the contact position on the resistor 8, while the AC component obtained is substantially independent of the contact position.
In one state of the operation of the invention, a switch S 1 for portamento is closed and a multicontact relay coil 11 is energized thereby to close all the relay contacts 12, so that the mixed signal of previously described DC and AC components is introduced to a line l 1 . Then, the AC component signal is applied to a gate signal shaping circuit 14 through a capacitor 13, while the DC component signal is charged into a capacitor 16 through a resistor 15, thereby to apply a predetermined DC voltage to the voltage memory oscillator 2. The voltage memory oscillator 2 is of a type such as a relaxation oscillator in which frequency is controlled by a DC voltage, and oscillates a musical scale tone signal of frequency decided by a DC potential developed at a mutual connection point between the capacitor 16 and the resistor 15. The DC potential is maintained even after the resistor 8 is disconnected from the contact 9, thereby to continue the oscillation of the same frequency, and to this end, the resistor 15 is selected higher in value in comparison with the capacitance of the capacitor 16 so as not to introduce the AC component to the oscillator 2. The AC component of the control signal is introduced as a gate control signal to the gate signal shaping circuit 14 through a DC blocking capacitor 13, and is rectified and shaped thereby to become an envelope signal having a building-up and decay time suitable for a musical sound. By this envelope signal the gate circuit 17 is controlled. The gate circuit 17 gates the output tone signal of the voltage memory oscillator 2 in accordance with the envelope signal thereby to lead the output signal to a terminal C. Further, intermediate contacts are provided between the contacts corresponding to musical scale notes among the contacts 9, and a multicontact relay RL is disposed between the contacts 9 and the gate signal shaping circuit 14. They are for the smoother portamento musical performance.
In addition, as shown in FIG. 1 each contact corresponding to the musical scale notes among the group of contacts 9, is connected to the gate signal shaping circuit 14 and to the resistor 15 also through a key switch K of each of manual keyboards. The multicontact relay switch S 1 is adapted to perform the change over operation between another (described hereinafter) musical performance effect and the portamento-effect.
When a portamento musical performance is to be carried out, the switch S 1 should be closed to connect the relay contacts 12 thereby to connect all of the contacts 9 with the line l 1 . And then a desired portion of each contact provided on an elastic member is depressed with a finger, and the finger is moved right or left so that the contacts 9 are successively brought in contact with the resistor 8.
When each of contacts 9a to 9k is made to be in contact with the resistor 8 by depressing the contacts with a finger and by moving the finger in the direction of an arrow mark A, the AC signal from the voltage memory oscillator 2 through the line l 1 is not greatly changed, but said DC component is raised up stepwise as shown in FIG. 3(a). Then, the DC component is applied through the resistor 15 to the capacitor 16, and is charged into the capacitor 16 depending on the time constant determined by the resistor 15 and the capacitor 16. Therefore, the DC voltage wave-form which appears at the mutual connection point of the resistor 15 and the capacitor 16, is built up smoothly as shown in FIG. 3(b). Consequently, the oscillation frequency of the voltage memory oscillator 2 is varied almost linearly, which means that the DC voltage change is substantially useful as a control voltage for portamento. Now, a gate control signal is produced by the gate signal shaping circuit 14 and a musical tone signal is gated by the gate circuit 17 in the same manner as described before. In other words, the gate signal shaping circuit 14 is to impart a predetermined envelope to an output signal at an output terminal C. For instance, in case of giving an envelope that is steep in building-up and is gradual in decaying, an envelope such as shown in FIG. 3(d) should be produced upon receiving the AC signal (FIG. 3(c)) applied to the input terminal of the gate signal shaping circuit 14.
In addition, when contacts 9 are successively brought to be in contact with the resistor 8 in the direction of an arrow B found in FIG. 1, it goes without saying that the portamento-effect in which the frequency successively decreases almost linearly can be obtained in the same way.
Each of the contacts corresponding to respective musical scale notes among the plurality of contacts 9, is also connected to respective key switches K 1 , K 2 , of the manual keybord. The contacts corresponding to a same note name in different octaves are commonly connected together, and the key switches are in turn connected to the line l 1 . In other words, C 1 of the first octave is connected as illustrated in FIG. 1, to C 2 which is the corresponding note in the second octave, D 1 is connected to D 2 , and so on.
Under the condition that the relay RL is not energized and the key switch K 1 is closed by depressing a key C 1 in the manual keyboard, when the contact A 1 is depressed as mentioned before, the signal obtained by mixing the abovementioned DC component and AC component are supplied to the line l 1 through the keyswitch K 1 . Then, the signal of the AC component is introduced to the gate signal shaping circuit 14 through the capacitor 13, while the signal of the DC component is charged into the capacitor 16 through the resistor 15, thereby to apply a predetermined DC voltage to the voltage memory oscillator 2. The voltage memory oscillator 2 now oscillates at a frequency corresponding to the note C 1 .
When an arpeggio musical performance is to be carried out by an apparatus according to the present invention, the switch S 1 should be opened to disconnect the relay contacts 12 and the proper keys in any octave corresponding to the notes constituting the chord should be depressed. And then the operational device will be manipulated simply in the same manner described herein before relating to the portamento performance. By depressing only the keys corresponding to the notes of a required chord in any octave of the manual keyboard, the broken chord notes in all the octaves can be produced successively. Now, assuming that the chord is composed by "do," "mi," and "sol," the key switches K 1 , K 5 , and K 8 are closed by depressing keys C 1 , E 1 , and G 1 . When, under this condition, a finger is glidingly moved successively and rapidly from contact A 1 to contact A 58 among the contacts 9, depressing the contacts with finger, the aforementioned DC and AC components reach the line l 1 through key switches K 1 , K 5 , and K 8 at only a time when contacts A 1 , A 13 , A 22 , A 37 , A 49 , A 58 , --- are brought in contact with the resistor 8. Thus, the sound of "do," "mi," and "sol" are respectively produced.
In addition, FIG. 1 shows the case where the manual keyboard is of two octaves, however, it goes without saying that the number of contacts 9 may be increased in accordance with the number of keys.
FIG. 2 shows an actual circuit diagram of a preferred embodiment of the part including the gate signal shaping circuit 14, the voltage memory oscillator 2 and the gate circuit 17 shown in FIG. 1, for realizing the present invention.
The voltage memory oscillator 2 is constituted by an astable multivibrator having two transistors and associated resistors and capacitors. Two field effect transistors are provided in the respective base biasing resistor circuits, acting as voltage controlled variable resistors whose values determine the oscillation frequency. The output tone signal is applied to a base of a gating transistor of the gate circuit 17, the transistor constituting an emitter grounded type amplifier together with associated resistors. Normally the transistor does not pass the tone signal to the output terminal C, and passes only when a negative voltage is applied at the emitter circuit. The AC component which is originally derived from the voltage memory oscillator and supplied to the resistor 8 through the capacitors 3, 4 and 5, and taken out to the line l 1 is applied to the gate signal shaping circuit 14 through the capacitor 13. The AC component is first amplified by a first stage transistor, second rectified by a voltage doubling rectifying circuit consisting of two capacitors and diodes thereby developing a gating envelope signal, and finally amplified by an emitter follower amplifier and an emitter grounded amplifier. The amplified gating envelope signal having a negative spike voltage is applied through a diode and a resistor to the emitter circuit of the gating transistor in the gate circuit 17, whereby the tone signal is gated in accordance with the gating envelope. The circuit arrangement having such a function can be constructed otherwise as described in the U.S. Pat. No. 3,511,917 and the copending U.S. application Ser. No. 864,047.
The present invention relates to a portamento circuit in a monophonic electronic musical instrument, said circuit being constructed so that a portamento-effect as well as an accurate musical scale can be easily produced and a note selection and a gating envelope trigger can be attained by means of the same performance operation, and furthermore it relates to an electronic musical instrument capable of easily attaining arpeggio performance.
In general, an electronic musical instrument, which is constructed so that an oscillation frequency of a single oscillator is varied in accordance with performance operation in order to produce any musical scale tone signal within a desired tone range, cannot perform simultaneously a plurality of tones, so that said electronic musical instrument is called as "a monophonic electronic musical instrument." Such musical instrument described above has been often used as a merely simple and small electronic musical instrument or as one part of an electronic musical instrument of large scale and complexity.
In the musical instrument described above, however, when a performance is to be carried out it is required to operate simultaneously a musical scale note deciding device for varying a frequency of the tone source and a gate control device for gating a tone source signal thereby to form a required envelope, and said requirement has been attained by utilizing a key-board provided with switches of several rows which are cooperated, whereby said key-board is made to carry out both functions of the above-mentioned devices. Consequently, the key-board requires at least two rows of cooperating switches, thus causing a complex and expensive structure of the key-board and accordingly of the musical instrument.
On the other hand, the portamento-effect in an electronic musical instrument can be produced by increasing or decreasing continuously the oscillation frequency and ordinarily said effect has been produced by varying resistance value of a certain variable resistor provided in the oscillator. For this variation of the variable resistor, it is conventional to slide a slide knob along a variable resistor with a finger or to adjust a contact point between a contact and a resistor with a finger, said contact consisting of a flexible conductive film and said contact and resistor being spaced from each other by a certain distance.
In the case of using a slide knob, however, a resistance variation from a desired resistance value cannot be attained by position of a slide knob, so that when the portamento performance is to be performed, the slide knob must be initially returned to the required starting position, thus causing inconvenience of the performance. Of course, in the latter case mentioned above, production of the portamento-effect is relatively easy, but performance of accurate musical scale is very difficult. Furthermore, the so-called arpeggio performance relates generally to a performance in which notes of a chord are successively employed upwardly or downwardly. For instance, the performance corresponds to the case, in which just after sounding of do, mi and sol in a certain octave, do mi and sol in the next higher octave is sounded and similarly notes of the chord in successively higher octaves are successively sounded.
The performance described above has been conventionally achieved by rapidly and successively pushing each of required note keys in the keyboard, but it is very difficult for the beginners to push successively the keys constituting a desired chord of each octave over a wide key range and furthermore, there is a limit in an extremely high speed arpeggio performance.
SUMMARY OF THE INVENTION
Therefore, an essential object of the invention is to provide an electronic musical instrument capable of producing a rapid glide over the notes in a scale such as a substantially smooth portamento-effect, and also producing accurate musical scale tones, said production being attained by using a portamento performance device, in which a plurality of contacts arranged so as to be spaced from each other at a certain distance and a resistor are provided so that said contacts are spaced by a certain distance from said resistor and brought into contact with said resistor when manipulated.
It is another object of the invention to provide an electronic musical instrument provided with a portamento circuit capable of producing musical scale note deciding signals and gate control signals at the same performance operational position.
It is a further object of the invention to provide an electronic musical instrument which can carry out a rapid glide over the selected notes in a scale such as arpeggio performance by using the circuit mentioned above.
It is still another object of the invention to provide an electronic musical instrument provided with a particular arpeggio performance device comprising, as its main constructional element, a particular oscillator adapted to impart a sustaining characteristic to chords, performance operation of said instrument being very simple.
The foregoing objects and other objects as well as the characteristic features of the invention will become more apparent from the following detailed description and the appended claims when read in conjunction with the accompanying drawings, in which like parts are designated by like reference numerals.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a block diagram showing an example of a portamento and arpeggio performance device according to the invention;
FIG. 2 is a detailed circuit diagram showing a gate signal shaping circuit, a voltage memory oscillator, and a gate circuit in FIG. 1; and
FIG. 3 shows graphs showing wave-forms at various parts of the circuit shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a portamento and arpeggio circuit which is capable of producing a continuous musical scale as well as a broken chord (Alberti bass). 1 is a DC source for controlling the oscillation frequency, and 2 is a voltage memory oscillator. The voltage from the DC source 1 and the output from the oscillator 2 are connected to a resistor 8 through capacitors 3, 4 and 5, and resistors 6 and 7 so that they are not interfered with each other. The resistor 8 is rod-shaped. A plurality of contacts 9 is provided at a predetermined distance from the resistor 8, and the contacts are arranged so as to be apart from one another with a certain distance, and further they are normally maintained so as not to make contact. When a contact 9 is depressed during a musical performance, the contact thus depressed is brought into contact with the resistor 8, whereby the required DC voltage and a certain AC signal from the oscillator are obtained at the point thus contacted. The DC component thus obtained becomes a voltage corresponding to the contact position on the resistor 8, while the AC component obtained is substantially independent of the contact position.
In one state of the operation of the invention, a switch S 1 for portamento is closed and a multicontact relay coil 11 is energized thereby to close all the relay contacts 12, so that the mixed signal of previously described DC and AC components is introduced to a line l 1 . Then, the AC component signal is applied to a gate signal shaping circuit 14 through a capacitor 13, while the DC component signal is charged into a capacitor 16 through a resistor 15, thereby to apply a predetermined DC voltage to the voltage memory oscillator 2. The voltage memory oscillator 2 is of a type such as a relaxation oscillator in which frequency is controlled by a DC voltage, and oscillates a musical scale tone signal of frequency decided by a DC potential developed at a mutual connection point between the capacitor 16 and the resistor 15. The DC potential is maintained even after the resistor 8 is disconnected from the contact 9, thereby to continue the oscillation of the same frequency, and to this end, the resistor 15 is selected higher in value in comparison with the capacitance of the capacitor 16 so as not to introduce the AC component to the oscillator 2. The AC component of the control signal is introduced as a gate control signal to the gate signal shaping circuit 14 through a DC blocking capacitor 13, and is rectified and shaped thereby to become an envelope signal having a building-up and decay time suitable for a musical sound. By this envelope signal the gate circuit 17 is controlled. The gate circuit 17 gates the output tone signal of the voltage memory oscillator 2 in accordance with the envelope signal thereby to lead the output signal to a terminal C. Further, intermediate contacts are provided between the contacts corresponding to musical scale notes among the contacts 9, and a multicontact relay RL is disposed between the contacts 9 and the gate signal shaping circuit 14. They are for the smoother portamento musical performance.
In addition, as shown in FIG. 1 each contact corresponding to the musical scale notes among the group of contacts 9, is connected to the gate signal shaping circuit 14 and to the resistor 15 also through a key switch K of each of manual keyboards. The multicontact relay switch S 1 is adapted to perform the change over operation between another (described hereinafter) musical performance effect and the portamento-effect.
When a portamento musical performance is to be carried out, the switch S 1 should be closed to connect the relay contacts 12 thereby to connect all of the contacts 9 with the line l 1 . And then a desired portion of each contact provided on an elastic member is depressed with a finger, and the finger is moved right or left so that the contacts 9 are successively brought in contact with the resistor 8.
When each of contacts 9a to 9k is made to be in contact with the resistor 8 by depressing the contacts with a finger and by moving the finger in the direction of an arrow mark A, the AC signal from the voltage memory oscillator 2 through the line l 1 is not greatly changed, but said DC component is raised up stepwise as shown in FIG. 3(a). Then, the DC component is applied through the resistor 15 to the capacitor 16, and is charged into the capacitor 16 depending on the time constant determined by the resistor 15 and the capacitor 16. Therefore, the DC voltage wave-form which appears at the mutual connection point of the resistor 15 and the capacitor 16, is built up smoothly as shown in FIG. 3(b). Consequently, the oscillation frequency of the voltage memory oscillator 2 is varied almost linearly, which means that the DC voltage change is substantially useful as a control voltage for portamento. Now, a gate control signal is produced by the gate signal shaping circuit 14 and a musical tone signal is gated by the gate circuit 17 in the same manner as described before. In other words, the gate signal shaping circuit 14 is to impart a predetermined envelope to an output signal at an output terminal C. For instance, in case of giving an envelope that is steep in building-up and is gradual in decaying, an envelope such as shown in FIG. 3(d) should be produced upon receiving the AC signal (FIG. 3(c)) applied to the input terminal of the gate signal shaping circuit 14.
In addition, when contacts 9 are successively brought to be in contact with the resistor 8 in the direction of an arrow B found in FIG. 1, it goes without saying that the portamento-effect in which the frequency successively decreases almost linearly can be obtained in the same way.
Each of the contacts corresponding to respective musical scale notes among the plurality of contacts 9, is also connected to respective key switches K 1 , K 2 , of the manual keybord. The contacts corresponding to a same note name in different octaves are commonly connected together, and the key switches are in turn connected to the line l 1 . In other words, C 1 of the first octave is connected as illustrated in FIG. 1, to C 2 which is the corresponding note in the second octave, D 1 is connected to D 2 , and so on.
Under the condition that the relay RL is not energized and the key switch K 1 is closed by depressing a key C 1 in the manual keyboard, when the contact A 1 is depressed as mentioned before, the signal obtained by mixing the abovementioned DC component and AC component are supplied to the line l 1 through the keyswitch K 1 . Then, the signal of the AC component is introduced to the gate signal shaping circuit 14 through the capacitor 13, while the signal of the DC component is charged into the capacitor 16 through the resistor 15, thereby to apply a predetermined DC voltage to the voltage memory oscillator 2. The voltage memory oscillator 2 now oscillates at a frequency corresponding to the note C 1 .
When an arpeggio musical performance is to be carried out by an apparatus according to the present invention, the switch S 1 should be opened to disconnect the relay contacts 12 and the proper keys in any octave corresponding to the notes constituting the chord should be depressed. And then the operational device will be manipulated simply in the same manner described herein before relating to the portamento performance. By depressing only the keys corresponding to the notes of a required chord in any octave of the manual keyboard, the broken chord notes in all the octaves can be produced successively. Now, assuming that the chord is composed by "do," "mi," and "sol," the key switches K 1 , K 5 , and K 8 are closed by depressing keys C 1 , E 1 , and G 1 . When, under this condition, a finger is glidingly moved successively and rapidly from contact A 1 to contact A 58 among the contacts 9, depressing the contacts with finger, the aforementioned DC and AC components reach the line l 1 through key switches K 1 , K 5 , and K 8 at only a time when contacts A 1 , A 13 , A 22 , A 37 , A 49 , A 58 , --- are brought in contact with the resistor 8. Thus, the sound of "do," "mi," and "sol" are respectively produced.
In addition, FIG. 1 shows the case where the manual keyboard is of two octaves, however, it goes without saying that the number of contacts 9 may be increased in accordance with the number of keys.
FIG. 2 shows an actual circuit diagram of a preferred embodiment of the part including the gate signal shaping circuit 14, the voltage memory oscillator 2 and the gate circuit 17 shown in FIG. 1, for realizing the present invention.
The voltage memory oscillator 2 is constituted by an astable multivibrator having two transistors and associated resistors and capacitors. Two field effect transistors are provided in the respective base biasing resistor circuits, acting as voltage controlled variable resistors whose values determine the oscillation frequency. The output tone signal is applied to a base of a gating transistor of the gate circuit 17, the transistor constituting an emitter grounded type amplifier together with associated resistors. Normally the transistor does not pass the tone signal to the output terminal C, and passes only when a negative voltage is applied at the emitter circuit. The AC component which is originally derived from the voltage memory oscillator and supplied to the resistor 8 through the capacitors 3, 4 and 5, and taken out to the line l 1 is applied to the gate signal shaping circuit 14 through the capacitor 13. The AC component is first amplified by a first stage transistor, second rectified by a voltage doubling rectifying circuit consisting of two capacitors and diodes thereby developing a gating envelope signal, and finally amplified by an emitter follower amplifier and an emitter grounded amplifier. The amplified gating envelope signal having a negative spike voltage is applied through a diode and a resistor to the emitter circuit of the gating transistor in the gate circuit 17, whereby the tone signal is gated in accordance with the gating envelope. The circuit arrangement having such a function can be constructed otherwise as described in the U.S. Pat. No. 3,511,917 and the copending U.S. application Ser. No. 864,047.