US3624263A

US3624263A - Electronic musical instrument with automatic bass performance circuitry

Info

Publication number: US3624263A
Application number: US115681A
Authority: US
Inventors: Yasuji Uchiyama
Original assignee: Nippon Gakki Co Ltd
Current assignee: Nippon Gakki Co Ltd
Priority date: 1970-02-16
Filing date: 1971-02-16
Publication date: 1971-11-30
Anticipated expiration: 1988-11-30
Also published as: DE2107409A1; DE2107409C3; NL7101958A; NL169243B; NL169243C; DE2107409B2

Abstract

This invention provides an electronic musical instrument capable of carrying out bass performance conforming with chord performance by merely depressing keys in a keyboard for the chord performance. To this end, there are provided a chord detector for detecting the type of the chord including various notes, that is, root, fifth, major on minor third, and major sixth or minor seventh notes when the keys of the keyboard are depressed for chord performance, and bass selectors responsive to the outputs from the chord detector for selectively deriving bass tone signals corresponding to respective notes of the chord from tone generators and supplying the derived bass tone signals to respective bass gate circuits. The bass gate circuits are sequentially opened by timing pulses from a rhythm pattern pulse generator in a specific order conforming with chord performance, thereby providing automatic bass performance in a desired rhythm.

Description

United States Patent Yasuji Uchiyama [72] lnventor 3,544,693 12/1970 Tripp 8411.01 Hamakita,J apan 3,546,355 12/1970 Maynard. 84/103 [21] Appl. No. 115,681 3,548,066 12/1970 Freeman 84/103 [22] Filed Feb. 16, 1971 3,567,838 3/1971 Tennes 84/101 [45] Patented 1971 Primar ExaminerLewis H M ers [73] Assignee Nippon Gakki Seizo Kabushiki Kaisha y I k llamammsu shi,shizuoka ken Japan Assistant Examiner-Stan ey .1. 1t owski Anome Fl nn& Fnshauf 321 Priorities Feb. 16, 1970 y y [33} Japan [31 45/12786; ABSTRACT: This invention provides an electronic musical in- 16, J P b 45/127873 strument capable of carrying out bass performance conform- 16, 1970,1998", 45/12788; P ing with chord performance by merely depressing keys in a 1970 Japan 45/2717, keyboard for the chord performance. To this end, there are provided a chord detector for detecting the type of the chord including various notes, that is, root, fifth, major on minor [54] ET ZHE third, and major sixth or minor seventh notes when the keys of 6 Claims 12 Drawing g the keyboard are depressed for chord performance, and bass selectors responsive to the outputs from the chord detector for 152] US. Cl 84/l.03, selectively deriving bass tone signals corresponding to respec- 84/l.24,84/D1G. 22 tive notes of the chord from tone generators and supplying the [51 1 Int. Cl Gl0h l/00 derived bass tone signals to respective bass gate circuits. The [50] Field of Search 84/ 1.01, bass gate circuits are sequentially opened by timing pulses 1.03, 1.17, 1.24, DIG. 22 from a rhythm pattern pulse generator in a specific order conforming with chord performance, thereby providing automatic [56] References cued bass performance in a desired rhythm.

UNITED STATES PATENTS 3,305,620 2/1967 Young 84/l.17

3 1 5 8 TONE CHORD KEYBOARD TONE 7 J GATE COLORIN GENERATORS g FILTER G '4 2 i C 13A 13B 8 GATE i SFGGFE S QEE CTOR L T LHEIB I GATE 1 14A'@ 1'3 FILL TONE '11 BASS is COLORING T L 31 SELEHCTOR GATE I FILTER 8 15A (9 14 L 24 X EE CTOR 19 55115 m GATE 1 l X I l q 1 I I 9 i I PULSE TIMING i 20 ENERATOR PULSE ENC.

RHYTHM PATTERN PULSE GENERATOR PATENTEU nuvso 1971 SHEET 3 [IF 7 G ON ON OFF OFF PATENTEI] NOV30 I37! SHEET 7 0F 7 T T DU U OT T HU AU C0 BO 0 O N E 1 m m U T 1 HU M M RMP Y Y ll DW W H E CM BM m U D RE m 0T 00 HE RB CD mm CK s m T A Em mm T G bKEY DEPRESSION AND RELEASE JED CEG 6 FIG. 12

ELECTRONIC MUSICAL INSTRUMENT WITH AUTOMATIC BASS PERFORMANCE CIRCUITRY BACKGROUND OF THE INVENTION This invention relates to an electronic musical instrument, and more particularly to an improved electronic musical instrument wherein bass performance can be carried out in a desired rhythm pattern with or without accompanying chord performance by mere operation of the chord keyboard.

A conventional electronic musical instrument, for example, an electronic organ, is usually provided with upper and lower manual keyboards and a pedal keyboard. Generally, the melody performance is played by operating the upper keyboard with the right hand, the chord performance is played by operating the lower keyboard with the left hand and the bass performance is played by operating the pedal keyboard with the left foot. In such a case, it is necessary to perform the chord and bass performances which are the accompaniments of the melody performance in consonance with the melody performance. Further, the chord performance should be played rhythmically with the left hand in consonance with the melody performance whereas the bass performance should be played with the left foot with a rhythm pattern different from that of the chord performance. To play the bass performance it is necessary to depress, in specific rhythm, the keys of the pedal keyboard corresponding to notes contained in the chord while the same chord is being played. In other words, for unskilled players, it is more difficult to play the bass performance by the manipulation of the pedal keyboard than to play the chord performance. Thus, with the prior art electronic musical instrument, a considerable skill is required to carry out the chord and bass performance in conformity with the melody performance so that it has been difficult for unskilled players to play electronic musical instruments.

SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide a novel electronic musical instrument capable of automatically carrying out a bass performance which is most suitable as the accompaniment of the melody performance without relying upon complicated operations of a pedal keyboard.

Another object of this invention is to provide a novel electronic musical instrument capable of carrying out a continuous chord performance in a desired rhythm pattern by depressing the keys of a manual keyboard for only a short period of time.

According to this invention there is provided an electronic musical instrument comprising tone generators; a keyboard provided with key switches for selectively keying tone signals from the tone generators; a chord detector including first, second and third detector matrixes for detecting the root and fifth notes, the third note, and the major sixth or the minor seventh note contained in the chord being played on the keyboard; first, second and third bass selectors responsive to the outputs from the respective chord detectors for selectively deriving bass tone signals corresponding to respective notes included in the chord from the tone generators; a chord gate circuit supplied with tone signals from the tone generators through the operation of the keyboard; first, second, third and fourth base gate circuits supplied with each bass tone signals corresponding respectively to the root note, fifth note, third note and major sixth or minor seventh note from the bass selectors; and a rhythm pattern pulse generator for applying timing pulses to the chord gate circuit for opening (conducting) the same in accordance with a predetermined rhythm pattern and for supplying timing pulses to the respectively bass gate circuits to open the same in a specific order proper to the chord being played.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I shows a block diagram of one example of the electronic musical instrument embodying the invention;

FIG. 2 shows a circuit diagram of the chord detector matrix shown in FIG. I;

FIG. 3 shows a partial circuit diagram useful in explaining the operation of the chord detector matrix shown in FIG. 2;

FIG. 4 shows waveforms of control outputs for explaining the operation of the circuit diagram shown in FIG. 3;

FIG. 5 is a circuit diagram of one example of the bass selector shown in FIG. 1;

FIG. 6 shows a circuit diagram of the pulse distributor shown in FIG. 1;

FIG. 7 shows a block diagram of a modified embodiment of the novel electronic musical instrument;

FIG. 8 shows a connection diagram of the pulse distributor shown in FIG. 7;

FIG. 9 shows waveforms of input and output pulses of the timing pulse encoder shown in FIG. 7;

FIG. 10 shows waveforms of output pulses of the pulse distributor shown in FIG. 8;

FIG. 11 shows a schematic block diagram of another embodiment of the novel electronic musical instrument; and

FIG. 12 shows musical notations useful in explaining the operation of the electronic musical instrument shown in FIG. I 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electronic musical instrument shown in FIG. 1 comprises a chord keyboard 1 including a plurality of key switches 2 (only one of them is shown) operated by respective keys (not shown) of the keyboard. As is well known in the art, when actuated by the associated key, the key switch 2 derives a tone signal of the selected pitch from tone generators 3. The term chord keyboard 1' is used herein to mean a lower manual keyboard in case of the electronic musical instrument including an upper manual keyboard and a lower manual keyboard as in a normal conventional electronicorgan, or to mean a lower half portion of a keyboard in case of the electronic musical instrument being provided with only one manual keyboard. The chord keyboard I is further provided with chord detector key switches 4 (one of them is shown). Where the chord keyboard is a lower keyboard, the chord detector key switches 4 are provided for every key, whereas where a single keyboard is utilized for both melody performance and chord performance, the chord detector key switches may be provided for the keys in the lower half of the keyboard which half being utilized for the chord performance.

The tone signal derived from the tone generators 3 by closure of the key switch 2 is applied to a chord gate circuit 5 and the output from the chord gate circuit is converted into a musical tone signal having a suitable timbre through the function of a tone-coloring filter 6. The output from the filter 6 is amplified by an amplifier 7 and then transduced into audible sound by means of a loudspeaker 8.

Although not shown in the drawings, tone signals for the melody performance are also derived from the tone generators 3 by the operation of the upper keyboard or the higher half portion of a single keyboard and such tone signals are converted into musical tone signals by the function of a tonecoloring filter, the output thereof being applied to the amplifier 7.

There is also provided a chord detector matrix 9 for detecting the type of the chord being played on the chord keyboard I by means of the key switch 4.

According to this invention, the type of the chord is detected in terms of the root, fifth, major or minor third and major sixth or minor seventh notes. To this end, the chord detector matrix 9 comprises a first matrix 10 for detecting the root and the fifth notes, a second matrix II for detecting the major or minor third note and a third matrix 12 for detecting the major six or minor seventh note. Detected output from the first, second and third matrixes I0, 11 and 12 are applied to first, second and third bass selectors l3, l4 and 15, respectively. Each bass selector is applied with the specific bass tone signals from the tone generators 3 corresponding to respective notes contained in the chord being played on the chord keyboard 1. More particularly, the first bass selector 13 which is connected to receive the control output from the first matrix is impressed from the tone generators 3 with pairs of bass tone signals 13A and 138 corresponding to the root notes and the fifth notes of respective chords being played on the chord keyboard 1. The second bass selector 14 connected to receive the control output from the second matrix 11 is applied with bass tone signals 14A corresponding to the major orminor third notes of respective chords. Likewise, the third bass selector connected to receive the control output from the third matrix 12 is impressed with bass tone signals 15A corresponding to the major sixth or minor seventh notes of respective chords.

In the presence of a control output from the first chord detector matrix 10, the first bass selector l3 derives from the tone generators 3

bass tone signals

13A and 13B corresponding to the root and fifth notes of the chord being played and these signals are applied to bass gate circuits l6 and 17, respectively. Where the played chord contains the minor or major third note, the second detector matrix 11 produces a control output, in response to which the second bass selector l4 derives from the tone generators 3 a bass tone signal 14A corresponding to the minor or major third note, which in turn is applied to a third bass gate circuit 18. Where the played chord contains the major sixth or minor seventh note, the third detector matrix 12 produces a control output, in response to which the third bass selector l5 derives from the tone generators 3 a base tone signal 15A corresponding to the major sixth or minor seventh note which in turn is applied to a fourth bass gate circuit 19. The bass selector may preferably have memory functions. In other words, these bass selectors may be constructed such that they memorize the types of the chords according to the control output signals from the chord detector matrixes so as to continuously derive out when the keys of the chord keyboard are once depressed and then released, bass tone signals corresponding to the played chord until a next other chord is played.

There is also provided a rhythm pattern pulse generator, generally designated by a reference numeral 20, for preparing a timing pulse of the desired rhythm pattern to open the chord gate circuit 5 so as to automatically carry out the desired rhythmic chord performance upon operation of the chord keyboard 1. The rhythm pattern pulse generator also prepares timing pulses to open the bass gate circuits 16 to 19 in a specific order conforming with the chord performance so as to automatically carry out the desired rhythmic bass performance with a rhythm conforming with the chord performance. The rhythm pattern pulse generator 20 comprises a pulse generator 21 which may be an astable multivibrator having variable oscillation frequencies, a timing pulse encoder 22 connected to receive the output pulse (clock pulse) from the pulse generator 21 for selectively producing a timing pulse sequence having a desired rhythm pattern and applied to the chord gate circuit 5, and a pulse distributor 23 connected to receive from the timing pulse encoder 22 a plurality of(for example, three) pulses of varying phases so as to produce timing pulses which open the bass gate circuits 16 through 19 in a predetermined sequence. As will be described later in detail, outputs from the second and third detector matrixes l1 and 12 are supplied also to the pulse distributor 23.

The outputs from the bass gate circuits 16 to 19 are applied to the loudspeaker 8 through the tone-coloring filter 24 and the amplifier 7.

Before describing in detail the construction and operation of essential elements of the electronic organ shown in FIG. 1, the outline of the operation will first be described. Let us assume that a waltz, a rhumba or the like is to played. The player plays a chord performance on the chord keyboard 1 in consonance with the melody performance of such music. Such chord performance can be made by intermittently deriving out from the chord gate circuit 5 tone signals which are continuously applied to the gate circuit 5 from the tone generators 3 by continuous operation of the chord keyboard 1 according to a timing pulse sequence having a rhythm pattern in consonance with the rhythm of the waltz or rhumba.

When playing a music of waltz, rhumba or beguine wherein bass tones are played with three beats per one measure, if a chord [C] were played on the chord keyboard I, in other words, if the keys corresponding to C, E and G notes are depressed, the first bass selector 13 will supply a bass tone signal of C note corresponding to the root note of the played chord and a bass tone signal of G note corresponding to the fifth note to the

gate circuits

16 and 17, respectively, in accordance with the output from the chord detector matrix 9 during the period in which the chord keyboard 1 is being operated. Further, a bass tone signal of E note corresponding to the third note of the chord being played is supplied to the gate circuit 18 from the second bass selector 14. These gate circuits are opened (rendered conductive) in an order of the first gate circuit 16, the third gate circuit 18 and the second gate circuit 17 by the timing pulses from the pulse distributor 23 which is controlled by the output from the chord detector 9. Thus, the bass performance is made by three beats in the order or C, E and G notes.

Where a chord [C containing four notes C, E, G and A is to be played, the bass performance is made according to the order of C, A and G.

In this manner, with the novel electronic musical instrument, it is not only possible to play a chord performance of the desired rhythm but also to play a bass performance in consonance with the chord being played, only by continuously depressing the keys of the chord keyboard in consonance with the melody performance. Furthermore, as above described as long as the bass selectors have memory functions, it is possible to continuously derive out bass tone signals from the bass selectors, until the next chord performance is done after the chord keyboard has been operated, thus automatically performing the bass performance. In other words, it is possible to perform the base performance alone without accompanying the chord performance.

Having completed the brief description regarding the outline of the operation of the novel electronic musical instrument shown in FIG. 1, the details of essential components thereof will now be described.

FIG. 2 shows a connection diagram of the chord detector matrix 9 including, first, second, and third matrixes 10, II and 12. In this figure, a group of chord detector key switches is designated by a reference numeral 4, the group including at least 12 key switches respectively actuated by 12 keys within one octave of the chord keyboard 1. Key switches 4A to 4L are commonly connected to [2 column conductors of the first to third matrixes. Column conductors of the first matrix 10 (also those of the second and third matrixes) are connected to the positive terminal (+12V) ofa source respectively through resistors r. Twelve rows or output conductors of the first matrix 10 are grounded, respectively, through resistors R. The first matrix 10 functions to detect the root and fifth notes of the chord being played. There are connected diodes D in the forward direction with respect to the source voltage between the uppermost output conductor for detecting the chord [C] and two column conductors connected to the key switches 4A and 4H actuated by the keys of the chord keyboard, the keys corresponding to notes C and G, that is the root and fifth notes of chord [C]. In the same manner, diodes D,. are connected between another one of the output conductors and two column conductors for the purpose of detecting the root and fifth notes in accordance with the type of the chord to be played.

The output conductors of the first matrix 10 are connected to corresponding output conductors of the second matrix 10 through diodes D,, and D which are connected in series op position as shown in FIG. 2. The positive terminal (+12V) of the source is connected to the junctures between diodes D and D or to the anode electrodes of these diodes D and D respectively, through resistors R. The uppermost output conductor of the second matrix 11 is used to detect the major third note E contained in chord [C] and there is connected a diode D between this output conductor and the column conductor connected to the key switch 4E actuated by a key of the chord keyboard, corresponding to the note E.

To detect D which is the minor third note of chord [C,,,] comprised by notes C, D and G, there is connected a diode D, of the polarity shown in the drawing between the juncture between diodes D and D which are connected to the lowermost output conductor of the second matrix II and the uppermost output conductor of the first matrix 10. In the same manner, diode D is connected between the lower most output conductor of the second matrix 11 and the column conductor connected to the key switch 4D actuated by a switch corresponding to note D#.

Output conductors of the first matrix are also connected to corresponding output conductors of the third matrix 12 respectively through diodes D and D connected in series opposition. The junctures between diodes D,.- and D that is the anode electrodes of these diodes are connected to the positive terminal (+l2V) of the source through respective resistors R. The uppermost output conductor of the third matrix 12 is used to detect A e.g. the minor seventh note of chord [C comprised by notes C, E, and A and there is connected a diode D between this output conductor and a column conductor connected to the key switch 4K which is actuated by a key corresponding to note A Furthermore, in order to detect the note A, that is the major sixth note of chord [C comprised by notes C, E, G and A, there is connected a diode D, having a polarity as shown between the juncture between diodes D and D connected to the lowermost output conductor of the third matrix 12 and the uppermost output conductor of the first matrix 10. There is connected a diode D between the lowermost output conductor of the third matrix 12 and a column conductor connected to the key switch 41 actuated by a key corresponding to note A. Outputs generated on respective output conductors of the first, second and third matrixes l0, l1 and 12 appear on output terminals 0,, O and 0,.

While the construction of the chord detector matrix 9 shown in FIG. 2 has been described with respect to the chord alone related to chord [C], it will be clear to those skilled in the art that the construction for other chords is similar to that described.

The operation of the chord detector matrix will be described hereunder with reference to FIGS. 3 and 4.

FIG. 3 shows the connection of various component elements with respect to the uppermost output conductor of respective matrixes of the chord detector matrix 9 shown in FIG. 2. Corresponding elements shown in FIGS. 2 and 3 are designated by the same reference characters. The resistance values of various resistors are shown by a relationship;

R R r. Where all

key switches

4A, 4H, 4E and 4K are opened, in

other words, where keys corresponding to notes C, G, E and A are not depressed, voltages substantially equal to the source voltage (+l2V). will appear on output terminals 0,, 0 and 0;, of

respective matrixes

10, 11 and [2. Similar voltages will be obtained when only one of the

key switches

4A, 4H, 45 and 4K is closed.

When key switches 4A and 4H are closed concurrently, a voltage determined by a potentiometer comprised by resistor R and four parallel-connected resistors R will appear on terminal 0,, the voltage being lowered toward ground potential. Since R' R, the positive voltage appearing at terminal 0, at this time is much smaller than the source voltage +l2V whereby the root note and fifth note of the played chord can be detected. Where key switch 4E is closed while the key switches 4A and 4H are held closed, a voltage having the same level as that appearing on terminal 0, will appear on the output terminal 0 of the second matrix. In the same manner, closure of key switch 4K provides an output voltage on terminal 0 of the third matrix having the same level as that on terminal Thus, in the ease of chords [C], [C,,,], [C,] and A[C,,] containing C and G as the root and fifth notes, closure of the key switches 4A and 4H produces a control output (negative spike from the +l2-volt level) on terminal 0, connected to the uppermost output conductor of the first matrix 10. In the case of a chord containing note E in addition to notes C and G, closure of the key switch 4E will produce a control output on terminal 0, connected to the uppermost output conductor of the second matrix 11. In the case of a chord containing note A closure of the key switch 4K produces a control output on terminal 0 connected to the uppermost output conductor of the third matrix 12.

With reference now to FIG. 4, upon closure of the switches 4A and 4H, a control output appears on terminal 0, whereas when the key switch 4E is closed while the key switches 4A and 4H are held closed, a control output appears on terminal This can be noted from the fact that the output disappears when the switches 4A and 4H are opened even when the switch 4E is held closed. Thus, the second and third matrixes I1 and 12 of the chord detector matrix 9 depend upon the operation of the first matrix 10.

FIG. 5 shows a circuit diagram of one example of the first bass selector 13 having a memory function and shown in FIG. 1. The bass selector 13 shown comprises a plurality of flip-flop circuits F F F,, corresponding to respective chords to be played, each flip-flop circuit being comprised by a pair of transistors T, and T The emitter electrodes of transistors T, of respective flip-flop circuits are commonly connected to the positive terminal (+3V of a source, whereas the emitter electrodes of transistors T are also connected to the same terminal through a common feedback impedance element L. The collector electrodes of transistors T, and T are connected to the positive terminal (+15V) of a source, respectively, through resistors R, and R and resistors R, and R, are provided between the collector electrode of one transistor and the base electrode of the other transistor. The base electrode of transistor T is connected to the positive terminal (+3V) of the source via resistor R The control output voltage from the first matrix 10 of the chord detector matrix 9 is applied to the base terminals K,, K, K, of respective transistors T, of respective flip-flop circuits through a diode D, with a polarity as shown.

Assuming that flip-flop circuit F, is used to select chord [C], a bass tone signal corresponding to the root note C are supplied to the collector electrode of transistor T, from the tone generators 3 through serially connected resistor R and diode D,. Also, a bass tone signal corresponding to the fifth note G is applied to the same collector electrode via serially connected resistor R and diode D,.

A resistor R, is connected between the juncture between resistor R and diode D, and the root note output terminal 0, of the first bass selector 13. Similarly, a resistor R, is connected between the juncture between resistor R, and diode D and the fifth note output terminal 0 It will be clear that transistors I, of respective flip-flop circuits are normally conductive because the transistors T are rendered nonconductive by means of the grounded resistor R As a consequence, the bass tone signals impressed upon the collector electrodes of transistors T, is short circuited and do not appear on the output terminals 0, and 0 When a chord containing notes C and G is played on the chord keyboard 1, a control output will appear on the output terminal 0 of the first matrix 10, shown in FIG. 2. Since this output impressed upon the base terminal K, of transistor T, of the flip-flop circuit F, has a lower level than the emitter voltage (+3V), transistor T, is rendered nonconductive, and hence transistor T is rendered conductive. As the transistor becomes nonconductive, bass tone signals are supplied to the output terminals 0, and 0, and hence to the first and second bass gate circuits l6 and 17.

Thus, the output from the first matrix 10 renders the transistor T, of flip-flop circuit F, nonconductive and the transistor T, conductive. This condition persists even after disappearance of the chord-detected output. This means that the depression of keys of chord keyboard 1 corresponding to notes C and G has been memorized. Next upon depression of a key of the chord keyboard 1 corresponding to notes G and D contained in chord [G the first matrix 10 supplies its control output to the base terminal K of transistor T, of the flip-flop circuit F to render transistor T, nonconductive to provide bass tone signals corresponding to notes G and D for the output terminals and 0 At this time the transistor T of that flip-flop circuit is rendered conductive. Upon conduction of transistor T of the flip-flop circuit F a current flows through the inductor L from its emitter electrode, thereby turning off the other transistor T which has been conductive and turning on transistor T which has been nonconductive of the flip-flop circuit F As above described, with the bass selector shown in F IG. 5 it is possible to derive desired bass tone signals from the bass selector and supply them to the bass gate circuit during a period from an instant when keys corresponding to notes contained in the chord are depressed once and then released to an instant at which the next chord is played on the chord keyboard. Accordingly, the player can use his left hand to manipulate another element of the electronic musical instrument. If the player keeps operating the chord keyboard with his left hand, it is possible to perform both bass performance and chord performance.

The second and third bass selectors l4 and may be constructed identically to the first bass selector 13, in which case a single bass tone signal is impressed on respective flip-flop circuits and this signal is supplied to bass gate circuits [8 and 19 via single output terminal.

FIG. 6 shows a circuit diagram of the pulse distributor 23 shown in FIG. 1.

Timing pulse encoder 22 supplies three negative pulses P P and P A3 of different phases corresponding to three beats of rhumba, beguine and waltz. Pulses P P, and P are impressed upon first, second and third

gate control circuits

60, 61 and 62, respectively. Each gate control circuit includes a monostable multivibrator comprised by transistors T and T and a phase inverter circuit comprised by a transistor T Each multivibrator is constructed such that its transistor T is made normally conductive. Input pulses P P and P,, are impressed upon the collector electrode of transistors T of respective multivibrators to render the respective transistors T nonconductive, thus producing positive pulses P P and P of a constant pulse width from their collector electrodes. These output pulses P P and P from the multivibrators are applied to the phase inverters T to produce negative output pulses P P and P respectively.

Pulse P is impressed upon the first bass gate circuit 16 through a diode whereas pulses P and P are combined and commonly impressed upon the second bass gate circuit 17 through independent diodes.

The output from the c second matrix 11 contained in chord detector 9 (see FIG. 1) for detecting the third note and the output from the third matrix 12 for detecting the major sixth or minor seventh note are also supplied to the pulse distributor 23. Negative-going output signals from the second and

third matrixes

11 and 12 are applied to normally conductive transistors T and T, of the fourth and fifth

gate control circuits

63 and 64, thus rendering these transistors nonconductive. Upon application of the negative-going input signals, the emitter follower outputs from transistors T and T, are applied to normally conductive transistors T and T thus rendering them nonconductive. The positive output pulse P from the monostable multivibrator contained in the second gate control circuit 61 is supplied to the collector electrodes of transistors T and T The positive pulse P impressed upon the collector electrode of transistor T while it is maintained nonconductive is applied to a shunting transistor T through a series circuit including a resistor and a diode, thus rendering conductive the shunting transistor T which is provided in the circuit with respect to the pulse P included in the second gate control circuit 61. Thus, the output pulse P is shunted by the transistor T so that it is prevented from being applied upon the transistor T of the second gate control circuit 61. Consequently, the pulse P is not impressed upon the second bass gate circuit 17.

The positive pulse P impressed upon the collector electrode of transistor T while it is maintained nonconductive is impressed upon transistor T and T, through a series circuit including a resistor and a diode thus rendering these transistors conductive. The pulse P impressed upon the collector electrodes of transistors T and T while they are maintained nonconductive is to be impressed upon the third and fourth bass gate circuits l8 and 19 respectively through phase inverter T and a diode. However, the transistors T, and T are turned on by the positive pulse P which is impressed upon the collector electrode of transistor T while it is maintained nonconductive. As a result, negative pulse P corresponding to pulse P is applied upon only the fourth bass gate circuit 19.

With the electronic musical instrument shown in FIG. 1 and comprising the pulse distributor just described, when a chord [C], for example, is played on the chord keyboard 1, the pulse P from the first gate control circuit 60 in response to the pulse P, from timing pulse encoder 22 derives a bass tone signal from the first bass gate circuit l6 corresponding to the C note which is the root note of the first beat, then the pulse P obtained from the fourth gate control circuit 63 in response to the output from the second matrix 11 and the pulse P from the timing pulse encoder 22 derives a bass tone signal from the bass gate circuit 18 corresponding to the E note which is the third note of the second beat. Thereafter, the pulse P obtained from the third gate control circuit 62 in response to pulse P derives a bass tone signal from the second bass gate circuit 17 corresponding to G note which is the fifth note of the third beat. In this manner, in the case of a chord [C], bass performances are automatically performed in the order of notes C, E and G to produce a music of high quality.

In the case of a chord [C containing notes C, E, G and A as the first beat, a bass tone signal corresponding to note C which is the root note is obtained. As the second beat, the pulse P produced by the fifth gate control circuit 64 by the output from the third matrix 12 in response to the presence of the note A which is the minor seventh note and the pulse P from the timing pulse encoder 22 derive a bass tone signal corresponding to note A from the fourth bass gate circuit 19. Thus, where the third note E and the minor seventh note A coexist, a preference is given to the bass tone signal corresponding to the minor seventh note. Then, as the third beat, a bass tone signal of G note, which is the fifth note, is produced. In this manner, in the case of the chord [C the bass performances are done in the order of notes C, A and G. Whereas in the case of a chord performance containing only the root and fifth notes, or notes C and G the bass performances are done in the order of notes C, G and G.

In the electronic musical instrument shown in FIG. 1, satisfactory bass performances are done by controlling the pulse distributor by the output from the chord detector so as to distribute pulses in a most suitable order among various bass gate circuits impressed with bass tone signals. Instead of controlling the pulse distributor by the chord detector, it is also possible to include suitable means in the distributor that can distribute the pulses among bass gate circuits in an appropriate order.

FIGS. 7 and 8 illustrate such a modified electronic musical instrument and a modified pulse distributor therefor. Corresponding elements shown in FIGS. 7 and l are designated by the same reference numerals for eliminating duplicated description.

In the modified embodiment shown in FIG. 7 an output pulse I as shown in FIG. 9 is supplied to the timing pulse encoder 22 from the pulse generator 21. The timing pulse encoder 22 comprises, for instance, a ring counter or a plurality of cascade-connected flip-flop circuits and a plurality of AND circuits to which are applied a plurality of combinations of the affirmation outputs and the negation outputs from respective flip-flop circuits. In the embodiment shown in FIG. 7 and 8, four AND gate circuits contained in the timing pulse encoder produce four output pulses I,, I,, l and I of different phases as shown in FIG. 9 and these output pulses are supplied to distributor 23. Pulses are supplied to the first through fourth bass gate circuits 16 through 19 from distributor 23 in the order of O, to selected by the distributor.

With the pulse distributor shown in FIG. 8, the output pulses I to I from the timing pulse encoder 22 are applied to four

input conductors

80A, 80B, 80C and 80D of the pulse distributor 23 through capacitors

C Input conductors

80A, 80B, 80C and 80D are connected to the positive terminal (+l2V) of a source respectively through a resistor R A plurality of output conductor groups 81 to 85 of the number corresponding to the number of rhythms desired to be played are provided to cross input conductors 80A to 80D. Each output conductor group comprises two to four output conductors and output conductors in each group are connected to the positive terminal (+l2V) of the source respectively through resistors R and rhythm selector switches S S S S, and S provided for respective groups. The juncture between the resistor R of each group of output conductors and a corresponding rhythm selector switch is grounded through a parallel circuit comprising a resistor R and a capacitor C Output conductors in each group are connected to respective output terminals O to 0., of distributor 23 through capacitors C output terminals O to 0, being grounded through resistors R respectively. At crossing points between output conductors included in respective groups and connected to respective rhythm selector switches S to S and input conductors 80A to 800 are connected diodes D according to the rhythm pattern to be played. With regard to the output conductor group 81 connected to rhythm selector switch S diodes D are connected at crossing points between an output conductor 81A and the input conductor 80A, between output conductor 81B and input conductor 80C, and between output conductor 81C and input conductor 80D, These

output conductors

81A, 81B and 81C are connected to output terminals 0,, O and 0 respectively.

With regard to the output conductor group 85 connected to rhythm selector switch S diodes D are connected at crossing points between output conductor 85A and input conductor 80A; between output conductor 85B and input conductor 80B; between output conductor 85C and input conductor 80C, and these

output conductors

85A, 85B, 85C and 85D are connected to output terminals 0,, O O and 0,, respectively.

The pulse distributor 23 shown in FIG. 8 operates as follows: when rhythm selector switches S, to S are opened, as the positive voltage (+l2V) is impressed upon the cathode electrodes of respective diodes D,, these diodes are maintained nonconductive. For this reason, even when input pulses I to I are impressed upon input conductors 80A to 80D, no output (negative spike) will appear on the output terminals O to 0,.

Then, when rhythm selector switch S for example is closed, the positive voltage (+l2V) will be impressed upon the anode electrodes of respective diodes D connected to

output conductors

81A, 81B and 81C with the result that these diodes are ready to be turned on. Accordingly, when output pulses I to l as shown in FIG. 9 are applied to input conductors 80A to 80D, respectively, from timing pulse encoder 22,

output conductors

81A, 81B and 81C produce outputs which are differentiated by the action of capacitor C and resistor R Differentiated pulses are sequentially applied to the first, third and second

bass gate circuits

16, 18 and 17 respectively through output terminals 0,, O and 0 as shown in FIG. 7.

FIG. 10A shows output pulses appearing at output terminals 0,, O and 0 of pulse distributor 23 when input pulses I, to I, shown in FIG. 9 are applied and when rhythm selector switch S, is closed, whereas FIG. 108 shows the output pulses when rhythm selector switch S is closed.

FIG. 11 shows another embodiment of this invention which is characterized by the provision of a chord memory 25. It

should be noted that the drawing is schematically shown as compared with FIG. 1 with respect to the circuitry for bass performance. More particularly, upon operation of chord keyboard 1 the notes of the keys actuated by the output from the chord detector 9 are stored in the chord memory 25 with the result that the tone signals from the tone generator 3 are supplied to the chord gate circuit 5 via chord memory 25 even after the operation of the chord performance key has ceased. Accordingly, by the momentary operation of the chord keyboard 1, the timing pulses from the rhythm pattern pulse generator 20 bring the gate circuit 5 in the opened state (conducting) according to the predetermined rhythm pattern thus enabling the desired chord performance without the necessity of continuously operating the chord keyboard 1. Also the bass performance is done in the same manner as in the embodiment shown in FIG. 1. FIG. 11, however, shows only one bass memory 13 and only one bass gate circuit 16.

The operation of the embodiment shown in FIG. 11 will now be described with reference to FIG. 12. Keys on the chord keyboard 1 corresponding to notes C, E G of the chord [C] are depressed for a short interval so as to store the type of the chord in the

memories

25 and 13, by the chorddetected output from the chord detector 9, whereupon tone signals are supplied to

respective gate circuits

5 and 16 from the memories. Since timing pulses are supplied to the

gate circuits

5 and 16 from the rhythm pattern pulse generator 20 the chord and bass performances as shown in FIG. 12 are performed. More particularly, when the chord keyboard is operated from a short interval at the beginning of the measure including a new chord the chord performance and the bass performance corresponding to the chord [C] will be automatically provided until the chord keyboard is operated next time, that is in the illustrated example, over a period of two measures. In the same manner, when keys corresponding to notes G, B and D contained in a chord [G] are depressed for a short interval at the beginning of the third measure, the chord and bass performances corresponding to the [G] chord can be provided.

It is to be understood that the chord memory 25 may be comprised by a plurality of flip-flop circuits in the same manner as the bass selector shown in FIG. 5.

What is claimed is:

1. An electronic musical instrument comprising tone generators; a chord keyboard provided with key switches for selectively keying tone signals from said tone generators; a chord detector including first, second and third detector matrixes responsive to operation of said chord keyboard for detecting the root and fifth notes, the third note, and the major sixth or minor seventh note contained in the chord being played on said chord keyboard and delivering control outputs for corresponding bass notes; first, second and third bass selectors responsive to said control outputs from said chord detector matrixes for selectively deriving bass tone signals corresponding to respective notes included in the chord from said tone generators; a chord gate circuit supplied with tone signals from said tone generators through the operation of said chord keyboard; first, second, third and fourth bass gate circuits supplied with each bass tone signal corresponding respectively to the root note, fifth note, third note and major sixth or minor seventh note from said bass selectors; and a rhythm pattern pulse generator coupled to said chord gate circuit for applying timing pulses to said chord gate circuit for opening the same in accordance with a predetermined rhythm pattern and further coupled to the individual base gate circuits for supplying timing pulses to said respective bass gate circuits to open the same in a specific order proper to said chord being played.

2. The electronic musical instrument according to claim 1 wherein each one of said first, second and third matrixes comprises a plurality of column conductors and a plurality of output conductors crossing said column conductors, said plurality of column conductors of each matrix corresponding to respective notes included in one octave and being connected to respective key switches actuated by the keys of said chord keyboard corresponding to said notes, each one of said column conductors of said first matrix being connect to a source of voltage via a first resistor, each one of the output conductors of said first matrix being connected to two selected output conductors of said second and third matrixes through a pair of diodes connected in series opposition, each one of the output conductors of the first matrix being grounded through a second resistor, the juncture between said diodes which are connected in series opposition being connected to said source of voltage through a third resistor, diodes being connected at two crossing points between one output conductor of said first matrix and said plurality of column conductors, and a diode being connected at a crossing point between each one output conductor of said second and third matrixes and said plurality of column conductors, whereby when keys of said chord keyboard are depressed, said key switches corresponding to said depressed keys are closed so as to produce outputs from predetermined output conductors of said first, second and third matrixes corresponding to respective notes contained in respective chords.

3. The electronic musical instrument according to claim 1 wherein each one of said bass selectors comprises a plurality of flip-flop circuits, each including a normally conductive first transistor and a normally conductive second transistor, the emitter electrodes of said second transistor being connected to a common feedback impedance element, the base electrode of said first transistor being connected to output terminal of said chord detector matrix, and the collector electrode of said first transistor being connected to said tone generators whereby a bass tone signal is derived from the collector electrode of said first normally conductive transistor only when said first transistor is rendered nonconductive in response to the output from said chord detector.

4. The electronic musical instrument according to claim 1 wherein said rhythm pattern pulse generator includes a pulse distributor for supplying timing pulses to said respective bass gate circuits which comprises first, second and third gate control circuits supplied respectively with pulses of different phases to produce timing pulses for controlling said first and second bass gate circuits, the outputs of said second and third gate control circuits being combined, a fourth gate control circuit responsive to the output from said second chord d detector matrix for preventing application of the timing pulse from said second gate control circuit to second bass gate circuit and for supplying said timing pulse to said bass gate circuit, and a fifth gate control circuit responsive to the output from said third chord detector matrix for preventing application of said timing pulse from said second and fourth gate control circuits to said second and third bass gate circuits and for supplying said timing pulse to said fourth bass gate circuit, thereby carrying out bass performance in conformity with the chord being played on said chord keyboard.

5. The electronic musical instrument according to claim 1 wherein said rhythm pattern pulse generator includes a pulse distributor for supplying timing pulses to said respective bass gate circuits which comprises a plurality of input conductors supplied respectively with pulses of different phases, a plurality of groups of output conductors of the number corresponding to a plurality of rhythms to be played, a plurality of normally nonconductive diodes which are disposed at crossing points between output conductors of said respective groups and said input conductors in accordance with rhythm pattern corresponding to said group of output conductors, and a plurality of rhythm selector switches connected to the respective groups of output conductors for rendering conductive the diodes connected to said output conductors, whereby when one of rhythm selector switches is selectively closed, said timing pulses are supplied to said respective bass gate circuits from said respective output conductors connected to said closed selector switch.

6. The electronic musical instrument according to claim 1 which further includes a chord memory which memorizes respective notes contained in a chord in response to respective outputs from said chord detector matrixes produced by operation of said chord detector matrixes produced by operation of said chord keyboard and applied continuously the tone signals to said chord gate circuit form said tone generators, thereby carrying out chord performance without necessity of continuously depressing the keys of said chord keyboard.

Claims

3. The electronic musical instrument according to claim 1 wherein each one of said bass selectors comprises a plurality of flip-flop circuits, each including a normally conductive first transistor and a normally conductive second transistor, the emitter electrodes of said second transistors being connected to a common feedback impedance element, the base electrode of said first transistor being connected to output terminal of said chord detector matrix, and the collector electrode of said first transistor being connected to said tone generators whereby a bass tone signal is derived from the collector electrode of said first normally conductive transistor oNly when said first transistor is rendered nonconductive in response to the output from said chord detector.

4. The electronic musical instrument according to claim 1 wherein said rhythm pattern pulse generator includes a pulse distributor for supplying timing pulses to said respective bass gate circuits which comprises first, second and third gate control circuits supplied respectively with pulses of different phases to produce timing pulses for controlling said first and second bass gate circuits, the outputs of said second and third gate control circuits being combined, a fourth gate control circuit responsive to the output from said second chord detector matrix for preventing application of the timing pulse from said second gate control circuit to second bass gate circuit and for supplying said timing pulse to said bass gate circuit, and a fifth gate control circuit responsive to the output from said third chord detector matrix for preventing application of said timing pulse from said second and fourth gate control circuits to said second and third bass gate circuits and for supplying said timing pulse to said fourth bass gate circuit, thereby carrying out bass performance in conformity with the chord being played on said chord keyboard.

6. The electronic musical instrument according to claim 1 which further includes a chord memory which memorizes respective notes contained in a chord in response to respective outputs from said chord detector matrixes produced by operation of said chord keyboard and applied continuously the tone signals to said chord gate circuit form said tone generators, thereby carrying out chord performance without necessity of continuously depressing the keys of said chord keyboard.