Title:
Electronic musical instrument capable of transposition
United States Patent 3910149
Abstract:
An electronic musical instrument capable of transposition and in which a high-frequency oscillator is provided on its output side with an octave frequency divider comprising 12 counter circuits to produce twelve tone signals based on a 12 tempered scale. These tone signals are respectively frequency divided by respective counter circuits to obtain a plurality of octave tone signals. An AND-gate circuit is interposed between the high-frequency oscillator and the octave frequency divider. A pulse-counter circuit for counting output pulses of the high-frequency oscillator is provided so that a pulse of the first order and pulses of proper orders other than the first order are taken out at the output side of the pulse-counter circuit. The AND-gate circuit is opened by the pulse of the first order and is closed by a pulse of one of the proper orders. The pulse-counter circuit is reset by a pulse of the last of the proper orders.
US Patent References:
Transposition apparatus for electrical musical instrument
Bode - March 1962 - 3023659
Electric organ transposing switch
Wick - April 1962 - 3030848
DIGITAL ELECTRONIC KEYBOARD INSTRUMENT WITH AUTOMATIC TRANSPOSITION
Deutsch - October 1971 - 3610800
KEYBOARD TRANSPOSITION OF ELECTRICAL MUSICAL INSTRUMENTS
Derry - July 1972 - 3674907
KEYNOTE SELECTOR APPARATUS FOR ELECTRONIC ORGANS
Hallman, Jr. - March 1974 - 3800060
Transposition apparatus for electrical musical instrument
Bode - March 1962 - 3023659
Electric organ transposing switch
Wick - April 1962 - 3030848
DIGITAL ELECTRONIC KEYBOARD INSTRUMENT WITH AUTOMATIC TRANSPOSITION
Deutsch - October 1971 - 3610800
KEYBOARD TRANSPOSITION OF ELECTRICAL MUSICAL INSTRUMENTS
Derry - July 1972 - 3674907
KEYNOTE SELECTOR APPARATUS FOR ELECTRONIC ORGANS
Hallman, Jr. - March 1974 - 3800060
Application Number:
05/405643
Publication Date:
10/07/1975
Filing Date:
10/11/1973
View Patent Images:
Export Citation:
Assignee:
Kabushiki Kaisha Kawai Gakki Seisakusho (Hamamatsu, JA)
Primary Class:
Other Classes:
84/445, 984/381, 84/648, 984/338, 84/685, 84/657
International Classes:
G06F7/68; G10H1/20; G10H5/06; G06F7/60; G10H5/00; G10H1/00; G10H5/06
Field of Search:
84/1.01,1.17,445,446,447,448,1.24
US Patent References:
| 3824325 | ELECTRONIC MUSICAL INSTRUMENT CAPABLE OF TRANSPOSING | July 1974 | Obayashi et al. |
Primary Examiner:
Hartary, Joseph W.
Assistant Examiner:
Witkowski, Stanley J.
Attorney, Agent or Firm:
Waters, Schwartz & Nissen
Claims:
What is claimed is
1. An electronic musical instrument comprising a high-frequency oscillator, an octave frequency divider, and adjustable means passing a selected number of pulses from said oscillator and then blocking a selected number of pulses from said oscillator; said means including a gating circuit between said oscillator and octave frequency divider and a flip-flop controlling said gating circuit; said flip-flop including set and reset terminals, said adjustable means further comprising a counter coupled to said oscillator, first and second pluralities of gates coupled to said counter, and first and second selector switches respectively coupled to said pluralities of gates, one of said switches being coupled to the reset terminal of the flip-flop, the other of said switches being coupled to said counter to reset the same, said adjustable means further including a gate coupling said counter to the set terminal of said flip-flop.
2. An instrument as claimed in claim 1, wherein the later said gate is coupled to the counter to set said flip-flop before the flip-flop and counter are reset, the flip-flop being reset before the counter.
1. An electronic musical instrument comprising a high-frequency oscillator, an octave frequency divider, and adjustable means passing a selected number of pulses from said oscillator and then blocking a selected number of pulses from said oscillator; said means including a gating circuit between said oscillator and octave frequency divider and a flip-flop controlling said gating circuit; said flip-flop including set and reset terminals, said adjustable means further comprising a counter coupled to said oscillator, first and second pluralities of gates coupled to said counter, and first and second selector switches respectively coupled to said pluralities of gates, one of said switches being coupled to the reset terminal of the flip-flop, the other of said switches being coupled to said counter to reset the same, said adjustable means further including a gate coupling said counter to the set terminal of said flip-flop.
2. An instrument as claimed in claim 1, wherein the later said gate is coupled to the counter to set said flip-flop before the flip-flop and counter are reset, the flip-flop being reset before the counter.
Description:
FIELD OF THE INVENTION
This invention relates to electronic musical instruments capable of transposition.
BACKGROUND
In an ordinary keyed instrument, natural keys are employed for natural tones and chromatic keys are employed for derivative tones. When flat families or sharp families are played in this kind of instrument, transposed tones require the use of the chromatic keys. As will be shown hereinafter, in the case of C major, C, D, E, F, G, A, B and C are respectively played by pressing natural keys. D major, for instance, begins with the D tone. Accordingly, certain natural keys and certain chromatic keys must be pressed. Thus, the operation of chromatic keys is required for transposition and this requirement similarly applies to the case of an electronic musical instrument. Playing with transposition is very difficult for a beginner.
SUMMARY OF THE INVENTION
An object of this invention is to provide an improved electronic musical instrument in which flat families and sharp families can be played by using only natural keys in almost the same manner as in the case of C major. Generally, this is accomplished by the shifting of the frequencies of sound sources associated with and relating to the respective keys.
According to the invention, in a musical instrument capable of transposition, a high-frequency oscillator is provided on its output side with an octave frequency divider comprising twelve counter circuits to produce twelve tone signals based on a twelve tempered scale. These tone signals are respectively frequency-divided by counter circuits to obtain a plurality of octavetone signals. An AND-gate circuit is interposed between the high-frequency oscillator and the octave frequency divider. A pulsecounter circuit for counting output pulses of the high-frequency oscillator is provided so that a pulse of the first order and pulses of proper orders other than the first order can be taken out at the output side of the pulse-counter circuit. The AND-gate circuit is closed by the pulse of the first of the proper orders and the pulse-counter circuit is reset by the pulse of the last of the proper orders.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a diagram showing the relationship between keys and key signals;
FIG. 2 is a block diagram showing an octave frequency divider;
FIG. 3 is a circuit diagram showing one embodiment of this invention;
FIG. 4 is a signal diagram explaining the operation thereof.
FIG. 5 is a further signal diagram explaining the operation of the invention; and
FIG. 6 is yet another explanatory signal diagram.
DETAILED DESCRIPTION
In an ordinary instrument, natural and chromatic keys are respectively used for natural and derivative tones. As shown in FIG. 1, for C major, C, D, E, F, G, A, B, C are played by pressing natural keys K1, K3, K5, K6, K8, K10, K12, K13. D major, however, begins with a D tone. Accordingly, natural keys K3 and K5, chromatic key K7, natural keys K8, K10, K12 and K13, chromatic key K14 and the natural key K15 must be pressed. THus, the operation of chromatic keys is required for transposition. This requirement is also used in the case of an electronic musical instrument.
FIG. 2 shows one example of an octave frequency divider. It comprises twelve counter circuits 20-1 . . . 20-12 connected in parallel with one another. The frequency dividing ratios thereof are 1/239, 1/253 . . . 1/451 as shown.
If it is desired that an oscillation frequency of 8372.02 Hz be obtained from the first counter circuit 20-1, the input frequency f m will be 2.00024 MHz. If the input frequency is 2.00024 MHz, the frequencies obtained at the respective output terminals O of the counter circuits 20-1 . . . 20-12 are shown under C major in the following Table 1. If the input frequency is varied to 1.88956 MHz, the output frequencies of the counter circuits 20-1 . . . 20-12 become those shown under B major in Table 1.
By varying the input frequency, the output frequencies of the counter circuits 20-1 . . . 20-12 are varied. In greater detail, by properly varying the input frequency, the output frequencies of the counter circuits 20-1 . . . 20-12 are transposed as shown in Table 1. Accordingly, by simply varying the input frequency, a player can play any desired family in almost the same manner as in the case of C major.
Table 1 ____________________________________________________________ ______________ C major B major A sharp major Octave frequency Input frequency Input frequency Input frequency divider 2.00024 MHz 1.88956 MHz 1.78379 MHz ____________________________________________________________ ______________ Counter Frequency Output Tone Output Tone Output Tone circuit dividing freq. Hz signal freq. Hz signal freq. Hz signal number ratio ____________________________________________________________ ______________ 20-1 1/239 8372.02 C 7902.13 B 7458.62 A sharp 20-2 1/253 7902.13 B 7458.62 A sharp 7040.00 A 20-3 1/268 7458.62 A sharp 7040.00 A 6644.88 G sharp 20-4 1/284 7040.00 A 6644.88 G sharp 6271.93 G 20-5 1/301 6644.88 G sharp 6271.93 G 5919.91 F sharp 20-6 1/319 6271.93 G 5919.91 F sharp 5587.65 F 20-7 1/338 5919.91 F sharp 5587.65 F 5274.04 E 20-8 1/358 5587.65 F 5274.04 E 4978.03 D sharp 20-9 1/379 5274.04 E 4978.03 D sharp 4698.64 D 20-10 1/402 4978.03 D sharp 4698.64 D 4434.94 C sharp 20-11 1/426 4698.64 D 4434.94 C sharp 4186.01 C 20-12 1/451 4434.94 C sharp 4186.01 C 3951.06 B ____________________________________________________________ ______________
The high-frequency oscillator 10 is required to be of high accuracy. When the frequency thereof is to be widely changed as mentioned above, it is difficult for such a highly accurate oscillator such as a quartz oscillator or a tuning fork oscillator to make such a great change. Though such a change is possible by using an LC oscillator such as a back coupling type oscillator or a Hartley oscillator, this kind of oscillator is low in stability and varies in frequency depending on temperature change or secular change so that the same is not suitable for use.
According to the invention, the input frequency for the octave frequency divider can be varied by using an oscillator which is high in accuracy and is difficult to change in frequency such as a quartz oscillator or a tuning fork oscillator. The invention provides for the use of such an oscillator by the feature of changing the output frequency of the oscillator by a control effected between the oscillator and octave frequency divider.
When the input frequency is varied as shown in Table 1, there occurs transposition such as also shown in Table 1. When it is assumed that the input frequency 2.00024 MHz corresponding to C major is 1, each frequency ratio is as shown in Table 2. Further, ech approximation ratio corresponding to each frequency ratio is obtained by calculation to fall within a ± 5 per cent error, because an error is not important if within ± 5 per cent. The approximation ratios shown in Table 2 satisfy this.
Table 2 ____________________________________________________________ ______________ Input Tone Frequency Approximation Cent frequency signal ratio ratio error ____________________________________________________________ ______________ 2.00024 MHz C 1/2 0 /12. f(=1.000000) f 0. 1.88956 B 1/2 1 /12. f(≉0.943874) 17/18 f(≉0.944444) +1.015 1.78379 A sharp 1/2 2 /12. f(≉0.890899) 8/9 f(≉0.888889) -3.802 1.68330 A 1/2 3 /12. f(≉0.840896) 21/25 f(≉0.840000) -1.794 1.58823 G sharp 1/2 4 /12. f(≉0.793701) 23/29 f(≉0.793103) -1.266 1.49861 G 1/2 5 /12. f(≉0.749153) 3/4 f(≉0.750000) +1.898 1.41437 F sharp 1/2 6 /12. f(≉0.707107) 12/17 f(≉0.705882) -2.917 1.33536 F 1/2 7 /12. f(≉0.667420) 2/3 f(≉0.666667) -1.900 1.26136 E 1/2 8 /12. f(≉0.629961) 17/27 f(≉0.629630) -0.884 1.18919 D sharp 1/2 9 /12. f(≉0.594603) 19/32 f(≉0.593750) -2.417 1.12220 D 1/2 10 /12. f(≉0.561231) 9/16 f(≉0.562500) +3.793 1.05999 C sharp 1/2 11 /12. f(≉0.529731) 9/17 f(≉0.529412) -1.015 1.00012 C 1/2 12 /12. f(≉0.500000) 1/2 f 0. ____________________________________________________________ ______________
Assuming the above, an embodiment of the invention will next be explained with reference to FIGS. 3 and 4. In FIG. 3, component 10 is a high-frequency oscillator and the oscillation frequency thereof is 2.00024 MHz. Component 20 is an octave frequency divider having the frequency dividing ratios shown in FIG. 2. An AND-gate circuit 40 is interposed in a connecting circuit 30 between the high-frequency oscillator 10 and the octave frequency divider 20. Additionally, a pulse-counter circuit 50 counting the output pulses of the high-frequency oscillator 10 is connected to the output terminal of the oscillator 10. On the output side thereof are provided output terminals for taking out output pulses ranging from the 1st order to the 32nd order.
Stated otherwise, the pulse-counter circuit 50 counts a series of pulses generated by the high frequency oscillator 10. The pulse-counter circuit 50 has 32 output terminals. The pulse generated at the first order from the high frequency oscillator 10 is taken out from the first order output terminal. The pulse of the second order is taken out from the second order output terminal. This is similar with respect to from the 3rd to the 32nd order pulses. Thus, a series of pulses applied to the pulsecounter circuit 50 is taken out in order from the 1st to 32nd order output terminals. The pulse taken out at the first output terminal is called "the first order pulse", the pulse taken out at the second order output terminal is called "the second order pulse" and so on. This is the same when the pulse-counter circuit 50 completes its counting operation and begins a new counting operation.
Actually, thirty-two output terminals are not required. This will be clear from the description which follows hereinafter. It will be sufficient if there are output terminals for pulses of the orders corresponding to the numbers of the denominators and the numerators (namely, 1, 2, 3, 4, 8, 9, 12, 16, 17, 18, 21, 23, 25, 27, 29, 32) of the approximation ratios in Table 2.
A first output terminal 70a-1 is connected to the input terminal of the AND-gate circuit 40 through a flip-flop circuit 60. If a first order pulse is sent from the high-frequency oscillator 10, the flip-flop circuit 60 is turned "on" and the AND-gate circuit 40 is opened by the output thereof. The output pulses sent from the high-frequency oscillator 10 are then permitted to pass through the AND-gate circuit 40.
A pulse of the order corresponding to the numerator of any selected approximation ratio is then applied to the flip-flop circuit 60 to turn the same "off". The AND-gate circuit 40 is thereby closed and the pulses of the orders following the said order are prevented from passing therethrough. Then, by a pulse of the order corresponding to the denominator of the same approximation ratio, the pulse-counter circuit 50 is reset.
If the pulse counter circuit 50 completes its counting and is reset, then a first pulse applied to the pulse counter circuit 50 is taken out as a new first order pulse at the 1st output terminal of the circuit 50. This new first order pulse is called "a first order pulse in the next cycle". Thus, the number of pulses between the pulse of the order corresponding to the numerator and the pulse of the order corresponding to the denominator are prevented from passing. In other words, a number of pulses corresponding to the number of the numerator are permitted to pass. This means that pulses of a number corresponding to the approximation ratio become an input frequency for the octave frequency divider.
As is seen, the pulse-counter circuit 50 comprises five flip-flop circuits FF1, FF2, FF3, FF4 and FF5. AND-gate circuits 70-n are provided at the output terminals thereof. By these AND-gate circuits, pulses of the orders corresponding to the denominators and the numerators of the approximation ratios are taken out. The output terminals of the flip-flop circuits FF1 to FF5 are denoted by Q1, Q1, Q2, Q2 . . . Q5,Q5 and the combinations of the AND-gate circuits are as the logic formulae in Table 3.
Table 3 ______________________________________ Pulse Logic Pulse Logic order formula order formula ______________________________________ 1 Q1,Q2,Q3,Q4,Q5 17 Q1,Q2,Q3,Q4,Q5 2 Q1,Q2,Q3,Q4,Q5 18 Q1,Q2,Q3,Q4,Q5 3 Q1,Q2,Q3,Q4,Q5 19 Q1,Q2,Q3,Q4,Q5 4 Q1,Q2,Q3,Q4,Q5 20 Q1,Q2,Q3,Q4,Q5 5 Q1,Q2,Q3,Q4,Q5 21 Q1,Q2,Q3,Q4,Q5 6 Q1,Q2,Q3,Q4,Q5 22 Q1,Q2,Q3,Q4,Q5 7 Q1,Q2,Q3,Q4,Q5 23 Q1,Q2,Q3,Q4,Q5 8 Q1,Q2,Q3,Q4,Q5 24 Q1,Q2,Q3,Q4,Q5 9 Q1,Q2,Q3,Q4,Q5 25 Q1,Q2,Q3,Q4,Q5 10 Q1,Q2,Q3,Q4,Q5 26 Q1,Q2,Q3,Q4,Q5 11 Q1,Q2,Q3,Q4,Q5 27 Q1,Q2,Q3,Q4,Q5 12 Q1,Q2,Q3,Q4,Q5 28 Q1,Q2,Q3,Q4,Q5 13 Q1,Q2,Q3,Q4,Q5 29 Q1,Q2,Q3,Q4,Q5 14 Q1,Q2,Q3,Q4,Q5 30 Q1,Q2,Q3,Q4,Q5 15 Q1,Q2,Q3,Q4,Q5 31 Q1,Q2,Q3,Q4,Q5 16 Q1,Q2,Q3,Q4,Q5 32 Q1,Q2,Q3,Q4,Q5 ______________________________________
The output terminal 70a-1 of the AND-gate circuit 70-1 for taking out the first order pulse is connected to the flip-flop circuit 60. Two ganged rotary switches 80 and 90 are provided. The output terminals 70a-17, 70a-8 and 70a-21 of the AND-gate circuits 70-17, 70-8 and 70-21, for taking out pulses of the orders corresponding to the numerators are in order connected to stationary contacts 80-1, 80-2 and 80-3 of the switch 80. Movable contact 80a thereof is connected to the flip-flop circuit 60 so that, when a pulse is applied therethrough, the circuit 60 is turned off and the output thereof becomes zero and the AND-gate circuit 40 is closed.
AND-gate circuits 70-18, 70-9 and 70-25 for taking out pulses of the orders corresponding to the denominators are respectively connected to stationary contacts 90-1, 90-2 and 90-3 of the switch 90. Movable contact 90a thereof is connected to reset terminals of the flip-flop circuits FF1, FF2, FF3, FF4 and FF5. When the first stationary contacts 80-1 and 90-1 of the rotary switches 80 and 90 are, for example, selected for selecting B major, the first order pulse FIG. 4b of the output pulses FIG. 4a which are sent out from the high-frequency oscillator 10 is applied to the flip-flop circuit 60 through the AND-gate circuit 70-1 for turning the same on to open the AND-gate circuit 40. Thereby, the output pulses of the high-frequency oscillator 10 are permitted to pass therethrough to become an input to the octave frequency divider 20. If, next, the 17th order pulse FIG.4c is, for example, applied to the flip-flop circuit 60 through the AND-gate circuit 70-17, the first contact 80-1 and the movable contact 80a, the AND-gate circuit 40 is closed FIG. 4 e. If, then, the 18th order pulse FIG. 4d is applied to the flip-flop circuits FF1, FF2, FF3, FF4 and FF5 through the AND-gate circuit 70-18, the first contact 90-1 and the movable contact 90a, the flip-flop circuits FF1, FF2, FF3, FF4 and FF5 are reset. Thus, as shown in FIG. 4f, the pulses ranging from the 1 t order to the 17 th order pass through the AND-gate circuit 40 and the 18th order pulse is prevented from passing. Accordingly, the number of the pulses passing through the AND-gate circuit 40 becomes 17/18 × f = 1.889115 MHz, and the per cent error thereof is + 1.015. This error is not important because it is within the range of ± 5 per cent.
If the rotary switches 80 and 90 are positioned at the second contacts 80-2 and 90-2 for selecting A sharp major, (FIG. 5) the first order pulse FIG. 5b 1 of the output pulses FIG. 5a 1 which are sent out from the high-frequency oscillator 10 is applied to the flip-flop circuit 60 through the AND-gate circuit 70-1 for turning the same on to open the AND-gate circuit 40. Thereby, the output pulses of the high-frequency oscillator 10 are permitted to pass therethrough to become an input to the octave frequency divider 20. If next, the 8th order pulse, FIG. 5c 1 , is, for example, applied to the flip-flop circuit 60 through the AND-gate circuit 70-8, the second contact 90-2 and the movable contact 80a, the AND-gate circuit 40 is closed, FIG. 5e 1 . If then, the ninth order pulse FIG. 5d 1 is applied to the flip-flop circuits FF1,FF2,FF3,FF4, and Ff5 through the AND-gate circuit 70-9, the second contact 90-2 and the movable contact 90a, the flip-flop circuits FF1,Ff2,FF3, FF4 and FF5 are reset. Thus, as shown in FIG. 5f 1 , the pulses ranging from the 1st order to the eighth order pass through the AND-gate circuit 40 and the ninth order pulse prevented from passing. Accordingly, the number of pulses passing through the AND-gate circuit 40 becomes 8/9 × f = 1.77799 MHz and the per cent error is 3.802. This error is also within the allowable range of ± 5 per cent. If the third contacts 80-3 and 90-3 are used for selecting A major, (FIG. 6) the first order pulse FIG. 6b 2 of the output pulses FIG. 6a 2 which are sent out from the high-frequency oscillator 10 is applied to the flip-flop circuit 60 through the AND-gate circuit 40. Thereby, the output pulses of the high-frequency oscillator 10 are permitted to pass therethrough to become an input to the octave frequency divider 20. If, next, the 21st order pulse FIG. 6c 2 is, for example, applied to the flip-flop circuit 60 through the AND-gate circuit 70-21, the third contact 80-3 and the movable contact 80a, the AND-gate circuit 40 is closed, FIG. 6e 2 . If, then, the 25th order pulse, FIG. 6d 2 is applied to the flip-flop circuits FF1,FF2,FF3,FF4, and FF5 through the AND-gate circuit 70-25, the third contact 90-3 and the movable contact 90a, the flip-flop circuits FF1,FF2,FF3,FF4, and FF5 are reset. Thus, as shown in FIG. 6f 2 , the pulses ranging from the 1 sr order to the 21st order pass through the AND-gate circuit 40 and the 18th to 25th order pulses are prevented from passing. Accordingly, the number of the pulses passing through the AND-gate circuit 40 becomes 21/25 × f = 1.68020 MHz and the per cent error is -1.794 which is within the range of ± 5 per cent.
Thus, by properly preventing pulses from passing through the AND-gate circuit 40, the number of the pulses corresponding to any approximation ratio shown in TAble 2 can become the input frequency for the octave frequency divider 20, this being by means of the switching-over of the rotary switches 80 and 90. Thus, any desired twenty tone signal transposition as shown in Table 2 can be obtained.
The arrows in FIGS. 4,5, and 6 indicate the portions acting on elements 40 and 50.
Where the pulses passing through the AND-gate circuit 40 are extremely lacking in uniformity, the same can be compensated by raising the output frequency of the oscillator 10 and the higher output frequency is then lowered before the octave frequency divider 20.
According to this invention, a quartz oscillator, a tuning fork oscillator or the like which is high in accuracy can be used for the high-frequency oscillator and additionally transposition becomes possible by a simple construction.
The octave frequency divider 20 is of the type that the output frequency of the high-frequency oscillator 10 is frequency-divided in parallel fashion as shown in the above example, but the same may be modified to be of a type, for example, such that the output frequency is frequency-divided from a first center circuit in series fashion.
This invention relates to electronic musical instruments capable of transposition.
BACKGROUND
In an ordinary keyed instrument, natural keys are employed for natural tones and chromatic keys are employed for derivative tones. When flat families or sharp families are played in this kind of instrument, transposed tones require the use of the chromatic keys. As will be shown hereinafter, in the case of C major, C, D, E, F, G, A, B and C are respectively played by pressing natural keys. D major, for instance, begins with the D tone. Accordingly, certain natural keys and certain chromatic keys must be pressed. Thus, the operation of chromatic keys is required for transposition and this requirement similarly applies to the case of an electronic musical instrument. Playing with transposition is very difficult for a beginner.
SUMMARY OF THE INVENTION
An object of this invention is to provide an improved electronic musical instrument in which flat families and sharp families can be played by using only natural keys in almost the same manner as in the case of C major. Generally, this is accomplished by the shifting of the frequencies of sound sources associated with and relating to the respective keys.
According to the invention, in a musical instrument capable of transposition, a high-frequency oscillator is provided on its output side with an octave frequency divider comprising twelve counter circuits to produce twelve tone signals based on a twelve tempered scale. These tone signals are respectively frequency-divided by counter circuits to obtain a plurality of octavetone signals. An AND-gate circuit is interposed between the high-frequency oscillator and the octave frequency divider. A pulsecounter circuit for counting output pulses of the high-frequency oscillator is provided so that a pulse of the first order and pulses of proper orders other than the first order can be taken out at the output side of the pulse-counter circuit. The AND-gate circuit is closed by the pulse of the first of the proper orders and the pulse-counter circuit is reset by the pulse of the last of the proper orders.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a diagram showing the relationship between keys and key signals;
FIG. 2 is a block diagram showing an octave frequency divider;
FIG. 3 is a circuit diagram showing one embodiment of this invention;
FIG. 4 is a signal diagram explaining the operation thereof.
FIG. 5 is a further signal diagram explaining the operation of the invention; and
FIG. 6 is yet another explanatory signal diagram.
DETAILED DESCRIPTION
In an ordinary instrument, natural and chromatic keys are respectively used for natural and derivative tones. As shown in FIG. 1, for C major, C, D, E, F, G, A, B, C are played by pressing natural keys K1, K3, K5, K6, K8, K10, K12, K13. D major, however, begins with a D tone. Accordingly, natural keys K3 and K5, chromatic key K7, natural keys K8, K10, K12 and K13, chromatic key K14 and the natural key K15 must be pressed. THus, the operation of chromatic keys is required for transposition. This requirement is also used in the case of an electronic musical instrument.
FIG. 2 shows one example of an octave frequency divider. It comprises twelve counter circuits 20-1 . . . 20-12 connected in parallel with one another. The frequency dividing ratios thereof are 1/239, 1/253 . . . 1/451 as shown.
If it is desired that an oscillation frequency of 8372.02 Hz be obtained from the first counter circuit 20-1, the input frequency f m will be 2.00024 MHz. If the input frequency is 2.00024 MHz, the frequencies obtained at the respective output terminals O of the counter circuits 20-1 . . . 20-12 are shown under C major in the following Table 1. If the input frequency is varied to 1.88956 MHz, the output frequencies of the counter circuits 20-1 . . . 20-12 become those shown under B major in Table 1.
By varying the input frequency, the output frequencies of the counter circuits 20-1 . . . 20-12 are varied. In greater detail, by properly varying the input frequency, the output frequencies of the counter circuits 20-1 . . . 20-12 are transposed as shown in Table 1. Accordingly, by simply varying the input frequency, a player can play any desired family in almost the same manner as in the case of C major.
Table 1 ____________________________________________________________ ______________ C major B major A sharp major Octave frequency Input frequency Input frequency Input frequency divider 2.00024 MHz 1.88956 MHz 1.78379 MHz ____________________________________________________________ ______________ Counter Frequency Output Tone Output Tone Output Tone circuit dividing freq. Hz signal freq. Hz signal freq. Hz signal number ratio ____________________________________________________________ ______________ 20-1 1/239 8372.02 C 7902.13 B 7458.62 A sharp 20-2 1/253 7902.13 B 7458.62 A sharp 7040.00 A 20-3 1/268 7458.62 A sharp 7040.00 A 6644.88 G sharp 20-4 1/284 7040.00 A 6644.88 G sharp 6271.93 G 20-5 1/301 6644.88 G sharp 6271.93 G 5919.91 F sharp 20-6 1/319 6271.93 G 5919.91 F sharp 5587.65 F 20-7 1/338 5919.91 F sharp 5587.65 F 5274.04 E 20-8 1/358 5587.65 F 5274.04 E 4978.03 D sharp 20-9 1/379 5274.04 E 4978.03 D sharp 4698.64 D 20-10 1/402 4978.03 D sharp 4698.64 D 4434.94 C sharp 20-11 1/426 4698.64 D 4434.94 C sharp 4186.01 C 20-12 1/451 4434.94 C sharp 4186.01 C 3951.06 B ____________________________________________________________ ______________
The high-frequency oscillator 10 is required to be of high accuracy. When the frequency thereof is to be widely changed as mentioned above, it is difficult for such a highly accurate oscillator such as a quartz oscillator or a tuning fork oscillator to make such a great change. Though such a change is possible by using an LC oscillator such as a back coupling type oscillator or a Hartley oscillator, this kind of oscillator is low in stability and varies in frequency depending on temperature change or secular change so that the same is not suitable for use.
According to the invention, the input frequency for the octave frequency divider can be varied by using an oscillator which is high in accuracy and is difficult to change in frequency such as a quartz oscillator or a tuning fork oscillator. The invention provides for the use of such an oscillator by the feature of changing the output frequency of the oscillator by a control effected between the oscillator and octave frequency divider.
When the input frequency is varied as shown in Table 1, there occurs transposition such as also shown in Table 1. When it is assumed that the input frequency 2.00024 MHz corresponding to C major is 1, each frequency ratio is as shown in Table 2. Further, ech approximation ratio corresponding to each frequency ratio is obtained by calculation to fall within a ± 5 per cent error, because an error is not important if within ± 5 per cent. The approximation ratios shown in Table 2 satisfy this.
Table 2 ____________________________________________________________ ______________ Input Tone Frequency Approximation Cent frequency signal ratio ratio error ____________________________________________________________ ______________ 2.00024 MHz C 1/2 0 /12. f(=1.000000) f 0. 1.88956 B 1/2 1 /12. f(≉0.943874) 17/18 f(≉0.944444) +1.015 1.78379 A sharp 1/2 2 /12. f(≉0.890899) 8/9 f(≉0.888889) -3.802 1.68330 A 1/2 3 /12. f(≉0.840896) 21/25 f(≉0.840000) -1.794 1.58823 G sharp 1/2 4 /12. f(≉0.793701) 23/29 f(≉0.793103) -1.266 1.49861 G 1/2 5 /12. f(≉0.749153) 3/4 f(≉0.750000) +1.898 1.41437 F sharp 1/2 6 /12. f(≉0.707107) 12/17 f(≉0.705882) -2.917 1.33536 F 1/2 7 /12. f(≉0.667420) 2/3 f(≉0.666667) -1.900 1.26136 E 1/2 8 /12. f(≉0.629961) 17/27 f(≉0.629630) -0.884 1.18919 D sharp 1/2 9 /12. f(≉0.594603) 19/32 f(≉0.593750) -2.417 1.12220 D 1/2 10 /12. f(≉0.561231) 9/16 f(≉0.562500) +3.793 1.05999 C sharp 1/2 11 /12. f(≉0.529731) 9/17 f(≉0.529412) -1.015 1.00012 C 1/2 12 /12. f(≉0.500000) 1/2 f 0. ____________________________________________________________ ______________
Assuming the above, an embodiment of the invention will next be explained with reference to FIGS. 3 and 4. In FIG. 3, component 10 is a high-frequency oscillator and the oscillation frequency thereof is 2.00024 MHz. Component 20 is an octave frequency divider having the frequency dividing ratios shown in FIG. 2. An AND-gate circuit 40 is interposed in a connecting circuit 30 between the high-frequency oscillator 10 and the octave frequency divider 20. Additionally, a pulse-counter circuit 50 counting the output pulses of the high-frequency oscillator 10 is connected to the output terminal of the oscillator 10. On the output side thereof are provided output terminals for taking out output pulses ranging from the 1st order to the 32nd order.
Stated otherwise, the pulse-counter circuit 50 counts a series of pulses generated by the high frequency oscillator 10. The pulse-counter circuit 50 has 32 output terminals. The pulse generated at the first order from the high frequency oscillator 10 is taken out from the first order output terminal. The pulse of the second order is taken out from the second order output terminal. This is similar with respect to from the 3rd to the 32nd order pulses. Thus, a series of pulses applied to the pulsecounter circuit 50 is taken out in order from the 1st to 32nd order output terminals. The pulse taken out at the first output terminal is called "the first order pulse", the pulse taken out at the second order output terminal is called "the second order pulse" and so on. This is the same when the pulse-counter circuit 50 completes its counting operation and begins a new counting operation.
Actually, thirty-two output terminals are not required. This will be clear from the description which follows hereinafter. It will be sufficient if there are output terminals for pulses of the orders corresponding to the numbers of the denominators and the numerators (namely, 1, 2, 3, 4, 8, 9, 12, 16, 17, 18, 21, 23, 25, 27, 29, 32) of the approximation ratios in Table 2.
A first output terminal 70a-1 is connected to the input terminal of the AND-gate circuit 40 through a flip-flop circuit 60. If a first order pulse is sent from the high-frequency oscillator 10, the flip-flop circuit 60 is turned "on" and the AND-gate circuit 40 is opened by the output thereof. The output pulses sent from the high-frequency oscillator 10 are then permitted to pass through the AND-gate circuit 40.
A pulse of the order corresponding to the numerator of any selected approximation ratio is then applied to the flip-flop circuit 60 to turn the same "off". The AND-gate circuit 40 is thereby closed and the pulses of the orders following the said order are prevented from passing therethrough. Then, by a pulse of the order corresponding to the denominator of the same approximation ratio, the pulse-counter circuit 50 is reset.
If the pulse counter circuit 50 completes its counting and is reset, then a first pulse applied to the pulse counter circuit 50 is taken out as a new first order pulse at the 1st output terminal of the circuit 50. This new first order pulse is called "a first order pulse in the next cycle". Thus, the number of pulses between the pulse of the order corresponding to the numerator and the pulse of the order corresponding to the denominator are prevented from passing. In other words, a number of pulses corresponding to the number of the numerator are permitted to pass. This means that pulses of a number corresponding to the approximation ratio become an input frequency for the octave frequency divider.
As is seen, the pulse-counter circuit 50 comprises five flip-flop circuits FF1, FF2, FF3, FF4 and FF5. AND-gate circuits 70-n are provided at the output terminals thereof. By these AND-gate circuits, pulses of the orders corresponding to the denominators and the numerators of the approximation ratios are taken out. The output terminals of the flip-flop circuits FF1 to FF5 are denoted by Q1, Q1, Q2, Q2 . . . Q5,Q5 and the combinations of the AND-gate circuits are as the logic formulae in Table 3.
Table 3 ______________________________________ Pulse Logic Pulse Logic order formula order formula ______________________________________ 1 Q1,Q2,Q3,Q4,Q5 17 Q1,Q2,Q3,Q4,Q5 2 Q1,Q2,Q3,Q4,Q5 18 Q1,Q2,Q3,Q4,Q5 3 Q1,Q2,Q3,Q4,Q5 19 Q1,Q2,Q3,Q4,Q5 4 Q1,Q2,Q3,Q4,Q5 20 Q1,Q2,Q3,Q4,Q5 5 Q1,Q2,Q3,Q4,Q5 21 Q1,Q2,Q3,Q4,Q5 6 Q1,Q2,Q3,Q4,Q5 22 Q1,Q2,Q3,Q4,Q5 7 Q1,Q2,Q3,Q4,Q5 23 Q1,Q2,Q3,Q4,Q5 8 Q1,Q2,Q3,Q4,Q5 24 Q1,Q2,Q3,Q4,Q5 9 Q1,Q2,Q3,Q4,Q5 25 Q1,Q2,Q3,Q4,Q5 10 Q1,Q2,Q3,Q4,Q5 26 Q1,Q2,Q3,Q4,Q5 11 Q1,Q2,Q3,Q4,Q5 27 Q1,Q2,Q3,Q4,Q5 12 Q1,Q2,Q3,Q4,Q5 28 Q1,Q2,Q3,Q4,Q5 13 Q1,Q2,Q3,Q4,Q5 29 Q1,Q2,Q3,Q4,Q5 14 Q1,Q2,Q3,Q4,Q5 30 Q1,Q2,Q3,Q4,Q5 15 Q1,Q2,Q3,Q4,Q5 31 Q1,Q2,Q3,Q4,Q5 16 Q1,Q2,Q3,Q4,Q5 32 Q1,Q2,Q3,Q4,Q5 ______________________________________
The output terminal 70a-1 of the AND-gate circuit 70-1 for taking out the first order pulse is connected to the flip-flop circuit 60. Two ganged rotary switches 80 and 90 are provided. The output terminals 70a-17, 70a-8 and 70a-21 of the AND-gate circuits 70-17, 70-8 and 70-21, for taking out pulses of the orders corresponding to the numerators are in order connected to stationary contacts 80-1, 80-2 and 80-3 of the switch 80. Movable contact 80a thereof is connected to the flip-flop circuit 60 so that, when a pulse is applied therethrough, the circuit 60 is turned off and the output thereof becomes zero and the AND-gate circuit 40 is closed.
AND-gate circuits 70-18, 70-9 and 70-25 for taking out pulses of the orders corresponding to the denominators are respectively connected to stationary contacts 90-1, 90-2 and 90-3 of the switch 90. Movable contact 90a thereof is connected to reset terminals of the flip-flop circuits FF1, FF2, FF3, FF4 and FF5. When the first stationary contacts 80-1 and 90-1 of the rotary switches 80 and 90 are, for example, selected for selecting B major, the first order pulse FIG. 4b of the output pulses FIG. 4a which are sent out from the high-frequency oscillator 10 is applied to the flip-flop circuit 60 through the AND-gate circuit 70-1 for turning the same on to open the AND-gate circuit 40. Thereby, the output pulses of the high-frequency oscillator 10 are permitted to pass therethrough to become an input to the octave frequency divider 20. If, next, the 17th order pulse FIG.4c is, for example, applied to the flip-flop circuit 60 through the AND-gate circuit 70-17, the first contact 80-1 and the movable contact 80a, the AND-gate circuit 40 is closed FIG. 4 e. If, then, the 18th order pulse FIG. 4d is applied to the flip-flop circuits FF1, FF2, FF3, FF4 and FF5 through the AND-gate circuit 70-18, the first contact 90-1 and the movable contact 90a, the flip-flop circuits FF1, FF2, FF3, FF4 and FF5 are reset. Thus, as shown in FIG. 4f, the pulses ranging from the 1 t order to the 17 th order pass through the AND-gate circuit 40 and the 18th order pulse is prevented from passing. Accordingly, the number of the pulses passing through the AND-gate circuit 40 becomes 17/18 × f = 1.889115 MHz, and the per cent error thereof is + 1.015. This error is not important because it is within the range of ± 5 per cent.
If the rotary switches 80 and 90 are positioned at the second contacts 80-2 and 90-2 for selecting A sharp major, (FIG. 5) the first order pulse FIG. 5b 1 of the output pulses FIG. 5a 1 which are sent out from the high-frequency oscillator 10 is applied to the flip-flop circuit 60 through the AND-gate circuit 70-1 for turning the same on to open the AND-gate circuit 40. Thereby, the output pulses of the high-frequency oscillator 10 are permitted to pass therethrough to become an input to the octave frequency divider 20. If next, the 8th order pulse, FIG. 5c 1 , is, for example, applied to the flip-flop circuit 60 through the AND-gate circuit 70-8, the second contact 90-2 and the movable contact 80a, the AND-gate circuit 40 is closed, FIG. 5e 1 . If then, the ninth order pulse FIG. 5d 1 is applied to the flip-flop circuits FF1,FF2,FF3,FF4, and Ff5 through the AND-gate circuit 70-9, the second contact 90-2 and the movable contact 90a, the flip-flop circuits FF1,Ff2,FF3, FF4 and FF5 are reset. Thus, as shown in FIG. 5f 1 , the pulses ranging from the 1st order to the eighth order pass through the AND-gate circuit 40 and the ninth order pulse prevented from passing. Accordingly, the number of pulses passing through the AND-gate circuit 40 becomes 8/9 × f = 1.77799 MHz and the per cent error is 3.802. This error is also within the allowable range of ± 5 per cent. If the third contacts 80-3 and 90-3 are used for selecting A major, (FIG. 6) the first order pulse FIG. 6b 2 of the output pulses FIG. 6a 2 which are sent out from the high-frequency oscillator 10 is applied to the flip-flop circuit 60 through the AND-gate circuit 40. Thereby, the output pulses of the high-frequency oscillator 10 are permitted to pass therethrough to become an input to the octave frequency divider 20. If, next, the 21st order pulse FIG. 6c 2 is, for example, applied to the flip-flop circuit 60 through the AND-gate circuit 70-21, the third contact 80-3 and the movable contact 80a, the AND-gate circuit 40 is closed, FIG. 6e 2 . If, then, the 25th order pulse, FIG. 6d 2 is applied to the flip-flop circuits FF1,FF2,FF3,FF4, and FF5 through the AND-gate circuit 70-25, the third contact 90-3 and the movable contact 90a, the flip-flop circuits FF1,FF2,FF3,FF4, and FF5 are reset. Thus, as shown in FIG. 6f 2 , the pulses ranging from the 1 sr order to the 21st order pass through the AND-gate circuit 40 and the 18th to 25th order pulses are prevented from passing. Accordingly, the number of the pulses passing through the AND-gate circuit 40 becomes 21/25 × f = 1.68020 MHz and the per cent error is -1.794 which is within the range of ± 5 per cent.
Thus, by properly preventing pulses from passing through the AND-gate circuit 40, the number of the pulses corresponding to any approximation ratio shown in TAble 2 can become the input frequency for the octave frequency divider 20, this being by means of the switching-over of the rotary switches 80 and 90. Thus, any desired twenty tone signal transposition as shown in Table 2 can be obtained.
The arrows in FIGS. 4,5, and 6 indicate the portions acting on elements 40 and 50.
Where the pulses passing through the AND-gate circuit 40 are extremely lacking in uniformity, the same can be compensated by raising the output frequency of the oscillator 10 and the higher output frequency is then lowered before the octave frequency divider 20.
According to this invention, a quartz oscillator, a tuning fork oscillator or the like which is high in accuracy can be used for the high-frequency oscillator and additionally transposition becomes possible by a simple construction.
The octave frequency divider 20 is of the type that the output frequency of the high-frequency oscillator 10 is frequency-divided in parallel fashion as shown in the above example, but the same may be modified to be of a type, for example, such that the output frequency is frequency-divided from a first center circuit in series fashion.