JPS6024960B2 - Musical sound synthesis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a musical tone synthesis method using a high frequency synthesis method, which generates a fundamental wave constituting a musical tone and its high frequency harmonic components, and forms a musical tone signal by adding and synthesizing these harmonic harmonic components. .

As an electronic musical instrument using harmonic synthesis method, for example, the patent application No. 47-90217 shown in Fig. 1,
, the name of the invention is "electronic musical instrument."

First, the configuration of the electronic musical instrument shown in FIG. 1 will be briefly explained. This electronic musical instrument calculates amplitude values at successive sample points of a musical sound waveform based on equation (1), and obtains musical tones from these amplitude values. (q=1,2...,n=
1, 2...) Xo(qR)...Waveform amplitude at each sample point.

R: A numerical value proportional to the frequency output from the frequency number memory 14 corresponding to the pitch of each key switch of the keyboard switch 12 (hereinafter referred to as frequency number 1).

n...Represents the order of harmonic components.

n=1 corresponds to the fundamental number (fundamental tone), n=2 corresponds to the second harmonic (second harmonic), n=3 corresponds to the third harmonic (third harmonic), etc.

Cn...Harmonic coefficients (Fourier coefficients) output from the harmonic coefficient memory (Fourier coefficient memory) 15 for harmonic components (overtones) of each order.

N: Number of amplitude sample points.

W...Harmonics included in amplitude calculation (double number of sounds).

There is a relationship of W=N/2.

A timing signal of a predetermined frequency is constantly outputted from the clock generator 20, and is integrated with the Q-force counter 22, gate 27, etc.

The lifter 22 counts the timing signal and generates the timing signal 戊 when the counted value becomes negative.

A change in the timing signal tc indicates a transition to the next order harmonic component, and a change in the timing signal tc indicates a transition from a sample point to the next sample point. In other words, 戊=
It has something to do with WTC. The timing signal tx is applied to the storage register 16 and the gate 17. That is, the signal causes the gate 17 to open and the contents of the accumulator 16 to be output to the D-A converter 18, and as a result, the contents of the accumulator 16 are cleared and used for waveform amplitude calculation at the next sample point. The initial state is now set. The timing signal is also applied to a gate 24 and a harmonic section adder 28. Each time the timing signal is generated, the gate 24 is opened and the frequency number R is added to the pitch section adder 25, that is, qR=q+q.
The calculation of R is performed, R is added sequentially, and a new addition value qR (q=1, 2, . . . ) is output on line 26. This value qR does not change until the next timing signal tx is generated, and this value qR does not change until the next timing signal tc is generated.
7 and is supplied to a harmonic section adder 28 each time this gate 27 is opened. As a result, the content of the harmonic interval adder 28 is the value nqR for the n-th harmonic component (n-th overtone) evaluated each time, and this value nqR is input to the memory address decoder 3 and is As a result, from the sine function table 29, the sine value Si of the harmonic component
nWxhqR is output, and this sine value is input to the harmonic amplitude multiplier 33. On the other hand, the harmonic amplitude multiplier 33
are supplied with harmonic coefficients (Fourier coefficients) Cn of each order n from a harmonic coefficient memory (Fourier coefficient memory) 15.

This harmonic coefficient memory 5 is connected to the memory address control device 3.
The address is controlled by 5. In this way, at each sample point of the musical waveform, for each harmonic (overtone) of each order n, the harmonic coefficient Cn of that order n is calculated for the sine value SinW (qR) output from the sine function table 29. is read out from the harmonic coefficient memory 15, and the harmonic amplitude multiplier 33 multiplies the sine value SinhqR by the harmonic coefficient Cn, and the multiplied value F(n)=CnSinnqR is applied to the accelerator 16. Added. The accumulator 16 adds these multiplication values F(n) for each order, and the added value Xo
(qR) is obtained. When all the amplitude calculations for one sample point are completed, the timing signal tx is output, the gate 17 is opened, and the amplitude value Xo (qR) of that sample point is supplied to the D-A converter 18, where it is converted into an analog quantity and converted into an acoustic signal. Added to system 11.

As is clear from the above explanation, in the harmonic synthesis electronic musical instrument, the timbre (musical waveform shape) of the generated musical tone is set by the harmonic coefficient Cn stored in the harmonic coefficient memory 5. In conventional electronic musical instruments, the harmonic coefficient Cn is always the same and does not change over time from the time the musical tone is generated until the end. Therefore, the timbre of the generated musical tone is always the same and does not change, producing a natural and rich musical tone. There are disadvantages that cannot be obtained. This invention was made to solve the above-mentioned problems of the conventional harmonic synthesis method electronic musical instruments.The purpose of this invention is to provide a simple structure in which the above-mentioned harmonic coefficients (amplitude coefficients) are To provide a musical tone synthesis method capable of generating natural sounds whose timbre changes over time by changing the tone.

Therefore, in the present invention, first and second amplitude coefficients are generated for each order, and the first and second amplitude coefficients are generated for each order.
The first amplitude coefficient for each order is modulated and controlled by the first time function, and the second amplitude coefficient for each order is modulated by the second time function. The amplitude of each corresponding order component is controlled by the first and second amplitude coefficients for each order subjected to the modulation control.

Embodiments of the present invention will be described below with reference to the drawings. Note that the same components in the embodiment of the present invention and the prior art shown in FIG.
FIG. 2 is an overall configuration diagram of the first embodiment of the present invention.
In this embodiment, the harmonic coefficient memory 15 and the harmonic amplitude multiplier 33 of the prior art shown in FIG. and multipliers 45, 46, 47, 48
, an adder 49 is provided. Other structures such as the keyboard switch 12 in FIG. 2 are the same as in FIG. 1. The timing signal output from the clock generator 20 is input to the memory address control device 35. The contents of this memory address control device 35 are shifted every time the timing signal is input, and a different address signal An is generated. This address signal An is simultaneously input to two types of amplitude coefficient group memories 41 and 42. The amplitude coefficient group memory 41 (storing the amplitude coefficient group Y, (n)) stores amplitude coefficients for each harmonic order n (n is a positive integer). Amplitude coefficient group memory 42 (amplitude coefficient group Y
2(n)] stores amplitude coefficients for each order n of harmonics of a different type from the above-mentioned limiter 41. These amplitude coefficient group memories 41 and 42 are simultaneously addressed by the address signal An, and both memories 41 and 4
2, the amplitude coefficient Y,(n)·Y2(n) of the same order n is read out from the memory 41, the amplitude coefficient Y,(n) from the memory 41 is sent to the multiplier 45, and the amplitude coefficient Y2(n) from the memory 42 is read out. is sent to multiplier 46. The time function generator 43 (generating the time function A, (t)) is a device that generates data that changes with time t, and has a configuration similar to, for example, an envelope generator used in conventional electronic musical instruments.

Time function generator 44 [generates time function A2(t)]
has the same structure as the generator 43 described above, and generates a different type of time function than the generator 43. These time function generators 43 and 44 are both driven by the output signal of the on/off detector 40 that detects the on/off state of the keyboard switch 12, and the time function A,(t) generated by the generator 43 is is input to the multiplier 45, and the time function (t) generated from the generator 44 is input to the multiplier 6. The multiplier 45 inputs an amplitude coefficient Y,(n) of a certain order and a time function A,
(t) and the multiplication value A, (t)・Y, (n)
is output to the multiplier 47. Similarly, the multiplier 46 outputs the input amplitude coefficient Y2(n) of a certain order [this order is the same as the order of the amplitude coefficient Y,(n) inputted to the multiplier 45 at this time] and the time function A2. (t) and outputs the multiplied value A2(t)·Y2(n) to the multiplier 48.
Multiply value A. (t)・Y, (n) and multiplication value A2(t)・Y
The values of 2(n) are different from each other. By the way, the multipliers 47 and 48 have sine values sinWsign-qR corresponding to harmonic components of the same order as the order of each amplitude coefficient Y, n) and Y2(n) output from the amplitude coefficient group memories 41 and 42. are sent simultaneously from the sine function table 29 in synchronization.

Therefore, in the multipliers 47 and 48, the multiplication value A, (t)・Y, (n) from the multiplier 45, the multiplication value n(t)-Y2(n) from the multiplier 46, and the sine value Sir rough nqR, respectively, and the multiplication result A, (t)・Y, (n)
．． SinW Shin-qR and A2(t)・Y2(n)・s
Send inW's qR to adder 49. Therefore, the adder 49 adds the above two multiplication results, and adds the added value F(
n)' is output. F(n)'={A, (t・Y, (n
)+A2(t)・Y2(n)}Sin Garlic hqR=Cn'
SinWヱkonqR...[2
1Cn'=A, (t)・Y, (n) ten (t)・Y2(
n)...[3' The above calculated value F(n)' is input to the accumulator 16, and the subsequent processing is exactly the same as in the case of FIG.

As can be seen from the above {2}, '3} formulas, the amplitude coefficient (harmonic coefficient) that shows a different time change for each order n is the (3rd harmonic coefficient).
- is given by Cn' of the equation, and by the {2} equation, the first
It can be seen that the amplitude of the waveform at each sample point of the musical sound waveform can be obtained in exactly the same way as the follow-up technique shown in the figure. Therefore, a musical tone whose timbre changes over time can be generated using a very small number of memories, for example, two types of amplitude coefficient group memories and a time function generator. Next, a modification of the first embodiment will be described in which another memory address control device 51 and an amplitude coefficient group memory 50 are added, which are shown by broken lines in FIG.

The memory address control device 51 generates an address signal Ak corresponding to each switch (that is, each key) of the keyboard switch 12.
There is a device in which the amplitude coefficient group memory 50 is addressed by the address signal Ak, which is output when the key is pressed. The amplitude coefficient group memory 50' stores the amplitude coefficient Ck for each key at a designated address, and when the address signal Ak corresponding to that key is output from the memory address control device 61 by pressing a key, the address is signal Ak
The amplitude coefficient Ck stored at the corresponding address is calculated and sent to the multipliers 45 and 46. Therefore, this amplitude coefficient Ck is multiplied by other inputs in multipliers 45 and 46, respectively, and the output Z of multiplier 45 is Ck·A, (
t)・Y, (n), and the output of the multiplier 46 is Ck・Y, (n).
A2(t)・Y2(n). As a result, adder 49
The output is expressed by equation {4). F(n)'
=C'n. Ck. SinW Kubokawa qR...
[41] Therefore, in this case, the amplitude coefficient Cn' formed according to the first embodiment is further modified by the amplitude coefficient Ck stored in the amplitude coefficient group memory 50, thereby causing the timbre to change over time, and Musical tones with different tones can be obtained for each key.

Next, a second embodiment of the present invention will be described with reference to FIG.

This invention includes a part of the waveform amplitude calculation circuit of the first embodiment,
That is, amplitude coefficient group memories 41, 42, time function generator 4
3, 44, multipliers 45, 46, 47, 48, frequency number memory 14, gate 24, pitch section adder 25, gate 27, harmonic section adder 28, memory address code/decoder 30, sine function table 29. In FIG. 3, the devices of the first series are distinguished by the suffix 1, and the devices of the second series are distinguished by the suffix 2. Also commonly used in both series are a keyboard switch 12, a clock generator 20, a counter 22, an adder 49, an accumulator 16, a gate 17, a DA converter 18, an audio system 11, and a memory address control. Device 35, on/off detector 4, has no suffix. From the first series frequency number memory 14,
A frequency number R corresponding to each keyboard switch 12 is output. Further, the frequency number memory 142 of the second series is configured to output a frequency number R different from the frequency number R described above. Therefore, the first series of sine function table 29 outputs the sine value sinW kiln mqR,
Further, from the second series of sine function table 292, subhqR' is outputted as the sine value Si. Also, the first series of amplitude coefficient group memories 41, 42 and the second series of amplitude coefficient group memories 41 are controlled by the memory address control device 35.
2,422 are provided.

These amplitude coefficient group memories 41, 42, 412, 42
2 have different amplitude coefficients Y, (n), Y
2(n), Y3(h), and Y4(n) are stored.
Then, the address signal An' of the address control device 35 is transmitted to the amplitude coefficient group memories 41, 421, 41.
2,422 are addressed simultaneously, each memory 411
,42・,412,422, the above amplitude coefficient Y,(n)
, Y2(n), Y3(n), Y4(n) are extracted and sent to the corresponding multipliers 45, 46, 452, 462. Further, a first series of time function generators 43, 44 and a second series of time function generators 432, 442 driven by the on/off detector 40 are provided, and these generators 43, 44, 432 , 442, respectively different types of time functions A, (t), n(t), n(t),
(t) is output to the corresponding multiplier 45. ,46・,
452, 462. As a result, the multipliers 45, 46 of the first series output multiplier values A, (t), Y
, (n), A2(t), Y2(n) are output as 0, and the first
are sent to corresponding multipliers 47, 48, of the series. In addition, from the second series multipliers 452 and 462, each (
t), Y3(n), A4(t), and Y4(n) are output and sent to corresponding multipliers 472 and 482 of the second series. The multipliers 47, 48 receive the sine value SinW-qR output from the first series sine function table 29, and the multipliers 472, 482 receive the sine function table 29 of the second series.
2, the output F(n) of the adder 49 is expressed by the formula (2).

F(n) river = {A, (t). Y, (n)+A2(t).
Y2(n)}Si endhqR(t). Y3(n) 10A4(t). Y4(n)}Sin ChonghqR'=C'n・
Sin Shimachi R 1 C' Ho n Takashi MR'...Additional value F (
n)... is input to the accumulator 16 and processed in the same manner as in FIG. 1 to generate musical tones.

The second embodiment of the present invention has the frequency number memory 14, gate 24, pitch section adder 25, gate 27, harmonic section adder 28,
Two sets of memory address decoder 30, sine function table 29, amplitude coefficient group memories 41, 42, time function generators 43, 44, and multipliers 45 to 48 are provided, and the configuration is such that different waveform amplitude calculations can be performed for each series. Therefore, compared to the case of the electronic musical instrument of the first embodiment, the timbre changes over time in a more complex manner, and it is possible to generate musical tones that are richer in naturalness.

However, if different types of amplitude coefficient group memories and time function generators are provided in advance, and they can be installed and removed from the electronic musical instrument or electrically switched freely, it is possible to perform a single electronic musical instrument. You can also improve your abilities.

As explained above, according to the present invention, it is only necessary to provide two time function generators having a relatively complicated configuration for each order, and therefore the overall configuration is simple.
This has the effect of freely generating natural musical tones whose timbre changes over time. Further, according to the present invention, since the time function is common to each order, the manner of time change of the amplitude coefficient of each order is always related to each other.
As a result, it is possible to obtain musical tones that approximate the spectral changes of natural musical instrument sounds.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional harmonic synthesis electronic musical instrument, FIG. 2 is a block diagram of a waveform amplitude calculation circuit according to a first embodiment of the present invention, and FIG. 3 is a waveform diagram of a second embodiment of the present invention. FIG. 2 is a block diagram of an amplitude calculation circuit. 11...Acoustic system, 12...Keyboard switch, 14...Frequency number memory, 16...
... Accumulator, 18 ... 4D-A converter, 20 ... Clock generator, 25, 25,
,252...Pitch section adder, 28,28,,
282...Harmonic interval adder, 29,29,,
292... Sine function table, 35, 51... Memory address control device, 41, 411, 412, 42,
42,,422...Amplitude coefficient group memory, 43,
43,,432,44,44,,442... Time function generator, 45,451,452,46,46,,
462,47,47,,472,48,48. ,482
...Multiplier, 49...Adder. Boat chart N Boat chart ship

Claims (1)

[Claims] 1. In a musical tone synthesis method that generates each order component of the fundamental wave and its high frequency constituting a musical tone, and forms a musical tone signal by adding and synthesizing each of these order components, the first and second generate the amplitude coefficient,
Further, first and second time functions are generated, the first amplitude coefficient for each of the above orders is modulated and controlled by the first time function, and the second amplitude coefficient for each of the above orders is controlled by the first time function. Each of the coefficients is modulated and controlled by the second time function, and the amplitude of the corresponding order component is controlled by the modulation-controlled first and second amplitude coefficients for each order. A method of musical tone synthesis.