JPH07140983A - Musical sound generator - Google Patents

Abstract

PURPOSE:To generate musical sound having rich expression and varieties by controlling the parameters of a khaos sound source in real time and generating waveform shapes which vary stepwise in accordance with the parameter values. CONSTITUTION:Parameters of a function (f) of a kahos sound source, which generates waveform data columns, are controlled in real time by a dynamic system that is varied in accordance with Xn of a difference equation Xn+1 =f (Xn) at time n (n=0,1,2,...). Namely, a delay circuit 101 of a kahos oscillator delays input data for equivalent to one period of a sampling clock and outputs them. In a function generator 102, the function (f) is applied to input data X and output data f (X) are outputted. A compensation circuit 103 performs a nonlinear conversion to the input data and outputs them as musical sound data and the output of the circuit 103 is also inputted to the circuit 101.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical tone generator used for a sound source of an electronic musical instrument.

[0002]

2. Description of the Related Art Conventionally, as a sound source of an electronic musical instrument, an actual musical sound is recorded by a PCM (pulse code modulation) system and stored in a memory, which is read at the time of performance and an envelope is added to the read waveform data. A method of giving and outputting is known. Further, a method is known in which waveform data is generated by FM (frequency modulation) calculation, an envelope is added to the waveform data, and the waveform data is output. Basically, the tone waveform by these methods has a continuously changing shape.

On the other hand, the dynamical system xn + 1 = f
A tone generation device (so-called chaotic sound source) provided with a waveform generator that outputs a sequence of numbers generated as (xn) (where n = 0, 1, 2, 3, ...) As a waveform data sequence is disclosed in Japanese Patent Laid-Open Publication No. No. 97197.

This is provided with a circulation path including a delay circuit for delaying and outputting input data by one cycle of a sampling clock, and a function operation circuit for applying a function f to input data and outputting it. By circulating numerical data in this circulation path, a dynamical system xn + 1 = f (xn)
A sequence xn that changes according to (n = 0, 1, 2, 3, ...) Is generated and output as waveform data.

With such a chaotic sound source, it is possible to synthesize a musical sound having an unstable amplitude behavior, a musical sound having an irregular amplitude fluctuation, and the like.

[0006]

By the way, the above-mentioned PC
Musical tone generators using M and FM sound sources can generate musical tones of various tones, but user demands are becoming more diverse and sophisticated, and more diverse and expressive musical tones are generated. There is a need for a device that can.

According to the chaotic sound source disclosed in Japanese Patent Laid-Open No. 4-97197, it is possible to generate a musical sound having a chaotic behavior different from that of the PCM sound source and the FM sound source. However, the circulation path of the chaotic sound source must be configured to be able to process data of sufficient data length so that the data circulating in the circulation path will not overflow. Further, in order to generate various waveforms, the function f to be used must be complicated, which causes a problem that the circuit becomes complicated.

An object of the present invention is to provide a musical tone generating apparatus capable of generating a variety of musical tones which cannot be generated by a PCM sound source or an FM sound source and have high expressive power.

Another object of the present invention is to provide a tone generating device capable of generating various waveforms in a chaotic sound source without increasing the data length of the circulation path and complicating the function calculation. To do.

[0010]

In order to achieve this object, the present invention uses time n (where n = 0, 1, 2,
The data value xn in 3, ...) is the difference equation xn + 1 = f
The present invention is characterized by comprising waveform generating means for generating a waveform data string by a dynamical system that changes according to (xn), and control means for controlling the parameters of the function f of the waveform generating means in real time.

Further, as a dynamical system in which a data value xn at time n (where n is an integer of 0, 1, 2, 3, ... Based on a sampling clock) changes according to a difference equation xn + 1 = f (xn). A musical tone generating apparatus having a functioning circuit, which includes a circuit for delaying input data by delaying one cycle of a sampling clock and outputting the data, and a function calculating device for applying a function f to the input data and outputting the function. In the above, the non-linear converting means for limiting the numerical value of the data circulating in the circulation path is provided in the circulation path.

Further, there is provided a musical tone generating apparatus having a waveform memory storing waveform data for at least one cycle,
Phase generating means for generating a phase data string by a dynamical system in which the data value xn at time n (where n = 0, 1, 2, 3, ...) Changes according to the difference equation xn + 1 = f (xn); Control means for controlling the parameter of the function f of the phase generating means in real time, and the waveform data is read out from the waveform memory on the basis of the phase data output from the phase generating means and output.

[0013]

Waveform generation for generating a waveform data train by a dynamical system in which the data value xn at time n (n = 0, 1, 2, 3, ...) Changes according to the difference equation xn + 1 = f (xn) By controlling the parameters of the function f of the means (so-called chaotic sound source) in real time, it is possible to generate a waveform in which the waveform shape changes stepwise over a plurality of stages. For example, the parameters of the function f may be changed with time according to a predetermined envelope, or the parameters of the function f may be changed according to performance operation information from the performance operator.

The chaotic sound source is usually provided with a circulation path including delay means for delaying input data by one cycle of a sampling clock and outputting the same, and function calculating means for applying a function f to the input data and outputting the same. Waveform data is generated by circulating data in this circulation path. At this time, if a non-linear conversion means is provided in the circulation path to limit the numerical value of the data circulating in the circulation path, the data length of the circulation path is not lengthened and the calculation therein remains simple. Various waveforms can be output with.

In this case, the function f is particularly simple and the number of completed coefficients may be small. Therefore, the sound source is suitable for real-time control of the parameters of the function f described above.

If a waveform memory is read by using a data string generated from a chaotic sound source as phase data, a novel sound source which has never been obtained can be obtained.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block configuration of a chaotic oscillator according to the first embodiment of the present invention. This chaotic oscillator includes a delay circuit 101, a function generator 102, and a correction circuit 103. These form the circulation path 104.

The delay circuit 101 is a delay circuit which delays the input data by one cycle of the sampling clock and outputs the delayed data. The output of the delay circuit 101 is input to the function generator 102. The function generator 102 applies the function f to the input data x.
To output output data f (x). The output of the function generator 102 is input to the correction circuit 103. The correction circuit 103 performs non-linear conversion (described later) on the input data and outputs it. The output of the correction circuit 103 is the delay circuit 10
Enter 1. Further, the output of the correction circuit 103 is output as musical tone waveform data.

Assuming that the correction circuit 103 is not provided, this circuit 104 realizes a dynamic system in which the data value xn changes according to the difference equation xn + 1 = f (xn). n is an integer of 0, 1, 2, 3, ... Based on the sampling clock and indicates time. The waveform data string generated by such a dynamical system looks like a periodic signal and is random, but if it is completely noise, it has something like periodicity. It is possible to generate a tone waveform signal having such chaotic behavior.

FIG. 2 shows the function generator 102 of the chaotic oscillator.
A configuration example of is shown. As the function generator 102, in addition to the example shown here, any order equation, a trigonometric function, an exponential function, or the like may be used.

FIG. 2A shows the function f (x) for the input x.
It is an example of the function generator 102 which outputs = ax + b. A multiplier 201 that multiplies an input x by a coefficient a, and an adder that adds a constant b (b for indicating a constant term is also referred to as a coefficient b) to the output ax of the multiplier 201. 202 is provided. Output a of adder 202
x + b becomes the final function output f (x).

FIG. 2B shows the function f (x) for the input x.
² is an example of the function generator 102 that outputs = a2 x ² + a1 x + b. For the input x, the multiplier 211 calculates the coefficient a1 / a
Multiply by 2, and the multiplier 212 calculates x ² . Multiplier 2
Output x ² outputs (a1 / a2) x, and the multiplier 212 of 11 are added by the adder 213. The multiplier 214 multiplies the output x ² + (a 1 / a 2) x of the adder 213 by the coefficient a 2. The multiplication ^{result, a2 {x 2 + (a1} /
the ^{a2) x} = a2 x 2} + a1 x. For this multiplication result, adding the coefficient b by the adder 215 to obtain a final function output ^{f (x) = a2 x 2} + a1 x + b.

The correction circuit 103 of FIG. 1 limits numerical values of data circulating in the circulation path 104 (in other words, amplitude limitation).
It is a circuit that performs a non-linear conversion for performing. The data (waveform data) circulating in the circulation path 104 needs to be within a certain range (here, -1 to 1). However, in the conventional circuit without the correction circuit 103, chaos
Overflow often occurred in the calculation of the algorithm. Therefore, in this embodiment, the correction circuit 103 carries out a non-linear conversion to limit the numerical value (amplitude limitation).

3A to 3D show the correction circuit 10
An example of amplitude limitation by 3 is shown. In both examples, the input data is numerically limited to the range of -1 to 1.

FIG. 3A shows the input / output of the correction circuit 103 which performs modulo arithmetic on the input data. Input x,
When the output is expressed as [x] mod, this modulo operation is expressed as [x] mod = (x + 1)% 2-1. However, the meaning of the operator% is "when expressed as p% q (p is a real number and q is a natural number), p% q is p.
Represents the remainder (0 or more and less than q) ".

FIG. 3B shows the input / output of the correction circuit 103 which performs the triangular wave function operation on the input data. When the input is expressed as x and the output is expressed as [x] S, this triangular wave function operation is [x] S = 1- (2x)% 2 (when 2r <x≤2r + 1) (2x)% 2-1 (2r + 1) <When x ≦ 2r + 2). However, r is an integer.

FIG. 3C shows the input / output of the correction circuit 103 by the limiter that limits the value of the input data. When the input is written as x and the output is written as [x] L, this operation is Is expressed as

FIG. 3D shows the input / output of the correction circuit 103 which performs the cos function operation on the input data. Input x,
When the output is expressed as [x] cos, this cos function operation is expressed as [x] cos = cos πx.

Other polynomials, trigonometric functions (tan-1
Numerical restrictions may be performed using an arbitrary function such as x) or a logarithmic function. As the configuration of the correction circuit 103 that performs such numerical limitation, a conventionally known configuration may be used.

When the correction circuit 103 limits the numerical value of the data circulating in the circulation path 104, it is not necessary to increase the processing data length in the circulation path 104. That is, the delay circuit 101, the function generator 102, and the correction circuit 103.
There is no need to increase the processing data length of. Further, the function calculation of the function generator 102 can generate various waveforms while remaining simple.

Next, with reference to FIGS. 4 to 8, an example of a concrete oscillation operation of the chaotic oscillator of FIG. 1 will be described. In the following, as the function generator 102, the function f (x) = ax +
2b for outputting the correction circuit 103
As an example, an example using a modulo operation shown in FIG.

FIG. 4A is a graph showing the locus of xn + 1 = f (xn). The horizontal axis represents xn and the vertical axis represents xn + 1. The graph 401 shows the function xn + 1 of the function generator 102 =
It is a graph of f (xn) = axn + b. Graph 402
Is an auxiliary line (graph of xn + 1 = xn). However, the coefficients a and b are 0 <a <1.0 and b> 0, and the graph 401 and the auxiliary line 402 always intersect. 430 shows the intersection. The correction circuit 103 causes the circuit 1
Since the data xn circulating 04 is always −1 ≦ xn ≦ 1, the graphs in FIGS. 4A to 8A are shown in that range.

Waveform data x0, x1, x2 in FIG.
, X3, ... are sequentially obtained as follows. First, x1 is obtained from the intersection 411 of the straight line parallel to the vertical axis and the graph 401 passing through x0 (here, x0 = 0). Next, x1 becomes an input and x2 = f (x1)
From the intersection 413 between the straight line parallel to the horizontal axis and the auxiliary line 402 through the intersection 411, and the intersection 413 between the straight line parallel to the vertical axis through the intersection 412 and the graph 401. Is required. Step arrow 420
Shows how to sequentially obtain x0, x1, x2, ... In this way.

As can be seen from FIG. 4A, a <1.0,
b> 0 and the graph 401 and the auxiliary line 402 intersect at 4
When crossing at 30, the output waveform data string x0,
The columns x1, x2, ... Asymptotically approach the intersection 430. FIG. 4B is a graph showing the temporal change of the waveform data sequence x0, x1, x2, .... As time passes,
The amplitude value converges on b / (1-a). b / (1-
a) is position coordinates (x coordinate = y coordinate) of the intersection 430.

FIG. 5A shows the same xn + 1 as FIG. 4A.
7 is a graph showing a locus of = f (xn). However,
In (a), the coefficient a of the function f of the function generator 102 is a =
1.0 and b> 0. 501A is a graph of the function f. Since a = 1.0, the graph 50 of the function f
1A is parallel to the auxiliary line 402.

In the graph 501A of the function f, xn + 1 = f (x
In the range of n)> 1 (the portion 501C indicated by the alternate long and short dash line), the correction circuit 103 of FIG. 1 (which performs the calculation of FIG. 3A) performs modulo calculation for limiting the numerical value. Therefore, the graph 501C in this range is
It becomes like 501B. In other words, the function generator 10
If the function obtained by combining 2 and the correction circuit 103 is g, the range of −1 ≦ xn + 1 ≦ 1 in the graph 501A and the graph 501
The graph obtained by combining B and B becomes the graph of the function g.

Also in FIG. 5A, as in the case of FIG. 4A, the waveform data string x is set in the same manner as the stepwise arrow 511.
0, x1, x2, ... Can be obtained. Arrow 5 in the figure
As can be seen from the locus of 11, waveform data strings x0, x1
, X2, ... First increase monotonically, and when it becomes a predetermined value or more, arrow 511 moves to graph 501B, and further arrow 511 moves to graph 501A and monotonically increases again.

FIG. 5B shows this waveform data string x0, x.
It is a graph which shows the time change of 1, x2, .... The amplitude value monotonically increases with the passage of time, and when it exceeds a predetermined value, it suddenly becomes a negative number and monotonically increases again. Since this is repeated, the output waveform has a substantially constant frequency (determined by the value of b).

FIG. 6A shows the same xn + 1 as FIG. 4A.
7 is a graph showing a locus of = f (xn). However, FIG.
In (a), the coefficient a of the function f of the function generator 102 is a>
1.0 and b> 0. 601A is a graph of the function f. In the graph 601A of the function f, xn + 1 = f (x
The range of n)> 1 (dashed line portion 601C) is also shown in FIG.
Similar to the graph 501B in (a), 601B is obtained by the modulo operation of the correction circuit 103.

Also in FIG. 6A, as in FIG. 4A, the waveform data string x is set in the same manner as the stepwise arrow 611.
0, x1, x2, ... Can be obtained. Arrow 6 in the figure
As can be seen from the locus of 11, waveform data strings x0, x1
, X2, ... Accelerately increase, and when it becomes a predetermined value or more, the arrow 611 moves to the graph 601B, and further the arrow 611 moves to the graph 601A and again accelerates.

FIG. 6B shows this waveform data string x0, x.
It is a graph which shows the time change of 1, x2, .... The amplitude value gradually increases with the passage of time, and when it becomes a predetermined value or more, the amplitude value suddenly becomes a negative number, and then again accelerates. Since this is repeated, the output waveform has a frequency that fluctuates slightly around a certain frequency.

FIG. 7A shows the same xn + 1 as FIG. 4A.
7 is a graph showing a locus of = f (xn). However,
In (a), a> 1.0 and b> 0, and the graph 7 of the function f
It is assumed that 01A and the auxiliary line 402 intersect at an intersection 730.

In the graph 701A of the function f, xn + 1 = f (x
The range of n)> 1 (dashed line portion 701D) is shown in FIG.
Similar to the graph 501B in (a), the graph 701B is obtained by the modulo operation of the correction circuit 103. Furthermore, xn + 1 = f (xn) <-1 of this graph 701A
Of the correction circuit 103 (the portion indicated by the alternate long and short dash line 701E) is
The graph 701C is obtained by the modulo operation of.

Also in FIG. 7A, as in FIG. 4A, the waveform data string x is set in the same manner as the stepwise arrow 711.
0, x1, x2, ... Can be obtained. Arrow 7 in the figure
As can be seen from the locus of 11, waveform data strings x0, x1
, X2, ... At first, they increase at an accelerated rate, and when they reach a predetermined value or more, the arrow 711 moves to the graph 701B, the arrow 711 moves to the graph 701A, and the arrow 71 moves.
1 moves to the graph 701C, and so on.

FIG. 7B shows this waveform data string x0, x.
It is a graph which shows the time change of 1, x2, .... The amplitude value increases at an accelerated rate with the passage of time, and when the amplitude value exceeds a predetermined value, it becomes like noise in which positive and negative numbers are mixed.

FIG. 8A is a graph in which the slope a is further increased from the state of FIG. 7A. Graph 8 of function f
01A and the auxiliary line 402 intersect at an intersection 830.
The range of xn + 1 = f (xn)> 1 (the part indicated by the alternate long and short dash line 801D) of the graph 801A of the function f becomes like the graph 801B by the modulo operation of the correction circuit 103. Further, xn + 1 = f (xn) <-1 of this graph 801A
Of the correction circuit 103 (the part indicated by the alternate long and short dash line 801E) is
The graph 801C is obtained by the modulo operation of.

Similar to FIG. 7A, stepwise arrow 8
As shown in 11, waveform data strings x0, x1, x2, ... Can be obtained. The waveform data sequence x0, x1, x2, ... Firstly increases in an accelerating manner, and when it reaches a predetermined value or more, the arrow 811 moves to the graph 801B, the arrow 811 moves to the graph 801A, and the arrow 811 moves to the graph 80.
Move to 1C, and so on.

FIG. 8B shows this waveform data string x0, x.
It is a graph which shows the time change of 1, x2, .... Figure 8
A graph 801A in (a) is a graph 701A in FIG. 7 (a).
Since the slope a is larger, the domain of the graphs 801B and 801C is wider than the domain of the graphs 701B and 701C.
Therefore, in FIG. 8 (b), the amplitude value increases more acceleratingly than that in FIG. 7 (b) with the passage of time. Become. In a state like noise, the swing width 840 of the amplitude value is the swing width 740 in FIG.
Get bigger.

In the above example, the generation of the output of the waveform data is started from x0 = 0, but the present invention is not limited to this, and the output may be started from any value. The initial value may be given to an appropriate position on the circulation path 104 (for example, the delay circuit 101).

In the examples of FIGS. 4 to 8, the function generator 102 of FIG. 1 outputs the function f (x) = ax + b.
The correction circuit 103 shown in FIG.
However, the present invention is not limited to this, and other function calculation or correction calculation may be used. More complex waveforms can be output by using complicated functions and correction circuits.

Further, the coefficients a and b are not limited to the ranges of the coefficients a and b described in FIGS. 4 to 8 above, but the coefficients a and b are values in other ranges (for example, when a and b are negative numbers). May be. In that case, the oscillation operation of the chaotic oscillator of FIG.
~ It can be known in the same manner as described in FIG.

FIG. 9 shows another example of the temporal change of the amplitude value. FIG. 9A is a graph similar to FIG. 4A.
g (x) = ax + b represents a function obtained by combining the function f of the function generator 102 and the modulo operation of the correction circuit 103.
It is assumed that g (x) and the auxiliary line 402 intersect at a point c.

FIG. 9 (i) shows the temporal change of the amplitude value when the coefficient a is 0 <a <1.0. This is the same as in FIG. 4B, and the amplitude value gradually converges to the point C. (I in FIG.
i) shows the case where the coefficient a = 0. At this time, the amplitude value suddenly reaches the point c for any input. FIG. 9 (iii)
Indicates the case where the coefficient a is -1 <a <0. At this time, the amplitude value gradually attenuates to point C and converges. (I in FIG.
v) shows the case where the coefficient a = -1. At this time, the amplitude value oscillates around the point C. 9 (iiv) shows the coefficient a <−1.
Shows the case. At this time, the amplitude value oscillates while increasing its absolute value.

In this first embodiment, the parameters of the function generator 102 shown in FIG. 1 are controlled in real time. The parameter of the function generator 102 is, for example, as shown in FIG.
In the case of the configuration of (a), the coefficient a and the coefficient b, and in the case of the configuration of FIG. By controlling these in real time, it is possible to realize a unique timbre change in which the waveform shape changes stepwise over a plurality of stages.

For example, in the example of FIGS. 4 to 8 described above, the coefficient b
Is set to a fixed value, and the coefficient a is controlled to be gradually decreased from a value larger than 1 to 1. At this time, the amplitude value of the output waveform data is as shown in FIG. 8B → FIG. 7B → FIG.
(B) → Changes as shown in FIG. 5 (b).

That is, initially, there are many noise components with large fluctuations in amplitude value (FIG. 8B), and gradually noises with small fluctuations in amplitude value (FIG. 7B). Waveform data having a frequency that fluctuates near an appropriate frequency is output (FIG. 6B), and finally waveform data having a substantially constant frequency is obtained (FIG. 5B). In this way, it is possible to output waveform data in which the waveform shape changes stepwise over a plurality of stages.

FIG. 10 shows a block configuration of an electronic musical instrument to which the musical tone generating apparatus according to the second embodiment of the present invention is applied.

This electronic musical instrument includes a performance operator 1001, a tone color switch (SW) 1002, a detector 1003, a detector 1004, a chaotic oscillator 1005, and a hold circuit 100.
6, multiplier 1007, digital filter 1008, effect circuit 1009, digital analog (D / A) converter 1010, sound system 1011, volume envelope generator (EG) 1012, and chaos EG1.
013 is provided.

The performance operator 1001 is an operator for performing a performance operation by the user. Here, the keyboard. When the user plays the keyboard 1001, the detector 1003 detects the performance operation and outputs performance information (for example, key-on signal or touch information). This performance information is the volume EG10.
12, chaos oscillator 1005, and chaos EG101
Enter in 3.

The tone color SW 1002 is a switch for designating the tone color of the generated musical tone. User selects tone SW1
When an operation for designating a tone color is performed with 002, the detector 1
004 detects the designation operation and outputs tone color information. This tone color information includes volume EG1012 and chaos oscillator 100.
5 and chaotic EG1013.

FIG. 11 shows a block configuration of the chaotic oscillator 1005. The chaotic oscillator 1005 is the coefficient generator 1
101, adder 1102, multiplier 1103, adder 11
04, delay circuit 1105, and modulo circuit 1106
Is equipped with.

The adder 1102, the multiplier 1103, and the adder 1104 correspond to the function generator 102 of FIG.
The same linear function operation as in FIG. 2A is performed. The function is f (x) = ax + b = (aEG (t) + aofs) x + b. aEG (t) is a parameter given from the chaotic EG 1013, and is an envelope value that changes with time t. aofs is an offset value given from the coefficient generator 1101.

The offset value aofs is set to the envelope value aEG
By adding to (t) to form coefficient a, coefficient a
Is always larger than a predetermined value. This prevents the output amplitude value from becoming a constant value as shown in FIG. 4 (b).

The modulo circuit 1106 corresponds to the correction circuit 103 in FIG. The modulo circuit 1106 is shown in FIG.
The modulo operation of (a) is performed. The delay circuit 1105 is
This corresponds to the delay circuit 101 in FIG. Delay circuit 1105
Delays the input data by one cycle of the operation clock (sampling clock) φs.

The coefficient generator 1101 is a detector 1003.
The performance information and tone color information output from 1004 are input, and the coefficients aofs and b are output according to them. As a result, waveform data of the designated tone color and tone color (tone color change) corresponding to the touch is generated.

When the pitch is specified by the performance information, the value of the coefficient b may be set according to the specified pitch.

The oscillation operation of the chaotic oscillator 1005 shown in FIG. 11 is basically the same as that described in the first embodiment. The examples of the oscillation operation described in FIGS. 4 to 9 can be applied as they are.

The envelope value aEG output from the chaotic EG 1013 of FIG. 10 and input to the adder 1102 of FIG.
(t) is a parameter that changes with time as shown in FIG. 13, for example. 13A to 13C, the horizontal axis represents time t and the vertical axis represents the envelope value aEG (t).

The graph 1301 in FIG. 13A is an envelope that rises sharply, reaches a peak, and then gradually decreases. The rising of the envelope starts when the key of the keyboard 1001 is pressed. Envelope value aEG (t) that changes as in this graph 1301
Is input to the chaotic oscillator of FIG. 11, the output waveform data changes according to the change of the coefficient a, and the waveform data of FIG.
→ FIG. 7 (b) → FIG. 6 (b) → FIG. 5 (b). As shown by a dotted line graph 1302 in FIG. 13A, it is also possible to use an envelope which is peak-held for a predetermined time after reaching the peak.

A graph 1303 in FIG. 13B is an envelope that gradually rises. This graph 13
The envelope value aEG (t) that changes as shown in FIG.
When input to the chaos oscillator of FIG. 5, the output waveform data is output in accordance with the change of the coefficient a as shown in FIG.
(B) → FIG. 7 (b) → FIG. 8 (b).

A graph 1304 of FIG. 13C shows a multi-segment function having different increasing rates so that the output waveform data changes as shown in FIG. 5B → FIG. 6B → FIG. 7B. It is an envelope composed of. In the first section 1311, since the increase rate is relatively small, the output as shown in FIG. 5B continues for a relatively long time. The output changes as shown in FIG. 6B in the next section 1312, and the output shown in FIG. 7B in the next section 1313.

By doing so, the state of FIG. 5B can be intentionally kept long, and as a result, the DC component time ratio in the entire output waveform increases. In terms of hearing, a sound similar to a plosive sound of a voice is likely to occur.

Referring again to FIG. 10, the chaos EG101
3 outputs a time-varying envelope value aEG (t) as described with reference to FIG. 13 according to the key-on signal, the touch information, the tone color information, and the like. Chaotic oscillator 10
05 outputs waveform data according to touch information, tone color information, and envelope value aEG (t).

The waveform data output from the chaotic oscillator 1005 is input to the hold circuit 1006. The hold circuit 1006 holds (resamples) the input data based on a resampling clock having a frequency φRS lower than the sampling frequency φs. As a result, the thinning process of the input data is performed.

In the preprocessing of the input of the hold circuit 1006, L
Since it is not passed through a PF (low-pass filter), so-called aliasing noise is generated by such thinning processing, and the spectrum component is changed. As a result, new timbre waveform data can be generated. In particular, it is possible to easily create a so-called TOM-like tone color by increasing the Q of the BPF (bandpass filter) in the digital filter 1008 in the subsequent stage. Note that the same spectral characteristic is realized by using the FIR filter. Yes, but the timbre (especially the attack part) is different because the waveform changes in the time dimension are different.
Is different.

The output of the hold circuit 1006 is the multiplier 1
Enter in 007. The volume EG1012 is a key-on signal from the detectors 1003 and 1004, touch information,
And tone color information are input, and a volume envelope VEG (t) corresponding to these is output.

The multiplier 1007 is a hold circuit 1006.
An envelope is added to the waveform data by multiplying the waveform data from the sound volume envelope VEG (t). The output of the multiplier 1007 (waveform data with an envelope) is input to the digital filter 1008.

FIG. 12 shows a block configuration of the digital filter 1008. The digital filter 1008 is
The coefficient generator 1201, the filter circuit 1202, and the mixer 1203 are provided.

The filter circuit 1202 has an HPF inside.
(High-pass filter), BPF (band-pass filter), and LPF (low-pass filter) are provided. The waveform data output from the multiplier 1007 is input to the filter circuit 1202 and filtered by each of these filters.

The coefficient generation unit 1201 uses the volume EG1012
Volume envelope from VEG (t) and chaos EG10
The envelope aEG (t) from 13 is input, and the cutoff frequency of the filter circuit 1202 and Q
And the mixing ratio in the mixer unit 1203 are output.

The mixer section 1203 includes a filter circuit 120.
The HPF output, the BPF output, the LPF output, and the original input waveform data from 2 are input to the coefficient generation unit 1201.
Mix at the mixing ratio given by and output.

Referring again to FIG. 10, the waveform data output from the digital filter 1008 is the effect circuit 10
Enter in 09. The effect circuit 1009 adds the envelope aEG from the chaos EG1013 to the input waveform data.
Add various effects based on (t). For example, when reverb is applied, the initial reflection, delay amount, level, reverberation density, reverb depth, etc. may be controlled by the envelope aEG (t). Further, in the case of applying the effect using the physical model, the loop delay length, the in-loop filter coefficient, the loop reflection coefficient, the attenuation rate, etc. may be controlled by the envelope aEG (t).

The waveform data to which the effect is applied by the effect circuit 1009 is converted into an analog tone signal by the D / A converter 1010, and the sound is emitted by the sound system 1011.

Next, another configuration example of the function generator described in the first and second embodiments will be described.

FIG. 14 is a graph similar to that of FIG. f (x) indicates the function of the function generator 102, and the dotted line 4
Reference numeral 02 indicates an auxiliary line (xn + 1 = xn). Where xn + 1
= F (xn) = xn, the input value xn is output as it is as the next value xn + 1, so the value does not change. In the range where the graph of the function f (x) is above the auxiliary line 402 (that is, the range of xn + 1 = f (xn)> xn),
A value xn + 1 larger than the input xn is output. vice versa,
In the range where the graph of the function f (x) is below the auxiliary line 402 (that is, in the range of xn + 1 = f (xn) <xn), a value xn + 1 smaller than the input xn is output.

That is, the result of subtracting the graph of the auxiliary line xn + 1 = xn from the graph of the function xn + 1 = f (xn) (hatched portion 1401 in the figure) is the value of the next timing at each value of x. Is the difference (time differential value) of.

Therefore, the function generator can be constructed as shown in FIG. The function generator of FIG. 15 includes a differential value generator 1501 and an adder 1502. The differential value generator 1501 generates a time differential value at that time for the input data x. The adder 1502 adds the time differential value and the original input data x, and outputs the function output f (x).
To get

FIG. 16 shows a block configuration of an electronic musical instrument to which the musical tone generating apparatus according to the third embodiment of the present invention is applied. This is an electronic musical instrument that uses a sound source that reads waveform data from a waveform memory using the output of a chaotic oscillator as phase data.

This electronic musical instrument includes a keyboard 1601, a wheel operator 1602, a detector 1603, a detector 1604, a parameter generator 1605, a chaotic EG 1606, an adder 1607, a chaotic oscillator 1608, and a waveform memory 161.
1, a volume EG 1612, a multiplier 1613, a D / A converter 1614, and a sound system 1615.

When the user plays the keyboard 1601, the detector 1603 detects the performance operation and outputs performance information (for example, key code, key-on signal, touch information, etc.). This performance information is the volume EG1612,
Parameter generator 1605 and chaos EG 1606
To enter. When the user operates the wheel operator 1602, the detector 1604 detects the operation and outputs wheel operation information. The wheel operation information is input to the parameter generator 1605.

The parameter generator 1605 is the same as in FIG.
Which is similar to the coefficient generator 1101 of 1
The performance information and the wheel operation information output from 3, 1604 are input, and the coefficients aofs and b are output according to them. The chaotic EG1606 is the chaotic EG10 of FIG.
Similar to No. 13, the envelope value aEG (t) is output based on the performance information output from the detector 1603 and the operation information output from the parameter generator 1605. The adder 1607 is similar to the adder 1102 in FIG. 11, and has an offset value aofs and an envelope value aEG.
(t) is added to form the coefficient a.

The chaotic oscillator 1608 corresponds to the multiplier 1103, the adder 1104, the delay circuit 1105, and the modulo circuit 1106 shown in FIG. That is, the chaotic oscillator 1608 inputs the coefficient a from the adder 1607 and the coefficient b from the parameter generator 1605, and outputs waveform data. Using the waveform data as phase data,
Waveform data is read from the waveform memory 1611.

The waveform data (phase data) output from the chaotic oscillator 1608 oscillates as described with reference to FIGS. 4 to 9. However, in this embodiment, the waveform data (phase data) shown in FIG.
The parameters a and b are controlled so that a large number of sawtooth waveforms are output as in (b). This is because the phase data generator used for a normal waveform memory read type sound source outputs a sawtooth wave.

Further, the parameter generator 1605 sets the value of the parameter b (and a) according to the inputted key code. Thereby, the pitch of the generated tone waveform is adjusted. Further, the parameter generator 1605 controls the value of the parameter b according to the wheel operation information. As a result, the pitch bend by the wheel operation is realized. The parameter generator 1605 controls the value of the parameter aofs according to the wheel operation information. Thereby, the control of the shape of the phase wave by the wheel operation is realized.

FM modulated wave oscillator 1609 and adder 161
0 may be provided, and the FM modulated wave from the FM modulated wave oscillator 1609 may be added to the waveform data output from the chaotic oscillator 1608 to obtain phase data.

The waveform data read from the waveform memory 1611 is input to the multiplier 1613. Also, the volume EG
1612 outputs the volume envelope VEG (t) according to the performance information from the detector 1603. Multiplier 1007
Adds the envelope to the waveform data by multiplying the waveform data from the waveform memory 1611 by the volume envelope VEG (t). The output of the multiplier 1007 (waveform data with an envelope) is the D / A converter 16
It is converted into an analog tone signal by 14 and is emitted by the sound system 1615.

[0098]

As described above, according to the present invention, since the parameters of the chaotic sound source are controlled in real time, the waveform shape changes stepwise in a plurality of stages according to such parameter values. Such a waveform can be generated. Further, the EG control may be performed such that the time for which the parameter value is within the predetermined range is long, and the time for waveform output with a predetermined waveform shape may be extended. If the parameter is changed according to the operation information from the operator, the timbre change according to the user's operation can be realized. Further, the waveform data output from a chaotic sound source whose parameters are controlled in real time can be used as phase data to read the waveform memory and generate and output the waveform data, whereby a new tone color tone can be generated. as a result,
It is possible to generate a wide variety of highly expressive musical sounds that cannot be generated by a PCM sound source or an FM sound source.

Since the non-linear conversion means for limiting the numerical value of the data is provided in the circulation path of the chaotic sound source, various waveforms can be obtained without increasing the data length of the circulation path and without complicating the function calculation. Can occur.

[Brief description of drawings]

FIG. 1 is a block diagram of a chaotic oscillator according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of a function generator of a chaotic oscillator.

FIG. 3 is a diagram showing an example of amplitude limitation by a correction circuit.

FIG. 4 is a view showing a locus (a <1.0) of xn + 1 = f (xn) and a temporal change of amplitude value.

FIG. 5 is a view showing a locus (a = 1.0) of xn + 1 = f (xn) and a temporal change of an amplitude value.

FIG. 6 is a diagram showing a locus (a> 1.0) of xn + 1 = f (xn) and a temporal change of an amplitude value.

FIG. 7 is a diagram showing a locus (a> 1.0) of xn + 1 = f (xn) and a temporal change of an amplitude value.

FIG. 8 is a diagram showing a locus (a> 1.0) of xn + 1 = f (xn) and a temporal change in amplitude value.

FIG. 9 is a diagram showing another example of temporal changes in amplitude value.

FIG. 10 is a block configuration diagram of an electronic musical instrument to which a musical sound generating device according to a second embodiment of the present invention is applied.

FIG. 11 is a block configuration diagram of a chaotic oscillator according to a second embodiment.

FIG. 12 is a block diagram of the digital filter of the second embodiment.

FIG. 13 is a diagram showing an example of an envelope of chaos EG according to the second embodiment.

FIG. 14 is a diagram showing a function f of a function generator.

FIG. 15 is a diagram showing another configuration example of the function generator.

FIG. 16 is a block configuration diagram of an electronic musical instrument to which a musical tone generating device according to a third embodiment of the invention is applied.

[Explanation of symbols]

101 ... Delay circuit, 102 ... Function generator, 103 ... Correction circuit, 104 ... Circular path, 1001 ... Performance operator, 100
2 ... Tone color switch (SW), 1003, 1004 ... Detector, 1005 ... Chaos oscillator, 1006 ... Hold circuit, 1007 ... Multiplier, 1008 ... Digital filter, 1009 ... Effect circuit, 1010 ... Digital analog (D / A) conversion Vessel, 1011 ... sound system, 1
012 ... Volume envelope generator (EG), 10
13 ... Chaos EG, 1101 ... Coefficient generator, 1102 ...
Adder 1103 ... multiplier, 1104 ... adder, 110
5 ... Delay circuit, 1106 ... Modulo circuit.

Claims (3)

[Claims] 1. Time n (where n = 0, 1, 2, 3,
The data value xn in the difference equation xn + 1 = f (x
A musical tone generating apparatus comprising: a waveform generating means for generating a waveform data string by a dynamical system that changes according to n); and a control means for controlling the parameter of the function f of the waveform generating means in real time. 2. A dynamic system in which a data value xn at time n (where n is an integer of 0, 1, 2, 3, ... Based on a sampling clock) changes according to a difference equation xn + 1 = f (xn). A musical tone generating apparatus having a functioning circuit, which includes a circuit for delaying input data by delaying one cycle of a sampling clock and outputting the data, and a function calculating device for applying a function f to the input data and outputting the function. In the musical tone generating apparatus, the non-linear converting means for limiting the numerical value of the data circulating in the circulation path is provided in the circulation path. 3. A tone generating apparatus having a waveform memory storing waveform data for at least one cycle, wherein a data value xn at time n (where n = 0, 1, 2, 3, ...) Has a difference. Phase generation means for generating a phase data string by a dynamical system that changes according to the equation xn + 1 = f (xn) and control means for controlling the parameters of the function f of the phase generation means in real time are provided. A musical tone generating apparatus which reads out waveform data from the waveform memory based on phase data output from the means and outputs the waveform data.