JP2803703B2 - Tone generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a musical sound generator used as 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 tone is recorded in a PCM (pulse code modulation) system and stored in a memory, which is read out during a performance and an envelope is added to the read-out waveform data. A method of adding and outputting is known. Also, a method is known in which waveform data is generated by an FM (frequency modulation) calculation, and an envelope is added to the waveform data and output. Basically, the tone waveform according to these methods has a continuously changing shape.

On the other hand, a dynamic system xn + 1 = f
A tone generator (so-called chaos sound source) having a waveform generator that outputs a sequence generated at (xn) (where n = 0, 1, 2, 3,...) As a waveform data sequence is disclosed in 97197.

This circuit has a circuit including a delay circuit for delaying input data by one cycle of a sampling clock and outputting the same, and a function operation circuit for applying a function f to the input data and outputting the result. By circulating the numerical data through this circulation path, the dynamic system xn + 1 = f (xn)
(N = 0, 1, 2, 3,...), And generates a sequence xn that changes in accordance with (n = 0, 1, 2, 3,.

According to such a chaotic sound source, it is possible to synthesize a musical sound exhibiting an unstable amplitude behavior or a musical sound whose amplitude fluctuates irregularly.

[0006]

By the way, the above-mentioned PC
Although tone generators using M and FM tone generators can generate a wide variety of tones, the demands of users are becoming more diverse and sophisticated, producing more varied and highly expressive tones. There is a need for a device that can do this.

According to the chaotic sound source disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 4-97197, it is possible to generate a musical tone having a chaotic behavior different from the PCM sound source and the FM sound source. However, the circulation path of the chaotic sound source must be configured to process data having a sufficient data length so that data circulating in the circulation path does 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 tone generator capable of generating a variety of tones having a high expressive power which cannot be generated by a PCM tone generator or an FM tone generator.

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

[0010]

According to the present invention, at least one cycle of waveform data is recorded.
A tone generator having a stored waveform memory.
Enter the pitch information of the musical tone to be
Parameter generating means for outputting a parameter;
Where n = 0, 1, 2, 3,...)
Changes according to the difference equation xn + 1 = f (xn)
Generates a phase data sequence by a dynamic system
Phase generating means, wherein the parameter of the function f is
Use the parameters generated by the above parameter generation means
The phase output from the phase generating means.
Read the waveform data from the waveform memory based on the phase data.
Output and output .

[0011]

[0012]

[0013]

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

The chaotic sound source generally has 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 result. The data is circulated through the circulation path to generate waveform data. 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 is also simple. Can produce various waveforms.

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

If a waveform string is read out from a chaotic sound source as a phase data in a waveform memory, a new sound source that has never existed before 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 a first embodiment of the present invention. This chaotic oscillator includes a delay circuit 101, a function generator 102, and a correction circuit 103. These constitute a circulation path 104.

The delay circuit 101 is a delay circuit that delays input data by one period of a sampling clock and outputs the result. The output of the delay circuit 101 is input to a function generator 102. The function generator 102 adds a function f to the input data x.
Is applied to output the output data f (x). The output of the function generator 102 is input to the correction circuit 103. The correction circuit 103 performs a nonlinear conversion (described later) on the input data and outputs the result. The output of the correction circuit 103 is
Enter 1 The output of the correction circuit 103 is output as musical sound waveform data.

Assuming that there is no correction circuit 103, the circulation path 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 sequence generated by such a dynamic system looks like a periodic signal and is random, but rather, it is completely noise-like. It is possible to generate a musical sound waveform signal having such a chaotic behavior.

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

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

FIG. 2B shows a function f (x) for an input x.
= It is an example of a function generator 102 for outputting ^{a2 x 2 + a1 x + b} . For the input x, the multiplier a1 / a
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. A multiplier 214 multiplies the output x ² + (a 1 / a 2) x of the adder 213 by a 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 in FIG. 1 limits the numerical value of data circulating in the circulation path 104 (in other words, limits the amplitude).
Is a circuit that performs nonlinear conversion for performing The data (waveform data) circulating in the circulation path 104 needs to fall within a certain range (here, -1 to 1). However, in the conventional circulation path without the correction circuit 103, chaos
Overflow often occurred in the calculation of the algorithm. Therefore, in this embodiment, the correction circuit 103 performs a non-linear conversion, and performs a numerical limit (amplitude limit).

FIGS. 3A to 3D show the correction circuit 10.
3 shows an example of the amplitude limitation by No. 3. In each example, the input data is numerically limited to a range from -1 to 1.

FIG. 3A shows the input and output of a correction circuit 103 for performing a modulo operation on 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
And the remainder (0 or more and less than q) ".

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

FIG. 3C shows the input and output of the correction circuit 103 by the limiter for limiting the value of the input data. Denoting the input as x and the output as [x] L, this operation is It is expressed as

FIG. 3D shows the input and output of the correction circuit 103 which performs a cosine function operation on the input data. Input x,
If the output is expressed as [x] cos, this cos function operation is expressed as [x] cos = cosπx.

Note that other polynomials and trigonometric functions (tan-1
x), and any function such as a logarithmic function may be used to limit the numerical value. The configuration of the correction circuit 103 that performs such a numerical limitation may use a conventionally known configuration.

When the correction circuit 103 limits the numerical value of 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
It is not necessary to lengthen the processing data length of. In addition, various waveforms can be generated while the function calculation of the function generator 102 remains simple.

Next, an example of a specific oscillating operation of the chaotic oscillator of FIG. 1 will be described with reference to FIGS. In the following, the function f (x) = ax +
2 (a) which outputs the signal b.
As an example, a description will be given of an example using a device that performs the modulo operation of 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 =
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 set to 0 <a <1.0, b> 0, and the graph 401 and the auxiliary line 402 always intersect. 430 shows the intersection. Note that the circulation circuit 1 is controlled by the correction circuit 103.
Since the data xn circulating in 04 always satisfies -1≤xn≤1, the graphs of FIGS. 4 (a) to 8 (a) are shown in that range.

In FIG. 4A, the waveform data x0, x1, x2
, X3,... Are sequentially obtained as follows. First, x1 is determined from the intersection 411 of a straight line parallel to the vertical axis through x0 (here, x0 = 0) and the graph 401. Next, x1 is input and x2 = f (x1)
Is calculated, an intersection 412 between the straight line parallel to the horizontal axis and the auxiliary line 402 is passed through the intersection 411, and x2 is calculated from the intersection 413 between the straight line parallel to the vertical axis through the intersection 412 and the graph 401. Is required. Staircase arrow 420
Indicates that x0, x1, x2,... Are sequentially obtained in this manner.

As can be seen from FIG. 4A, a <1.0,
b> 0 and the graph 401 and the auxiliary line 402 are at the intersection 4
When they cross at 30, the output waveform data sequence x0,
x1, x2,... form a column approaching 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 to b / (1-a). b / (1-
a) is the position coordinates (x coordinate = y coordinate) of the intersection 430.

FIG. 5A shows xn + 1 similar to FIG. 4A.
= F (xn). However, FIG.
In (a), the coefficient a of the function f of the function generator 102 is represented by a =
1.0 and b> 0. 501A is a graph of the function f. Since a = 1.0, a graph 50 of the function f is obtained.
1A is parallel to the auxiliary line 402.

Xn + 1 = f (x in the graph 501A of the function f
In the range of n)> 1 (dashed-dotted line portion 501C), the correction circuit 103 of FIG. 1 (performing the operation of FIG. 3A) performs a modulo operation for limiting the numerical value. Therefore, the graph 501C in this range is (the whole is -1).
It becomes like 501B. In other words, the function generator 10
Assuming that a 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 with the graph becomes the graph of the function g.

In FIG. 5A, similarly to FIG. 4A, the waveform data string x
0, x1, x2,... Arrow 5 in the figure
As can be seen from the trajectory 11, the waveform data strings x0 and x1
, X2,... Increase monotonically at first, and when the value exceeds a predetermined value, the arrow 511 moves to the graph 501B, and the arrow 511 moves to the graph 501A, and monotonically increases again.

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

FIG. 6A shows xn + 1 similar to FIG. 4A.
= F (xn). However, FIG.
In (a), the coefficient a of the function f of the function generator 102 is represented by a>
1.0 and b> 0. 601A is a graph of the function f. Xn + 1 = f (x in graph 601A of function f
n)> 1 (dashed-dotted line portion 601C) is also shown in FIG.
Similarly to the graph 501B of FIG.

In FIG. 6A, similarly to FIG. 4A, a waveform data string x
0, x1, x2,... Arrow 6 in the figure
As can be seen from the trajectory 11, the waveform data strings x0 and x1
, X2,... Increase at an accelerating rate. When the value exceeds a predetermined value, the arrow 611 shifts to the graph 601B, and the arrow 611 shifts to the graph 601A, and increases again at an accelerated rate.

FIG. 6B shows the waveform data strings x0 and x
It is a graph which shows the time change of 1, x2, .... The amplitude value increases at an accelerating rate with the passage of time. When the amplitude value exceeds a predetermined value, the amplitude value suddenly becomes a negative number and increases again at an accelerating rate. By repeating this, the output waveform has a frequency that fluctuates slightly near a certain frequency.

FIG. 7A shows xn + 1 similar to FIG. 4A.
= F (xn). However, FIG.
In (a), a> 1.0 and b> 0, and the graph 7 of the function f
01A and the auxiliary line 402 intersect at an intersection 730.

In the graph 701A of the function f, xn + 1 = f (x
n)> 1 (dashed-dotted line portion 701D) is shown in FIG.
Similarly to the graph 501B of FIG. 7A, the graph 701B is obtained by the modulo operation of the correction circuit 103. Further, xn + 1 = f (xn) <-1 of the graph 701A.
(A dashed line portion 701E) corresponds to the correction circuit 103
Is obtained as a graph 701C.

In FIG. 7A, similarly to FIG. 4A, the waveform data string x
0, x1, x2,... Arrow 7 in the figure
As can be seen from the trajectory 11, the waveform data strings x0 and x1
, X2,... Increase at an accelerated rate at first, and when it exceeds a predetermined value, arrow 711 moves to graph 701B, arrow 711 further moves to graph 701A, and arrow 71 further moves.
1 moves to the graph 701C, and so on.

FIG. 7B shows the waveform data strings x0 and x
It is a graph which shows the time change of 1, x2, .... The amplitude value initially increases at an accelerating rate with the passage of time, and when the amplitude value exceeds a predetermined value, the noise value looks 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 in the graph 801A of the function f (the dashed-dotted line portion 801D) is as shown in the graph 801B by the modulo operation of the correction circuit 103. Further, xn + 1 = f (xn) <-1 of the graph 801A.
(A dashed line portion 801E) corresponds to the correction circuit 103
Is obtained as a graph 801C.

In the same manner as in FIG.
11, a waveform data string x0, x1, x2,... Can be obtained. The waveform data strings x0, x1, x2,... Initially increase at an accelerated rate, and when the value exceeds a predetermined value, the arrow 811 moves to the graph 801B, the arrow 811 moves to the graph 801A, and the arrow 811 further moves to the graph 80.
It moves to 1C, and so on.

FIG. 8 (b) shows the waveform data strings x0 and x
It is a graph which shows the time change of 1, x2, .... FIG.
A graph 801A of FIG. 7A is a graph 701A of FIG.
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 rapidly with the passage of time than in the case of FIG. 7 (b), and when the amplitude value exceeds a predetermined value, like a noise in which positive and negative numbers are disturbed. Become. In a state like noise, the fluctuation width 840 of the amplitude value is the fluctuation width 740 in FIG.
Be larger.

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 an arbitrary value. The initial value may be given to an appropriate position in the circulation path 104 (for example, the delay circuit 101).

4 to FIG. 8 show the function generator 102 of FIG. 1 which outputs a function f (x) = ax + b.
3A is used as the correction circuit 103 using FIG.
This is an example in the case of using the one that performs the modulo operation, but the present invention is not limited to this, and another function operation or correction operation may be used. By using complicated functions and correction circuits, more various waveforms can be output.

The coefficients a and b are not limited to the ranges of the coefficients a and b described with reference to FIGS. 4 to 8, but may be values in another range (for example, when a and b are negative numbers). You may. In this case, the oscillation operation of the chaotic oscillator in FIG.
8 can be obtained in the same manner as described with reference to 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 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 FIG. 4B, and the amplitude value gradually converges to the point C. (I of FIG. 9)
i) shows the case where the coefficient a = 0. At this time, the amplitude value suddenly reaches point c for an arbitrary input. (Iii) of FIG.
Indicates a case where the coefficient a is -1 <a <0. At this time, the amplitude value gradually attenuates to the point C and converges. (I of FIG. 9)
v) shows the case where the coefficient a = -1. At this time, the amplitude value oscillates around the point C. FIG. 9 (iiv) shows the coefficient a <−1.
The case of is shown. At this time, the amplitude value oscillates while increasing its absolute value.

In the first embodiment, the parameters of the function generator 102 shown in FIG. 1 are controlled in real time. The parameters of the function generator 102 are, for example, those shown in FIG.
In the configuration of (a), the coefficients are a and b, and in the configuration of FIG. 2B, the coefficients are a1, a2, and b. By controlling these in real time, it is possible to realize a unique tone color change in which the waveform shape changes stepwise in a plurality of steps.

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

That is, at first, there are many noise components having large fluctuations in the amplitude value (FIG. 8 (b)), gradually becoming noises having small fluctuations in the amplitude value (FIG. 7 (b)). Waveform data having a frequency fluctuating around an appropriate frequency is output (FIG. 6B), and finally becomes waveform data having a substantially constant frequency (FIG. 5B). As described above, it is possible to output waveform data in which the shape of the waveform changes stepwise in a plurality of steps.

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

This electronic musical instrument includes a performance operator 1001, a tone switch (SW) 1002, a detector 1003, a detector 1004, a chaos oscillator 1005, 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.

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

The tone color switch 1002 is a switch for designating the tone color of a generated tone. The user sets the tone SW1
When an operation for designating a tone is performed by using the 002 command, the detector 1
004 detects the designation operation and outputs timbre information. The timbre information includes a volume EG1012, a chaos oscillator 100
5 and chaos EG1013.

FIG. 11 shows a block configuration of the chaotic oscillator 1005. The chaos oscillator 1005 includes the coefficient generator 1
101, adder 1102, multiplier 1103, adder 11
04, delay circuit 1105, and modulo circuit 1106
It has.

An adder 1102, a multiplier 1103, and an adder 1104 correspond to the function generator 102 in FIG.
A linear function operation similar to that shown in FIG. The function is f (x) = ax + b = (aEG (t) + aofs) x + b. a EG (t) is a parameter given from the chaos EG 1013 and is an envelope value that changes according to time t. aofs is an offset value given from the coefficient generator 1101.

The offset value aofs is changed to the envelope value aEG.
(t) to form 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. 4B.

The modulo circuit 1106 corresponds to the correction circuit 103 shown in FIG. The modulo circuit 1106 corresponds to 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 period of the operation clock (sampling clock) φs.

The coefficient generator 1101 includes a detector 1003,
The performance information and timbre 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 timbre and timbre (timbre change) according to the touch or the like is generated.

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

The oscillating operation of the chaos oscillator 1005 in FIG. 11 is basically the same as that described in the first embodiment. The example of the oscillating operation described with reference to FIGS. 4 to 9 can be applied as it is.

The envelope value aEG output from the chaos EG 1013 in FIG. 10 and input to the adder 1102 in FIG.
(t) is, for example, a parameter that changes over time as shown in FIG. 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 is started when a key on the keyboard 1001 is pressed. The envelope value aEG (t) changing as shown in the graph 1301
Is input to the chaotic oscillator shown in FIG. 11, the output waveform data changes according to the change in the coefficient a.
→ FIG. 7 (b) → FIG. 6 (b) → FIG. 5 (b). As shown by a dotted line graph 1302 in FIG. 13A, an envelope in which the peak is held for a predetermined time after reaching the peak can be used.

A graph 1303 in FIG. 13B is an envelope rising gradually. This graph 13
The envelope value aEG (t) changing as shown in FIG.
6B, the output waveform data is changed according to the change of the coefficient a.
(B) → FIG. 7 (b) → FIG. 8 (b).

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

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 audibility, a sound similar to a plosive sound of a voice is likely to be generated.

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

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

In the pre-processing of the input of the hold circuit 1006, L
Since the signal is not passed through a PF (low-pass filter), by performing such a thinning process, a so-called aliasing noise is generated and a change occurs in a spectral component. Thereby, waveform data of a new tone color can be generated. In particular, by increasing the BPF (bandpass filter Q) in the digital filter 1008 at the subsequent stage, it is possible to easily create a kind of so-called TOM-like tone. In addition, similar spectral characteristics are realized using an FIR filter. However, since the waveform changes in the time dimension are different, the timbre (especially the attack part)
Is different.

The output of the hold circuit 1006 is
Enter 007. The volume EG1012 is a key-on signal from the detectors 1003 and 1004, touch information,
And timbre information, and outputs a volume envelope VEG (t) corresponding to these.

The multiplier 1007 includes a hold circuit 1006
Is multiplied by the waveform data VEG (t) and the volume envelope VEG (t) to give an envelope to the waveform data. The output of the multiplier 1007 (waveform data to which an envelope has been added) is input to the digital filter 1008.

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

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

The coefficient generator 1201 has a volume EG1012
Volume envelope VEG (t) and chaos EG10
13, the envelope aEG (t) is input, and based on these, the cutoff frequency and Q
And the mixing ratio in the mixer unit 1203.

The mixer section 1203 includes a filter circuit 120
The output of the HPF, the output of the BPF, the output of the LPF, and the original input waveform data are output from the coefficient generator 1201.
Are mixed at the mixing ratio given by and output.

Referring again to FIG. 10, the waveform data output from digital filter 1008 is
09. The effect circuit 1009 adds the envelope aEG from the chaos EG1013 to the input waveform data.
Various effects are provided based on (t). For example, when reverb is applied, the initial reflection, delay amount, level, reverberation density, reverb depth, and the like may be controlled by the envelope aEG (t). When an effect is applied using a physical model, the loop delay length, the in-loop filter coefficient, the loop reflection coefficient, the attenuation rate, and the like may be controlled by the envelope aEG (t).

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

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

FIG. 14 is a graph similar to FIG. 4 (a). f (x) indicates a function of the function generator 102, and a dotted line 4
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 that the value does not change. In a range where the graph of the function f (x) is above the auxiliary line 402 (that is, a range of xn + 1 = f (xn)> xn),
A value xn + 1 greater than the input xn is output. vice versa,
In a range where the graph of the function f (x) is below the auxiliary line 402 (that is, a 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) (the hatched portion 1401 in the figure) shows the value of the next timing for each value of x. (Time differential value).

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

FIG. 16 shows a block configuration of an electronic musical instrument to which a tone generator according to a third embodiment of the present invention is applied. This is an electronic musical instrument using 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 chaos EG 1606, an adder 1607, a chaos 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, a key code, a key-on signal, and touch information). This performance information includes 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 that shown in FIG.
1 and a detector 1601
3, 1604, the performance information and the wheel operation information are input, and the coefficients aofs, b are output according to them. The chaos EG1606 is the chaos EG10 of FIG.
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. An adder 1607 is similar to the adder 1102 in FIG. 11, and includes an offset value aofs and an envelope value aEG.
(t) is added to form a coefficient a.

The chaos oscillator 1608 corresponds to the multiplier 1103, the adder 1104, the delay circuit 1105, and the modulo circuit 1106 in FIG. That is, the chaos oscillator 1608 receives 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,
The 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. In this embodiment, however, the waveform data (phase data) shown in FIGS.
The parameters a and b are controlled so that many sawtooth waveforms are output as shown in FIG. This is in accordance with the fact that a phase data generator used for a normal waveform memory reading type sound source outputs a sawtooth wave.

The parameter generator 1605 sets the value of the parameter b (and a) according to the input key code. This adjusts the pitch of the generated tone waveform. Further, the parameter generator 1605 controls the value of the parameter b according to the wheel operation information. Thereby, 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.

The FM modulated wave oscillator 1609 and the adder 161
By providing 0, the FM data from the FM modulator 1609 may be added to the waveform data output from the chaos 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
Reference numeral 1612 outputs a volume envelope VEG (t) corresponding to the performance information from the detector 1603. Multiplier 1007
Adds an envelope to the waveform data by multiplying the waveform data from the waveform memory 1611 by the volume envelope VEG (t). The output (waveform data with an envelope) of the multiplier 1007 is output to the D / A converter 16.
The signal is converted into an analog tone signal by 14 and 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 steps according to such parameter values. Such a waveform can be generated. Also, the EG control may be performed so that the time during which the parameter value is within the predetermined range becomes longer, and the time for outputting a waveform in a predetermined waveform shape may be made longer. If the parameters are changed in accordance with the operation information from the manipulators, the timbre change according to the operation of the user can be realized. Furthermore, waveform data output from a chaotic sound source whose parameters are controlled in real time can be read out from a waveform memory as phase data to generate and output waveform data, thereby generating a new musical tone. as a result,
It is possible to generate a variety of highly expressive musical tones that cannot be generated by a PCM sound source or an FM sound source.

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

[Brief description of the 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 illustrating a configuration example of a function generator of a chaotic oscillator.

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

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

FIG. 5 is a diagram 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 of an amplitude value;

FIG. 9 is a diagram showing another example of a temporal change of an amplitude value.

FIG. 10 is a block diagram of an electronic musical instrument to which a tone generator according to a second embodiment of the present invention is applied;

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

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

FIG. 13 is a diagram illustrating an example of an envelope of a chaotic 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 diagram of an electronic musical instrument to which a tone generator according to a third embodiment of the present invention is applied;

[Explanation of symbols]

Reference numeral 101: delay circuit, 102: function generator, 103: correction circuit, 104: circulation path, 1001: performance operator, 100
2 ... tone 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 , 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.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G10H 7/08

Claims (1)

(57) [Claims] 1. A tone generator comprising a waveform memory storing at least one cycle of waveform data , wherein pitch information of a tone to be generated is inputted, and
A phase data sequence by a parameter generating means for outputting the calculated parameters and a dynamical system in which a data value xn at time n (where n = 0, 1, 2, 3,...) Changes according to a difference equation xn + 1 = f (xn). A phase generating means for generating
Parameters generated by the parameter generation means
A those using meter, musical tone generating apparatus characterized by reading output waveform data from said waveform memory on the basis of the phase data outputted from the phase generation means.