JPH0795236B2 - Music synthesizer - 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 tone synthesizer capable of realizing waveform transformation by multi-order multiplication calculation by simple calculation.

[0002]

2. Description of the Related Art Conventionally, waveforms are stored in a waveform memory,
There is known a sound source device of an electronic musical instrument that generates a musical tone waveform by reading this. In such a sound source device, musical tones having tone colors other than the stored waveform cannot be generated.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and the original waveform stored in the waveform memory is easily transformed by a simple operation to generate musical tone waveform signals of various tones. It is an object of the present invention to provide a musical tone synthesizing device that can be performed.

[0004]

A tone synthesizer according to the first invention of the present application has a storage means for storing digital data representing a logarithmic amplitude value of a predetermined waveform and a rate corresponding to a desired pitch. Based on the phase data for reading the waveform, a reading unit that reads the digital data from the storage unit, a multiplying unit that multiplies the digital data read by the reading unit by a predetermined value, and a predetermined multiple by the multiplying unit. Conversion means for performing logarithmic linear conversion of digital data so as to correspond to the logarithm of the logarithm, and a waveform signal whose waveform is transformed by a multi-order multiplication operation according to the predetermined multiple is output from the conversion means. It is what

A tone synthesizer according to a second aspect of the present application is a storage means for storing digital data representing a logarithmic amplitude value of a predetermined waveform, and a waveform for reading the waveform at a rate corresponding to a desired pitch. Reading means for reading the digital data from the storage means based on phase data;
Multiplying means for multiplying the digital data read by the reading means by a predetermined number; specifying means for specifying a predetermined phase section in which the phase data is within a predetermined value range based on the phase value indicated by the phase data; Control means for controlling the multiplier in the multiplying means to be different between the predetermined phase section specified by the means and another section; and the logarithm of the digital data multiplied by the predetermined multiplication by the multiplying means so as to correspond to the true logarithm. A conversion means for performing linear conversion, wherein a waveform signal which is waveform-transformed by a complex multi-order multiplication operation according to the predetermined multiple different according to the phase section is output from the conversion means. is there.

[0006]

According to the first aspect of the invention, the storage means stores digital data representing a logarithmic amplitude value of a predetermined waveform,
The multiplication means multiplies the digital data read from the storage means by a predetermined value. When the function of the predetermined waveform stored in the storage means is f (x), the logarithmic expression is log [f (x)], and the predetermined multiple in the multiplication means is m, the multiplication result is m · lo.
g [f (x)]. When this is subjected to logarithmic linear conversion by the conversion means, the digital waveform data obtained by the conversion becomes equation 1 and the original predetermined waveform function f (x) stored in the storage means.
Is a waveform function of m. In this way, a waveform function deformed according to a multi-order multiplication operation can be obtained by simply multiplying the waveform data read from the storage means by a predetermined number and subjecting this to logarithmic linear conversion.

[Equation 1] Therefore, according to the first aspect of the present invention, it is possible to easily perform the waveform transformation of the original waveform by the multi-order multiplication operation, and the degree can be easily changed by changing the predetermined multiple m in the multiplication. Since it can be changed, it has an excellent effect that various waveforms can be modified to synthesize musical tone waveform signals having various tones.

Further, according to the second invention, based on the phase value indicated by the phase data for reading the digital data from the storage means, a predetermined phase section in which the phase data is within a predetermined value is specified, Control is performed so that the multiplication factor in the multiplication means is made different between the specified phase section identified by this and other sections. Therefore, the multiple m of the predetermined multiple is different between the specific phase section and the other section, and the waveform function shown in the equation 1 obtained by the logarithmic linear conversion is different between the specific phase section and the other section. Becomes
As a result, it is possible to obtain a complex waveform signal formed by combining different waveforms in a specific phase section and another section. Therefore, according to the second aspect of the present invention, when the waveform is transformed easily by the multi-order multiplication operation of the original waveform, the order of the multi-order multiplication operation is made different between the predetermined phase section and the other phase section. As a result, it is possible to perform more complicated waveform transformation, and to synthesize musical tone waveform signals of a wider variety of tones.

[0008]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows an operator unit OP having a waveform changing function according to an embodiment of the present invention.
It shows U. This operator unit OPU
Is provided inside an electronic musical instrument or other musical tone synthesizer and is used to generate a musical tone waveform signal. This operator unit OPU is provided with a waveform table 92 as a storage means for storing digital data representing the logarithmic amplitude value of a predetermined waveform, and the phase table is used as the phase data for reading the waveform at a desired pitch frequency. The angle data x is input from another circuit (for example, the phase data generation circuit 41 as shown in FIG. 6), and the phase angle data x
Based on the above, the digital waveform data of logarithmic expression is read from the waveform table 92, and the waveform changing process is performed on the waveform before and after the reading.

In the example shown in FIG. 1, the operator unit OPU is roughly divided into two waveform changing functions. One is a function of performing a waveform change process by controlling the phase angle data (read address data) by the shifter 90 in the pre-reading stage (for convenience,
This is referred to as a first waveform changing function. The other is a function of performing the waveform changing process by controlling the read waveform data by the shifter 93 and the logarithmic linear converter 94 in the subsequent stage of the reading (for convenience, The second
Waveform change function). The latter, that is, the second waveform changing function corresponds to an embodiment of the invention according to this application.

The operator unit OPU shown in FIG.
As for the details, first, the phase angle data x is input to the shifter 90, and the phase angle data x is shifted by the shift amount instructed by the phase shift data ASFT given from the waveform control unit 91 to the upper bit side or By shifting to the lower bit side, the phase angle data kx whose one cycle is multiplied by k is extracted. However, k is the power of 2 ± j, that is, Equation 2, j is the shift amount instructed by the data ASFT, + j is the shift to the upper bit side, and −j
Indicates a shift to the lower bit side. Next, the phase angle data kx is input as an address signal to the waveform table 92 in which the sine waveform data is stored as logarithmic value log sinx, and the sine waveform data of log sin kx is read from the waveform table 92. As a result, the first waveform changing function is realized.

[Equation 2]

Next, the sine waveform data log sinkx read from the waveform table 92 is input to the shifter 93, and the waveform shift data D supplied from the waveform control unit 91.
By shifting to the upper bit side or the lower bit side by the shift amount designated by SFT, the sine waveform data lo
Change g sinkx to waveform data m · log sinkx. Here, m is 2 to the power of ± i, that is, Equation 3, i indicates the shift to the upper bit side, and −i indicates the shift to the lower bit side. This ± i is indicated by the data DSFT. Next, the waveform data m · log sinkx is input to the logarithmic linear converter 94 and converted into logarithmic or natural number waveform data, as shown in Equation 4. That is,
When the shift amount ± i in the shifter 93 is, for example, i = 1 (when the output of the waveform table 92 is shifted by 1 bit to the upper bit side or the lower bit side), sink
Waveform data of the square of x, that is, Equation 5, or the square root of sinkx, that is, √ (sinkx) is obtained. As a result, the second waveform changing function is realized.

[Equation 3]

[Equation 4]

[Equation 5]

Next, this waveform data (that is, equation 4) is input to the gate 96 via the selector 95, and only the specific phase section in which the control signal / INH supplied from the waveform control section 91 is "1" is output. Furthermore, the sign data SD of the positive and negative polarities given from the waveform control unit 91 is added to the waveform data of the specific phase section (that is, the equation 4) and is output to the outside. Here, the phase shift data ASFT, the waveform shift data DSFT, the select control signal SEL of the selector 95, the control signal / INH, and the code data SD are controlled to be different according to the tone color selection signal TC. The phase angle data kx output from the shifter 90 is selected by the selector 95 for the specific selected tone color.
It is output via the gate 96.

Therefore, for example, the waveform shift amount ± i instructed by the DSFT is +1, the phase shift amount ± j instructed by the ASFT is 0, the phase section in which the control signal INH is “0” is π to 2π, and the selector is When 95 is in the A input selection state (the output of the logarithmic linear converter 95 is selectively output) and the code data SD is positive in the phase section of 0 to π, the waveform of the equation 6 is obtained as shown in FIG. Data is only acquired during the phase interval 0 to π.

[Equation 6] Further, by setting the data ASFT and the like output from the waveform control unit 91 as shown in Table 1 below, for example,
Waveform data having a waveform shape as shown in FIG. 2B is obtained.

[0014]

[Table 1]

Further, to give some examples, by setting the data ASFT and the like output from the waveform control section 91 as shown in Tables 2 to 5 below in correspondence with a predetermined phase section, FIG. Waveform data having a waveform shape as shown in (c) to FIG. 2 (f) is obtained.

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

[0019]

[Table 5]

As can be understood from the above example, by appropriately setting the data ASFT, DSFT, etc. output from the waveform control unit 91 in correspondence with a predetermined phase section, a waveform having a waveform shape corresponding to various timbres can be obtained. The data can be combined in the operator unit OPU. Therefore, such an operator unit OPU can be used to generate a musical tone signal having a complicated waveform shape, and this can be used as a modulated wave function or an arithmetic operator for generating a modulated wave function of a musical tone synthesizer by frequency modulation calculation. If it is used, it is possible to generate a modulated wave function or a modulated wave function with a complicated waveform shape.
A musical tone waveform signal having a complicated characteristic can be realized relatively easily.

Next, the operator unit OPU of FIG.
A configuration example of a frequency modulation calculation type or amplitude modulation calculation type musical tone synthesizer that can be used as a modulated wave function generator or a modulated wave function generator will be described. FIG. 3 is a block diagram showing an embodiment of a frequency modulation (hereinafter abbreviated as FM) operation type musical tone synthesizer, which is roughly classified into a modulated wave function generating section 10, a modulated wave function generating section 20 and a modulated wave. An adder 30 for performing phase modulation of a carrier wave is provided. In the modulating wave function generating section 10, the sine wave table 11 outputs the sine waveform data in accordance with the modulating wave phase angle data ωmt.
The sinωmt is read out, and this is multiplied by the modulation index data I (t) by the multiplier 12 and output as modulated wave data. In the adder 30, the modulated wave data I (t) · sin ωmt output from the multiplier 12 is added to the carrier phase angle data ωct.
Are added to perform phase modulation of the carrier wave.

The modulated wave function generator 20 outputs the phase angle data θ of the phase-modulated carrier wave output from the adder 30.
A predetermined modulated wave function is generated according to (= ωct + I (t) · sin ωmt), and the tone signal G is output based on this modulated wave function. In the embodiment of FIG. 3, the operator unit OPU can be applied to the modulated wave function generator 20, and a waveform changing process corresponding to the first waveform changing function is performed.

That is, the modulated wave function generator 20 comprises a shift circuit 21, a control circuit 22, a sine wave table 23, and a multiplier 24, and the phase angle data θ of the carrier wave inputted from the adder 30 is the shift circuit. At 21, the predetermined number of bits is shifted to the upper bit side or the lower bit side. The shift direction and shift amount in this case are determined by the control circuit 2
0 is designated by the phase shift data SFT, and the phase shift data SFT is the phase angle data θ.
Is output only in a specific phase section in one cycle of. Further, the specific phase section in which the phase shift data SFT is output is changed according to the tone color selection signal TC. Therefore, if the shift amount to the high-order bit side is + j and the shift amount to the low-order bit side is −j, the phase angle data θ is multiplied by k in the specific phase section of one cycle (where k is the number 2). ).

[Equation 2]

Phase angle data θ obtained by multiplying the specific phase section by k
′ Is input to the sine wave table 23 as an address signal. When the phase angle data θ ′ is input to the sine wave table 23, the sine wave data sin θ ′ of the sine wave phase corresponding to the phase angle data θ ′ is read.

To simplify the explanation, the phase angle data θ
4 is a data that simply increases as shown in FIG. 4A (when θ = ωct), the control circuit 22 controls the tone color selection signal TC while the phase angle data θ changes from “0 to 2π”. In accordance with the above, for example, as shown in FIG. 4B, j = 0, j
The phase shift data SFT of +1 is output. As a result, from the shift circuit 21, as shown in FIG.
In the phase section up to 2π, the phase angle data θ ′ obtained by doubling the original phase angle data θ is output. As a result, from the sine wave table 23, as shown in FIG. 4D, one cycle of the sine waveform data sin instead of the half cycle of the sine waveform data indicated by the broken line in the phase section from π to 2π.
θ ′ is read.

That is, in the specific phase section within one cycle of the original phase angle data θ, the sine waveform data sin θ ′ having a different waveform shape from the remaining phase sections is read. The sine waveform data sin θ ′ read from the sine waveform table 23 in this manner is supplied to the multiplier 24, where the amplitude coefficient data A (t) is multiplied to perform amplitude setting control. It is output as a musical tone signal G. This tone signal G contains many harmonic components because the waveform shape of the sine waveform data sin θ ′ read from the sine wave table 23 is changed in a specific phase section as shown in FIG. 4D. Therefore, as shown in FIG. 5, a complex frequency spectrum is exhibited. Therefore, it is possible to obtain a musical tone signal containing a large number of harmonic components with a simple configuration without performing a complicated polynomial modulation calculation.

By the way, the parameters ωmt, I (t), ωct, TC, A (t) used in this embodiment are
Is given by a circuit as shown in FIG. In FIG. 6, a keyboard circuit 40 detects a key pressed by a keyboard of an electronic musical instrument and outputs key pressing data. Phase data generation circuit 41
Generates modulated wave phase angle data ωmt and carrier wave phase angle data ωct that change in a cycle corresponding to the pitch of the pressed key according to the key pressing data given from the keyboard circuit 40. On the other hand, the envelope generator 42 generates the modulation index data I (t) and the amplitude coefficient data A (t) that sequentially change in response to the key-on signal KON generated when the keyboard circuit 40 presses the key. . These phase data generation circuit 4
1 and envelope generator 42 include tone color selection circuit 4
The tone color selection signal TC is given from 3 to control the frequency ratio of ωct and ωmt and the waveform shape of the time function of I (t) and A (t) according to the selected tone color.

In the embodiment of FIG. 3, the phase angle data θ is changed by shifting the phase angle data θ to the upper bit side or the lower bit side by a predetermined number of bits. As described above, the bit inhibit circuit 25 is provided in place of the shift circuit, and, for example, the lower 3 bits of the phase angle data θ input to the bit inhibit circuit 25 in the specific phase section according to the tone color selection signal TC is transmitted. A control circuit 26 for generating a control signal INH for prohibiting the above is provided, and for example, the control signal INH is generated only in a specific phase section from "π to 2π" in one cycle "0 to 2π" of the phase angle data θ. And then "π-2π"
In the phase section up to, the lower 3 bits of the phase angle data θ may be changed to “0”. In this case, the sine waveform data sin θ ′ read from the sine wave table 23 has a waveform shape that changes stepwise in the phase section from “π to 2π” as shown in FIG. The signal G can be obtained.

Although the operator unit OPU is applicable to the modulated wave function generator 20 in the above description, the operator unit OPU is applicable to the modulated wave function generator 10 instead. With this configuration, the waveform changing process corresponding to the first waveform changing function may be performed. That is, the modulating wave function generator 10 is configured as shown in FIG. 9, and the modulating wave phase angle data ω
mt is the phase shift data SFT output from the control circuit 14 in the shift circuit 13 according to the tone color selection signal TC.
According to the above, the modulation wave phase angle data ωmt ′ is changed by shifting the upper bit side or the lower bit side by a predetermined number of bits, and the changed modulated wave phase angle data ωmt ′ is input as an address signal of the sine wave table 11. As a result, a modulated wave function including many harmonic components can be generated.

In this case, the shift circuit 13 and the control circuit 14 may be replaced with the configuration shown in FIG. Further, both the modulating wave function generating unit 10 and the modulated wave function generating unit 20 are configured so that the operator unit OPU can be applied, and perform a waveform changing process corresponding to the first waveform changing function. Good. Further, if the output waveform data of the sine wave table 11 in FIG. 3 is fed back to the input side as shown by the broken line and the phase angle data ωmt is modulated by this output waveform data, the musical tone signal G having a more complicated harmonic component is generated. Can be obtained. Furthermore, the control signals SFT, INH generated from the control circuits 22, 26, 14 may be changed in their generation conditions not only in accordance with the tone color selection signal TC, but also in accordance with an envelope waveform signal which changes over time. .

FIG. 10 is a block diagram showing an example of an amplitude modulation (hereinafter abbreviated as AM) operation type musical tone synthesizer. The modulated wave function generator 50 has the operator unit OPU.
Is applicable, and a waveform changing process corresponding to the first waveform changing function is performed. That is, the modulated wave function generator 50 includes the shift circuit 51 and the control circuit 5.
2, the sine wave table 53, and the phase angle data ωct of the carrier wave is transmitted to the control circuit 5 in the shift circuit 51.
It is changed by shifting a predetermined number of bits to the upper bit side or the lower bit side according to the phase shift data SFT output according to the tone color selection signal TC and the phase angle data ωct from 2. Then, the changed phase angle data ωct ′ is input as an address signal of the sine wave table 53.

As a result, the sine waveform data sinωct ′ corresponding to the phase angle data ωct ′ is read from the sine wave table 53. In this case, the phase angle data ωct is changed in the specific phase section of the one cycle and input as the address signal of the sine wave table 53. Therefore, from the sine wave table 53, the same as shown in FIG. A modulated wave function having a complex waveform shape is generated.

On the other hand, the modulating wave function generator 60 for modulating the modulated wave function has a sine wave table 61, a multiplier 62 and a cosine wave table 63, and the modulating wave phase angle data ωmt is a sine wave table. When input as an address signal to 61, sine waveform data sinωmt corresponding to the phase angle data ωmt is read from the sine wave table 61. The sine waveform data sinωmt is multiplied by the modulation index data I (t) in the multiplier 62 and then supplied to the cosine wave table 63 as an address signal. As a result, the cosine waveform data cos {I (t) .sin from the cosine wave table 63 is generated.
ωmt} is read. This cosine waveform data cos {I
(t) · sin ωmt} is supplied to the multiplier 70 as a modulation wave function and is multiplied by the modulated wave function to perform amplitude modulation calculation. The output of the multiplier 70 is the multiplier 80
Is output to the post-tone signal G whose amplitude setting is controlled by being multiplied by the amplitude coefficient data A (t).

Therefore, also in this embodiment, since the modulated wave function itself already contains many harmonic components, the finally obtained musical tone signal G also contains many harmonic components. In this embodiment, too, if the modulated wave function is changed by the same configuration as shown in FIG. 7, it is possible to generate a musical tone signal containing more harmonic components. Further, the operator unit OPU can be applied only to the modulated wave function generator 60,
That is, the waveform changing process corresponding to the first waveform changing function may be performed, or the modulated wave function generator 50 may be used.
This may be applied to both.

In the examples of FIGS. 3 to 10, the waveform changing function in the function generating section to which the operator unit OPU can be applied is shown as only the first waveform changing function, but these parts are not shown. It is obvious that if the operator unit OPU shown in FIG. 1 is completely applied, not only the first waveform changing function but also the second waveform changing function can be applied to these modulation operation type musical tone synthesizers. is there. Thus, by using the operator unit OPU shown in FIG. 1 as a modulated wave function generator or a modulated wave function generator, it is possible to generate a musical tone signal having a waveform shape that changes more complicatedly. In this case, the modulated wave function or the modulated wave function can be selectively generated only by changing the phase angle data x input to the operator unit OPU, so that the modulated wave function and the modulated wave function can be easily provided by a common circuit. There is an advantage that it can be generated and the cost can be reduced.

The circuit for the above-mentioned waveform changing function is
It is needless to say that the present invention can be applied not only to FM and AM modulation calculation consisting of terms, but also to a musical tone synthesizing device using a polynomial or multiplex or cyclic FM and AM modulation calculation formula at an appropriate position. Further, dedicated waveform tables may be used to generate the modulated wave function and the modulated wave function, respectively, but one function may be used to generate each function by time division. Further, the waveform table is not limited to the sine wave, but may store cosine wave, triangular wave, rectangular wave, and other complex waveform data. Further, the modulation calculation is not limited to digital calculation, but may be analog calculation. Further, the control circuits 22, 26, 1
The generation conditions of the control signals SFT and INH generated from 4, 52 may be sequentially changed with the lapse of time from the time when the musical tone is generated.

[0037]

As described above, according to the present invention, the waveform function read out from the storage means is simply multiplied by a predetermined number and is linearly logarithmically converted, and the waveform function is transformed according to the multi-order multiplication operation. Can be obtained, and its order can be easily changed by changing a predetermined multiple in the multiplication. Therefore, the waveform can be variously modified to synthesize musical tone waveform signals having various tones. it can,
It has an excellent effect. Further, according to the present invention,
Since the multiple of the predetermined multiple can be different between the specific phase section and the other section, the waveform function obtained by the logarithmic linear conversion is different between the specific phase section and the other section. As a result, it is possible to obtain a waveform signal of a more complicated and diverse timbre, which is formed by combining different waveforms in a specific phase section and other sections.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an operator unit for generating a musical tone waveform having a waveform changing function according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing some examples of the shapes of function waveforms obtained by the waveform changing function of the operator unit of FIG.

FIG. 3 is a block diagram showing an application example of the operator unit in an FM arithmetic tone synthesizer.

FIG. 4 is a diagram showing an example of output waveforms of respective portions of FIG.

5 is a diagram showing an example of a frequency spectrum of a musical tone signal obtained in the example of FIG.

6 is a block diagram showing an example of a circuit for generating various calculation parameters used in FIG.

7 is a block diagram showing another example of a portion for changing phase data in the embodiment of FIG.

8 is a waveform chart for explaining the operation of the circuit of FIG.

FIG. 9 is a block diagram showing an application example of the operator unit in a modulated wave function generator.

FIG. 10 is a block diagram showing an application example of the operator unit in an AM operation type musical sound synthesizer.

[Explanation of symbols]

 OPU operator unit 90,93 shifter 91 waveform control unit 92 waveform table storing waveform data in logarithmic representation 94 logarithmic linear converter 10,60 modulated wave function generator 20,50 modulated wave function generator

Claims (5)

[Claims] 1. Storage means for storing digital data representing a logarithmic amplitude value of a predetermined waveform, and phase data for reading the waveform at a rate corresponding to a desired pitch based on the digital data from the storage means. Read-out means for reading the data, multiplying means for multiplying the digital data read by the read-out means by a predetermined number, and conversion means for performing logarithmic linear conversion of the digital data predetermined by the multiplying means so as to correspond to the antilogarithm of logarithm And a waveform signal whose waveform is transformed by a multi-order multiplication operation according to the predetermined multiple, is output from the converting means. 2. The musical tone synthesizing apparatus according to claim 1, wherein the multiplication means shifts the read digital data to a higher bit or a lower bit by a predetermined bit. 3. Digital data from the storage means based on phase data for reading the waveform at a rate corresponding to a desired pitch, the storage means storing digital data representing a logarithmic amplitude value of a predetermined waveform. And a multiplication means for multiplying the digital data read by the reading means by a predetermined value, and a predetermined phase section in which the phase data is within a predetermined value range is specified based on the phase value indicated by the phase data. Specifying means, control means for controlling the multiplier in the multiplying means to be different between the predetermined phase section specified by the specifying means and another section, and the digital number obtained by multiplying the digital data by the multiplying means by a predetermined logarithm And a conversion unit that performs logarithmic linear conversion so as to correspond to the above, and by a complex multi-order multiplication operation according to the predetermined multiple different according to the phase section. Musical tone synthesizing apparatus characterized by shape modified waveform signal is outputted from said converting means. 4. A musical tone synthesizing apparatus, characterized in that introduction means is provided for introducing a modulation signal into the phase data, and the predetermined section is determined based on the phase value of the changing phase data. 5. A musical tone synthesizing apparatus, wherein the digital data converted by the converting means is introduced into a frequency modulation arithmetic circuit as a modulated wave signal for frequency modulation arithmetic.