JPS638958Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a musical tone synthesis device used in electronic musical instruments, etc., and more particularly to a device for synthesizing a musical tone of a desired timbre by digital calculation.

A method or apparatus for synthesizing a musical tone of a desired tone by frequency modulation calculation or similar calculation is disclosed in U.S. Pat.
126406) or the specification of JP-A-55-7733. However, the prior art as shown in those prior applications only shows the basic structure of musical tone synthesis using frequency modulation calculations or similar calculations; The means by which this was done had not been fully elucidated.

This idea was made in view of the above points,
It is an object of the present invention to provide a musical tone synthesizing device suitable for synthesizing a predetermined tone, particularly attenuated tones such as a piano, in a device for synthesizing musical tones by frequency modulation calculations. This invention uses a plurality of operators, which are the basic elements for musical sound synthesis calculations, and achieves the above objective by elucidating the combination of operators suitable for synthesizing attenuated sounds such as piano sounds. .

An embodiment of this invention will be described in detail below with reference to the accompanying drawings.

In Figure 1, three operators OP0, OP
2. OP3 are provided in series, and the first stage operator OP0 is a cyclic frequency modulation calculation circuit 10 (hereinafter, frequency modulation calculation is abbreviated as FM).
It consists of First stage operator OP0, that is, cyclic FM circuit 10 and second stage operator OP
An adder 11 is provided between the operator OP1 and the operator OP2, and the adder 11 adds the output signal of the operator OP1 to the output signal of the operator OP0 and provides the result to the operator OP2. Each operator OP
The internal configurations of 0 to OP3 are the same, for example, the second
It looks like the picture.

In FIG. 2, operators OP0 to OP3 include a sine wave table 12, and read out the sine wave sample point amplitude value corresponding to a predetermined phase angle from the table 12 using data given from an adder 13 as an address signal. This operator OP0~
OP3 functions as a basic calculation element for frequency modulation calculation. That is, data indicating the instantaneous amplitude value of a suitable modulated wave signal (temporarily denoted by f(ω _n t)) is applied to one input of the adder 13 via the modulated wave signal input 14, and the other input is supplied with data indicating the instantaneous phase angle of the carrier signal (temporarily denoted by ω _c t) via a carrier phase input 15 and a multiplier 16. The multiplier 16 is provided with a coefficient (temporarily designated k) for controlling the carrier frequency via a carrier frequency control input 17. Therefore,
A value “kω _c t” obtained by multiplying the phase angle data ω _c t given from the input 15 by the coefficient k is input to the adder 13 . With the above configuration, the sine wave table 12
The instantaneous amplitude value sin {kω _c t+(ω _n t)} (1) of a signal obtained by frequency-modulating the carrier wave signal with the modulating wave signal is read out from .

The output of the sine wave table 12 passes through a multiplier 18 and becomes output signals of operators OP0 to OP3. Multiplier 18 is provided with a coefficient for controlling the amplitude of the output signal of sine wave table 12 via an amplitude control input 19 . The amplitude control coefficient externally applied to this input 19 is a coefficient (temporarily denoted as E(t)) that sets the amplitude envelope of the musical tone depending on the purpose of the operators OP0 to OP3.
or a coefficient corresponding to the modulation index (temporarily assume this is I
(t)). When using the output of the operator as a modulated wave signal, the multiplier 18
The coefficient given to represents the modulation index I(t), and when used as a musical tone signal, the coefficient represents the instantaneous value E(t) of the amplitude envelope.

In FIG. 1, the output signal of each of the operators OP0, OP2, and OP3 provided in series, except for the final stage operator OP3, is the modulated wave signal input (the modulated wave signal input) of the next stage operators OP2, OP3. Shift circuit 22 at 14) in Figure 2,
23 respectively. first stage operator
In OP0, that is, the cyclic FM circuit 10,
Its output signal returns to the modulated wave signal input (14 in FIG. 2) of the operator OP0 via the averaging circuit 24 and the shift circuit 20. It is assumed that there is an appropriate time delay between the input and output of operator OP0. No signal is applied to the modulated wave signal input (14 in FIG. 2) of operator OP1. Operator OP1 therefore operates as a mere sine wave generator. Shift circuits 20, 22, 2
3 is to shift the digital value of the modulated wave signal given to each operator OP0, OP2, OP3 by an appropriate amount to the upper digit or lower digit, and the shift amount for each can be varied according to the data S ₀ , S ₂ , S ₃ It's becoming like that. By this shift, the regression rate is controlled in the cyclic FM circuit 10, and the operator
In OP2 and OP3, the modulation index is controlled.

The carrier wave phase input (15 in Figure 2) of each operator OP0 to OP3 is provided with instantaneous phase angle data qF (corresponding to ω _c t in Figure 2) that repeatedly changes in accordance with the frequency of the musical tone to be generated. ) are input respectively. Although a device that generates this phase angle data qF is not particularly shown, it reads out a constant F corresponding to a predetermined frequency in response to a key press on the keyboard, and this number F
A device that regularly accumulates the value "qF" (q is a variable that accompanies the progress of calculation timing) or other well-known devices can be used. Each operator OP
Carrier frequency control input from 0 to OP3 (17 in Figure 2)
Carrier frequency control coefficients k ₀ , k ₁ , k ₂ , and k ₃ are input separately to . Normally, common phase angle data qF is input to each operator OP0 to OP3, but by controlling this according to coefficients _k0 to _k3 , the carrier frequency for each operator can be controlled independently. .

Amplitude coefficients I _{0 (t), I 1} (t), and I 2 (t) corresponding to the modulation index are given to the amplitude control inputs (19 in FIG. 2) of operators OP0, _OP1 , and _OP2 , respectively.
Modulated wave signals used by each operator OP0, OP2, OP3 according to these coefficients I ₀ (t), I ₁ (t), I ₂ (t) and data S ₀ , S ₂ , S ₃ indicating the shift amount The modulation index is set. Final stage operator OP
The amplitude control input 3 (19 in FIG. 2) is given a coefficient E ₃ (t) indicating the amplitude envelope.

In the cyclic FM circuit 10, the frequency-modulated signal is fed back as a modulated wave signal at an arbitrary regression rate, so the harmonic components are abundant, and the lower the harmonic, the higher the level, and the higher the harmonic, the higher the level. It has the advantage that it is possible to synthesize a signal having a highly applicable spectral distribution with a monotonically decreasing tendency, and that the number of overtones can be easily controlled by controlling the regression rate (that is, the shift amount of the shift circuit 20). ing. That is, the shift circuit 20
By increasing the regression rate by controlling the shift amount of
In the output signal of the FM circuit 10, relatively high-order overtone components are enhanced both in number and level, and conversely, when the regression rate is lowered, relatively high-order overtone components are decreased in both number and level. The averaging circuit 24 is provided to prevent the hunting phenomenon of signal amplitude caused by circulation, and is
The average value of the amplitudes of adjacent sample points of the signal inputted to the circuit 24 from 0 is calculated and output.

Now, according to the combination of operators shown in Figure 1, an operation similar to a single nesting (multiple) frequency modulation operation is performed in the series of operators OP0, OP2, and OP3, but the first operator
Since the cyclic frequency modulation calculation is performed in OP0, the same effect as a nesting calculation that is more complicated than a normal single nesting calculation can be obtained. On the other hand, operators OP1, OP2,
If you pay attention to the series of OP3, in this series, 1
A heavy nested frequency modulation operation is performed. Operators OP2 and OP3 are shared by both series, and the outputs of first-stage operators OP0 and OP1 are added together and used as a modulated wave signal, so the nesting frequency modulation calculation is performed using the two modulation terms. will be carried out. Therefore, complex tones can be synthesized. Also,
Output amplitude control coefficient I ₀ of operators OP0 and OP1
(t) and I ₁ (t), it is possible to emphasize one of the nesting sequences by operators OP0, OP2, and OP3 or the nesting sequence by operators OP1, OP2, and OP3, and weaken the other. A rich variety of nesting effects can be obtained using operators.

It is known that the spectral distribution of attenuated sounds such as pianos varies greatly depending on the pitch range, so if each of the two types of nesting series mentioned above is used depending on the pitch range, the device of this invention can be used. Attenuated sounds such as piano or harpsichord can be advantageously synthesized. In one type of nested frequency modulation, when the ratio of the main carrier frequency and the subcarrier frequency is each "1" and the ratio of the modulation frequency is N, the spectral bandwidth is determined by the value of N. . Therefore, this N
The spectral distribution can be changed by controlling the value of . For attenuated sounds such as pianos, for example, the above N is set to about 8 in the low range,
In the high frequency range, it is preferable to set N to about 2 to 3. Therefore, the carrier frequency control coefficients k ₀ to _{k 3} of each operator OP0 to OP3 are, for example, k ₀ =5 to 8, respectively.
Set k ₁ = 3, k ₂ = 1, k ₃ = 1, and the operator
The series of operators OP0, OP2, and OP3 is used for the low range, and the series of operators OP1, OP2, and OP3 is used for the high range. Which series to use more heavily can be controlled using a so-called key scaling method. That is, the lower the tone frequency corresponding to the phase angle data qF is, the larger the coefficient I ₀ (t) is, and the I ₁
By making (t) relatively small, the operator OP0,
OP2 and OP3 series are heavily used. Conversely, as the musical tone frequency becomes higher in the range, the coefficient I ₀ (t) is made relatively smaller, I ₁ (t) is made relatively larger, and the series of operators OP1, OP2, and OP3 is used more heavily. .

Note that the number of operators OP0 to OP3 provided in series is not limited to three, and may be more than three. Furthermore, since the operator OP1 is not required to have a frequency modulation function, a simple sine wave (or predetermined waveform) generator may be used. Also, operator OP0~
Instead of providing OP3 individually, one operator may be used in a time-sharing manner to perform the functions of OP0 to OP3. Moreover, this invention can be implemented not only by hardware logic but also by software processing of a microcomputer.

Note that the cyclic FM circuit 10 may use a plurality of operators to form a cyclic loop. Further, the sine wave table 12 included in each operator is not limited to sine waves, but may store other predetermined waveforms. Furthermore, the shift circuits 22 and 23 can be omitted as appropriate.

As explained above, according to this invention, a musical tone synthesis device having the characteristics of both a nesting type frequency modulation calculation sequence including a cyclic frequency modulation calculation circuit and a normal nesting type frequency modulation calculation sequence can be realized in a small-scale device configuration. This is advantageous when synthesizing attenuated sounds with key scaling characteristics such as piano or harpsichord.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of this invention, and FIG. 2 is a block diagram showing an example of the operator used in FIG. OP0, OP1, OP2, OP3...Operator,
10...Cyclic frequency modulation calculation circuit, 11, 13
... Adder, 12 ... Sine wave table, 14 ...
Modulated wave signal input, 15... Carrier wave phase input, 1
6, 18... Multiplier, 17... Carrier frequency control input, 19... Amplitude control input, 20, 22, 23...
…Shift circuit, f(ω _n t)…Modulated wave signal, ω _c
t, qF...phase angle data, k, k ₀ , k ₁ , k ₂ , k ₃
...carrier frequency control coefficient, I(t), I ₀ (t), I ₁
(t), I ₂ (t)...amplitude coefficient corresponding to the modulation index,
E(t), E ₃ (t)...amplitude coefficient.

Claims (1)

[Claims for Utility Model Registration] 1. A plurality of calculation means for performing a frequency modulation calculation using a modulated wave signal and carrier wave information corresponding to a musical tone frequency, and the output signal of each of the calculation means is transmitted to the next stage. A calculation in which each of the calculation means is provided in series so as to be added as the modulation wave signal of the calculation means, and the output signal of the calculation means in the first stage among the calculation means is returned as the modulation wave signal of the calculation means itself. and a waveform generation means for generating a predetermined waveform signal corresponding to a musical tone frequency, and the output signal of the waveform generation means is added to the output signal of the first stage calculation means in the calculation series to perform the second stage calculation. A musical tone synthesis device characterized in that it is used as a modulated wave signal of a means. 2. The musical tone synthesis device according to claim 1, wherein the amplitudes of the output signal of the waveform generation means and the output signal of the first stage calculation means to be applied to the second stage calculation means can be independently controlled. . 3. The musical tone synthesis device according to claim 2, wherein the amplitudes of the output signal of the waveform generating means and the output signal of the first-stage calculating means are respectively controlled according to the range of the musical tone to be generated.