JPS6336519B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a musical tone generator for an electronic musical instrument, and more particularly to a musical tone generator capable of generating musical tones similar to natural musical instrument sounds through digital data processing.

Conventionally, a musical tone generating device that generates an addressing signal corresponding to the frequency of the musical tone to be generated, reads a nonlinear conversion memory using this addressing signal, and generates a musical tone has been developed, for example, by
It is known from the publication No. 51-78217.

Although such conventional devices are excellent in that they can produce musical tones with a variety of tones with a simple configuration, they are not sufficient in simulating the sounds of natural instruments and forming musical tones that more closely resemble the sounds of natural instruments. .

In addition, with natural instruments, the player can control not only the intensity of the sound but also the timbre by controlling the operating speed and/or operating pressure of the performance controls such as keys (hereinafter collectively referred to as touch control). However, in the above-mentioned conventional devices, no consideration was given to such touch control.

The first object of this invention is to further improve the prior art to generate musical sounds that more closely resemble the sounds of natural instruments, and the second object is to control the timbre by touch control, for example, on a piano. The aim is to obtain performance effects similar to those of natural instruments.

The first object of the present invention is achieved by a musical tone generator having the following configuration. That is, an address function signal generator that generates a periodic waveform signal corresponding to the frequency of a musical tone to be generated as an address function signal, an address function signal modulator that modulates and controls the address function signal, and an address function subjected to modulation control. a non-linear conversion table memory device from which a musical sound waveform is read by inputting a signal as an address signal, and a conversion function stored in the non-linear conversion table memory device, where x is the address signal and y is the output, y= a ₀ + a ₁ x + a ₂ x ² +
The coefficients a _{0 ,} a ₁ ^, a ₂
... _ak and the modulation control of the address function signal by the address function signal modulation device are set to a predetermined state.

Further, the second object of the present invention is achieved by a musical tone generator having the following configuration. That is, it has a periodic function signal generation means for generating a periodic function signal corresponding to the frequency of the generated musical tone, and a nonlinear conversion table memory, and converts the periodic function signal according to nonlinear conversion characteristics corresponding to the contents stored in the memory. a nonlinear conversion means for converting and outputting a musical sound waveform, and a control means for changing and controlling the nonlinear conversion characteristics of the nonlinear conversion means in response to a touch control signal obtained by detecting the operating speed or operating pressure of a key operation, etc. It is equipped with the following.

Here, if the address signal of the nonlinear conversion table memory device mentioned above is x, and the corresponding output is y, there is generally a functional relationship expressed by y=f(x) (1). However, equation (1) is more approximately y=a ₀ +a ₁ x+a ₂ x ² +a ₃ x ³ +…+a _k x ^k +…
......It can be expressed by the polynomial in (2). The values of the coefficients a ₀ , a ₁ , a ₂ . . . in Equation (2) can be approximately calculated from Equation (1) and Equation (2) once the change range of x is determined.

The value of the address signal x in equation (2) is, for example, a sine function x ₀ = A ₀ sin (ωt + θ ₀ ) (3) (where A ₀ is the amplitude, ω is the angular frequency, t is the time,
θ ₀ is the phase angle).

Substituting equation (3) into equation (2), y=a ₀ +a ₁ {A ₀ sin (ωt+θ ₀ )} +a ₂ {A ₀ sin (ωt+θ ₀ )} ² +... =a ₀ + _k=K0 〓 ^k=1 B _0k sin (kωt+θ _0k ) ......(4), that is, the frequency spectrum of the output y read from the nonlinear conversion table memory device using x ₀ in equation (3) as an address signal is given by equation (4). It will be expressed as In equation (4), k is the harmonic order,
Therefore, k=1, 2, 3,...K ₀ .

By the way, in order to change the frequency spectrum of the output y read out from the nonlinear conversion table memory device, it is possible to change the frequency spectrum of the output y read out from the nonlinear conversion table memory device by, for example, appropriately modulating x ₀ in equation (3) to obtain the address signal x of the memory device. .

That is, depending on the modulator, the amplitude of x ₀ in equation (3)
Modulate A ₀ with modulation signal h ₁ so that A = A ₀ · h ₁ , x ₀
Add the modulation signal D = h ₂ as a bias, and modulate the phase angle θ ₀ of x ₀ with the modulation signal h ₃ to make θ = θ ₀ · h ₃ ,
As a result, an address signal x expressed as x=Asin(ωt+θ)+D (5) can be created. In this case, if the modulation signals h ₁ , h ₂ , h ₃ are each a function of time t, A, D, θ in equation (5)
will change over time.

Substituting equation (5) into equation (2), y=a ₀ +a ₁ {Asin(ωt+θ)+D} +a ₂ {Asin(ωt+θ)+D} ² +... =B ₀ + _k=K 〓 ^k=1 B _k sin (kωt+θ _k ) ......(6), that is, if x in equation (5) is the address signal, the frequency spectrum of the output y read from the nonlinear conversion table memory device is expressed by equation (6). It turns out. In equation (6), k is the harmonic order, so k=1, 2, 3, . . .K.

In this invention, _k=K 〓 ^k=1 B _k sin in equation 6
(kωt+θ _k ) resembles the frequency spectrum of natural musical instrument sounds, the functional form of y=f(x) ………(1) and x ₀ =A ₀ sin(ωt+θ ₀ ) ………(3) are The function form and modulation signals h ₁ , h ₂ , h ₃ , etc. for creating x=Asin(ωt+θ)+D (5) from x ₀ are appropriately selected.

The invention will now be described in detail with reference to embodiments shown in the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, in which 1 is a keyboard circuit, 2 is a frequency information memory, 3 is an accumulator, 4 is an address counter, and 5 is, for example, the above-mentioned x ₀ = A ₀ sin (ωt + θ ₀ ) ......(3) This is an address function signal memory device that stores a sine wave function corresponding to 5 constitutes an address function signal generator.

6 is an address function signal modulation device, and 7 is the above formula (2).
8 is an envelope signal generator; 8 is an envelope signal generator;
9 is an address function signal modulation control device, and 10 is a sound system.

When a key is operated on the keyboard, a signal representing the operated key is output from the keyboard circuit 1 and sent to the conductor 1.
1 to the frequency information memory 2. The frequency information memory 2 outputs a numerical value F corresponding to the pitch of the operating key. In addition, from the keyboard circuit 1, a key-on signal indicating the time when the operating key is pressed and the time when the key is released.
KON and touch control signal TS are output to conductors 12 and 13, respectively. The touch control TS is detected by, for example, providing a known pressure-to-electrical converter, speed-to-electrical converter, etc. to each key.

The numerical value F read out from the frequency information memory 2 is sequentially accumulated in the accumulator 3 at the timing of the clock pulse φ, and from this accumulator 3, the frequency of the clock pulse φ is accumulated.
If f ₀ and the modulus of the accumulator are M, then an overflow pulse with a frequency of f=Ff ₀ /M (7) is generated and output through the conductor 31. As shown in equation (7), this overflow pulse has a frequency f corresponding to the frequency of the generated musical tone, and the memory device 5 uses this frequency f as the sampling frequency.
Read out. That is, overflow pulses are counted by the address counter 4, and the memory device 5 is read out using the parallel output of the address counter 4 as an address. For example, the memory device 5 is 0, 1, 2,...
n,...N-1, and these N
x ⁰ = A ₀ sin2π/N(0), x ⁰ = A ₀ sin2π/N(1), x ₀ = A ₀ sin2π/N(2)...x ₀ = A ₀ sin2π /N(n),...x ₀ =A ₀ s
Suppose that you have memorized the numerical value in 2π/N (N-1). In this case, the modulus of the address counter 4 is designed equal to N,
The count values of 0, 1, 2, . . . , n, . . . N-1 are represented by the parallel outputs of the address counter 4. For example, at time t=0, if the parallel output of address counter 4 is m, then 1/f
Since one pulse is input to the address counter 4 every second, t=1/f, t=2/f,...t=
As time passes as n/f,..., the parallel outputs of the address counter 4 become m+1, m+2,...m+
x ₀ changes as n,... and is read out from the memory device 5
The values of are sequentially A ₀ sin2π/N (m+1), A ₀ sin2π/N (m+2), ...A ₀ sin2π/N (m+n), starting from the initial value A ₀ sin2π/Nm.
... It changes. That is, the address function signal x ₀ read out from the memory device 5, where n is the order of the sample points, can be expressed in the form x ₀ =A ₀ sin2π/N(m+n).

A modulation signal for modulating and controlling the address function signal _x0 is formed, for example, on the basis of the envelope signal ES and/or the touch control signal TS. Envelope signal in electronic musical instruments
Since the method of creating ES is conventionally well known, a general explanation thereof will be omitted, but in the embodiment shown in FIG. 1, in the envelope signal generator 8,
The key-on signal KON from the keyboard circuit 1 is input and predetermined signal processing is performed to generate an envelope signal.
Form ES.

The envelope signal ES and the touch control signal TS are input to the address function signal modulation control device 9, where they are processed and output as a modulation signal for modulating and controlling the address function signal _x0 . As is well known, in natural musical instruments, there is a close relationship between a touch control and the envelope waveform of the musical tone generated in response to that touch control. The modulation signal that modulates and controls the envelope signal ES or touch control signal TS
It may be formed from only one of them. Also,
In the embodiment shown in FIG. 1, the above-mentioned modulation signals are used as envelope signal ES and touch control signal TS
However, in this case, the envelope signal ES formed from the key-on signal KON described above may be modulated by the touch control signal TS to form the modulated signal described above.

In the embodiment described in the previous section, the address function signal is output in the form x ₀ = A ₀ sin2π/N (m + n) and is expressed as a function of the order n of sample points, so the above modulation signal h ₁ , h ₂ , h _3, etc., are also sampled at the same sample point, and it is more convenient to form functions h ₁ (n), h ₂ (n), h ₃ (n) that represent the values at those sample points. .

The shape of these modulation signals h ₁ (n), h ₂ (n), h ₃ (n), etc. in accordance with the shape of the envelope signal ES and/or touch control signal TS depends on the desired shape. Since this is a design problem that should be determined depending on the tone color and the shape of the function stored in the nonlinear conversion table memory device 7, a general explanation thereof will be omitted.

The modulation signal h ₁ (n) output from the address function signal modulation control device 9 is input to the address function signal modulation device 6 via the conductor 91, modulates the amplitude A 0 of the address function signal x 0, and modulates the amplitude A ₀ of the address function signal x ₀ so that A= Let A ₀ =・h ₁ (n). The modulated signal h ₂ (n) is also input to the address function signal modulator 6 via the conductor 92, and applies a bias D=h ₂ (n) to the address function signal x ₀ . Furthermore, the modulation signal h ₃ (n) is input to the address counter 4 via the conductor 93, and modulates the phase angle 2π/Nm of the address function signal x ₀ to obtain θ=2π/Nm・h ₃ (n). do. Note that it is possible to modulate the frequency of the address function signal _x0 with another modulation signal, but this is not shown in FIG.

Therefore, the output of the address function signal modulator 6, that is, the modulated address function signal x, has _the form Represented by a digital number.
The memory device 7 is read out using this modulated address function signal x as an address signal. This memory device 7 stores a nonlinear conversion table expressed by equation (2). Memory device 7
Interpolation is required when reading. In such a case, known interpolation techniques such as linear approximation and quadratic approximation can be used, but their explanation will be omitted here.

The values of A, D, and θ in equation (5) are the modulation signals h ₁ (n), h ₂
(n), h ₃ (n) with time, and is therefore included in the output y read out from the memory device 7 in response to the temporal change in the modulated address function signal x. The values of amplitude B _k and phase θ _k (see equation (6)) change over time, making it possible to simulate the state in which the frequency spectrum of a natural musical instrument changes over time.

The sound system 10 is a device that performs necessary processing on the output read from the memory device 7 and produces musical tones, but since sound systems are well known in the past, a description thereof will be omitted.

Next, an example of a nonlinear conversion table and an example of a modulation signal for modulating the address function signal will be described. In the embodiment shown in FIG. 1, the address function signal modulating device 6 modulates the amplitude and phase of the address function signal and changes its bias, but in order to simplify the circuit, only the amplitude of the address function signal is modulated. Needless to say, it is okay to do so. In the following, in the embodiment described with reference to FIG.
In order to clarify that the desired effect can be obtained even with a simple address function signal modulation device, an example in which the address function signal modulation device is a simple multiplication circuit will be described.

FIG. 2 is a block diagram showing another embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same or corresponding parts. In the embodiment shown in FIG. 2, only the touch control signal TS is input to the address function signal modulation control device 9, and only the modulation signal h ₁ (n) is output. The multiplication circuit 60 in FIG. 2 corresponds to the address function signal modulation device ₆ in _FIG . Performs only multiplication.

3 is a graph showing an example of a function waveform stored in the memory devices 5 and 7 of FIG. 2, in which FIG. 3a shows a sine function stored in the memory device 5; FIG. b shows a nonlinear conversion table stored in the memory device 7. FIG.

4 is a waveform diagram showing an example of a waveform read from the memory device 7 of FIG. 2, and FIG. 5 is a waveform diagram showing an example of a change in the modulated address function signal x that addresses the memory device 7 of FIG. 2. FIG.

The memory device 5 outputs an address function signal x ₀ =8sin2π/16n (according to the numerical example shown in FIG. 3) that changes as shown in FIG. 3a as the order n of the sample points changes, and the multiplication It is input to circuit 60. The modulation signal h ₁ (n)=1, and the multiplier circuit 60
The output of, that is, the modulated address function signal x is x=
x ₀ , the shape of the signal y read out from the memory device 7 using the modulated address function signal x as an address signal can be easily plotted from FIG. It will look like A. Further, when the modulation signal h ₁ (n) = 1/2 and x = x ₀ /2, the output signal y read out from the memory device 7 using the modulation address function signal x as an address.
can be drawn in the same way by drawing a curve of x ₀ /2 in FIG. 3a and from this and FIG. 3b, resulting in waveform B in FIG. 4.

As is clear from comparing waveforms A and B in Figure 4, these waveforms A and B not only have different amplitudes, but also different waveform shapes, and therefore their frequency spectra also differ. .

The modulation signal shown by the dotted line as h ₁ (n) in FIG.
The output of the address function signal modulation control device 9, which is the touch control signal in the embodiment of FIG.
Created from TS. The modulated address function signal x of the multiplication circuit 60 obtained by multiplying the modulated signal h ₁ (n) by the address function signal x ₀ becomes as shown by the solid line x in FIG. It is easy to understand that the waveform of the read output signal y changes sequentially from waveform A to waveform B in FIG.

In the above-described embodiment described with reference to _FIG . The nonlinear conversion table memory device 7 stores the nonlinear conversion table shown in FIG.
It has been experimentally confirmed that the modulation signal h ₁ (n) provides satisfactory results regarding the timbre of musical sounds that change over time.

In the above explanation, an example was explained in which a sine function signal is used as the address function signal x ₀ , but it goes without saying that the address function signal x ₀ may be any appropriate periodic function such as a triangular wave function or a trapezoidal wave function. .

6 is a graph showing another example of the function waveform stored in the memory devices 5 and 7 of FIG. 1 or 2, and FIG. 6 a shows a triangular wave function stored in the memory device 5, FIG. 6b shows a nonlinear conversion table stored in the memory device 7. FIG. 7 also shows the output signal y read out from the memory device 7 by the modulated address function signal x when using the memory devices 5 and 7 storing function waveforms as shown in FIG. FIG. 3 is a waveform diagram showing an example of a waveform.

Waveform A' in FIG. 7 is the waveform of the output signal y of the memory device 7 read out using x = x ₀ (h ₁ (n) = 1) as an address, and is drawn from FIG. 6 a and b. can do. Also, the waveform B' in Fig. 7 is x = 1/2
The waveform of the output signal y of the memory device 7 read out using x ₀ as an address can be drawn from a triangular waveform of x ₀ /2 in FIG. 6a and from this and FIG. 6b. In this case, the waveform A' in FIG. 7 is almost the same as the waveform A in FIG. 4, and the waveform A' in FIG.
B' is different from waveform B in FIG. 4, and the transition from waveform A' to waveform B' is different from the transition from waveform A to waveform B. Therefore, the address function signal x ₀
When changes from a sine function to a triangular wave function, the waveform shape near the attack part of the sound is almost the same, but the way it changes over time changes, so a variety of tone settings are possible.

Note that when the address function signal x ₀ has a simple waveform such as a triangular wave or a trapezoidal wave, the address counter 4 and the address function signal memory device 5 can be replaced with a simple arithmetic circuit. Moreover, without using the frequency information memory 2 and the accumulator 3, the frequency f shown by equation (7) can be calculated by another known method.
It is also possible to generate pulses with the same frequency as . Therefore, it goes without saying that any known address function signal generating device may be used to generate the address function signal.

As is clear from the above description, according to the present invention, the conversion function stored in the nonlinear conversion table memory device is set according to equation (2), and the frequency spectrum of the musical sound waveform as the output of the memory device is natural. Since the coefficients a ₀ , a ₁ , a ₂ ...a _k in equation (2) and the modulation control state of the address function signal are set to resemble musical instrument sounds, for example, when executing the calculation shown in equation (6), A musical sound waveform equivalent to the above can be easily obtained, and this musical sound waveform is substantially the same as that of the harmonic synthesis method, and has the effect of being very close to a natural musical instrument sound. In addition, by performing modulation control according to the touch control signal, it is possible to control the timbre according to the touch of a key with an extremely simple configuration, and it is possible to obtain a performance effect similar to that of a natural instrument such as a piano. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the invention, FIG. 2 is a block diagram showing another embodiment of the invention, and FIG. 3 shows the address function signal memory device of FIG. FIG. 4 is a graph showing an example of a function waveform stored in the nonlinear conversion table memory device; FIG. 4 is a waveform diagram showing an example of a waveform read from the nonlinear conversion table memory device of FIG. 2;
FIG. 5 is a waveform diagram showing an example of a modulated address function signal output from the multiplication circuit of FIG. 2, and FIG. 6 is a waveform diagram showing a function stored in the address function signal memory device and nonlinear conversion table memory device of the present invention. FIG. 7 is a graph showing another example of a waveform. FIG. 7 is a waveform diagram showing an example of a waveform read from a nonlinear conversion table memory device that stores the function waveform shown in FIG. 1...Keyboard circuit, 2...Frequency information memory, 3
...Accumulator, 4...Address counter,
5...Address function signal memory device, 6...Address function signal modulation device, 7...Nonlinear conversion table memory device, 9...Address function signal modulation control device.

Claims (1)

[Scope of Claims] 1. An address function signal generation device that generates a periodic waveform signal corresponding to the frequency of a generated musical tone as an address function signal, an address function signal modulation device that modulates and controls the address function signal, and an address function signal modulation device that modulates and controls the address function signal. a nonlinear conversion table memory device from which a musical sound waveform is read by inputting a controlled address function signal as an address signal, and the conversion function stored in the nonlinear conversion table memory device is such that the address signal is x and the output is y. y=a ₀ + a ₁ x + a ₂ x ² +...a _k x ^k , and the frequency spectrum of the musical sound waveform output from the nonlinear conversion table memory device corresponds to the natural instrument sound. Similarly, the coefficients a ₀ , a ₁ ,
A musical tone generation device for _an electronic musical instrument, characterized in that _modulation control of the address function signal by the address function signal modulation device is set to a predetermined state. 2. In the musical tone generation device for an electronic musical instrument according to claim 1, the address function signal is x ₀
=A ₀・F(ωt+θ ₀ ) (However, F is any function, A ₀
is the amplitude, ω is the angular frequency, t is the time, and θ ₀ is the phase angle)
The address function signal modulation device is expressed as
An electronic device that changes at least one of A ₀ , θ ₀ , ω in the address function signal x ₀ =A ₀ ·F (ωt+θ ₀ ) and a bias D applied to the signal x ₀ Musical tone generator for musical instruments. 3. Periodic function signal generating means for generating a periodic function signal corresponding to the frequency of the generated musical tone, and a nonlinear conversion table memory, which converts the periodic function signal according to nonlinear conversion characteristics corresponding to the stored contents of the memory. nonlinear conversion means for converting and outputting as a musical sound waveform; and control means for changing and controlling nonlinear conversion characteristics in the nonlinear conversion means in response to a touch control signal obtained by detecting operating speed or operating pressure in key operation. A musical tone generator for an electronic musical instrument. 4. In the musical tone generation device for an electronic musical instrument according to claim 3, the control means modulates the periodic function signal in accordance with the touch control signal, and the nonlinear conversion means: A musical tone generation device for an electronic musical instrument, characterized in that the modulation-controlled periodic function signal is input to the nonlinear conversion table memory as an address signal, and the read output of the memory is sent out as a musical sound waveform.