JPH0419797A - Musical sound generating device - Google Patents

Abstract

PURPOSE:To generate a musical sound signal with a complicate higher harmonic spectrum by simple constitution by arranging an amplitude modulator in the circuit loop of an all-pass filter and varying the frequency and waveform of an amplitude-modulated input signal. CONSTITUTION:The device is equipped with a 1st waveform generating means 1 which generates a fundamental musical sound waveform, a 2nd waveform generating means 2 which generates a waveform for varying the spectrum of the fundamental waveform, and an all-pass filter means 4 which gives specific filter characteristics to the output of the 1st waveform generating means 1 and is provided with the amplitude modulator in the circuit loop. The fundamental waveform varies in the component and amplitude of higher harmonics by passing through the all-pass filter 4 and the amplitude modulator provided in its circuit loop. The waveform which is varied in the higher harmonic component and amplitude is circulated in the circuit loop to increase or decrease the higher harmonics of the fundamental waveform. Consequently, large timbre variation is enabled by the simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electronic musical instruments, and more particularly to a musical tone generator capable of arbitrarily generating various musical tone signals.

BACKGROUND OF THE INVENTION In recent years, with the advancement of digital technology, various electric sound generation systems have been proposed, and electronic musical instruments that can produce a wide variety of tones are being considered.

As a conventional technique, for example, Japanese Patent Application Laid-Open No. 52-121313
There is an electronic musical instrument as shown in the publication.

The above electronic musical instrument will be described below with reference to the drawings.

FIG. 6 shows the configuration of a musical tone generating section of a conventional electronic musical instrument.

In FIG. 6, 19 is a flip-flop, 20 is an AND circuit, 21 is a waveform memory 1, and 22 is an addresser.

The operation of the electronic musical instrument configured as described above will be described below.

First, when a key press pulse KD is generated due to an operation such as a key press operation, the flip-flop 19 is set and Q output begins to be output, and the Q output continues to be output from the flip-arrogate 19.
Accordingly, a clock pulse φ having a predetermined period is sent to the addresser 22 via the AND circuit 20.

Next, the addresser 22 outputs addresses at timings according to the sequentially inputted clock pulses φ, and sequentially reads out the waveform data stored in advance from the waveform memory υ21. Here, the waveform data stored in advance in the waveform memory 21 is as shown in FIG. 7, for example.

Furthermore, when the addresser 22 sends out the last bit output, the flip-flop 19 is reset and the waveform memory 2
Reading from 1 ends.

Further, the addresser 22 can be constructed of a counter 23 and a decoder 24, for example, as shown in FIG. 8, and the contents of the counter 23 are cleared by the key press pulse KD before starting counting.

Through the above operations, the desired waveform data is transferred to the waveform memory 21.
Musical tones can be obtained by storing the waveform data in advance in , and sequentially reading out the waveform data according to the addresses output from the addresser 22 .

Problems to be Solved by the Invention However, with the above configuration, waveform data must be stored in advance for each timbre of musical tones to be output, and therefore a large amount of memory is required. Furthermore, in order to expand the degree of freedom in changing the tone color,
1) This can be achieved by simultaneously reading out the Naa Se Catfish Wings and mixing them by changing the mixing ratio between multiple waveforms.
There were problems in that the circuit size had to be large, and the musical tones to be synthesized were limited to changes between mixed waveforms.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a musical tone synthesis device that has a simple configuration (small circuit scale) and enables large timbre changes.

Means for Solving the Problems In order to achieve this object, the musical tone synthesis device of the present invention has the following features:
a first waveform generating means for generating a basic waveform of a musical sound waveform;
A second waveform generating means for generating a waveform for changing the spectrum of the basic waveform, a predetermined filter characteristic is imparted to the output of the first waveform generating means, and an amplitude modulator is provided in the circuit loop. and all-pass filter means.

Effect According to the above configuration, the basic waveform is an all-pass filter,
Amplitude modulators connected within the circuit loop →
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2θ) amplitude changes. The harmonics of the fundamental waveform can be increased or decreased by circulating the harmonic components and the waveform whose amplitude has been changed in a circuit loop.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a block diagram of a musical tone synthesizer according to an embodiment of the present invention.

In FIG. 1, 1 is a first waveform generating section that generates a basic waveform of a musical tone signal, 2 is a second waveform generating section that generates a waveform for changing the harmonic spectrum of the musical tone signal, and 3 is a second waveform generating section that generates a waveform for changing the harmonic spectrum of the musical tone signal.
Amplitude control means for controlling the amplitude of the waveform generated by the waveform generator 2, 4 is an all-bus filter, 5 is a musical tone signal output terminal, 6 and 10 are adders, 7 is a multiplier, 8 and 8
11 to 13.14 are coefficient multipliers that multiply the characteristics of the all-bus filter 4 by coefficients determining the characteristics thereof. Adder 6.10, delay section 8゜9, coefficient multiplication section 11
14 operates as an all-bus filter if the multiplier 7 is ignored and the coefficients of the coefficient multipliers 11 to 14 are appropriately set.

The operation of the musical tone synthesis apparatus configured as described above will be explained below.

The first waveform generating section 1 contains waveform data W that is the basis of musical sound waveforms.
Generates D. For example, it is configured to sequentially and repeatedly read out waveform data stored in a memory at address intervals based on pitch data, and an example of the configuration is shown in FIG.

In FIG. 2, an adder 15 adds the waveform memory skipping width ND corresponding to the pitch specified by a keyboard (not shown) and the latch output data AD. 1θ is a latch, which latches the output of the adder 15 at the timing of the clock φ. Further, the latch 16 is cleared when the key is released by the key press signal KD generated by the keyboard. 17 is a waveform memory including a decoder (not shown), which stores a plurality of waveform data, and the waveform data is stored in the waveform memory 17 using the result of decoding the output AD of the latch 16 as an address.
is read from. The address RA created by the decoder in the waveform memory 17 is the starting address of one waveform data selected by the waveform selection signal WS among the plurality of waveform data stored in the waveform memory 17, and the address RA of the selected waveform data. If the number of samples is SN1, the output data of latch 16 is ADl, and the waveform memory skipping width corresponding to the pitch is ND, then RA=SA+((AD+ND)
MOD SN) However, the decoder is configured so that MOD is a remainder. That is, the first waveform generator 1 obtains a waveform of a desired pitch by repeatedly reading out the waveform data of the selected waveform from the waveform memory 17 at address intervals based on the pitch while the key is pressed. .

Note that although a waveform generation method by reading waveform data has been described in waveform generation, it goes without saying that methods other than waveform reading may be used for waveform generation.

The all-bus filter 4 has phase and time delay characteristics as shown in FIGS. 3 and 4, and these characteristics can be controlled by coefficients A and H determined by the following equations.

A=2cos (2πF)exp'-π"'f3 = 6
X I) l -2πF/Q However, F = turnover frequency The second waveform generating section 2 generates a waveform WM for changing the harmonic spectrum of the musical tone signal, and its configuration is similar to that of the first waveform generating section. 1, but the waveform memory skipping width ND, the waveform selection signal WS, and the start address SA of the waveform data based thereon can be set to different values from those of the first waveform generation section 1. The waveform WM is generated by the adder 6,
The waveform WD generated in the first waveform generating section 1 is used to perform amplitude modulation by the multiplier 7 in the loop of the all-bus filter consisting of the delay section 819 and the coefficient multipliers 11 to 14. In the circuit loop, the waveform WD undergoes amplitude modulation by the waveform WM, and filter processing is performed, thereby changing the spectrum and amplitude of the harmonics of the waveform WD.

Further, the modulation degree of the amplitude modulation is controlled by a signal obtained by adding the waveform WM controlled by the amplitude control means 3 and the DC signal.

Further, if the waveform data whose harmonic spectrum and amplitude have been changed by amplitude modulation in the multiplier 7 is defined as FD, the FD circulates through the circuit loop of the all-pass filter 4, goes through the delay units 8 and 9, the coefficient multiplication units 11 and 13, and the addition unit. After passing through the multiplier 6, the signal is subjected to amplitude modulation by the multiplier 7, and the harmonic spectrum and amplitude change again. In this way, since the waveform data circulates within the circuit loop of the all-pass filter 4, it is possible to obtain a harmonic spectrum spread that cannot be obtained by simply performing modulation.

Changes in the harmonic spectrum are shown based on FIG.

In FIG. 5, (a) shows the spectrum of waveform data generated in the first waveform generating section 1 and the second waveform generating section 2, and both waveforms are sine waves.

The frequency of the waveform data WD generated by the first waveform generator 1 is 1, and the frequency of the waveform data WM generated by the second waveform generator 2 is 2. (b) shows the waveform data WD as a modulated wave,
It shows a frequency spectrum resulting from amplitude modulation using the waveform data WM as a carrier wave. On the other hand, (C) shows the frequency spectrum of the waveform data WM and WD generated by the first and second waveform generators 1.2 synthesized by the musical tone synthesizer shown in FIG. It's a mess. This shows that odd-order harmonics, which cannot be obtained by amplitude modulation alone, are generated.

In addition, (d) is the frequency spectrum when the sine waveform is generated with the frequencies of WD and WM each being 1°3, and (e)
shows the frequency spectrum of the signal obtained by amplitude modulation using these, and (f) shows the signal shown in (d) by W
This figure shows the frequency spectrum of waveform data synthesized by the musical tone synthesizer shown in FIG. 1 when D and WM.

Further, the type and amplitude of the waveform generated by the second waveform generator 2, and the coefficient A of the coefficient multipliers 11 to 14.

By changing B, the harmonic level of the output waveform changes.

As you will see, over time the second waveform generator 2
By changing the amplitude of the waveform generated in (modulation degree in amplitude modulation) and the coefficients A and B of the coefficient multipliers 11 to 14, the harmonic spectrum and the amplitude change over time, that is, the timbre can be changed. I can do it.

Although the above explanation was made using a second-order all-pass filter, it goes without saying that an all-pass filter of any order may be used.

Effects of the Invention As described above, the present invention arranges an amplitude modulator in the circuit loop of an all-pass filter and changes the frequency and waveform of an amplitude modulation input signal, thereby producing a complex harmonic spectrum with a simple configuration. A musical tone signal can be generated.

We also place an amplitude modulator inside the circuit loop of the all-pass filter, which modulates the frequency of the input signal.

By changing the waveform and the coefficients of the all-pass filter, a musical tone signal having a complex harmonic spectrum can be generated with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a musical tone generator for an electronic musical instrument showing one embodiment of the present invention, FIG. 2 is a block diagram of a waveform generator in the same embodiment, and FIG. 3 is a phase characteristic of an all-pass filter in the same embodiment. 4 is a time delay characteristic diagram of the all-pass filter in the same embodiment, FIG. 5 is a frequency spectrum diagram of a synthesized waveform in the same embodiment, FIG. 6 is a block diagram of a conventional musical tone generator for an electronic musical instrument, and FIG. FIG. 7 is a block diagram of the conventional system. Engineering: first waveform generator, 2: second waveform generator, 3: amplitude control unit, 4: all-pass filter, 5: musical tone signal output terminal, 6.10.15.
... Adder, 7... Multiplier, 8, 9... Delay section, 11-14... Coefficient multiplication section, 16...
・Latch, 17, 21... Waveform memory, 18
...Waveform output terminal, 19...Flip-flop,
20...AND circuit, 22...Addresser. Figure No.■ (cL) (Approximately Peng DELAY (9PLset) PHASE (DE6REES) Waist O

Claims (11)

[Claims] (1) A first waveform generating means that generates a fundamental waveform of a musical sound waveform, a second waveform generating means that generates a waveform for changing the spectrum of the fundamental waveform, and an output of the first waveform generating means. 1. A musical tone generating device, comprising: an all-pass filter means for imparting a predetermined filter characteristic to a circuit loop, an amplitude modulator provided in a circuit loop, and performing amplitude modulation using the output of the second waveform generating means. (2) The second waveform generating means can generate a waveform having a different frequency from that of the first waveform generating means, and the frequency of the waveform generated by the second waveform generating means is generated by the first waveform generating means. 2. The musical tone generating device according to claim 1, wherein the musical tone generating device changes according to the frequency of the waveform. (3) The musical tone generating device according to claim 1, wherein the second waveform generating means generates a waveform different from that of the first waveform generating means. (4) The musical tone generating device according to claim 1, wherein the second waveform generating means generates a waveform whose frequency changes with time. (5) The musical tone generating device according to claim 1, wherein the amplitude of the waveform generated by the second waveform generating means is changed over time. (6) The musical tone generating device according to claim 1, wherein the all-pass filter is configured so that the turnover frequency and Q can be changed. (7) The musical tone generating device according to claim 6, wherein the turnover frequency and Q of the all-pass filter means are changed over time. (8) The second waveform generating means can generate a waveform having a different frequency from that of the first waveform generating means, and the frequency of the waveform generated by the second waveform generating means is determined by the first waveform generating means. 7. The musical tone generating device according to claim 6, wherein the frequency varies depending on the frequency of the generated waveform. (9) The musical tone generating device according to claim 6, wherein the second waveform generating means generates a waveform different from that of the first waveform generating means. (10) The musical tone generating device according to claim 6, wherein the second waveform generating means generates a waveform whose frequency changes with time. (11) The musical tone generating device according to claim 6, wherein the amplitude of the waveform generated by the second waveform generating means is changed over time.