JPH07295573A - Waveform generation device and electronic musical instrument using its output waveform - Google Patents

Abstract

PURPOSE:To provide the waveform generation device which can generate waveform data varying in timbre continuously and naturally before and after a repetition period of a waveform read and generating no noise, and the electronic musical instrument which can obtain more this natural timbre variation by using the processed waveform of the device. CONSTITUTION:The waveform generation device divides a source sound signal into plural bands by harmonics (50), corrects frequency parameters so that variation of parameters of an amplitude, a frequency, etc., decreases gradually to zero from a certain point of time to the start point of the repetitive period, band by band, and the signal is included in the specific repetitive period by integral cycles (51), and recomposes a musical sound signal on the basis of the correction parameters (60). Further, the electronic musical instrument stores the waveform data, processed by the device, in a waveform memory.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveform forming device and an electronic musical instrument for storing a waveform processed by the device in a waveform memory, and more particularly to correction of waveform data when the waveform is repeatedly read from the waveform memory.

[0002]

2. Description of the Related Art In conventional electronic musical instruments, there has been a system in which a musical tone waveform is stored in a waveform memory and the waveform is read out based on performance information such as key-on to generate a musical tone signal. Among these, in order to produce subtle changes in the tone of the attack part immediately after key-on and the decay and sustain parts after that, there is a method of recording the original sound of the instrument from the start to the end of sound generation and storing it in the waveform memory. In this case, since there is almost no change in tone color in the latter half of the waveform, there is a method of saving the capacity of the waveform memory by repeatedly reading the same waveform section after a certain period of time.

[0003]

Generally, the original sound of the musical instrument has a temporal change in both the frequency component and the amplitude component, but in the conventional electronic musical instrument as described above, the period for repeatedly reading from the waveform memory is entered. Then, there is a problem in that the spectrum suddenly disappears, so that it feels unnatural. In addition, if the repeated portion contains anharmonic overtone components, the waveforms will not be connected well, and noise will occur in the repeated portion.

The object of the present invention is to improve the above-mentioned problems of the prior art, and to create waveform data in which the timbre continuously and naturally changes before and after entering the repeating section of the waveform reading and no noise is generated. An object of the present invention is to provide a possible waveform forming device and an electronic musical instrument that can obtain a more natural timbre change by using a waveform processed by this device.

[0005]

SUMMARY OF THE INVENTION The present invention divides an original sound signal into a plurality of bands for each harmonic, and changes in parameters such as amplitude and frequency for each band from a certain point to the start point of a repeating period. A device for gradually reducing the frequency to zero and modifying the frequency parameter so that the signal enters an integer period within a predetermined repeating interval, and resynthesizing the musical tone signal based on the modified parameter, and the waveform processed by the device. The characteristic is the electronic musical instrument that stores the data.

[0006]

According to the present invention, since the original sound is divided into bands and processed by such means, it is possible to accurately control the change of the parameter and arbitrarily control the way of changing the timbre. Therefore, it is possible to create a waveform in which the degree of change of the tone color changes smoothly before and after entering the repeated section, and it is possible to obtain an electronic musical instrument with a more natural tone color change. Furthermore, since the frequency parameter is modified so that the signal enters an integer cycle within a predetermined repeating section, the waveform is continuous during the repeating period and no noise is generated.

Further, if the average value data for parameter correction is generated from different original sounds, for example, musical tone waveforms having different tone colors at the attack portion and the repeated portion can be synthesized with a natural feeling. Furthermore, it was not separated and extracted,
Alternatively, if a tone signal that has not been re-synthesized is extracted from the original tone signal, and the extracted signal is processed so that it fades out up to the repeated portion and then mixed with the re-synthesized signal, a tone sound that is more faithful to the original tone can be obtained. It can occur.

[0008]

Embodiments First, embodiments of an electronic musical instrument to which the present invention is applied will be described. FIG. 2 is a block diagram showing the configuration of an electronic musical instrument to which the present invention is applied. The CPU 1 controls the entire electronic musical instrument, such as well-known key assignment processing and sound generation processing, according to a program stored in the ROM 2. In addition to the control program, the ROM 2 stores various tables, music data for automatic performance, various tone color data, and the like. RAM3
In addition to being used as a work area of the CPU 1, it stores various control data such as a key assignment table and a sound source control information table, and may be backed up by a battery. The keyboard 4 comprises, for example, a plurality of keys each having two switches, and a keyboard interface (not shown) scans the switch of each key under the control of the CPU 1.

The panel 5 is composed of, for example, tone color and rhythm pattern selection switches on the panel, various switches such as a numeric keypad for inputting numerical values, display devices such as LEDs, and a panel interface circuit. As will be described later, the tone generator circuit 6 can generate independent digital tone signals of 16 channels, for example, by time division multiplexing processing under the control of the CPU 1. The D / A converter 7 converts the digital signal output from the sound source circuit 6 into an analog signal. The amplifier 8 amplifies the analog musical tone signal and is emitted from the speaker 9. The bus 10 connects each circuit in the electronic musical instrument. In addition to this, a MIDI interface or the like may be provided.

FIG. 3 is a block diagram showing the configuration of the sound source circuit 6 of FIG. The address generation circuit 20 includes accumulators for channels for accumulating the address interval information corresponding to the pitch of the pressed key set by the CPU 1, for example, the read address of the waveform memory for each sampling cycle. Occur. The address is controlled so that the waveform data in the last predetermined range is repeatedly read. The waveform memory 21 is a ROM or a RAM that stores waveform data formed by the method described later, and stores different waveform data for each tone color and for each pitch range.

The digital filter 22 controls tone color or tone quality under the control of the CPU 1. The envelope generator 24 changes the frequency characteristic of the digital filter 22 with time. Under the control of the CPU 1, the envelope generating circuit 23 generates a musical tone envelope signal corresponding to a tone color and touch information. The multiplier 24 multiplies the output signal of the digital filter 22 by the envelope signal output from the envelope generating circuit 23, and outputs a musical tone signal. The feature of the present invention resides in the waveform data stored in the waveform memory 21.

Next, a waveform forming device for creating data to be stored in the waveform memory will be described. FIG. 4 is a block diagram showing the configuration of the waveform forming apparatus of the present invention. The waveform forming apparatus 30 is an ordinary computer system to which an A / D converter 42 for inputting a microphone signal is added and a program for waveform forming processing is incorporated. The CPU 31 executes various calculations according to programs. Memory 3
2 stores programs and data. The console interface 33 is an interface circuit for the CRT display 34 and the keyboard 35.

The I / O interface 36 is an interface circuit between the computer system and various I / O devices 37 such as a printer, a communication device, and a ROM writer. The disk 38 stores files of programs and data.
The bus 39 connects each circuit in the system. Musical instrument 4
0 is for generating an original sound that is the basis of the waveform data of the electronic musical instrument. The generated original sound signal is converted into an electric signal by the microphone 41 and further converted into a digital signal by the A / D converter 42. It becomes the original sound data.

FIG. 1 is a functional block diagram showing the processing functions of the waveform forming apparatus of FIG. The harmonic separation means 50 is shown in FIG.
Original sound data having a waveform shown in (a) is separated into a plurality of harmonic components. This processing is performed, for example, by first obtaining the frequency and level of each harmonic component from the spectrum of the original sound obtained by FFT (Fast Fourier Transform), etc. This is performed by independently extracting the harmonic components as shown in b). Harmonic processing means 51, 52
Are prepared by the number of extracted harmonics, and each extracted harmonic is independently processed by a plurality of harmonic processing means 51, 52.

The amplitude component extracting means 53 detects, for example, the peak of the amplitude of the harmonic signal and connects them with a line to output amplitude component data as shown in FIG. 7 (c). The frequency component extraction means 54 outputs the frequency component data as shown in FIG. 7D, for example, by obtaining the period from the interval of the zero cross points of the harmonic signal and taking the reciprocal thereof. The average value detecting means 55 and 56 find the average value of the amplitude component and the frequency component in a predetermined range, for example, the range A in FIG. Frequency average value detection means 56
Further determines the frequency (target value) closest to the average value among the frequencies such that the waveform falls within an integer period within a predetermined waveform repeating section. For example, if the length of the repeating section is 1 second, a signal whose frequency is an integer has an integer cycle of the waveform in the repeating period. Therefore, the average value of the frequencies found in the range A is rounded off. Convert to an integer.

Amplitude component correction means 57 is arranged for a predetermined period C.
At (t: v to k), the deviation from the average value of the amplitude component data is gradually reduced, and the amplitude component data is corrected so that it becomes the average value after a certain time (t = k), and FIG. The corrected amplitude component data as shown in is output. The range B in FIG. 7 shows the range in which the waveform is repeatedly read. The processing is expressed by the following equation, where the amplitude component data is a (t), the corrected amplitude component data is a ′ (t), and the average value is A.

A ′ (t) = a (t). (T: 0-v-1).

A '(t) = A + (a (t) -A) * (k
-T) / (k-v). (T: v-k-1).

A '(t) = A.
(T: k-).

The frequency component correction means 58 also gradually reduces the deviation of the frequency component data from the target value in a predetermined period C (t: v to k), and after a certain time (t = k), the target value becomes the target value. Correct the frequency component data so that
The corrected frequency component data as shown in (f) is output.
The process can be expressed by the following formula, where f (t) is the frequency component data, f ′ (t) is the corrected frequency component data, and F is the target value.

F '(t) = f (t).
(T: 0-v-1).

F '(t) = F + (f (t) -F) * (k
-T) / (k-v). (T: v-k-1).

F '(t) = F.
(T: k-).

The waveform synthesizing means 59 re-synthesizes harmonics as shown in FIG. 7 (g) based on the corrected amplitude and frequency component data. The harmonic data can be expressed as C (t)
Then, C (t) = {a ′ (t) * sin (2πf ′ (t) *
t)}. The mixing means 60 mixes the outputs of the respective harmonic wave processing means 51, 52 and outputs the corrected tone waveform data.

In the first embodiment, the waveform is corrected by the above processing so that the change in the parameter gradually decreases from the rising portion to the beginning of the repeated portion. Therefore, in the electronic musical instrument using the waveform, , It is possible to obtain a natural musical sound whose tone color changes smoothly. Further, the frequency of the period B is corrected to the frequency closest to the average value among the frequencies such that the waveform enters an integer period within the predetermined waveform repeating section, so that the waveform does not become discontinuous at the time of repetition, and noise Does not occur.

FIG. 5 is a functional block diagram showing the function of the second embodiment of the waveform forming apparatus. In this embodiment, the average value which is the target value of the repeated portion is obtained not from the original sound data but from another original sound data dedicated to the repeated portion. In FIG. 5, the same numbers are assigned to the same functional blocks as in FIG. The second embodiment differs from the first embodiment in that there is no average value detecting means inside each harmonic processing means 76, and an average value is separately obtained from the original sound data for repeated parts and supplied to the correcting means. It is provided with means 70, 75 for doing so.

The band separating means 70 separates another original sound data dedicated to the returning portion into the same band as the original sound by the same processing as the harmonic separating means 50 for the original sound data. The average value processing means 75 is provided for each separated harmonic, and supplies the average value of the amplitude and the frequency to the corresponding harmonic processing means 76. Amplitude component extraction means 7 in average value processing means 75
1 and the frequency component extracting means 72 both perform the same processing as the amplitude component extracting means 53 and the frequency component extracting means 54 in the harmonic processing means. Further, both the amplitude component average value detecting means 73 and the frequency average value detecting means 74 perform the same processing as the average value detecting means 55 and 56 of the first embodiment.

If the harmonics extracted from the original sound data for the repetitive part include those of an order not extracted from the original sound data, a new harmonic wave processing means is provided to The processing means may synthesize the waveforms based on components in which the amplitude component increases from 0 to the average value in the period C and the frequency component remains the average value. Conventionally, when a plurality of waveforms are combined, a technique such as cross-fade is used. Therefore, when mixed, the waveforms sometimes cause phase interference, which causes an unnatural feeling. However, the method of the second embodiment is used. According to the above, since the harmonics of the same order are not mixed with each other, the above problem does not occur, and for example, the musical tone waveform in which the attack part is the piano and the release part is the strings feels natural. Can be synthesized with.

FIG. 6 is a functional block diagram showing the function of the third embodiment of the waveform forming apparatus. In the third embodiment, a tone signal that has not been separated / extracted or re-synthesized is extracted from the original tone signal, and the extracted signal is processed so that it fades out to the repeating portion and then mixed with the re-synthesized signal. It is something that is done. In FIG.
The same functional blocks are assigned the same numbers. The third embodiment differs from the first embodiment in that an adder 80, a subtractor 81, a fade-out processing means 82,
The mixing means 83 is added.

The adder 80 adds all the output signals of the harmonic separating means 50. The subtractor 81 subtracts the output signal of the adder 80 from the original sound data. Fade-out processing means 8
2 gradually attenuates (fade out) the output signal of the subtractor 81 until the level becomes 0 within the period C of FIG. The mixing means 83 mixes the output signal of the mixing means 60 and the output signal of the fade-out processing means 82. By such processing, it becomes possible to re-synthesize a harmonic component that has not been extracted by the harmonic separation means because the level is low or the frequency is out of the extraction range, and a tone waveform closer to the original sound is obtained. can get.

Next, a modification of the third embodiment will be described.
In this modified example, as shown by the dotted line in FIG. 6, the output signal of the mixing means 60 is used instead of the signal obtained by adding the outputs of the harmonic separation means 50. With such a configuration, although it is extracted in the harmonic separation means 50, an accurate frequency average value cannot be calculated in the harmonic processing means 51, 52 due to, for example, a large level attenuation rate. In addition, the harmonics that could not be synthesized by the waveform synthesizer 59 are also extracted from the original sound and re-synthesized. Also with this modification, a musical sound waveform closer to the original sound can be obtained.

Although the embodiment has been described above, the following modifications are also possible. In the waveform forming device, any method can be used for detecting the amplitude component and the frequency component. For example, the amplitude may be detected (absolute value is obtained) and passed through a low-pass filter. Further, with respect to the detection of the frequency (cycle) component, a method of detecting the cycle of the zero-cross point or the peak point, and obtaining it from an autocorrelation function can be considered. Each function in the functional block diagram does not need to be processed in real time, and each function may be processed one by one.

The ranges A, B, and C in FIG. 7 may be arbitrarily determined, but B (or k) is determined by, for example, the degree of decrease in timbre change and the memory capacity usable as the waveform memory. Further, since the average value of the range A becomes the parameter value of the repeated portion, it may be a predetermined range centered on the k point in consideration of continuity at the k point. For C, without modifying the original sound more than necessary,
And it may be experimentally determined so that the timbre changes smoothly.

Although the third embodiment and its modified example have been disclosed as applied to the first embodiment, they can be applied to the second embodiment as well. In the embodiment, the example in which the parameters of both the amplitude and the frequency are corrected has been described, but only the frequency parameter may be corrected. By adding the function of the present invention to an electronic musical instrument having a sampling function, it becomes possible to compress and store and use the data amount of collected musical tones, thereby reducing the memory capacity.

[0035]

As described above, according to the present invention, since the original sound is divided into bands and processed, it is possible to accurately control the change of the parameters and arbitrarily control the way of changing the timbre. Become. Therefore, it is possible to create a waveform in which the degree of change in tone color changes smoothly before and after the start of the repeating period, and it is possible to obtain an electronic musical instrument in which the change in tone color is more natural. Further, since the frequency parameter is modified so that the signal enters an integer cycle within a predetermined repeating section, there is an effect that the waveform is continuous during the repeating period and no noise is generated.

If the average value data for parameter correction is generated from different original sounds, for example, musical tone waveforms having different tone colors at the attack portion and the repeated portion can be synthesized with a natural feeling. Furthermore, it was not separated and extracted,
Alternatively, if a tone signal that has not been re-synthesized is extracted from the original tone signal, and the extracted signal is processed so that it fades out up to the repeated portion and then mixed with the re-synthesized signal, a tone sound that is more faithful to the original tone can be obtained. There is also an effect that it can occur.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing functions of a waveform forming device.

FIG. 2 is a block diagram showing a configuration of an electronic musical instrument.

FIG. 3 is a block diagram showing a configuration of a sound source circuit 6 shown in FIG.

FIG. 4 is a block diagram showing a configuration of a waveform forming apparatus of the present invention.

FIG. 5 is a functional block diagram showing a second embodiment of the waveform forming apparatus.

FIG. 6 is a functional block diagram showing a third embodiment of the waveform forming device.

FIG. 7 is a waveform chart 1 showing a signal waveform in each waveform forming process.

FIG. 8 is a waveform diagram 2 showing a signal waveform in each waveform forming process.

[Explanation of symbols]

1 ... CPU, 2 ... ROM, 3 ... RAM, 4 ... Keyboard, 5 ... Panel, 6 ... Sound source circuit, 7 ... D / A converter, 8
... amplifier, 9 ... speaker, 10 ... bus 31 ... CPU, 32 ... memory, 33 ... console interface, 34 ... CRT, 35 ... keyboard, 36 ...
I / O interface, 37 ... I / O equipment, 38 ... Disk, 39 ... Bus, 40 ... Musical instrument, 41 ... Microphone, 42
... A / D converter

Claims (7)

[Claims] 1. A band dividing unit that divides a frequency band for each harmonic component of an original sound and outputs a band signal, an amplitude extracting unit and a frequency component extracting unit that extracts an amplitude and a frequency parameter for each band signal, Frequency component average value detection means for detecting an average value of a predetermined range of frequency components, and determining a frequency closest to the average value among frequencies such that the waveform has an integer period within a predetermined waveform repeating section; Based on the output data of the frequency component average value detection means, the first
From the point of time, the deviation from the output value of the frequency component average value detecting means gradually decreases, and after the second point of time, it becomes the output value of the frequency component average value detecting means. A frequency component correcting means, a combining means for combining each band signal using at least the frequency parameter corrected by the frequency component correcting means, and a mixing means for mixing and outputting each combined band signal. A waveform forming device characterized by: 2. Band dividing means for dividing a frequency band for each harmonic component of an original sound and outputting a band signal, and amplitude component extracting means and frequency component extracting means for extracting amplitude and frequency parameters for each band signal. An amplitude component average value detecting means for detecting an average value of the amplitude component in a predetermined range, and a deviation from the average value of the amplitude component from the first time point based on output data of the amplitude component average value detecting means. Gradually decreases and becomes the average value after the second time point. Amplitude component correcting means for correcting the amplitude component of each band signal and an average value of a predetermined range of frequency components are detected, A frequency component average value detecting means for determining a frequency closest to the average value among frequencies such that the waveform enters an integer period in the waveform repeating section; and a first component based on output data of the frequency component average value detecting means.
From the point of time, the deviation from the output value of the frequency component average value detecting means gradually decreases, and after the second point of time, it becomes the output value of the frequency component average value detecting means. A frequency component correcting means for correcting the frequency component, a synthesizing means for synthesizing the respective band signals using the parameters corrected by the amplitude component correcting means and the frequency component correcting means, and a mixing for mixing and outputting the respective synthesized band signals. A waveform forming apparatus comprising: 3. A first band division means for dividing a frequency band for each harmonic component of an original sound and outputting a band signal, and a first amplitude component extraction means for extracting an amplitude and a frequency parameter for each band signal. And a first frequency component extracting unit, a second band dividing unit that, like the first band dividing unit, divides a frequency band for each harmonic component of another original sound and outputs a band signal, Second frequency component extracting means for extracting a frequency parameter for each output band signal of the second band dividing means, and an average value of a predetermined range of output frequency components of the second frequency extracting means is detected, and a predetermined waveform is repeated. A frequency component average value detecting means for determining a frequency closest to the average value among frequencies in which a waveform enters an integer period, and a first component based on output data of the frequency component average value detecting means.
The deviation from the output value of the frequency component average value detection means gradually decreases from the time point of, and becomes the output value of the frequency component average value detection means after the second time point. Frequency component correcting means for correcting the frequency component of, the synthesizing means for synthesizing each band signal using at least the frequency parameter corrected by the frequency component correcting means, and the mixing means for mixing and outputting each synthesized band signal. A waveform forming apparatus comprising: 4. A first band dividing means for dividing a frequency band for each harmonic component of an original sound and outputting a band signal, and a first amplitude extracting means for extracting an amplitude and a frequency parameter for each band signal, A first frequency component extracting means, a second band dividing means for dividing a frequency band for each harmonic component of another original sound, and outputting a band signal, similarly to the first band dividing means, Second amplitude extracting means and second frequency component extracting means for extracting the amplitude and frequency parameters for each output band signal of the band dividing means, and an average of a predetermined range of output amplitude components of the second amplitude component extracting means. An amplitude component average value detecting means for detecting a value, and a deviation from the average value of the first amplitude component gradually decreases from a first time point on the basis of output data of the amplitude component average value detecting means, After the second point, the flat So that the value,
An amplitude component correction means for correcting the first amplitude component of each band signal, and an average value of a predetermined range of the output frequency component of the second frequency extraction means are detected, and the waveform has an integer period within a predetermined waveform repetition section. A frequency component average value detecting means for determining a frequency closest to the average value among the frequencies to be entered; and a first component based on output data of the frequency component average value detecting means.
The deviation from the output value of the frequency component average value detection means gradually decreases from the time point of, and becomes the output value of the frequency component average value detection means after the second time point. A frequency component correcting means for correcting the frequency component of, a synthesizing means for synthesizing the respective band signals using the parameters corrected by the amplitude component correcting means and the frequency component correcting means, and mixing the respective synthesized band signals, A waveform forming apparatus comprising: a mixing unit for outputting. 5. An adding means for adding all output signals of the band dividing means, a subtracting means for subtracting the output of the adding means from a source sound signal, and an output signal of the subtracting means for the second time point. 2. A fade-out processing unit for gradually attenuating the output signal, and a second mixing unit for mixing an output signal of the fade-out processing unit with an output signal of the mixing unit.
The waveform forming device according to any one of items 1 to 4. 6. A subtracting means for subtracting the output of the mixing means from the source sound signal, a fade-out processing means for gradually attenuating the output signal of the subtracting means by the second time point, and an output of the fade-out processing means. A second mixing means for mixing a signal with the output signal of the mixing means.
The waveform forming device according to any one of items 1 to 4. 7. An electronic musical instrument having a waveform storage means for storing a musical tone waveform, and a musical tone signal generating means for generating a musical tone signal by reading the waveform data, wherein the waveform storage means has any one of claims 1 to 6. The output waveform of the waveform forming device according to any one of the above is stored, and the tone generating means is
When the reading reaches the end of the waveform data, the second
An electronic musical instrument characterized by repeatedly reading out waveform data after the point.