JPH0743597B2 - Musical sound generator - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a musical tone generating device effective as a sound source of an electronic musical instrument.

(Prior art and its problems) Conventionally, in the case where a musical tone signal is obtained by storing from the start of sounding of a natural musical instrument to the end of sounding and reading this, a plurality of periodic waveforms to be repeatedly read are provided separately. Prepare multiple cycle waveforms for the rising part,
In some cases, a continuous sound is obtained by reading the rising portion once and then repeatedly reading the repeated portion.

An example thereof is described in JP-A-59-188697.

However, even in the tone generator as described above, a long section may be required from the rise of the tone in order to obtain a stable waveform for the repeated portion, and the capacity of the storage device may be enormous.

(Object of the Invention) An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a musical tone generating device capable of generating a high-quality musical tone signal with a smaller storage capacity.

(Summary of the Invention) The present invention relates to a plurality of cycles of first waveform data including a rising portion at the start of tone generation of a musical sound (A, which will be described later in the embodiment and is the same in the embodiment), and the first waveform data (A) And a second waveform data (B) of a plurality of cycles subsequent to the second waveform data (B) are stored, and the second waveform data (B) is repeatedly read after reading the first waveform data (A). In the musical tone generating device, the first waveform data (A)
Is the waveform data (AW) that starts from the rising edge of the original waveform data and ends at a portion closer to the rising edge than the beginning of the section used for the second waveform data (B). The end portion of the first waveform data (A) includes the end section of the original waveform data (AW) used to create the first waveform data and the end section of the second waveform data (B). , The second waveform data (B) is cut out from a specific section (SW) of the original waveform data, and the beginning part and the ending part are cross-faded to be endless, and any It was cut at the position.

(Embodiment) FIG. 1 is a block diagram of an electronic musical instrument provided with a musical tone generating apparatus according to an embodiment of the present invention.

Waveform data as shown in FIG. 2 (2-5) is stored in the waveform storage device 7, and the waveform data is obtained as follows.

Waveform AW generated by a musical instrument, etc. from the original musical sound waveform in Fig. 2 (2-1) including the rising portion and waveform SW for creating continuous sound
(This waveform SW is discontinuous from the waveform AW as is clear from FIG. 2 (2-1).) And ) Obtain waveforms AW1 and SW1 as shown in FIG. When the waveform SW1 is further cut in the vicinity of the center and connected so that both ends are cross-faded, the waveform becomes that of SW2 in FIG. 2 (2-3) that can be reproduced endlessly. (The method of obtaining the waveform SW2 is a known method and is described in Japanese Patent Laid-Open No. 57-58195.) Therefore, in order to connect the waveform AW1 and the waveform SW2 in a natural state, the waveform SW2 is provided at the beginning. The end portion of the continuous waveform SW2 is modulated into a waveform whose volume gradually increases as shown in FIG. 2 (2-4) and added to the beginning portion of the waveform SW2.

The first waveform data A and the second waveform data are obtained by cross-fading the front end of the waveform having the waveform SW2 obtained as described above and the rear end of the waveform AW1 including the rising portion. The waveform of FIG. 2 (2-5) consisting of B and B is obtained, and the waveform data is stored in the waveform storage device 7 of FIG.

The rising part AW and the continuous part SW can be easily edited by the performer by using a computer having a display device and designating the section. This is
61-45299.

Although the phase is ignored in FIG. 2,
It is better to match the phase especially when overlapping. If the phase becomes opposite, the amplitude at this part will become smaller.

The electronic musical instrument of FIG. 1 which stores the above waveform data will be described.

The CPU 2 detects the operation states of the keyboard and the operator 1.

When it is detected that the keyboard is pressed, the frequency information F corresponding to the key is set in the register A.

The editing of the waveform is performed by displaying the waveform on the display device 3 and using an operator.

The frequency information F is accumulated in the accumulator 6 in a predetermined cycle (the same as the sampling cycle when a waveform is generated),
It becomes the waveform address WA for outputting the waveform amplitude value WS from the waveform memory 7.

As described above, there is an invention described in Japanese Examined Patent Publication No. 59-17838, in which the sampling period is constant and the step width of the address for reading the waveform is controlled according to the key pressing position. According to the present invention, the frequency information F is composed of an integer part and a decimal part, and an interpolation operation is performed according to the value of the decimal part to generate a high quality musical sound.

In the present embodiment, the frequency information F also has a decimal part and the waveform address WA also has a decimal part, but only the integer part acts on the waveform memory to output a waveform.

If the waveform address WA exceeds the final address EA of the waveform, the waveform address is returned to the beginning of the repeated waveform. By the editing operation, the first and last addresses REA and EA of the repeated portion are set in the registers B and C, respectively.

Every time the frequency information F is accumulated, the subtracter 10 changes the waveform address WA to the final address EA stored in the register C.
Subtract. If the subtractor outputs a borrow, it means that the waveform address WA has not yet reached the final address EA. If no borrow is output, it means that the final address has been exceeded, so the accumulator value is cleared,
Value of subtracter and first address of repeated part of register B
REA is added by the adder 9, and this added value is input to the accumulator 6 selected by the selector 5.

Similarly, the waveform of the repeated portion is read out. In the above description, the leading address STA of the rising portion is the leading address of the waveform memory 7.

Pitch Correction When a part of a plurality of waveforms is cut out and repeatedly read out, there are the following problems regarding the pitch.

That is, since the section to be cut out is specified by the address, its value (REA and EA) is an integer value. However, the section to be cut out must be an integral multiple of the tone cycle, and that value is rarely an integer.

As shown in FIG. 3, even if the start point of the segment to be cut out is selected as the address position of the zero cross point, the zero cross point of the end point does not come to the address position. Therefore, the section to be stored in the memory is the integer address D or E, and the pitch is different from the case of reading in the section C originally. There are two methods to prevent this deviation.

(1) A decimal part is provided in the register C (or B).

The integer part of the register C stores the integer address indicating the section D stored in the waveform memory 7, and the decimal part stores the value of the period (CD) corresponding to the decimal address.

(2) Change the frequency information F.

The frequency information F is generated assuming that a cycle of an integral multiple of the waveform is stored in the repeating portion of the waveform memory 7. However, as described above, when there is an error in cutting out the waveform and the pitch changes, the Frequency information F when reproducing waveform data
Is set in advance.

(Effect of the Invention) According to the musical tone generating apparatus as described above, the first waveform data including the rising portion and the second waveform data of the repeating portion are not continuously extracted from the original waveform, and thus the first waveform data is not extracted. In the waveform data and the second waveform data, the original waveform data between the first and second waveform data can be omitted to the extent that the change in tone such as tone color is not noticeable, and the storage capacity can be made smaller than the conventional one. You can

Furthermore, it is an unprecedented musical tone generating device capable of processing musical tones such as changing the timbre of repetitive waveform portions and adding effects.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is
Figure 3 shows the process of editing the waveform stored in the memory.
It is a figure regarding cutting out of a waveform. AW: Waveform including the rising portion SW: Waveform for creating continuous sound A: First waveform data B: Second waveform data

Claims (1)

[Claims] 1. A plurality of cycles of first waveform data (A) including a rising portion at the start of tone generation of a musical sound, and a plurality of cycles of second waveform data (B) following the first waveform data (A). A waveform storage device for storing the first waveform data (A) and the second waveform data (B) are repeatedly read out after reading the first waveform data (A). Is the waveform data (AW) that starts from the rising edge of the original waveform data and ends at a portion closer to the rising edge than the beginning of the section used for the second waveform data (B). The end portion of the first waveform data (A) includes the end section of the original waveform data (AW) used to create the first waveform data and the end section of the second waveform data (B). , Crossfaded The second waveform data (B) is obtained by cutting out a specific section (SW) of the original waveform data, crossfading the beginning portion and the ending portion into an endless shape, and cutting at an arbitrary position. Musical tone generator.