JPH06250662A - Generating method and memory for waveform data - Google Patents

Abstract

PURPOSE:To reduce the capacity of the memory. CONSTITUTION:The waveform data which are stored in the waveform memory 30 and period in correlativity like beats, the murmur of a stream, a rain sound, etc., are divided into three at every 200msec, the respective waveform data are multiplied by a window function and added, and the sum data are stored in a composite waveform memory 45 having storage capacity for 200msec. When the data are reproduced, the processes are repeated to read the data out. The data have no discontinuous point, so that an effect sound which has no sound skip, etc., can be reproduced at the time of the repetitive data reproduction. The capacity of the composite waveform memory 45 suffices for only the capacity for 200msec of each of the data blocks 31-33, so while a tremolo feeling is reduced, the storage capacity of the composite waveform memory 45 is greatly reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to applause, river murmuring,
The present invention relates to a waveform data generation method and a waveform data memory suitable for reproducing a sound having a correlative period such as a rain sound as a sound effect.

[0002]

2. Description of the Related Art Conventionally, various methods have been used to generate a waveform of a musical sound or the like. As one of them, for example, in Japanese Patent Laid-Open No. 61-99193, a plurality of sets of waveforms having a plurality of cycles are stored in advance, and these are sequentially switched and read in an appropriate order to generate a tone signal. A musical tone signal generating device is disclosed.

That is, as shown in FIG. 1, when a pitch is designated by the keyboard 1, a key depression detecting circuit 2 detects a depressed key and a key code KC corresponding to the detected depressed key.
Is output. The key-depression detection circuit 2 also outputs a key-on signal KON indicating the duration of key depression and a key-on pulse KONP indicating the start of key depression.

The note clock generation circuit 3 generates a note clock signal NCK having a frequency corresponding to the pitch of the pressed key based on the key code KC, and the address counter 4 outputs an address signal AD for reading the waveform memory 5. To do. The waveform memory 5 stores waveform data of a plurality of waveform sections sampled from the original musical tone signal for each tone color type. The data length of each of these waveform sections is arbitrary.

The reading sequence control means 6 sequentially switches and specifies the waveform section to be read from the waveform memory 5, and outputs a start address designating signal SAD for designating one waveform section to be read.
Start address designation signal SAD and address counter 4
The address signal AD from is added by the adder 7, and the addition output is given to the address input of the waveform memory 5. With this addition output, the absolute address of each sample point of one waveform section to be read is specified, and the waveform data of the sample point stored at the specified address is read from the waveform memory 5.

A random numerical value signal RBN generated from a random numerical value generator 8 for randomly selecting a waveform section is input to a latch circuit 9, and a key-on pulse KONP is input to a reset input R of the latch circuit 9. So
When the key is pressed, the reset value of the latch circuit 9 is latched every time the latch control input L is input, and the random numerical value signal RBN input at that time is latched and output as the bank (storage area) number BN. In addition, data of a data length corresponding to one set of waveform data is selected in accordance with the tone color selection information TC provided from the tone color selection circuit 12, and data of one waveform section corresponding to the bank number BN which is address-input is selected from the data. The length is selectively read.

The read data length signal DL is used in the comparator 1.
3 is compared with the address signal AD applied to one input of the other input 3 and compared with the address signal AD applied to the other input, and when the values of both inputs match, a signal is output from the coincidence output EQ, to the latch control input L of the latch circuit 9, and It is supplied to the reset input R of the address counter 4 via the circuit 14.

The start address memory 11 stores in advance the start address of each waveform section for each tone color type, and the start address corresponding to one set of waveform data is selected according to the tone color selection information TC. The start address of one waveform section corresponding to the bank number BN to which the address is input is selectively read.

The read start address is input to the adder 7 as a start address designating signal SAD. Since the latch circuit 9 is reset when the key-on pulse signal KONP is generated, the bank number B is initially set.
N is zero, and the waveform section of the attack part of the musical sound is designated.

On the other hand, the address counter 4 starts counting the note clock signal NCK after being reset by the key-on pulse signal KONP, and the address signal AD
Is sequentially increased from zero. Each time the reading of one waveform section is completed, the next waveform section is randomly selected and read. The envelope generator 16 generates an envelope signal which maintains a constant level during key depression and attenuates with a predetermined decay characteristic after key release in response to the key-on signal KON.

According to the tone signal generator having such a configuration, the same waveform is not read out repeatedly,
The generation of periodic noise can be eliminated.

Further, Japanese Patent Publication No. 63-67196, for example, discloses a waveform generating method in which a time change is freely generated by interpolation calculation of a plurality of waveforms to produce a natural-sounding voice or musical sound. .

That is, as shown in FIG. 2, the memory 2 in which the waveform generators 20 and 21 store a plurality of types of waveforms.
Generate a waveform based on the sample waveform from 4, 25,
It outputs to the multipliers 26 and 27. In the multipliers 26 and 27,
The window functions from the window function generators 22 and 23 are supplied, and the waveforms from the waveform generators 20 and 21 are multiplied by the window function and output to the adder 28. The envelope from the envelope generator 29 is added to the output of the adder 28 by the multiplier 29a.

In such a waveform generating method, since the window function switches a plurality of waveform types at zero value or substantially zero value, the sound of the natural musical instrument is accompanied by the generation of extra noise. It is possible to synthesize without.

[0015]

However, in the above-mentioned conventional tone signal generator, the original waveform data is used as it is as the waveform data. Therefore, even if the waveform data of the short section is repeatedly read, there is a limit to the reduction of the memory capacity.

The present invention has been made in consideration of such a situation, and in view of the characteristics of the target sound, the memory capacity is reduced by minimizing the waveform data to be reproduced. It is an object of the present invention to provide a waveform data generation method and a waveform data memory capable of performing the above.

[0017]

According to the waveform data generating method of the present invention, original waveform data of a predetermined period is equally divided into a plurality of parts, and a window function for fading in from the starting point of the predetermined period and fading out at the ending point is multiplied and added. It is characterized in that the waveform data is generated thereby. The waveform data memory of the present invention stores the waveform data obtained by equally dividing the original waveform data of a predetermined period into a plurality of parts, multiplying by a window function that fades in from the starting point of the predetermined period and fades out at the end point, and adds. It is characterized by being

[0018]

In the waveform data generating method and the waveform data memory of the present invention, the original waveform data for a predetermined period divided into a plurality of equal parts are multiplied by a window function that fades in from the start point of the predetermined period and fades out at the end point, and is added. By repeatedly reproducing the obtained waveform data, a sound having a period of correlation is generated.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 3 shows a waveform data generating apparatus according to an embodiment of the waveform data generating method of the present invention.
A waveform memory 30 for storing data of sounds having a correlative period such as river murmuring and rain sounds is provided. The waveform stored in the waveform memory 30 is, for example, 44.1.
By sampling at a sampling frequency of kHz and dividing into 200 msec,
The data blocks 31 to 33 are divided into three data. Incidentally, in the waveform memory 30 in the figure, analog waveforms are shown instead of digital waveforms for convenience of explanation.

The address pointers 34, 35, 36 controlled by the controller 37 are provided corresponding to the data blocks 31-33 of the waveform memory 30, and the address from these address pointers 34, 35, 36 causes The waveform data in the waveform memory 30 is sequentially read with the read timing being controlled.

The multipliers 38, 39 and 40 are used for the waveform memory 3
0 corresponding to the data blocks 31 to 33, the waveform data from each of the data blocks 31 to 33 is multiplied by the window function generated by the envelope generators 41, 42, 43 and output.

The outputs of the multipliers 38, 39 and 40 are added by an adder 44 as will be described later and then stored in a composite waveform memory 45 which is a waveform data memory of a ring-shaped memory. The storage capacity of the composite waveform memory 45 is 200 msec which is the division period of the above data blocks 31 to 33.
It is said to be minutes. The reading of the waveform data stored in the synthetic waveform memory 45 is performed according to the address of the address pointer 46 controlled by the controller 37.

Next, a method of generating waveform data by the waveform data generator having such a configuration will be described with reference to FIG. First, as shown in FIG.
The original waveform stored in 3 is divided into three data blocks 31 to 33 at intervals of 200 msec.

Next, the address pointers 34, 35, 3
6, the waveform data stored in the data blocks 31 to 33 are sequentially read by controlling the address and the read timing. The sequentially read waveform data of the data blocks 31 to 33 are sent to the corresponding multipliers 38, 39 and 40, respectively. Each multiplier 38,
39 and 40 are given window functions from the corresponding envelope generators 41, 42 and 43, and the respective multipliers 38, 39 and 40 are based on the respective window functions, and the respective data blocks 31 to 33. Multiply the data from.

As shown in FIG. 4B, the window function here is faded in from the starting point of the first data block 31 for a predetermined period corresponding to each sample point of the waveform data, and the final data block 33. Is a continuous function that fades out at the end of. When multiplied by such a window function, the waveform data of each of the data blocks 31 to 33 becomes a waveform that fades in from the starting point and fades out at the ending point, as shown in FIG.

The data multiplied by the respective multipliers 38, 39, 40 are added by the adder 44. That is, as shown in FIG. 5, from time t1 to time t, which is a 200 msec period for each data block.
The respective data (a) to (c) in 2 are added in a state where the time t1 and the time t2 are matched. At the time of this addition, the peak value a1 in FIG. 4 (a) and the peak value a2 in FIG. 4 (b) are continuous, and the peak value b1 in FIG. 4 (b) and the peak value in FIG. Since b2 is continuous, the data levels of the read start time t1 and the read end time t2 after addition are continuous. The 200 msec data thus added is stored in the ring-shaped composite waveform memory 45 in accordance with the address instruction of the address pointer 46.

When reproducing data, the composite waveform memory 45
The data added for 200 msec is repeatedly read. At this time, as described above, since the data level of the read start time t1 and the read end time t2 after addition are continuous, no sound skipping occurs during repetitive data reproduction, and the effect sound is natural. It will be played in a normal state. Further, generally, a sound that fades in and out in a short time, for example, if the waveform shown in FIG. 4 (c) is simply repeated, it sounds like a perfect tremolo.
In the present invention, the waveforms are equivalently overlapped with a time difference, and the tremolo feeling is reduced.

As described above, the capacity of the composite waveform memory 45 is 200 for one block of the data blocks 31 to 33.
Since msec is sufficient, the storage capacity of the composite waveform memory 45 is significantly reduced.

FIG. 6 shows another embodiment in which the configuration of the waveform data generator of FIG. 3 is changed. As shown in the figure, the waveform data generating device is provided with two waveform data memories, ie, synthetic waveform memories 45 and 45A. The storage capacity of the composite waveform memory 45 is the same as above.
It is set to 200 msec. Further, the synthetic waveform memory 45A has a capacity of 177 msec.

That is, as shown in FIG. 7A, the composite waveform memory 45 has two divided waveform memories 30.
The waveform data for every 00 msec is multiplied by the window function generated by each of the envelope generators 41, 42 and 43, and the sum of the waveform data thus multiplied by the adder 44 is stored for 200 msec. . On the other hand, in the composite waveform memory 45A, as shown in FIG. 7B, the window functions generated by the four envelope generators in the same manner as described above are applied to the waveform data for every 177 msec divided into four in the waveform memory 30. 177 ms after the multiplication and the addition of the waveform data multiplied by the adder 44
It is stored for ec.

Further, these composite waveform memories 45, 45A
Is stored in the address pointers 46, 46A controlled by the controller 37.
Are circulated and read according to the addresses of, and are added by the adder 47 and output.

In the waveform data generating apparatus having such a configuration, since the storage capacities of the respective synthetic waveform memories 45 and 45A are different, the cycle of the tremolo phenomenon is different. If the ratio of the storage capacities is not set to a simple integer ratio, the data read positions of both composite waveform memories are complicatedly displaced, so that the periodic tremolo feeling is further reduced as compared with the above embodiment.

In each of the above embodiments, the waveform data in the composite waveform memories 45 and 45A are each 200 msec.
The case where the period is divided into three and the 177 msec period is divided into four has been described, but the present invention is not limited to this. However, if the number of divisions is too large or the period of the waveform data is too short, the characteristics of the original sound are lost from the waveforms to be stored in the synthetic waveform memories 45 and 45A, and the noise approaches the white noise. It is reproduced in the same way,
In addition, it is preferable to set the range so as not to increase the storage capacity.

The waveform data generating method of the present invention can be implemented by a DSP, and in this case, reading of data from each data block and multiplication with a window function can be performed by time division. Further, the waveform data generated by the waveform data generating method of the present invention is RAM, ROM
It can be recorded on a recording medium or other recording medium and used.

[0035]

As described above, according to the waveform data generating method and the waveform data memory of the present invention, the original waveform data for a predetermined period divided into a plurality of equal parts are faded in from the starting point of the predetermined period and then terminated. The window function that fades out is multiplied and the waveform data obtained by addition is played back repeatedly, so it is possible to play voice data that has a correlation such as applause with the minimum required waveform data. It is possible to reduce the memory capacity while reducing the above.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional tone signal generator.

FIG. 2 is a block diagram showing a conventional waveform generation method.

FIG. 3 is a block diagram showing a waveform data generation device according to an embodiment of the waveform data generation method of the present invention.

FIG. 4 is a diagram showing a waveform data generation method by the waveform data generation device of FIG.

5 is a diagram showing a data addition method by the waveform data generation device of FIG.

FIG. 6 is a diagram showing another embodiment when the configuration of the waveform data generation device of FIG. 3 is changed.

7 is a diagram showing two combined waveform memories with different storage capacities shown in FIG. 6;

[Explanation of symbols]

 30 waveform memory 31-33 data block 34, 35, 36, 46, 46A address pointer 37 controller 38, 39, 40 multiplier 41, 42, 43 envelope generator 45, 45A composite waveform memory

Claims (2)

[Claims] 1. A waveform, wherein original waveform data for a predetermined period is equally divided into a plurality of parts, and waveform data is generated by multiplying and adding a window function that fades in from a starting point of the predetermined period and fades out at an ending point. Data generation method. 2. The waveform data obtained by equally dividing the original waveform data of a predetermined period into a plurality of parts and multiplying by a window function that fades in from the starting point of the predetermined period and fades out at the ending point and is added is recorded. Characteristic waveform data memory.