JPS6353596A - Sound source working for electronic musical instrument - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a sound source processing method for an electronic musical instrument, and particularly to an electronic musical instrument in which the pitch of a musical tone, that is, the frequency, can be freely changed with respect to the elapsed time from the sound generation. This paper relates to a sound source processing method.

(Prior art) For example, the conventional method of changing the pitch while generating a musical tone is to change the sampling rate of the sound source waveform data that is the basis for creating the musical tone, call out the sound source waveform data at a different interval than before, and then change the pitch. Changes in pitch are realized by producing sounds at the same predetermined intervals as the ni7. Alternatively, the sound source waveform data that has been sampled in advance and stored in memory is normally read out and produced at the same intervals, and if the pitch is to be raised, the sound source waveform data is skipped at the desired pitch, and the sound source waveform data is read out at the same predetermined intervals as before. There are methods such as raising the pitch by making sounds.

(Problems to be Solved by the Invention) In the former method of changing the sampling rate of the sound source waveform data that is the basis for creating musical tones, when simultaneously changing the pitch of a plurality of musical tones.

Each instrument must be equipped with an oscillator for the sampling rate, requiring a large investment. Furthermore, the latter method of skipping reading the sound source waveform data at a certain pitch naturally has problems such as the data density of the sound source waveform data at the time of sound generation becoming low and the sound quality decreasing. Furthermore, the sound source waveform data can only be read at pitches that are multiples of integers, making it impossible to create sophisticated and delicate sounds that involve pitch changes.

This invention was proposed in view of the above-mentioned problems, and in particular, by improving the method of reading out sound source waveform data, it is possible to prevent deterioration in sound quality due to pitch changes, and to
The purpose of the present invention is to provide a sound source processing method for an electronic musical instrument that realizes more flexible pitch changes.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention stores a ROM in which a plurality of sound source waveform data are stored in advance, and a counter to which a pitch based on timbre data is added as a ROM address. A sound source processing circuit for an electronic musical instrument, comprising a RAM for selecting a tone, and reading the sound source waveform data from the ROM with a desired pitch change, the ROM address being read from the ROM for tone selection.
Consisting of an M-L address and a ROM lower address for reading sound source waveform data, by using the musical tone selection section of the RAM address as the musical tone selection ROM upper address, all bits of the counter stored in the RAM can be read out as the sound source waveform data. ROM for reading out the sound source waveform data
The sound source waveform data is read by changing the lower address and the upper part of the counter corresponding to four digit bits as the ROM lower address for reading the sound source waveform data in the ROM.

(Function) Starting with a signal from a musical instrument, the RAM address of the musical tone corresponding to the musical instrument among a plurality of musical tones is given to the RAM. As a result, the counter of the tone corresponding to the RAM address is read out from the RAM. Subsequently, the pitch of the tone color data set in advance is added to the counter.

The added counter is stored in the RAM at the same RAM address again.
will be written to. Further, the musical tone selection part of the RAM address is given to the ROM as the upper address of the ROM for musical tone selection, and the lower address of the ROM for reading tone source waveform data and the 4-digit bits of the ROM lower address of the added counter are given. The upper part of the counter is a ROM for reading sound source waveform data.
Given as a lower address. Said musical tone selection ROM
When a ROM address is constituted by the upper address and the lower address of the ROM for reading sound source waveform data and is applied to the ROM, the sound source waveform data of the musical tone at the ROM address is read out. Similarly, pitches are added one after another to the counter in the RAM, and the sound source waveform data corresponding to the ROM address by the counter is read out. The sound source waveform data read out intermittently in this manner is converted into an analog signal, as is well known, and converted into a continuous signal, which is then subjected to processing such as voltage control and amplification before being sounded.

As described above, with this method, the sound source waveform data stored in the ROM can be read out (calculated precisely using a number of digits greater than the number of digits of the 0M address). In other words, the ROM address apparently has digits below the decimal point.

To explain this with a concrete example, in the conventional method, if the pitch to be added to the RAM counter is 2 (16
The Yf source waveform data read out first is data in which the lower 4 bits of the ROM lower address for reading sound source waveform data are (2, 4, 8, 8 degrees...), or , if the pitch is 3 (3, 8, 9, C, ・
...) data.

However, with the method of the present invention, it is possible to read the sound source waveform data from the ROM even when there are digits below the decimal point in the pitch in addition to the integer pitch described above. 2.7, the lower 8 bits of the RAM counter are C2, 7, 4, E,
? , 5, 9. C,...), and the sound source waveform data whose lower 4 bits of the ROM lower address for reading sound source waveform data are (2, 4, 7, 9,...) can be read out. This makes it possible to make fine pitch changes that would otherwise be impossible.

Also, if the pitch to be added to the counter in the ROM is changed over time and the sound source waveform data is read out.

Advanced and delicate sound creation such as vibrato is the turning part.

(Embodiment) An embodiment of the present invention will be described below with reference to the attached drawings. Fig. 1 is a block diagram showing the configuration and processing flow of the present device, which is an embodiment of the present invention, and Fig. Equipment RO
FIG. 3 is a diagram showing an example of the sound source waveform data stored in the ROM; FIG.
The figure shows a storage state of a RAM that stores a counter for reading out the sound source waveform data, FIG. 5 shows an example of how this device is used, and FIG. 6 shows an electrical signal from a musical instrument.
FIG. 7 is a diagram showing a control term $1 voltage signal synthesized with noise etc. based on the voltage change of the electric signal, FIG. 8 is a diagram showing an example of processing of sound source data performed by this device, and FIG. The figure shows the sound source waveform that is finally produced.

This embodiment is for use in percussion instruments such as electronic drums. Figure 5 shows a water bag 211 in which the method of this invention is implemented.
An example of the use of 0 is shown below.

The physical vibrations generated in the striking part of the musical instrument are converted into vibrations of electric signals by the piezoelectric element 12 etc. attached to the musical instrument 11 (FIG. 6).The vibrations of the electric signals are converted by the A/D converter 13. It is converted into a digital signal that conveys the amplitude of the vibration (the strength of the sound).

The digital signal becomes a trigger signal that tells the water bag 2210 to start, and is also sent to the sound source synthesis circuit 15. In the sound source synthesis circuit 15, a control amplification voltage signal is obtained by synthesizing noise and the like based on the digital signal (FIG. 7).

Hereinafter, the sound source processing by the water bag 22to will be explained with reference to FIG. 3rd latch 4
2.8 bit high ROM 50.8 bit low ROM
It consists of a 51.16-bit D/A converter 60, a multiplexer, and a sample hold 70.

The above-mentioned trigger signal is provided to the control WCPU 20. First, the control CPU 20 provides the RAM address of the musical tone corresponding to the stamped musical instrument to the calculation CPU 25 from the first port 21 based on the trigger signal. Further, the control CPU 20 sends the tone data for processing the counter stored at the address to the second port 22 and the third port.
It is given to the arithmetic CPU 25 from the port 23. The calculation C-PU 25 uses the RAM2 based on the RAM address.
7, the corresponding counter is read out and counter calculation is performed.

This process will be explained in detail with reference to FIG.

First, the RAM 27 stores counters that are ROM addresses for each musical tone, arranged in order for each musical tone.
The sound sources of different types of musical tones are processed simultaneously, and the counters are from counter 1 to counter 8. Further, the counter for each tone is divided into a high counter and a low counter. Since the RAM 27 has 8 bits, the counter consisting of a high counter and a low counter has 16 bits. All 16 bits are calculated to designate the lower 12 bits of the ROM address for reading sound source waveform data.

The upper 12 digits of the RAM address from A4 to A15 are common to each tone. The lowest AO distinguishes whether each counter is a high counter or a low counter, and At,
A2 and A3 are tone selection sections g. As can be understood from the figure, the ROM address AO has a high counter of (0).
), the low counter is (1), and the tone selection section g
A1. A2゜A 3 ha, 5'ff l ka (000
), 51ff 2 Ka (OOl), etc., and musical tone 8
Each tone number up to (111) is expressed in binary notation.

The first port 21 for the RAM 27 having the above configuration.
When the RAM address is given to the calculation CPU 25,
The arithmetic CPU 25 determines whether the RAM address is normal or not, and uses AO for this determination. In other words, AO can be used as a flag. In this way, AO becomes (0
), the arithmetic CPU 25 reads the high counter of the musical tone corresponding to the RAM address, and high tone color data corresponding to the high counter is fetched from the second port 22 and added to the high counter. The added high counter is written to the RAM 27 at the original RAM address.

At this time, the decoder 30 is provided with AO from A4 to A15, which are common to each musical tone, among the RAM addresses, and if they are filled normally, the AO is (0) in this case, so the first latch 40 A clock signal 31 is provided.

The high counter thus added is latched into the first latch 40 from its input terminals DO to DI.

Next, rAAOPU25 writes 1 to the FIAM address.
is added and AO is set as (+), which is used as the RAM address of the low counter, and the low counter of the same instrument, which is a pair with the previously read high counter, is read out.

Also, low tone data is taken in from the third boat 23,
The low tone color data is added to the low counter. The added low counter is stored in the RAM of the original RAM address.
27.

As in the case of the high counter described above, the decoder 30 uses the RAM addresses A4 to A1, which are common to each tone.
5 and AO is given, and if it is normally filled, in this case AO is (1), so the clock signal 32 is given to the second latch 41. The added low counter is transferred from the input terminal Do of the latch to the second latch DI.
More latched. The decoder 30 has a third latch 4
A clock signal 32 is also applied to the clock signal 2. Said third latch 42
Among the RAM addresses, At and A are the musical tone selection section g.
2. A3 is the input terminal DO of the corresponding chip.

It is latched from DI and D2.

As mentioned above, the counter to which the pitch is added is RA
Since it is output to the latch at the same time as the write operation to M,
Compared to the conventional method of writing a counter and then reading the counter from the RAM, which is a conventional method of calculation for this type of processing, the calculation time can be reduced by a factor of -1.

This allows for more leeway in arithmetic processing, makes the sampling rate of the sound source waveform smaller than usual, increases the density of the sound source waveform data, and enables sound source processing of better sound quality.

Note that the above-described processing is performed as one subroutine for musical tones 1 to 8. Therefore, a plurality of musical tones can apparently be produced at the same time by receiving the sound source processing by the wooden piece 2210.

On the other hand, the sound source waveform data is stored in the ROM 50.51 as follows. As shown in FIG. 2, the sound source waveform is sampled for a predetermined period of time, and in the case of the illustrated musical instrument 1, the sampled sound source waveform data is changed from (0000) to (
A ROM address up to (OFF) is given. However, for convenience, the figure is shown in hexadecimal notation.

The topmost ROM address (0) is the ROM for musical tone selection.
The upper address G is the upper address, and the lower address (000) to (F
The digits up to FF) are the ROM lower address S for reading sound source waveform data. Note that in order to make the level data of the sound source waveform data data having precise values, the same sound source waveform data is divided into high sound source waveform data and low sound source waveform data. The high sound source waveform data is high ROM5
0, the low FF source waveform data is stored in the low ROM 51.

As can be understood in detail from FIG. 3, the high ROM 50 stores the sound source waveform data of each musical tone, arranging each musical tone in a single incline in the same way as the RAM 27 mentioned above. The same figure is high RO
Although the M50 is shown, the low ROM 51 is also exactly the same.

Also, in FIG. 3, the ROM address is shown in binary notation, so the musical tone selection ROM upper address G in FIG. 1 is A12. A13, A14. Indicated by A15. Here, the musical tone selection section g selects A14. A13. As understood from the 0 diagram of A12, musical tone l is (000),
Musical note 2 is (Got), and musical note 8's (11)
1) is expressed in the same way as the RAM 27. In addition, the ROM lower address S for reading sound source waveform data is from AO to Al.
Consists of addresses up to l, (00000000000
The sound source waveform data from 0) to (111111111111) is stored.

Therefore, as shown in FIG.
And in low ROM51, A15 is common to each sound source (0
), and A12. A13. AI4 is ROM for musical tone selection
In the musical tone selection section g of the upper address G, AO and up to All are used as the ROM lower address S for reading sound source waveform data.

Next, as mentioned above, select A in the tone selection section g of the RAM address.
The process in which sound source waveform data is read from the ROM after I, A2, and A3 are latched by the third latch 42, the high counter by the first latch 40, and the low counter by the second latch 41 will be explained with reference to FIG. do.

As shown in FIG. 1, among the ROM addresses of the high ROM 50 and the low ROM 51, A12. A13. A
14 to AI, A2.
A3 is output from the output terminals Do, DI, and D2 of the third latch 42.

The 8 bits of the high counter are applied from the output terminals Do to D7 of the first latch 40 to the lower addresses A4 to All of the ROM lower addresses S for reading sound source waveform data. The upper 4 bits of the low counter are applied to the lower addresses AO to A3 of the ROM for reading sound source waveform data from the output terminals D4 to D7 of the second latch. In this way, R.O.
M address is configured. Therefore, the counter operation is performed using 16 bits, of which 1 of the upper part U of the counter is used.
Two bits are given as the address S for reading sound source waveform data. That is, the lower 4 of the counter to be truncated.
Bits exist as digits below the decimal point in counter calculations, allowing more accurate counter calculations. Thereby, the pattern changes of the read sound source waveform data can be made more continuous and precise.

Next, the high ROM 50 reads out the high sound source waveform data corresponding to the given ROM address as described above, outputs it from the output terminal DO to D7 of the high ROM 50, and outputs it from the input terminal D8 of the D/A converter 60. Input to 015. Similarly, the low ROM 51 reads the low sound source waveform data corresponding to the ROM address, outputs it from its output terminal DO to D7, and inputs it from the input terminal DO of the D/A converter 60 to D7. As described above, one sound source waveform data is constituted by the high sound source waveform data and the low sound source waveform data, and is converted into an analog signal by the D/A converter 60.

This converted analog signal is distributed to predetermined musical tones by the multiplexer 70 according to the RAM addresses from the output terminals Do, Di, and D2 of the third latch 42 and the addresses of the musical tone selection section g, AI, A2, and A3. Sample hold 70 is performed.

The distributed analog signals are sent to a musical tone synthesis section 15 through a filter 16 for each musical tone and a VCA (Voltag
e Control Amplifier) 17 to synthesize a desired musical tone and output it as a musical tone. As is well known, the filter 16 and VCA 17 have their noise, timbre, attenuation of sound strength, etc. adjusted by external inputs, stamp signals from musical instruments, and the like.

As described above, this device 10 first reads out one sound source waveform data, then new timbre data is added to the counter, and the next sound source waveform data is read out.The pitch as the timbre data is changed every time the counter is calculated. For example, the frequency of the sound source waveform to be generated can be changed over time, making it possible to create various tones.

To explain this processing form by illustrating it with the accompanying drawings, as mentioned above, the electrical signal from the musical instrument (FIG. 6) is sent to the sound source synthesis section 15 after A/D conversion, and based on the voltage change of the electrical signal. A control amplification @voltage signal is created by synthesizing noise, etc. (Fig. 7).Meanwhile, after A/D conversion, a trigger signal is given to this device, and the sound source waveform shown in Fig. 2 becomes the one shown in Fig. 8. The signal is processed so that the frequency changes as time passes (Fig. 8), and is synthesized with the control amplified voltage signal in the sound source synthesis section 15 to produce a sound with the waveform shown in Fig. 9. .

Note that the above-mentioned embodiment is used for percussion instruments such as electronic drums, but it goes without saying that it can be easily applied to keyboard instruments, etc. by preparing a plurality of the devices and adjusting the pitch as a reference. .

(Effects) As illustrated and explained above, according to the present invention, a ROM that stores a plurality of sound source waveform data in advance.

A sound source processing circuit for an electronic musical instrument, comprising a RAM storing a counter to which a pitch based on tone data is added as a ROM address, and reading out the sound source waveform data from the ROM with a desired pitch change, the ROM The address is composed of an upper address of the ROM for musical tone selection and a lower address of the ROM for reading sound source waveform data, and by using the musical tone selection part of the RAM address as the upper address of the ROM for musical tone selection, all bits of the counter stored in the RAM are The upper part of the counter corresponding to the same digit bits as the lower address of the ROM for reading the sound source waveform data is used for reading the sound source waveform data of the ROM.
By simply having the feature that the sound source waveform data is read by giving it as the M lower address, the readout pattern of the sound source waveform data can be changed in various ways and with excellent accuracy. This is because when calculating the ROM address with a counter, the counter calculation can be performed with a larger number of digits than the lower address of the ROM for reading sound source waveform data of the I'lOM address. Therefore, even techniques that require delicateness, such as vibrato, can be performed according to the method of the present invention.

In addition, the RAM counter is set to the RO for reading sound source waveform data.
When giving the M lower address to the ROM, the counter to which the pitch has been added is written to the RAM and latched at the same time and given to the ROM, thereby greatly reducing the time it takes to execute a subroutine for one counter operation. The sampling rate of the sound source waveform data can be made smaller, the density of the sound source waveform data can be increased,
Enables sound source processing with better sound quality.

Therefore, compared to conventional methods, the accuracy of sound creation is greatly improved, and the contribution of the present invention is significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration and processing flow of this device which is an embodiment of the present invention, FIG. 2 is a diagram showing an example of sound source waveform data stored in the ROM of this device, and FIG. R
FIG. 4 is a diagram showing the storage state of the sound source waveform data of the OM.
A diagram showing the memory state of AM, FIG. 5 is a diagram showing an example of the use of this device, FIG. 6 is a diagram showing an electrical signal from a musical instrument, and FIG. FIG. 8 is a diagram showing an example of the processing of sound source data performed by this device, and FIG. 9 is a diagram showing the sound source waveform finally produced. 10...Water bag 21, 20...Control CPU, 25...
- Arithmetic CPU, 27... RAM, 30... Decoder, 40... First latch, 41... Second latch, 42
...Third latch, 50...High ROM, 51...
Low ROM, 60... D/A converter, 70... Multiplexer and sample hold, G... Address for musical tone selection, g... Musical tone selection section, S... Address for reading sound source waveform data, U: Upper part of the counter.

Claims (1)

[Claims] 1. A ROM that stores a plurality of sound source waveform data in advance;
A sound source processing circuit for an electronic musical instrument, comprising a RAM storing a counter to which a pitch based on timbre data is added as a ROM address, and reading out the sound source waveform data from the ROM with a desired pitch change, the ROM The address consists of a ROM upper address for musical tone selection and a ROM lower address for reading sound source waveform data, and by using the musical tone selection part of the RAM address as the musical tone selection ROM upper address, all bits of the counter stored in the RAM can be used as the tone source. Used for reading waveform data,
A sound source of an electronic musical instrument, characterized in that the sound source waveform data is read by providing the upper part of the counter corresponding to the same digit bits as the low-order ROM address for reading sound source waveform data in the ROM as the low-order ROM address for reading the sound source waveform data. Processing method. 2. Transfer the RAM counter to the ROM for reading sound source waveform data.
2. The sound source processing method for an electronic musical instrument according to claim 1, wherein when providing the counter to the ROM as a lower address, the counter to which the pitch has been added is written to the RAM and at the same time is latched and provided to the ROM.