JPH04260099A - Musical sound generating device - Google Patents

Abstract

PURPOSE:To offer the musical sound generating device which can easily be constituted at low cost by reading loop waveform data for generating a sustain sound and a one-shot waveform through a common circuit. CONSTITUTION:This device consists of a waveform memory 8 stored with musical sound waveform data consisting of a single read section where musical sound waveform data extracted to optional length from the rising part of a musical sound is stored and a repetitive read section where musical sound waveform data which generates a zero-level output is stored, a read means which consists of an adder 20 and an address calculating circuit 21 and reads the musical sound waveform data out of the memory 8 in the order of the single read section and repetitive read section, an interpolating circuit 24 which generates a musical sound according to the read musical sound waveform data, a waveform generating circuit 25, an envelope generating circuit 26, and a multiplier 27.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to, for example, a synthesizer,
Regarding musical tone generators used in electronic musical instruments such as electronic pianos, electronic organs, and single keyboards, one-shot waveform readout is particularly important for sound sources that adopt a waveform readout method that generates musical tone signals by reading musical waveform data from a waveform memory. The present invention relates to a musical tone generating device which performs the following in a simple manner.

0002

2. Description of the Related Art Conventionally, musical tone generators (sound sources) used in electronic musical instruments and the like are equipped with a waveform memory that stores a plurality of musical waveform data corresponding to various tones. Then, from this waveform memory, a musical sound signal is generated by selecting musical waveform data corresponding to the tone specified by, for example, a panel switch, etc., and reading this at a speed corresponding to the pitch specified by the keyboard. Sound is emitted by supplying a musical tone signal to an acoustic circuit.

[0003] In such a musical tone generator, since the capacity of the waveform memory is limited, musical waveform data corresponding to each tone color is stored only to a predetermined length. That is, as shown in FIG. 7, for example, the musical waveform data stored in the waveform memory is composed of waveform data A that is read out only once from the beginning of the musical waveform data, and loop waveform data B that is repeatedly read out. The loop waveform data B is specified by an address on the waveform memory at which reading should start (loop top address LT) and an address on the waveform memory at which reading should end (loop end address LE).

[0004] There are two reading methods for reading out such musical waveform data from the waveform memory and producing sound: ``normal reading'' and ``alternate reading.''

In normal reading, as shown in FIG. 7(a), first, waveform data A and loop waveform data B are successively read once from the beginning of musical waveform data (in the figure,
After reading to the end, only the loop waveform data B is read out repeatedly in the same direction (indicated by ■, ■ in the figure).
,...). As a result, a sustained musical tone signal is generated.

On the other hand, alternate reading is performed as shown in FIG. 7(b).
), first, waveform data A and loop waveform data B are read out once in succession from the beginning of the musical waveform data (indicated by ■ in the figure), and after reading to the end, loop waveform data B is read out. (indicated by ■, ■, ... in the figure). As a result, a sustained musical tone signal similar to that described above is generated.

[0007] Through such processing, it is possible to faithfully reproduce the complex and subtle sounds included in the rising part of a musical sound (part A of the waveform data), and to create a musical waveform with fewer sounds in the continuing part (part B of the loop waveform data). The data can be used to generate sounds, and the data can be compressed.

By the way, in such a musical tone generator, in addition to producing sustained tones as described above, there are many cases in which the musical sound waveform data stored in the waveform memory is read out only once and produced (such as this). This method of reading musical waveform data is hereinafter referred to as "one-shot waveform reading").

As shown in FIG. 8, this one-shot waveform readout is a process of reading out the musical waveform data once from the beginning to the readout end address RE. In this case, a read end address RE is newly defined in order to distinguish it from the above-mentioned reading of a sustained tone, and the read operation is stopped when the reading of musical waveform data from the waveform memory reaches the read end address RE. It was necessary to provide a special readout stop circuit.

FIG. 9 is a flowchart showing the operation of the one-shot waveform readout circuit. Although the circuit diagram is not shown, an RE that holds the read end address RE
It consists of a register, an address calculation circuit containing a temporary register, an adder, and a control circuit that controls these.

First, an adder adds the frequency number ω output from an external CPU to the current read address Σa output from the address calculation circuit to obtain the next read address Σ.
a is calculated and stored in a register provided inside the address calculation circuit (step S31).

Next, the next read address Σa obtained in step S31 is subtracted from the read end address RE value set in the RE register to obtain a difference Δ (step S32). Then, it is checked whether this difference Δ is larger than zero (step S33), and if the difference Δ is larger than zero,
That is, if the next sampling position does not exceed the read end address RE, the next read address Σa is restored by subtracting the difference Δ from the read end address RE (step S34).
). Then, the process returns to step S31 and the same process is repeated again.

In the process of the above-described repeated execution, if it is determined in step S33 that the difference Δ is less than zero,
That is, when the next sampling position exceeds the readout end address RE, it is assumed that the readout of the series of tone waveform data has been completed and the readout is stopped (step S35).

[0014] As described above, the conventional musical tone generator needs to have two types of circuits: a circuit for reading loop waveform data to generate a sustained tone, and a readout stop circuit for realizing one-shot waveform reading. However, the disadvantage is that the musical tone generator is complicated and expensive.

[0015]

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and by reading out loop waveform data for generating a sustained sound and reading out one-shot waveform data using a common circuit, It is an object of the present invention to provide a musical tone generating device that can be configured simply and inexpensively.

[0016]

[Means for Solving the Problems] The musical tone generating device of the present invention has a first section in which musical waveform data extracted from a rising portion of a musical tone of an arbitrary length is stored, and an arbitrary length following the first section. a second section in which musical sound waveform data having a length of , and the output is zero, is stored; and a second section, and a reading means for repeatedly reading out the second section, and a musical sound generating means for generating a musical sound based on the musical sound waveform data read by the reading means. It is characterized by

[0017]

[Operation] When storing musical waveform data in the waveform memory, the present invention extracts an arbitrary length from the rising part of the musical tone and sets it as the first section, and extracts an arbitrary length from the rising part of the musical tone and sets it as the first section. Therefore, if you try to read out and generate a musical tone, the musical sound waveform data will be such that the output will be zero.
These sections are stored in the waveform memory in the order of the first and second sections.

When reading tone waveform data from the waveform memory, first, the first and second sections are read out successively, and then, after reading out to the end of the second section, the second section is repeatedly read out.

This operation is the same as when reading loop waveform data when generating a normal sustained tone, but even if the second section is repeatedly read out, no sound is generated because the stored content is zero. In other words, the same function as sound emission by one-shot waveform reading is achieved.

[0020] Therefore, there is no need for a readout stop circuit to realize one-shot waveform readout, and the loop waveform data readout circuit and one-shot waveform readout circuit can be configured with a common circuit, which saves hardware. This allows for savings.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a schematic block diagram showing the overall structure of an electronic musical instrument to which a musical tone generator according to the present invention is applied.

In the figure, 1 is a group of keyboard switches;
It includes a keyboard and a key scan circuit for detecting the pressed state of each key.

Reference numeral 2 denotes a panel switch group, which includes various switches such as a power switch, a mode designation switch, a melody selection switch, and a rhythm selection switch. The set state of each switch is the same as the keyboard switch group 1 above.
It is detected by an internal panel scan circuit.

Reference numeral 3 denotes a switch interface, which checks the states of the keyboard switch group 1 and panel switch group 2, and records the panel switch data that is in the ON state, the keyboard code of the key that is newly turned on, and the like. It outputs the touch and the keyboard code of the key that is newly turned off. Note that the touch information is generated by a known touch detection circuit (not shown).

A central processing unit (CPU) 4 controls each part of the electronic musical instrument according to a program stored in a program memory section of a read-only storage device (ROM) 5.

The ROM 5 contains, in addition to the program for operating the CPU 4 described above, timbre data and other various fixed data.

Reference numeral 7 denotes a sound source circuit directly related to the features of the present invention, to which a waveform memory 8 is connected. Details of the sound source circuit 7 and waveform memory 8 will be described later.

[0028] The above switch interface 3, CPU 4
, ROM 5 and sound source circuit 7 are connected to each other via a system bus 11.

Further, the digital musical tone signal outputted from the tone generator circuit 7 is sent to a D/A converter 9. The D/A converter 9 converts the input digital musical tone signal into an analog musical tone signal. This D
The analog tone signal converted by the /A converter 9 is supplied to an audio circuit 10.

The acoustic circuit 10 converts an input analog musical tone signal as an electric signal into an acoustic signal. That is, the acoustic circuit 10 is a sound generating means represented by, for example, a speaker or headphones, and emits sound.

FIG. 3 is a block diagram showing the waveform memory 8 and tone generator circuit 7 in more detail.

The waveform memory 8 stores musical waveform data created through a predetermined process. FIG. 1 shows the process of creating musical waveform data to be stored in the waveform memory 8.

First, (a) in the same figure shows a PCM waveform serving as original waveform data (original data), which is A/D converted and provided as digital data. In this case, for example, in the case of a musical sound signal of a decaying sound such as a piano, as shown in FIG.
As shown in , the envelope is normalized and converted to musical waveform data with constant amplitude. Next, as shown in FIG. 4(c), a repeated readout section B of a predetermined length at the end of the tone waveform data is set to zero.

The musical waveform data thus generated is stored in the waveform memory 8. When reading out the musical sound waveform data from the waveform memory and producing a sound, reading starts from the beginning of the musical sound waveform data, as shown by the arrow ■ in FIG. Repeated reading section B is read out once in succession.

Next, as shown by the arrows ■, ■, . . . , a repetitive reading section B surrounded by the loop top address LT and the loop end address LE is repeatedly read. However, no sound is produced by repeatedly reading out the portion of the repeated reading section B. Therefore, although the tone waveform data readout operation operates as if it were a loop waveform readout, a one-shot waveform readout function is realized.

Further, as shown in FIG. 2D, the predetermined length C at the end of the one-time reading section A of the tone waveform data can be made to have attenuation characteristics. In this case, although the details will be described later, a smooth transition can be made without generating noise when transitioning from sound generation to mute by one-shot waveform reading.

Next, the configuration of the sound source circuit 7 will be explained with reference to FIG. It is assumed that the waveform memory 8 stores not only the above-mentioned musical waveform data but also envelope data.

The adder 20 adds the read address Σa calculated by the address calculation circuit 21 and the frequency number ω (both include decimal parts) given from the CPU 4. The result of addition by this adder 20 is supplied to an address calculation circuit 21.

The address calculation circuit 21 calculates a read address to be given to the waveform memory 8, and generates an address for reading out only once from the beginning of the musical waveform data, and also sets it in the LT register 22 and LE register 23. An address for repeated reading is generated according to each address value.

This address calculation circuit 21 calculates a read address integer part K1, which is the integer part of the read address Σa, and an interpolation integer address K2, which is the read address integer part K1 plus "1", and stores them in the waveform memory 8. Supplied. Further, the read address Σa is supplied not only to the adder 20 but also to the interpolation circuit 24.

The interpolation circuit 24 uses the read address integer part K1.
, interpolation is performed on the two tone waveform data read out from the waveform memory 8 using the interpolation integer address K2 according to the decimal part of the current read address Σa, and the result is supplied to the waveform generation circuit 25.

That is, if the calculated read address Σa includes a decimal part, the interpolation circuit 24
Read address integer part K1 which is two integers before and after a
, calculates the value that should be the memory content of the read address Σa according to the difference (slope) in the memory content of the interpolation integer address K2, and uses this value as the musical waveform data value in the waveform generation circuit 2.
5.

The waveform generation circuit 25 generates a waveform signal based on the data from the interpolation circuit 24 and supplies it to the multiplier 27 .

On the other hand, the envelope generating circuit 26 generates an envelope signal based on the envelope data read from the waveform memory 8 and supplies it to the multiplier 27 .

The multiplier 27 multiplies the musical waveform signal from the waveform generating circuit 25 and the envelope signal from the envelope generating circuit 26 to generate a musical tone signal to which an envelope signal is added. This musical tone signal is converted into an analog signal by a D/A converter 9, and is converted into an analog signal by a D/A converter 9.
The sound is emitted at 0 (see Figure 2).

Next, the operation of the embodiment of the present invention in the above configuration will be explained with reference to the flowcharts of FIGS. 4 and 5. Note that this flowchart shows the case of alternate reading, and the operation is shown in Figure 6 (
b) Normal reading is realized by the flowchart shown in FIG. 4 (excluding step S11), and its operation is as shown in FIG. 6(a), but since it is included in the above-mentioned alternate reading operation, the explanation will be omitted.

The waveform memory 8 contains the data shown in FIG. 1(c) or (d).
It is assumed that musical waveform data shown in is stored. Further, it is assumed that the UD flag is set to "1" in the initial state.

First, it is checked whether the UD flag is "1" (step S11). Here, the UD flag is a flag that instructs the reading direction; when it is "1", it instructs to read in the up direction, that is, from the loop top LT to the loop end LE direction, and when it is "0", it instructs to read out in the down direction, that is, from the loop end LE. This is an instruction to read in the loop top LT direction.

[0049] In step S11 above, the UD flag is set to "1".
If it is determined that this is the case, the upward readout and interpolation processing in steps S12 to S20 is performed.

That is, the adder 20 adds CP to the current read address Σa output from the address calculation circuit 21.
The next read address Σa is calculated by adding the frequency number ω output from U4, and is stored in an internal register (not shown) of the address calculation circuit 21 (step S12).
.

Next, the next read address Σa obtained in step S12 is subtracted from the loop end LE value set in the LE register 23 to obtain a difference Δ (step S13). Then, it is checked whether this difference Δ is larger than zero (step S14), and if the difference Δ is larger than zero, that is, if the sampling position does not exceed the loop end LE, the difference Δ is subtracted from LE and the next read address is Σa
is restored (step S15).

On the other hand, if the difference Δ is smaller than zero, that is, if the sampling position exceeds the loop end LE,
Next, to perform reading in the down direction and interpolation processing, use U
The D flag is set to "0" (step S16). Then,
Add the difference Δ to the loop end LE and get the next read address Σa
(Step S17). Since the difference Δ in this case is a negative value, a position separated by Δ from the loop end LE in the direction of the loop top LT becomes the next read address Σa.

This next read address Σa is a point-symmetric waveform with multiple periods, that is, 180 degrees around the loop end LE.
If we consider a waveform that is a combination of a plurality of periodic waveforms with opposite phases formed when rotated by .degree., the value will be the same as the address value obtained by adding the frequency number ω to the current read address Σa.

Next, the integer part of the next read address Σa calculated in step S15 or S17 is extracted and set as the read address integer part K1 (step S18), and "1" is added to this read address integer part K1 for interpolation. Integer address K2 (step S19). Next, the interpolation circuit 24 executes interpolation processing using the current read address Σa, the read address integer part K1, and the interpolation integer address K2 (step S20).

At this time, the current read address Σa is "LE-
If it is within the range of 1≦Σa≦LE, interpolation processing is performed using “LE-1” as the read address integer part K1 and “LE” as the interpolation integer address K2.

On the other hand, if it is determined in step S11 that the UD flag is "0", step S2
The readout and interpolation processing in the down direction from step S1 to step S29 is performed.

First, in the adder 20, the current read address Σa outputted from the address calculation circuit 21 to C
The next read address Σa is calculated by subtracting the frequency number ω output by the PU 4, and is stored in an internal register (not shown) of the address calculation circuit 21 (step S21). As described above, the read address Σa and the frequency number ω include a decimal part.

Next, the next read address Σa obtained in step S21 is subtracted from the loop top LT value set in the LT register 22 to obtain a difference Δ (step S22). Then, it is checked whether this difference Δ is smaller than zero (step S23), and if the difference Δ is smaller than zero, that is, if the sampling position does not exceed the loop top LT, the difference Δ is subtracted from LT and the next read address is Σ
a is restored (step S24).

On the other hand, if the difference Δ is greater than or equal to zero, that is, if the sampling position exceeds the loop top LT, then the UD flag is set to "1" in order to perform upward reading and interpolation (step S25). ). Next, the difference Δ is added to the loop top LT to obtain the next read address Σa (step S26). As a result, since the difference Δ is a positive value, Δ
The read address is a position that is away from the address.

Next, the integer part of the current read address Σa calculated in step S24 or S26 is extracted and set as the read address integer part K1 (step S27), and "1" is added to this read address integer part K1 for interpolation. Integer address K2 (step S28). Next, the interpolation circuit 24 executes interpolation processing using the current read address Σa, the read address integer part K1, and the interpolation integer address K2 (step S29).

At this time, the current read address Σa is "LT≦Σ
a≦LT+1”, the read address integer part K
1, "LT+1" is used as the interpolation integer address K2.
Interpolation processing will be performed using "LT" as follows.

In addition, in the interpolation process in the down direction,
The phase of the musical waveform data will be inverted. This is the same as when a plurality of periodic waveforms with point symmetry about the loop end LE are continuously generated.

As described above, according to this embodiment, when musical waveform data is stored in the waveform memory 8, an arbitrary length is extracted from the rising part of a musical tone and read out only once.
The waveform memory 8 stores musical sound waveform data that has an arbitrary length following the one-time readout period and which produces a zero output when read out to generate a musical tone. Remember it in
When reading out musical waveform data from the waveform memory 8, first, a one-time readout section and a repeated readout section are successively read out, and then, when the end of the repeatable readout section is read out, the repeated readout section is thereafter read out repeatedly.

This operation is the same as when reading loop waveform data when generating a normal sustained tone, but even if the repeated reading section is repeatedly read out, no sound is generated because the stored content is zero. In other words, the same function as sound emission by one-shot waveform reading is achieved.

Therefore, a readout stop circuit for realizing one-shot waveform readout is not required, and the circuit for reading out loop waveform data and the one-shot waveform readout circuit can be configured with a common circuit, which reduces hardware. This allows for savings.

Note that in the above embodiment, the original data shown in FIG. 1(a) is directly cut out and used as the data for the rising part of a musical tone, but the imported original data is once resampled and a new source data is created. It is better to generate the above-mentioned tone waveform data after generating the data. This is because the pitch of the captured data may fluctuate, and if used as is to generate musical waveform data, there is a possibility that an out-of-tune musical tone will be generated. Therefore, better musical tones can be obtained by adjusting the tuning pitch by resampling and then using the original data.

[0067]

[Effects of the Invention] As detailed above, according to the present invention, the reading of the loop waveform data for generating a sustained sound and the reading of the one-shot waveform are performed in a common circuit, thereby making the device simple and inexpensive. It is possible to provide a musical tone generating device that can be configured.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a procedure for generating musical tone waveform data according to an embodiment of the present invention.

FIG. 2 is a block diagram schematically showing the overall configuration of an electronic musical instrument to which the present invention is applied.

FIG. 3 is a block diagram showing details of a waveform memory and tone generator circuit according to an embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of an embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of an embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of an embodiment of the present invention.

FIG. 7 is a diagram for explaining normal readout and alternate readout during conventional loop waveform readout.

FIG. 8 is a diagram for explaining conventional one-shot waveform readout.

FIG. 9 is a flowchart showing conventional one-shot waveform readout.

[Description of symbols] 8...Waveform memory, 20...Adder (reading means), 21...Address calculation circuit (reading means), 24...Interpolation circuit (musical tone generation means), 25...Waveform generation circuit (musical tone generation means), 26... Envelope generation circuit (musical tone generation means), 27... Multiplier (musical tone generation means).

Claims (3)

[Claims] 1. A first section in which musical waveform data extracted from an arbitrary length from a rising portion of a musical tone is stored;
a second section that is an arbitrary length following the first section and stores musical waveform data whose output is zero; a waveform memory that stores musical waveform data consisting of; The musical sound waveform data is divided into the first section and the second section.
A musical sound characterized by comprising: reading means for reading out the intervals in the order of and then repeatedly reading out the second interval; and musical sound generation means for generating the musical sound based on the musical waveform data read by the reading means. Generator. 2. An arbitrary section adjacent to the second section of the musical waveform data stored in the first section of the waveform memory is formed such that the musical waveform data is attenuated. Item 1. The musical tone generator according to item 1. 3. The reading means reads out the second section alternately in ascending order or descending order.
The musical tone generator described above.