JP3134587B2 - Effect adding device and effect adding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an effect-adding apparatus and an effect-adding method, and more particularly, to an effect-adding apparatus and an effect-adding method for applying a compressor effect that does not fluctuate in tone with a simple process to an input audio signal. About.

[0002]

2. Description of the Related Art In a conventional electronic stringed musical instrument (for example, an electronic guitar or the like), a picked-up string vibration is converted into an electric signal by a pickup to generate a musical tone corresponding to the vibration of each string. In recent years, there has been proposed an electronic stringed musical instrument or the like that imparts an acoustic effect to the generated musical sound. One of such sound effects is a compressor.

This compressor is used to compress the dynamic range of an input signal. In an electronic stringed instrument, a string vibration is detected, and a detection signal of the string vibration is rectified and integrated to extract an envelope (EV). A compressor effect is provided by multiplying the input signal (string vibration detection signal) by an inverted signal (1-EV) obtained by inverting the envelope.

[0004]

However, in such a conventional electronic stringed musical instrument having a compressor effect, a string vibration is detected, an envelope of a detection signal of the string vibration is extracted, and the envelope of the envelope is extracted. Since a compressor effect is imparted by multiplying the input signal by the inverted signal, in an electronic stringed musical instrument having a plurality of strings, there is a problem that the compressor effect is not uniformly applied to each string.

That is, for example, in the case of an electronic stringed musical instrument having six strings, the vibration of the thin first string has a small energy amount,
Since the vibration of the thick sixth string has a large amount of energy, if the envelope due to these string vibrations is extracted and a compressor effect is applied, the compressor effect is too deeply applied to the sound of the sixth string, and There is a problem that the compressor effect is applied to the sound of one string only shallowly, and the compressor effect is not applied equally to each string.

Further, even with the same string, the compressor effect varies depending on the fret pressing position of the string, and there is a problem that a uniform compressor effect cannot be provided.

That is, even if the strings are the same, the vibration energy of the strings greatly differs depending on the fret pressing position of the strings.
For example, in the first string, the vibration frequency is 1 KH when open.
z, 1.5KHz at fret holding position closest to body
In the sixth string, the vibration frequency is 8
0Hz, 300H at the fret holding position closest to the body
Therefore, there is a problem in that the vibration energy is smaller as the fret holding position is closer to the body side, and the compressor is less applied, because the fret holding position is different.

Therefore, in order to solve the problem that the compressor effect becomes non-uniform, a hexa pickup that can detect a string vibration for each string is used, and the degree of compressor operation for each string is externally controlled. Although it is conceivable to correct by such as, the current hexa pickup has a small number of turns of the coil of its detection unit,
There is a disadvantage that the sound quality is inferior.

If the envelope of the input signal is changed carelessly to adjust the degree of the compressor effect, the balance of the vibration energy of the first to sixth strings will differ from that of an acoustic stringed instrument.
A new problem of unnatural sound occurs.

Further, in order to equalize the degree of the compressor effect depending on the fret pressing position, for example, it is conceivable to raise the level around 300 Hz by an equalizer. However, in this method, the sixth string is corrected to some extent. However, for other strings, for example, the fifth and fourth strings, it is necessary to apply the compressor deeply at a frequency higher than 300 Hz. If the level near 300 Hz is increased, the compressor effect will be excessively applied. New problems arise.

In view of this, the present applicant has previously proposed an electronic stringed musical instrument (Japanese Patent Application No. 315774) capable of uniformly applying a compressor effect regardless of the type of string.

In this electronic stringed musical instrument, the first detecting means detects any vibration of a plurality of strings and converts it into an electric signal corresponding to the vibration, and the second detecting means detects the vibration of each string. To convert it into an electric signal corresponding to the vibration of each string. Weighting and adding means weights and adds each of the electric signals of each string detected by the second detecting means, and the envelope extracting means extracts the envelope of the output signal obtained by the weighting and adding means. The extracted envelope signal is inverted by the envelope inverting means, and the multiplying means multiplies the inverted envelope signal from the envelope inverting means by the electric signal from the first detecting means and outputs the result.

Therefore, the compressor effect can be added by weighting and adding the string vibration detected for each string and multiplying the inverted signal of the envelope resulting from the weighted addition processing by the separately detected string vibration. Regardless of the type of string, the compressor effect can be imparted evenly.

However, this electronic stringed instrument still has the following points to be improved.

[0015] First, there is a concern that the envelope signal often fluctuates, which may affect the timbre. Second, the number of processing steps is large and the processing time is long.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an effect adding device and an effect adding method which can provide a compressor effect with a simple process and in which a tone does not fluctuate.

[0017]

According to the first aspect of the present invention,
An effect adding device for squaring and weighting the input audio signal, weighting means for weighting the input audio signal, and adding the input audio signal to the signal weighted by the weighting device; Addition means for performing
Discriminating means for discriminating whether or not the input sound signal is equal to or higher than a predetermined level; and when the input sound signal is judged to be not lower than a predetermined level, the signal from the adding means is used. Adding and subtracting means for subtracting the signal calculated by the multiplying means and adding and outputting the signal from the adding means and the signal calculated by the multiplying means when it is determined that the signal is below a predetermined level; , The above object is achieved.

In this case, the determination means may determine whether or not the input audio signal has a level of 0 or more, for example, as described in claim 2.

According to a third aspect of the present invention, the method for adding an effect comprises:
Multiplication processing for squaring and weighting the input audio signal, weighting processing for weighting the input audio signal, and addition processing for adding the input audio signal to the signal weighted in the weighting processing. A discriminating process of discriminating whether or not the input audio signal is equal to or higher than a predetermined level, and calculating in the adding process when the input audio signal is judged to be higher than a predetermined level by the discriminating process. Subtracting the signal calculated by the multiplication process from the processed signal, and adding or subtracting the signal calculated by the addition process and the signal calculated by the multiplication process when it is determined that the signal is below a predetermined level. The above object is achieved by performing the processing.

In this case, the discrimination processing may be, for example, a step of discriminating whether or not the input audio signal is at or above a zero level.

[0021]

According to the present invention, the input audio signal is squared and weighted, and after the squared signal is weighted, the input audio signal is added. Then, it is determined whether or not the input audio signal is equal to or higher than a predetermined level. When the determination result is equal to or higher than the predetermined level, a signal obtained by squaring the input audio signal and weighting the input signal is subtracted from the added signal. When the signal is equal to or lower than a predetermined level, a signal weighted by squaring from the added signal is added and output, so that a compressor effect can be given by simple processing, and the input sound signal Even if the level fluctuates, a compressor effect in which the tone does not fluctuate can be provided.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

FIGS. 1 to 10 are diagrams showing an embodiment of the effect adding device and the effect adding process of the present invention.

FIG. 1 is a block diagram of an effect adding circuit 1 to which an effect adding device and an effect adding method of the present invention are applied. The effect adding circuit 1 is applied to an electronic stringed instrument, for example, an electronic guitar. .

In FIG. 1, the effect adding circuit 1 has an A / D
Converter 2, DSP (Digital Signal Processor) 3, C
PU (Central Processing Unit) 4, D / A converter 5,
ROM (Read Only Memory) 6, RAM (Random Access
Memory 7) and the like, and the A / D converter 2 receives an analog sound signal detected by a pickup provided in an electronic guitar or the like.

The A / D converter 2 converts the input audio signal of the analog to digital signal, and outputs the DSP3 as an acoustic signal W _IN digital.

The DSP3 has at its input terminal, an acoustic signal W _IN from A / D converter 2 is input, performs signal processing, output as a digital output signal from the output terminal to the D / A converter 5 I do.

The D / A converter 5 converts the digital output signal input from the DSP 3 into an analog signal, and outputs the analog output signal to a musical sound generator including an amplifier and a speaker (not shown).

The CPU 4 controls each part of the effect adding circuit 1 in accordance with a program in the ROM 6 to execute processing as the effect adding circuit 1. That is, the ROM 6 stores a program as the effect adding circuit 1 and other necessary data and coefficients, and the CPU 4 executes various processes using the RAM 7 as a work area. CPU4
Transfers the program in the ROM 6 to the DSP 3, and causes the DSP 3 to perform various processes such as a multiplication process, a weighting process, a sign discrimination process, and an addition / subtraction process, as described later, to perform a compressor effect adding process.

The effect adding circuit 1 includes a console unit 8
The console unit 8 is provided with various switches, volumes, and the like that are used when performing a performance operation of a guitar or the like to which the effect adding circuit 1 is applied. The console unit 8 is connected to the CPU 4, and the CPU 4 scans the console unit 8 and performs various processes according to the operation state of the console unit 8.

The DSP 3 has a circuit configuration as shown in FIG. 2, and includes a program memory 11, a control circuit 12, an input register (PI) 13, a coefficient memory (P) 14, a work memory (W) 15, and a flag register ( SF0) 16, output register (OR) 17, multiplication unit 100, and addition / subtraction unit 2
00 etc. Each part of the DSP 3 is connected by an internal bus 18.

A processing program for adding a compressor effect is stored in the program memory 11, and this program is written from the CPU 4 shown in FIG. An address counter (not shown) is connected to the program memory 11, and the program memory 11 sequentially supplies the program contents to the control circuit 12 by specifying the address of the address counter.

The control circuit 12 controls each part of the DSP 3 according to a program in the program memory 11 to execute a compressor effect adding process. The details of the processing will be described later.

The input register (PI) 13 has A
/ D converter 2 from the acoustic signal W _IN is input, the input register (PI) 13, after temporarily storing the audio signal W _IN, is transferred to the work memory (W) 15 through the internal bus 18.

The coefficient memory (P) 14 is a register for storing various coefficients necessary for the DSP 3 to perform a compressor effect adding process. These various coefficients are stored in the ROM 6 of FIG.
The CPU 4 reads out the coefficients from the ROM 6 and writes them into the coefficient memory (P) 14. As a coefficient set in the coefficient memory (P) 14, a weighting coefficient is set as a coefficient name P (00) as shown in a memory map of the coefficient memory (P) 14 in FIG.

The work memory (W) 15 temporarily stores the acoustic signal W _IN input via the input register (PI) 13 and data of the calculation result in the multiplication unit 100 and the addition / subtraction unit 200 described later. Work memory. The data stored in the work memory (W) 15 includes:
For example, as shown in FIG. 4 as a memory map of the work memory (W) 15, an input waveform is used as a data name W (INP), an addition waveform is used as a data name W (CRT), and a multiplication waveform is used as a data name W (VRT). Is the data name W (CM
P) is the output waveform, and data name is W (ZRO)
Is stored as a constant (= 0).

As will be described later, the flag register (SF0) 16 determines whether the value of a register (AR) 208 to which the result of addition / subtraction performed by the adder / subtractor 207 of the adder / subtractor 200 is input is positive or negative. This is a register for setting a flag indicating "."

The multiplication unit 100 includes gates 101 and 102,
Register (M0) 103, (M1) 104, gate 10
5, a multiplier 106 and a register (MR) 107, and outputs from the coefficient memory (P) 14, the work memory (W) 15 and the input register (PI) 13 are input to the gates 101 and 102. Is done.

The gates 101 and 102 are connected to the control circuit 1
2 controls its operation, and controls which input data is output to the register (M0) 103 and the register (M1) 104. Register (M0) 103
Temporarily stores data input through the gate 101, outputs the data to the multiplier 106, and feeds back the data to the gate 101. The register (M1) 104 temporarily stores data input through the gate 102, outputs the data to the multiplier 106 through the gate 105, and feeds back the data to the gate 102. In the gate 105,
The data from the addition / subtraction unit 200 described later is also input, and the gate 105 operates under the control of the control circuit 12 to select the data from the register (M1) 104 and the addition / subtraction unit 200 and output the data to the multiplier 106. The multiplier 106 multiplies the data input from the register (M0) 103 and the register (M1) 104, and outputs the result of the multiplication to the register (MR) 107. Register (MR) 107
After temporarily storing the multiplication result of the multiplier 106, the multiplication result is output to the gate 102 and the addition / subtraction unit 200.

The addition / subtraction unit 200 includes gates 201 and 20
2. Register (A0) 203, Register (A1) 20
4, gates 205 and 206, adder / subtractor 207, register (AR) 208, clipper 209, and register (S
R) 210 and the like, and the gates 201 and 202 have the coefficient memory (P) 14 and the work memory (W) 1
5 and the output from the input register (PI) 13 are input.

The gates 201 and 202 are connected to the control circuit 1
2 controls its operation, and controls which input data is output to the register (A0) 203 and the register (A1) 204. Register (A0) 203
Temporarily stores data input through the gate 201, outputs the data to the gate 205, and feeds back the data to the gate 201. The register (A1) 204 temporarily stores data input through the gate 202, outputs the data to the gate 206, and feeds back the data to the gate 202. Data from the register (MR) 107 of the multiplication unit 100 is also input to the gate 205,
The gate 205 operates under the control of the control circuit 12 to select data from the register (A0) 203 and the multiplication unit 100 and output the data to the adder / subtractor 207. The gate 206 stores, in addition to the data from the register (A1) 204, the data of the operation result of the adder / subtractor 207 in the register (AR) 20.
The gate 206 operates under the control of the control circuit 12 to select the input data and output it to the adder / subtractor 207.

The adder / subtractor 207 performs an addition process or a subtraction process on the input data, and stores the operation result in a register (A
R) Output to 208. The register (AR) 208 outputs the operation result of the adder / subtracter 207 to the clipper 209 and the gate 206, and uses the most significant bit as flag data F (AR) as the flag register (SF0) 16
Output to The flag data F (AR) set in the flag register (SF0) 16 is "1" when the operation result of the adder / subtractor 207 is negative.
Is "0" when the calculation result of is positive. Clipper 2
09 is for preventing data overflow, and the data that has passed through the clipper 209 is supplied to a register (SR) 210. Register (SR) 21
The output of 0 is output to the gate 105 of the multiplying unit 100, and is also supplied to the work memory (W) 15 via the internal bus 18 as an operation result of the processing for one channel of one sound.

The operation results of the multiplication unit 100 and the addition / subtraction unit 200 are output from the addition / subtraction unit 200 to the work memory (W) 15 via the internal bus 18, and the data on which all the arithmetic processing has been completed are stored in the work memory (W). W) 15 to the output register (OR) 17.

The output register (OR) 17 outputs the input data to the D / A converter 5 shown in FIG. 1 via an output terminal.

[0045] The effect adding circuit 1, by DSP3 having a configuration as described above, in order to perform a compressor effect imparting processing, to the acoustic signal W _IN input, addition processing, weighted addition processing, the code discrimination Processing, addition / subtraction processing, multiplication processing and the like are sequentially performed to generate an output signal.

Therefore, the DSP 3 executes the above-described processing by forming a pseudo circuit shown in FIG. 5 based on a program and a coefficient from the CPU 4. Hereinafter, this pseudo circuit will be described.

First, the DSP 3 is composed of multipliers 20, 21, 22, adders 23, 24, a sign discriminator 25, and an adder / subtractor 26, as shown in FIG.

The input waveform W (INP) and the weighting coefficient P (00) are input to the multiplier 20.
Multiplies the input waveform W (INP) by the weighting coefficient P (00), and outputs the multiplication result to the adder 23. The input waveform W (INP) is further input to the adder 23, and the adder 23 adds the input waveform W (INP) to the multiplication result output from the multiplier 20, and adds / subtracts the addition result. Output to the device 26.

The input waveform W (IN
P) is input twice, and the multiplier 21 multiplies the input waveform W (INP) by the input waveform W (INP), that is, calculates the square of the input waveform W (INP), and calculates The result of the multiplication is output to the multiplier 22.

The multiplier 22 further includes a weighting coefficient P
(00) is input, and the multiplier 22
Weighting coefficient P (00)
And outputs the result of the multiplication to the adder / subtractor 26.

The input waveform W (INP) and the constant W (ZRO) are input to the adder 24.
The input waveform W (INP) is subtracted from the constant W (ZRO), and the result of the subtraction is output to the code discriminator 25.

The sign discriminator 25 discriminates the sign of the output of the adder 24, that is, the sign of the subtraction result obtained by subtracting the input waveform W (INP) from the constant W (ZRO), and outputs the discrimination result to the adder / subtractor 26. .

The adder / subtractor 26 performs an addition process or a subtraction process on the addition result input from the adder 23 and the multiplication result input from the multiplier 22 based on the result of the discrimination by the sign discriminator 25, and calculates the operation result. As an output waveform W (CMP). That is, the adder / subtractor 26 is the sign discriminator 2
5 is negative, that is, the input waveform W (IN
P) is equal to or greater than the constant W (ZRO) and is positive,
3 is subtracted from the multiplication result of the multiplier 22, and the subtraction result is output as an output waveform W (CMP). When the determination result of the code discriminator 25 is positive, that is, the input waveform W (INP) Is less than the constant W (ZRO) and negative
The addition result of the adder 23 and the multiplication result of the multiplier 22 are added, and the addition result is output as an output waveform W (CMP).

Next, the operation will be described.

The effect adding circuit 1 adds a compressor effect to an input audio signal, and the compressor effect compresses a dynamic range of the audio signal. That is, when the input audio signal exceeds a certain level, the compressor effect decreases the gain as the input audio signal increases, thereby preventing the output level from increasing.

Therefore, as shown in FIG. 1, the effect adding circuit 1 converts the input analog sound signal into an A / D converter 2.
In digitally converted input to DSP3 as an acoustic signal W _IN digital. The effect adding circuit 1 performs the above-described processing, adds a compressor effect to the acoustic signal W _IN , and outputs the result to the D / A converter 5. The D / A converter 5 converts the digital output signal into an analog signal. The signal is converted to a signal and output to an external tone generator.

When the power is turned on, the effect adding circuit 1
First, an initialization process is performed.
And reads out the program and the coefficient from the CPU 3 and supplies them to the coefficient memory (P) 14 of the DSP 3. DSP from this CPU4
3 are the coefficients shown in FIG. 3 described above. At this time, the CPU 4 reads a constant W (ZRO) from the RAM 7 and supplies it to the DSP 3. After that, CPU4
Scans the operation unit 8 and checks whether a switch operation has been performed. When the switch operation is performed, the coefficients and constants are changed and supplied to the DSP 3 according to the switch operation. When the switch operation is not performed, the initial processing is terminated without changing the coefficient.

When the program and the supply of the coefficients and the constants to the DSP 3 are completed in this way, the effect adding circuit 1
Starts the processing by the DSP3.

[0059] DSP3 the multiplication processing according to the procedure shown in FIG. 6, addition processing, by performing determination processing and subtraction processing or the like, performs the compressor effect adding process, the acoustic signal W _IN this compressor effect adding process with predetermined sampling timing It is performed sequentially for each input.

The compressor effect adding process by the DSP 3 will be described below with reference to the flowchart shown in FIG.

The DSP 3 first receives the signal from the A / D converter 2
An acoustic signal W _IN that has been input to the input register (PI) 13 of SP3 was transferred to the work memory (W) 15, written as input waveform W (INP) (step S1). This acoustic signal _WIN is generated at every predetermined sampling timing.
Input to SP3.

Next, the weighting coefficient P (00) is read out from the coefficient memory (P), transferred to the register (M0) 103, and the input waveform W (INP) written into the work memory (W) 15 in step S1. Is the work memory (W)
15 and transferred to the register (M1) 104 (step S2).

The weighting coefficient P (00) of the register (M0) 103 and the input waveform W of the register (M1) 104
(INP) is transferred to the multiplier 106 and multiplied by the multiplier 106. The result of the multiplication [P (00) × W (INP)]
Is transferred to the register (MR) 107, the input waveform W (INP) is read from the work memory (W) 15, and transferred to the register (A1) 204 (step S3).

By the processing in step S3, the above-mentioned FIG.
The acoustic signal _WIN and the weighting coefficient P (0
0) has been multiplied.

Next, the multiplication result [P (00) × W (INP)] of the register (MR) 107 is transferred to the adder / subtractor 207 via the gate 205 and the register (A)
1) The input waveform W (INP) of 204 is transferred to the adder / subtractor 207, and the multiplication result and the input waveform W
(INP) and the result of the addition [P (00) × W
(INP) + W (INP)] to the register (AR) 208
Transfer to Further, the input waveform W (INP) is read from the work memory (W) 15 and is read from the register (M0) 103.
And to the register (M1) 104 (step S
4).

Then, the input waveform W (INP) of the register (M0) 103 and the register (M1) 104 is multiplied by the multiplier 1
06 and multiplied by the multiplier 106 to obtain the square of the input waveform W (INP), and the addition result of the register (AR) 208 to the register (SR) 21
0 (step S5).

By the processing in step S5, the above-mentioned FIG.
Has been performed by the multiplier 21 to square the input waveform W (INP).

Next, the weighting coefficient P (00) is read out from the coefficient memory (P) 14 and stored in the register (M0) 103.
(Step S6). This register (M0) 1
03 and the above register (M
R) The multiplication result of 107 is transferred to the multiplier 106 and subjected to multiplication processing, and the multiplication result [W (INP) × W (INP) ×
P (00)] to the register (MR) 107 (step S7). Further, the addition result [P (00) × W (INP) + W (INP)] of the register (SR) 210 is transferred to the work memory (W) 15 and written as an addition waveform (step S7).

Then, the input waveform W (INP) is read from the work memory (W) 15 and the register (A0) 20
3 and the multiplication result [W (INP) × W (INP) × P (00)] of the register (MR) 107 is transferred to the register (AR) 208 (step S8). The multiplication result of the register (AR) 208 is stored in the register (SR) 2
10 and transferred to the work memory (W) 15 and written as a multiplied waveform W (VRT) (steps S9 and S1).
0), a constant W (ZRO) is read from the work memory (W) 15 and transferred to the register (A1) 204 (step S9).

Next, the constant W of the register (A1) 204
(ZRO) and input waveform W of register (A0) 203
(INP) is transferred to the adder / subtractor 207, and the constant W (ZR
O) is subtracted from the input waveform W (INP), and the subtraction result [W (ZRO) -W (INP)] is stored in the register (AR) 2.
08 and read the output waveform W (CMP) from the work memory (W) 15 to register (A1)
Transfer to step 204 (step S10).

By the process in step S10, the input waveform W (IRO) is calculated from the constant W (ZRO) by the adder 24 in FIG.
NP) has been subtracted.

Then, the most significant bit of the register (AR) 208 is set to the flag data F (AR) [FRAG (A
R)] to the flag register (SF0) 16
The multiplied waveform W (VRT) is read from the work memory (W) 15 and transferred to the register (A0) 203 (step S11). The flag SF0 set in the flag register (SF0) 16 is "1" when the operation result of the adder / subtractor 207 is negative, and is "0" when the operation result of the adder / subtractor 207 is positive. . That is, the constant W
(ZRO) is set to “0”, and this constant W
Since the most significant bit of the result of subtracting the input waveform W (INP) from (ZRO) is set as the flag SF0, the flag SF0 is positive when the input waveform W (INP) is smaller than “0” (negative). (= “0”), and is negative (= “1”) when the input waveform W (INP) is larger (positive) than “0”.

Next, it is checked whether or not the flag SF0 transferred to the flag register (SF0) 16 is "1" (step S12). If the flag SF0 is "0", the input waveform W (IN
P) is determined to be smaller (negative) than “0”, and the addition waveform W (CRT) of the register (A1) 204 and the multiplication waveform W (VRT) of the register (A0) 203 are added, and the addition is performed. The result [W (CRT) + W (VRT)] is transferred to the register (AR) 208 (step S13). Also,
When the flag SF0 is “1”, the input waveform W (IN
P) is determined to be larger (positive) than “0”, and the multiplied waveform W (VRT) of the register (A0) 203 is subtracted from the added waveform W (CRT) of the register (A1) 204,
The subtraction result [W (CRT) -W (VRT)] is transferred to the register (AR) 208 (step S14).

From step S12 to step S13,
By the processing in S14, the sign discrimination processing and the addition / subtraction processing by the sign discrimination circuit 25 and the adder / subtractor 26 in FIG. 5 have been performed.

Then, the addition result or the subtraction result of the register (AR) 208 is transferred to the work memory (W) 15 via the register (SR) 210, and the work memory (W)
15 is written as an output waveform W (CMP) (steps S15 and S16). This output waveform W (CMP) is transferred to the output register (OR) 17, and the process is terminated (step S17).

The above compressor effect adding process is shown in FIG.
Will be described based on FIG.

7 to 10, x is an input, y is an output, and P is a weighting coefficient.

First, as shown in FIG. 7, the effect adding circuit 1 multiplies an input x by a coefficient P to obtain an output y (y = Px). This processing is performed by the multiplier 20 shown in FIG.
This corresponds to the processing of multiplying (INP) by the weighting coefficient P (00), and corresponds to the processing of steps S1 to S3 in FIG.

Then, as shown in FIG. 8, the effect adding circuit 1 squares the input x, multiplies the squared input x by a coefficient P, and outputs an output y (y = Px ² , y = − Px ² ). This processing is performed by the multiplier 21 shown in FIG.
P) is squared and multiplied by the weighting coefficient P (00) by the multiplier 22, and corresponds to the processing from step S4 to step S7 in FIG.

Next, as shown in FIG. 9, the effect adding circuit 1 compares the input with a predetermined value (“0” in this embodiment), and when the input is positive, the output obtained in FIG. (Y = P
x) is subtracted from the output (y = Px ² ) obtained in FIG.
The output y (y = (x−Px ² )) is obtained. When the input is negative, the output (y = Px ² ) obtained in FIG. 8 is added to the output (y = Px) obtained in FIG. Output y (y = (x + Px
² )) seeking. In this process, the input waveform W (INP) is subtracted from the constant W (ZRO) by the adder 24 in FIG. 5, and the sign of the subtraction result is discriminated by the sign discriminator 25.
The process corresponds to a process of adding or subtracting in the adder / subtractor 26 based on the determination result. This processing corresponds to the processing from step S8 to step S15 in FIG.

Then, as shown in FIG. 10, the effect adding circuit 1 inputs the output y (y = P (xx−x) obtained in FIG.
² ) or y = P (x + x ² )) and add the final output y (y = x + P (xx− ² ) or y = x + P (x + x
² )) seeking. This processing corresponds to the processing of adding the input waveform W (INP) to the multiplication result of the multiplier 20 in FIG. 5 by the adder 23 and further adding or subtracting the multiplication result of the multiplier 22 by the adder / subtractor 26. 6 corresponds to the processing from step S3 to step S17 in FIG.

In FIGS. 5 and 6, the addition processing corresponding to FIG.
This is performed in advance by adding the input waveform W (INP) to the addition result obtained by adding (00).

As described above, in this embodiment, the input waveform W
(INP) is determined to be positive or negative, and the input waveform W (INP)
Is positive, the input waveform W (INP) is
(INP) is subtracted, and the input waveform W (INP) is subtracted.
When P) is negative, the input waveform W (INP) and the signal obtained by squaring the input waveform W (INP) are added. Then, after performing a weighting process of multiplying the signal of the calculation result by a weighting coefficient P (00), the input waveform W (INP) is added to calculate the output waveform W (CMP). A compressor effect can be provided with a few simple processes, and the input waveform W (INP)
A compressor effect can be provided in which the timbre does not change even if the level changes.

In the above embodiment, the input waveform W
Although the 0 level is set as the predetermined level to be compared with (INP), it is needless to say that the present invention is not limited to this.

[0085]

According to the present invention, it is determined whether or not an input audio signal is equal to or higher than a predetermined level. If the result of the determination is equal to or higher than the predetermined level, the input audio signal is divided into two from the input audio signal. The input signal is subtracted. If the signal is equal to or lower than a predetermined level, the input audio signal and a signal obtained by squaring the input audio signal are added. Then, after weighting the signal of the calculation result, the input audio signal is further added and output, so that the compressor effect can be given by simple processing, and even if the level of the input audio signal fluctuates. A compressor effect that does not fluctuate in tone can be provided.

[Brief description of the drawings]

FIG. 1 is an overall block configuration diagram of an effect adding circuit to which an effect adding device of the present invention is applied.

FIG. 2 is a circuit configuration diagram of the DSP of FIG. 1;

FIG. 3 is a diagram showing a memory map of a coefficient memory (P) shown in FIG. 2;

FIG. 4 is a diagram showing a memory map of a work memory (W) in FIG. 2;

FIG. 5 is a pseudo circuit diagram showing a compressor effect adding process of the DSP of FIG. 2;

FIG. 6 is a flowchart showing a compressor effect adding process in the DSP.

FIG. 7 is a waveform chart showing a process of multiplying an input by a coefficient.

FIG. 8 is a waveform diagram showing a process of squaring an input and multiplying by a coefficient.

9 is a waveform chart showing a process of adding and subtracting the output of FIG. 8 from the output of FIG. 7;

FIG. 10 is a waveform chart showing a process of adding an input to the output of FIG. 9;

[Explanation of symbols]

 Reference Signs List 1 effect adding circuit 2 A / D converter 3 DSP 4 CPU 5 D / A converter  6 ROM  7 RAM  Reference Signs List 8 console section 11 program memory 12 control circuit 13 input register (PI) 14 coefficient memory (P) 15 work memory (W) 16 flag register (SF0) 17 output register (OR) 18 internal bus 100 multiplication section 200 addition / subtraction section 20, 21, 22 multiplier 23, 24 adder 25 sign discriminator 26 adder / subtractor

Claims (4)

(57) [Claims] 1. A multiplying means for squaring and weighting an input audio signal, a weighting means for weighting the input audio signal, and adding the input audio signal to a signal weighted by the weighting means. Adding means for determining whether or not the input audio signal is equal to or higher than a predetermined level; and determining whether the input audio signal is equal to or higher than a predetermined level by the determination means. The signal calculated by the multiplying means is subtracted from the signal from the means, and when it is determined that the signal is below a predetermined level, the signal from the adding means is added to the signal calculated by the multiplying means. An effect adding device comprising: an adding / subtracting means for outputting. 2. The effect adding apparatus according to claim 1, wherein said determination means determines whether or not the input audio signal is at or above a zero level. 3. A multiplication process for squaring and weighting the input audio signal, a weighting process for weighting the input audio signal, and a process of adding the input audio signal to the signal weighted by the weighting process. An adding process for adding; a discriminating process for discriminating whether or not the input audio signal is equal to or higher than a predetermined level; and The signal calculated by the multiplication process is subtracted from the signal calculated by the addition process, and when it is determined that the signal is below a predetermined level, the signal calculated by the addition process and the signal calculated by the multiplication process are subtracted. And an addition and subtraction process for adding and. 4. The effect adding method according to claim 3, wherein said discriminating process discriminates whether or not the input audio signal has a level of 0 or more.