JP2778415B2 - Distortion effect device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for imparting a distortion effect to a sound signal such as a tone signal, and more particularly to a device for adding a distortion to a signal component in a desired frequency band and then enhancing the signal component in another frequency band. This makes it possible to impart an effect to a desired frequency band without deteriorating the frequency characteristics.

[0002]

2. Description of the Related Art FIG. 11 shows a known distortion effect device.

[0003] In FIG. 11, the input sound signal S _i such musical tone signal is converted to an analog / digital (A / D) sound signal in digital form by the transducer 1. The sound signal from the A / D converter 1 is supplied to the nonlinear function table memory 2 as an address signal.

As an example, the memory 2 stores data such that the relationship between an address value (input amplitude value) X and an output amplitude value Y shows a non-linear characteristic in a high-positive / negative high-amplitude part. For this reason, a signal in which distortion is added to the high-amplitude part is transmitted from the memory 2 as a digital sound signal.

The sound signal from the memory 2 is supplied to a digital / analog (D / A) converter 3 and is converted into an analog output sound signal _So. The output sound signal _So is converted into sound by a suitable sound system.

[0006]

According to the above-mentioned prior art, a distortion effect cannot be given to a desired frequency band, and the characteristics of an analog amplifier cannot be simulated.

Therefore, it is conceivable to provide a filter in a signal input path to the memory 2 to impart a distortion effect to a desired frequency band. However, in this case, the filter suppresses frequency components other than the desired frequency band, so that there is a disadvantage that the frequency characteristics of the entire device deteriorate.

An object of the present invention is to provide a novel distortion effect device capable of imparting a distortion effect to a desired frequency band without deteriorating frequency characteristics.

[0009]

SUMMARY OF THE INVENTION A distortion effect device according to the present invention receives an input sound signal and outputs a signal component of a desired frequency band, and adds distortion to an output signal from the filter device. And a correction output means for correcting the output signal from the distortion addition means so that the suppression frequency component in the filter means is enhanced and outputting the corrected signal.

[0010]

According to the structure of the present invention, since the filter means is provided, it is possible to impart a distortion effect to a desired frequency band. Further, since the correction output means is provided, the suppression frequency component in the filter means is enhanced, and the frequency characteristics of the entire apparatus are improved.

[0011]

FIG. 1 shows a distortion effect device according to one embodiment of the present invention.

In FIG. 1, an input sound signal S such as a tone signal is shown.
_i is the distortion circuit 12 via the filter 10
, And the sound signal from the circuit 12 is supplied to the filter 14. From the filter 14, the output sound signal S _o is taken out. The circuit form may be either a digital form or an analog form.

As shown in FIG. 2A, the filter 10 having a characteristic of passing a signal component in a desired frequency band is used. The distortion circuit 12, the input amplitude as shown in FIG. 2 (b) values V _i and the output amplitude V _o
A high-amplitude portion having a non-linear characteristic with a positive / negative relationship is used. As shown in FIG. 2C, the filter 14 has a characteristic of enhancing the suppression frequency component in the filter 10,
That is, the product of the transfer function with the filter 10 is 1 (H
× 1 / H = 1). In addition, FIG.
In (b), f indicates a frequency, and A indicates an output.

Since the signal components in the frequency bands P ₁ and P ₂ shown in FIG. 2A have large amplitudes, the circuit 12 adds distortion. Signal component of the frequency band P ₃ in FIG. 2 (a), since the amplitude is small, not added distortion in the circuit 12. Between P ₁ and P _{3 in} FIG.
The frequency band between ₂ and P _3, a large waveform amplitudes are added distortion, small waveform amplitude is hardly added distortion.

The signal component of the frequency band between the P ₁ and P ₂ in FIG. 2 (a), the level in the filter 10 is suppressed, the level in the filter 14 increases, as the output sound signal S _o , the frequency components between P ₁ and P ₂ are signals approximately equal the input level of the sound signal S _i is obtained.

When the apparatus shown in FIG. 1 is realized in a digital form, the differentiator shown in FIG.
4 can be used as the filter 14, and the nonlinear function table memory as described above with reference to FIG. 11 can be used as the distortion circuit 12. Figure 3,
4, IN is a digital input sound signal, and OUT is
This is a digital output sound signal.

According to such a configuration, it is possible to obtain the effect of passing a sine wave through an analog amplifier having a low slew rate (a rising speed of an output when a signal is input). By appropriately selecting the characteristics of the filters 10 and 14 and the characteristics of the circuit 12, the characteristics of various analog amplifiers can be simulated.

FIG. 5 shows a distortion effect device according to another embodiment of the present invention, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

The filter 10 includes an analog input sound signal AS
It receives a digital input sound signal obtained by passing _i through an A / D converter 16 or a digital input sound signal DS _i separately supplied. The output signal of the filter 10 is supplied to a distortion circuit 12. The output signal of the distortion circuit 12 is supplied to the D / A converter 18 via the filter 14, and the analog output sound signal from the D / A converter 18 is converted into sound by the sound system 20.

As for the filters 10 and 14, a filter characteristic selecting section 22, a filter coefficient memory 24 and a filter coefficient supplying section 26 are provided. In the memory 24,
The coefficients for determining the transfer functions H ₁ , H ₂ ... For the filter 10 are stored, and the coefficients for determining the transfer functions 1 / H ₁ , 1 / H ₂ . Filter characteristic selector 22
Is for selecting an arbitrary one of a plurality of first, second,... Plural filter characteristics. Filter characteristic specifying information for specifying the selected filter characteristic is transmitted to the filter coefficient supply unit 2.
6 is output.

The filter coefficient supply section 26 reads out a coefficient related to the selected filter characteristic from the memory 24 in accordance with the filter characteristic designation information from the filter characteristic selection section 22 and supplies the coefficient to the filters 10 and 14. ing. For example, when the first filter characteristic is selected by the filter characteristic selection unit 22, the filter coefficient supply unit 26
The coefficients for H ₁ and 1 / H ₁ are read from the memory 24 and supplied to the filters 10 and 14, respectively. Therefore, in the filters 10 and 14, H ₁ and 1 /
H ₁ transfer functions is set.

In the distortion circuit 12, a primary interpolation operation circuit 30, an adder 32, a read control unit 34, a non-linear function table memory 36, an offset address memory 38, a non-linear characteristic selection unit 40, an offset address supply unit 42, etc. Is provided. Storage area M of memory 36
Data indicating different nonlinear characteristics as shown in FIGS. 6, 7, and 8 are stored in 1, M2, and M3, respectively. The memory 38 stores offset addresses A _{01 to} A ₀₃ corresponding to the center of the shake as shown in FIGS.

The nonlinear characteristic selecting section 40 is for selecting an arbitrary one of a plurality of nonlinear characteristics as shown in FIGS. 6 to 8, and offsets the nonlinear characteristic specifying information for specifying the nonlinear characteristic related to the selection. The data is output to the address supply unit 42.

The offset address supply section 42 reads an offset address related to the selected nonlinear characteristic from the memory 38 in accordance with the nonlinear characteristic designation information from the nonlinear characteristic selection section 40 and supplies the offset address to the adder 32. I have. For example, when the nonlinear characteristic selection section 40 selects the nonlinear characteristic shown in FIG. 6, the offset address supply section 42 reads the offset address A ₀₁ from the memory 38 and supplies it to the adder 32.

A part of the digital sound signal is supplied from the filter 10 to the adder 32, and is added to the offset address read from the memory 38. As an example, if the digital sound signal from the filter 10 is constituted by 16-bit amplitude data per sample, the adder 3
2 is supplied with a signal of the upper 5 bits, and the arithmetic circuit 30
Is supplied with a signal of the remaining 11 bits.

The read control section 34 reads from the memory 36 the data of the address value indicated by the addition output and the data of the next address value obtained by adding 1 to the address value based on the addition output of the adder 32. It is. The arithmetic circuit 30 performs a primary interpolation operation in consideration of the 11-bit signal from the filter 10 every time data for two addresses is read from the memory 36. For example, when the non-linear characteristic shown in FIG. 6 is selected and the data of the address values _An and _{An + 1} shown in FIG. 6 are read from the memory 36, the arithmetic circuit 30 outputs the read data and the 11-bit signal. The amplitude value V _n represented by
And based on V _{n + 1} amplitude value V _m between these amplitude values
Look, sequentially sends the data representing _{V n, V m, V n} + 1 , respectively. Thus performing an interpolation operation, the memory 36, since it is not necessary to store data relating V _m, can be reduced storage capacity of the memory 36.

According to the configuration shown in FIG. 5, a desired distortion effect can be added to a desired frequency band by selecting an arbitrary filter characteristic and an arbitrary nonlinear characteristic. Further, since the filter 14 is provided, it is possible to prevent the frequency characteristics from deteriorating.

FIG. 9 shows a distortion effect device according to still another embodiment of the present invention.

The input sound signal S _i is passed through a filter 50, a distortion circuit 52 and a filter 54 to an adder 5.
Is supplied to 6, the filter 58, is supplied to the adder 56 via the distortion circuit 60 and the filter 62, the adder 56, the output sound signal S ₀ is taken.

In such a configuration, the filter 50,
The characteristics of the frequency band different from those of the filters 54 and the filters 58 and 62 are made to complement each other. Moreover, the filter 50 and 54, the product of the transfer function is 1 (H ₁₁ · 1
/ H ₁₁ = 1), and also in the filters 58 and 60, the product of the transfer function becomes 1 (H ₂₁ · 1 / H ₂₁ = 1). By doing so, it is possible to impart a distortion effect to a plurality of desired frequency bands and prevent deterioration of frequency characteristics.

FIG. 10 shows a distortion effect device according to still another embodiment of the present invention.

The input sound signal S _i is supplied to an adder 7 via a filter 70 having a transfer function H and a distortion circuit 72.
Is supplied to the 4, it is supplied to the adder 76 via the filter 76 of the transfer function (1-H), from the adder 76, the output sound signal S _o is taken. Even with such a configuration, it is possible to impart a distortion effect to a desired frequency band without deteriorating the frequency characteristics.

The present invention is not limited to the above-described embodiment, but can be implemented in various modifications. For example, the distortion circuit is not limited to the table memory type, but may use a clipping circuit or a circuit that shifts a waveform to overflow. In the embodiment shown in FIG. 5, all necessary data may be stored in the table memory without providing the interpolation operation circuit.

[0034]

As described above, according to the present invention, the filter means and the correction output means are provided on the input side and the output side of the distortion adding means, respectively, so that the desired frequency band can be obtained without deteriorating the frequency characteristics. The effect that a distortion effect can be given to the object is obtained.

In addition, there is an advantage that complicated and various characteristics of an analog amplifier or the like can be simulated by changing the combination of the filter characteristics and the non-linear characteristics.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a distortion effect device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram for explaining the operation of the device of FIG.

FIG. 3 is a circuit diagram showing a differentiator that can be used as a filter 10 in the apparatus of FIG.

FIG. 4 is a circuit diagram showing an integrator that can be used as a filter 14 in the device of FIG.

FIG. 5 is a block diagram showing a distortion effect device according to another embodiment of the present invention.

FIG. 6 is a characteristic diagram showing non-linear characteristics based on data in a storage area M1 of the table memory 36.

FIG. 7 is a characteristic diagram showing non-linear characteristics based on data in a storage area M2 of the table memory 36.

FIG. 8 is a characteristic diagram showing non-linear characteristics based on data in a storage area M3 of the table memory 36.

FIG. 9 is a block diagram showing a distortion effect device according to still another embodiment of the present invention.

FIG. 10 is a block diagram showing a distortion effect device according to still another embodiment of the present invention.

FIG. 11 is a block diagram showing a conventional distortion effect device.

[Explanation of symbols]

10, 14, 50, 54, 58, 62, 70, 76: filter, 12, 52, 60, 72: distortion circuit, 22: filter characteristic selector, 40: nonlinear characteristic selector, 56, 74: adder.

Claims (1)

(57) [Claims] 1. Filter means for receiving an input sound signal and outputting a signal component in a desired frequency band, distortion adding means for adding distortion to an output signal from the filter means, and output signal from the distortion adding means Correction output means for correcting the output so that the suppression frequency component of the filter means is enhanced, and outputting the corrected output.