JP3268616B2 - Dynamic range extender - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic range extending device, and more particularly, to a dynamic range extending device which enhances, by level correction, an average level drop of an output in an input level region to be emphasized after extension.

[0002]

2. Description of the Related Art A dynamic range extending apparatus controls a small sound to be smaller and a large sound to be close to an input level. For an input signal waveform shown in FIG. The output signal waveform is shown in FIG.
The level difference is controlled to be about 24 dB as shown in (1), and there are effects such as emphasizing a reproduced sound that can be placed when the level of the input signal suddenly increases and then decreases, that is, a so-called attack sound.

As shown in FIG. 9, the basic input / output characteristics of the dynamic range expansion device are such that the output level is reduced according to the degree of expansion. In FIG. 9, when the degree of expansion is set to 0, the input signal is in the non-expanded state, and the input level is output as it is. The wave signal is output as it is. When the degree of expansion is set to 1, when a sine wave signal having an average level of -40 dB is input, a sine wave having an average level of -60 dB is output.

FIG. 8 shows such a dynamic range extending device. The conventional dynamic range extender shown in FIG. 8 includes a converter 1 for A / D converting an input analog signal, and a dynamic range extender for extending a dynamic range of the A / D converted input data by digital signal processing. 2, a D / A converter 3 for D / A converting the output of the dynamic range expander 2, a keyboard 4, and a microcomputer for receiving expansion degree information sent from the keyboard 4 and converting it into an expansion coefficient G. And a control circuit 5 for converting an input analog signal into a digital signal, expanding the digital signal by digital signal processing, converting the input analog signal into an analog signal, and outputting the analog signal.

The dynamic range extender 2 typically includes a variable gain amplifying circuit 21 for amplifying input data, a buffer amplifier circuit 22 having a gain of 1 to which an output of the variable gain control amplifying circuit 21 is input, and a variable gain amplifying circuit 21. And a variable amplifying circuit 21 based on the level x detected by the level detecting circuit 23.
And a calculation circuit 24 for calculating the gain a (= (1−x) G) of the input data. The expansion degree information sent from the keyboard 4 is converted into the expansion coefficient G, and the calculation circuit 24 calculates the gain based on the expansion coefficient G. a is calculated, the gain of the variable gain amplifying circuit 21 is controlled to a, the output of the dynamic range expander 2 becomes (xin × a), and expansion is performed based on the expansion degree information. xin is the input of the dynamic range extender 2.

On the other hand, in the dynamic range extender 2, as shown in FIG.
(No sound state), the 0 dB sine wave is processed as a sine wave having a positive peak of 1.0 to a negative peak of -1.0,
It is usually used within the range of ± 1.0. Therefore, 0d
In the case of an input exceeding B, a portion exceeding ± 1.0 overflows as indicated by a broken line in FIG.

[0007]

However, in the case of the above-mentioned dynamic range expansion device, the average level of the output decreases in the entire input level region as the degree of expansion increases, and the case of voice will be described as an example. To the listener of the reproduced sound, it sounds as if the level had just dropped. Therefore, it is desired to increase the average level of the output for the input level region that is desired to be emphasized by the dynamic range expansion device. Therefore, in order to increase the average level of the output, the dynamic range extender 2 shown in FIG.
1 (b), when the characteristic of the degree of expansion 1 is translated by, for example, 10 dB as shown by the arrow, FIG.
There is a problem that overflow occurs in a portion of 1 (a) exceeding 1.0 (0 dB). This is because the dynamic range expander 2 is used in the range of ± 1 as described above. As a result, FIG.
As shown in (2), when an input of -8 dB or more is supplied, there is a problem that expansion cannot be performed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dynamic range extending device which does not cause a user to feel a decrease in average output level in an input level region to be emphasized.

[0009]

According to the present invention, there is provided a dynamic range extending apparatus comprising: an A / D converter for converting an input signal into digital data; an extension degree setting means for setting an extension degree;
A dynamic range extender that receives an output of the A / D converter and extends the dynamic range by digital signal processing based on the degree of extension set by the degree of extension setting means, and converts the output of the dynamic range extender to an analog signal D / A converter, variable attenuation means for receiving the output of the D / A converter as an input, and controlling the amount of attenuation based on an external signal; attenuation setting means for setting the amount of attenuation by the main volume; Storage means for storing a correction amount based on the correction amount, and a correction amount based on the degree of expansion set by the expansion degree setting means, from the storage means, and calculating and calculating a difference between the read correction amount and the attenuation amount due to the main volume. Control means for outputting a signal for controlling the amount of attenuation of the variable attenuating means to the amount of attenuation based on the difference as an external signal to the variable attenuating means. The features.

[0010] The dynamic range extending device of the present invention comprises:
An A / D converter for converting an input signal into digital data;
Expansion degree setting means for setting the expansion degree, a dynamic range expander to which the output of the A / D converter is input and which expands the dynamic range by digital signal processing based on the expansion degree set by the expansion degree setting means; D / which converts the output of the dynamic range extender to an analog signal
An A converter, an amplifier for amplifying the output of the D / A converter,
Variable attenuation means for receiving the output of the amplifier as input and controlling the attenuation amount based on an external signal; attenuation amount setting means for setting the attenuation amount by the main volume; storage means for storing a correction amount based on the degree of expansion; A correction amount based on the degree of expansion set by the degree setting means is read from the storage means, an operation of adding the gain of the amplifier to a difference between the read correction amount and the amount of attenuation by the main volume, and an attenuation based on the calculated value are performed. Control means for outputting a signal for controlling the amount of attenuation of the variable attenuation means to the variable attenuation means as an external signal.

[0011]

According to a first aspect of the present invention, there is provided a dynamic range extending device in which a dynamic range of an input signal is extended by a dynamic range extender, and an output of the dynamic range extender is adjusted by a correction amount based on the degree of extension of the dynamic range extender. Attenuated by the variable attenuating means with an amount of attenuation based on the difference from the amount of attenuation by the volume. As a result, the average output level of the dynamic range expander is increased without overflow, and the enhancement effect by the dynamic range expansion can be obtained without lowering the average output level for the input level region to be emphasized.

According to a second aspect of the present invention, the output from the dynamic range expander is amplified, and the amplified output is the difference between the correction amount based on the degree of expansion of the dynamic range expander and the attenuation amount due to the main volume. Is attenuated by the variable attenuation means with an attenuation amount based on As a result, the average output level of the dynamic range expander is increased without overflow, and the enhancement effect by the dynamic range expansion can be obtained without lowering the average output level for the input level region to be emphasized. Further, since the output from the dynamic range extender is amplified, the limit of the attenuation by the main volume is widened.

[0013]

The present invention will be described below with reference to examples. FIG.
FIG. 1 is a block diagram showing a configuration of an embodiment of a dynamic range extending device according to the present invention.

A dynamic range expansion device 10 according to one embodiment of the present invention expands a dynamic range by A / D conversion of an analog input signal and digital signal processing of A / D converted input data. A dynamic range extender 2, a D / A converter 3 for D / A converting the output of the dynamic range extender 2, an electronic volume 6 for attenuating the output of the D / A converter, and a degree of extension and attenuation by the main volume A keyboard 4 including operation keys such as a numeric keypad for setting the amount, a memory 7 storing an expansion coefficient based on the expansion degree and a correction amount, and a expansion coefficient G which receives expansion degree information transmitted from the keyboard 4. A microcomputer that converts and controls the amount of attenuation by the electronic volume 6 based on the amount of attenuation by the main volume and the amount of correction. And a composed controller 8 converts the input analog signal into a digital signal, is extended by the digital signal processing, and outputs the converted analog signal.

Here, the main volume is a substantial volume in which the amount of attenuation is set based on the audibility of the listener who listens to the reproduced sound obtained by reproducing the output of the dynamic range expansion device 10. In this embodiment, the signal is attenuated on the basis of the designated attenuation amount by designating the attenuation amount instead of the substantial volume.

The dynamic range extender 2 performs an extension operation by digital signal processing, but schematically shows a variable gain amplifying circuit 21 for amplifying input data and a gain 1 having an output of the variable gain control amplifying circuit 21 as an input. , A level detection circuit 23 for detecting an output level of the variable gain amplification circuit 21, and a gain a (= (1-x) of the variable amplification circuit 21 based on the level x detected by the level detection circuit 23. ) G), and the expansion degree information sent from the keyboard 4 is converted into an expansion coefficient G, and the arithmetic circuit 24 calculates a gain a based on the expansion coefficient G, and a variable gain amplifier circuit. 21 is controlled to a, the output of the dynamic range extender 2 becomes (xin × a), and the dynamic range is extended based on the degree of extension. The thing that made the same as in the conventional example. xin is the input of the dynamic range extender 2.

The information stored in the memory 7 is an expansion coefficient G and a correction amount based on the degree of expansion, and is schematically shown, for example, as shown in FIG.

The operation of the embodiment constructed as described above will be described with reference to the flowchart shown in FIG. The input signal is converted into digital data by the A / D converter 1,
It is input to the dynamic range extender 2.

In the initial setting, under the control of the control circuit 8, the dynamic range expander 2 is controlled not to perform the expansion operation, and the expansion degree is preset to 0 as an initial value. The attenuation in the main volume is preset to (40 dB) as an initial value, and the input digital data is directly output to D / A
The operation of the expansion degree 0 sent to the converter 3 is performed (step S1).

After step S1, the expansion coefficient G based on the degree of expansion is read from the memory 7 (step S2).
In the case of execution following the initial setting, the degree of expansion is 0 as described above, and 0 is read from the memory 7 as the expansion coefficient G and sent to the arithmetic circuit 24 (step S3). Therefore, the data input to the dynamic range extender 2 is output from the dynamic range extender 2 as it is. Subsequent to step S3, a correction amount based on the degree of expansion is read (step S4). In the case of the execution following the initial setting, the expansion degree is 0 as described above, and the correction amount 0 is read from the memory 7.

After step S4, the amount of attenuation to be set in the electronic volume 6 is calculated (step S5). In the case of execution following the initial setting, the attenuation of the main volume is set to (40 dB) as described above. Therefore, the correction amount (0 dB) and the attenuation value (4
0 dB) is calculated in the control circuit 8 (step S5), and the amount of attenuation in the electronic volume 6 is controlled based on the amount of attenuation as a result of the calculation (step S6). In this case, the calculation result is 40 dB (= 40 dB-0 dB (correction amount)), and the attenuation amount in the electronic volume 6 is 40 dB.
It is controlled to dB.

Subsequent to step S6, it is checked whether or not the attenuation of the main volume has been set by operating the operation keys of the keyboard 4 (step S7).
When it is determined that the setting has been made, the process is executed again from step S2. When the amount of attenuation in the main volume is set in step S6, the listener of the reproduced sound thinks that the amount of attenuation due to the main volume is insufficient or too large.

If it is determined in step S7 that the attenuation has not been set in the main volume, it is checked whether the expansion degree has been set by operating the operation keys of the keyboard 4 (step S8).
When it is determined that the setting has been made, the process is executed again from step S2. If it is not determined that the extension has been set, step S7 is executed following step S8, and the process waits until the attenuation in the main volume or the extension is set.

When the attenuation of the main volume is set in step S7, the attenuation of the electronic volume 6 is calculated based on the newly set attenuation, and the attenuation of the electronic volume 6 is calculated based on the calculated attenuation. The amount is set. When the degree of expansion is set in step S8, the expansion coefficient G based on the newly set degree of expansion is set.
And the correction amount are read from the memory 7. The degree of expansion of the dynamic range expander 2 is controlled based on the read expansion coefficient G. Further, the control circuit 8 controls the control circuit 8 based on the read correction amount and the attenuation amount in the main volume.
Thus, the attenuation of the electronic volume 6 is calculated, and the attenuation of the electronic volume 6 is set as the attenuation amount of the calculation result.

To explain the calculation in step S7 as an example in which the expansion degree is set to 2, the correction amount +16 dB corresponding to the expansion degree 1 is read, and the main volume attenuation value is initially set to -40 dB. , The calculation of (40 dB−16 dB = 24 dB) is performed, and the electronic volume 6 is set to the attenuation of 24 dB.

If the electronic volume 6 is not provided, the attenuation by the main volume is 40 dB, and if the degree of expansion is set to 2, as shown in FIG. The average level of the output has dropped over the region, and no attack sound has been emphasized. Hereinafter, the region α indicates a region where the average output level is lower than the case where the degree of expansion is zero. However, by connecting the electronic volume 6 as in the present embodiment and setting the attenuation amount of the electronic volume 6 based on the correction amount and the attenuation amount by the main volume, the attack sound as shown in FIG. The average level of the level region (referred to as an attack region β) that occupies the majority is raised.

Further, when using the dynamic range extender 10 of this embodiment, the dynamic range extender 2
In this case, no overflow occurs in the dynamic range extender 2 because the average level of the output is not corrected. In order to correct the level of the output signal by the electronic volume 6, if the input signal is in the β region,
A decrease in the average output level is prevented, and the effect of extending the dynamic range can be obtained without lowering the average output level.

In the above-described embodiment, the case where the expansion coefficient and the correction value are stored in the memory 7 when the expansion degree is 0, 1, or 2 has been described. The expansion coefficient and the correction amount can be stored. Further, the case of the electronic volume 6 has been illustrated, but any volume whose attenuation is controlled by an external signal may be used.

Next, a modification of the above-described embodiment will be described. This modification is an example in which the user can set the expansion coefficient and the correction amount by operating the operation keys of the keyboard 4 in the same manner as the setting of the attenuation amount in the main volume. FIG. 5 is a flowchart for explaining the operation of this modification.

In the case of this modification, if it is not determined in step S8 shown in FIG. 2 that the setting of the expansion degree has been made, it is checked whether the expansion coefficient G or the correction amount has been set following step S8. (Step S
9). When it is determined in step S9 that the expansion coefficient G or the correction amount has been set, the storage content of the memory 7 is updated based on the expansion coefficient G and the attenuation amount set in step S9 (step S10). Step S
If it is not determined in step 9 that the expansion coefficient G and the correction amount have been set, step S9 is followed by step S9.
7 will be executed.

Next, another embodiment of the present invention will be described. FIG. 6 is a block diagram showing the configuration of another embodiment according to the dynamic range extending device of the present invention.

The dynamic range extending device 11 according to the present embodiment differs from the dynamic range extending device 10 according to the above-described embodiment in that the output of the D / A converter 3 is provided between the D / A converter 3 and the electronic volume 6. Is connected to an amplifier 9 for amplifying and outputting the amplified signal to the electronic volume 6. The gain of the amplifier 9 is γ dB, for example, 16 dB.
It is fixed to.

Therefore, the output of the D / A converter 3 is given by γ dB by the amplifier 9 before being attenuated by the electronic volume 6.
Amplified. As a result, the attenuation of the electronic volume 6 becomes
(Memory 7 based on main volume attenuation value-extension degree)
From the correction value + the gain γ of the amplifier 9).

In the case of the dynamic range extending device 10 in one embodiment, the attenuation value of the main volume is 0
When the electronic volume 6 is set to dB, the electronic volume 6 is set to the attenuation amount, that is, since the electronic volume 6 has no function of amplifying, the electronic volume 6 is set to 0 dB, and the correction stored in the memory 7 is set. The value is effectively invalid.

Conversely, in the example shown in FIG. 3, since the maximum value of the correction amount is +16 dB, the attenuation by the main volume when the electronic volume 6 is set to 0 dB is 16 dB.
B, and the attenuation by the main volume is in the range of 16 dB or less. FIG. 7A shows the input / output characteristics in this case.
As shown in FIG. As described above, when the dynamic range expansion device 10 is used, the amount of attenuation by the main volume is limited.

However, when the dynamic range expansion device 11 of this embodiment is used, since the amplifier 9 (gain γ dB) is provided, the dynamic range expansion device 11 has the same value as that of the first embodiment when the expansion degree is the same. Then, the attenuation amount of the electronic volume 6 to be set is 56 dB (= 40 dB-0 dB + 16) when the degree of expansion is 0.
dB) When the degree of expansion is 1; 48 dB (= 40 dB−8 dB + 16)
dB) When the degree of expansion is 2; 40 dB (= 40 dB−16 dB + 1)
6 dB).

Therefore, the amount of attenuation in the electronic volume 6 is further increased by 16 dB from the amount of attenuation in the embodiment.
Can be lowered. Therefore, the electronic volume 6 can be set even if the attenuation of the main volume is set to a value of 16 dB or more. Therefore, even if the attenuation by the main volume is set to 0 dB, the average level of the output of the attack area β is emphasized as compared with the case where the degree of expansion is 0 as shown in FIG. 7B.

[0038]

As described above, according to the dynamic range extending apparatus of the present invention, input digital data corresponding to an input signal is input, and the dynamic range of the input signal is processed by digital signal processing based on the set expansion degree. The output from the dynamic range expander is converted into an analog signal and output, and the output is attenuated by the variable attenuating means and output. The attenuation of the variable attenuating means is corrected by the expansion degree and attenuated by the main volume. The average level of the output for the input level region to be emphasized can be increased without overflowing the dynamic range extender, and the output of the output for the input level region to be emphasized can be increased without causing the dynamic range expander to overflow. Emphasis effect by extending dynamic range without lowering average level An effect that is obtained.

Further, the output from the dynamic range expander is converted into an analog signal and output, the output is amplified, and the amplified output is attenuated by the variable attenuating means and output. Input to be emphasized without overflowing the dynamic range expander because the amount of attenuation is controlled to the amount of amplification gain added to the difference between the amount of correction based on the degree of expansion and the amount of attenuation by the main volume. It is possible to increase the average level of the output for the level area, obtain the enhancement effect by extending the dynamic range without lowering the average level of the output for the input level area that you want to emphasize, and further increase the limit of attenuation by the main volume The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a dynamic range extending device according to the present invention.

FIG. 2 is a flowchart for explaining the operation of an embodiment of a dynamic range extending device according to the present invention.

FIG. 3 is a schematic diagram for explaining the contents stored in a memory in one embodiment of the dynamic range extending device according to the present invention.

FIG. 4 is an input / output characteristic diagram for explaining the operation of an embodiment of the dynamic range extending device according to the present invention.

FIG. 5 is a flowchart for explaining the operation of a modification of the embodiment of the dynamic range extending device according to the present invention.

FIG. 6 is a block diagram showing a configuration of another embodiment of the dynamic range extending device according to the present invention.

FIG. 7 is an input / output characteristic diagram for explaining the operation of another embodiment of the dynamic range extending device according to the present invention.

FIG. 8 is a block diagram showing a configuration of a conventional dynamic range extending device.

FIG. 9 is a basic input / output characteristic diagram of the dynamic range extending device.

FIG. 10 is a waveform chart for explaining an extension effect of the operation of the dynamic range extension device.

FIG. 11 is a waveform diagram and an input / output characteristic diagram for explaining the characteristics of the dynamic range extender.

[Explanation of symbols]

 Reference Signs List 1 A / D converter 2 Dynamic range extender 3 D / A converter 4 Keyboard 6 Electronic volume 7 Memory 8 Control circuit 9 Amplifier

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03G 5/00-11/08

Claims (2)

(57) [Claims] An A / A converter for converting an input signal into digital data.
A D converter, expansion degree setting means for setting an expansion degree,
A dynamic range extender that receives the output of the D converter and extends the dynamic range by digital signal processing based on the extension set by the extension setting unit, and a D that converts the output of the dynamic range extender to an analog signal. A / A converter, a variable attenuator that receives the output of the D / A converter as an input, and controls the amount of attenuation based on an external signal; an amount of attenuation setting unit that sets the amount of attenuation by the main volume; A storage unit that stores the correction amount, and a correction amount based on the degree of expansion set by the expansion degree setting unit is read from the storage unit, and a difference between the read correction amount and the attenuation amount due to the main volume is calculated, and the calculated difference is calculated. Control means for outputting a signal for controlling the amount of attenuation of the variable attenuator to the amount of attenuation based on the external signal to the variable attenuator as an external signal. Dynamic range expansion device according to symptoms. 2. An A / D converter for converting an input signal into digital data.
A D converter, expansion degree setting means for setting an expansion degree,
A dynamic range extender that receives the output of the D converter and extends the dynamic range by digital signal processing based on the extension set by the extension setting unit, and a D that converts the output of the dynamic range extender to an analog signal. A / A converter, an amplifier for amplifying the output of the D / A converter, a variable attenuator having the output of the amplifier as an input, the amount of attenuation being controlled based on an external signal, and an attenuation for setting the amount of attenuation by the main volume An amount setting unit, a storage unit that stores a correction amount based on the degree of expansion, and a correction amount based on the degree of expansion set by the degree of expansion setting unit, and reads out the amount of correction from the read amount of correction and the amount of attenuation by the main volume. Performs an operation of adding the gain of the amplifier to the difference, and outputs a signal for controlling the amount of attenuation of the variable attenuation means to an amount of attenuation based on the calculated value. Dynamic range expansion apparatus being characterized in that a control means for outputting to the variable attenuating means as No..