JPH07254832A - Dynamic range extending device - Google Patents

Abstract

PURPOSE:To provide the dynamic range extending device in which the user does not sense a reduction in an average output level with respect to an input level range desired to be emphasized. CONSTITUTION:A dynamic range extending device 2 extends a dynamic range of an input signal converted into digital data by an A/D converter 1 based on a setting extension and an output of the dynamic range extending device 2 is converted into an analog signal by a D/A converter 3 and the converted analog signal is attenuated by the attenuation of an electronic volume 6. The attenuation of the electronic volume 6 is controlled to the attenuation based on an arithmetic operation output by a control circuit 8 calculating a difference between a correction value based on the extension read from a memory 7 and the attenuation by a set main volume.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic range expansion device, and more particularly to a dynamic range expansion device for emphasizing a decrease in average level of output with respect to an input level region to be emphasized after expansion by level correction.

[0002]

2. Description of the Related Art A dynamic range expansion device controls a small sound to be smaller and a large sound to a level close to an input level. For an input signal waveform shown in FIG. The output signal waveform is shown in Fig. 10 (b).
As shown in, the level difference is controlled to be about 24 dB, and there is an effect such as emphasizing a reproduced sound that can be placed when the level of the input signal suddenly increases and then decreases, so-called attack sound.

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

FIG. 8 shows such a dynamic range expansion device. The conventional dynamic range expansion device shown in FIG. 8 includes a converter 1 for A / D converting an input analog signal, and a dynamic range expansion device for expanding a dynamic range by digital signal processing of A / D converted input data. 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 the expansion degree information sent from the keyboard 4 and converting it to an expansion coefficient G. The control circuit 5 is provided, and the input analog signal is converted into a digital signal, expanded by digital signal processing, converted into an analog signal, and output.

The dynamic range expander 2 schematically includes a variable gain amplifier circuit 21 for amplifying input data, a buffer amplifier circuit 22 having a gain of 1 which receives an output of the variable gain control amplifier circuit 21, and a variable gain amplifier circuit 21. Level detection circuit 23 for detecting the output level of the variable amplification circuit 21 and the variable amplification circuit 21 based on the level x detected by the level detection circuit 23.
Of the gain a (= (1-x) G), and the expansion degree information sent from the keyboard 4 is converted into the expansion coefficient G, and the gain is calculated based on the expansion coefficient G by the arithmetic circuit 24. a is calculated, the gain of the variable gain amplifier 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 an input of the dynamic range expander 2.

On the other hand, in the dynamic range expander 2, as shown in FIG.
Expressing (soundless state), the 0 dB sine wave is processed as a positive peak 1.0 to a negative peak −1.0 sine wave,
It is usually used within a range of ± 1.0. Therefore, 0d
When the input exceeds B, the portion exceeding ± 1.0 overflows as shown by the broken line in FIG.

[0007]

However, in the case of the above-mentioned dynamic range expansion device, the average level of the output in the entire input level region decreases as the expansion degree 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 simply dropped. Therefore, it is desired to increase the average level of the output for the input level region to be emphasized by the dynamic range expanding device. Therefore, in order to raise the average level of the output, the dynamic range expander 2 is used to
In the input / output characteristic shown in FIG. 1 (b), when the characteristic of the extension degree 1 is translated by 10 dB as shown by an arrow,
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. 11 (b)
As shown in (3), there is a problem that it cannot be expanded when an input of -8 dB or more is supplied.

It is an object of the present invention to provide a dynamic range extending apparatus in which the user does not feel a reduction in the average level of the output with respect to the input level region that he or she wants to emphasize.

[0009]

A dynamic range expansion device of the present invention comprises an A / D converter for converting an input signal into digital data, an expansion degree setting means for setting an expansion degree,
The output of the A / D converter is input and the dynamic range is expanded by digital signal processing based on the expansion degree set by the expansion degree setting means, and the output of the dynamic range expander is converted into an analog signal. D / A converter, variable attenuation means for controlling the attenuation amount based on an external signal with the output of the D / A converter as input, attenuation amount setting means for setting the attenuation amount by the main volume, and expansion degree. And a correction amount based on the expansion degree set by the expansion degree setting means are read from the storage means, and the difference between the read correction amount and the attenuation amount by the main volume is calculated and calculated. And a control means for outputting a signal for controlling the attenuation amount of the variable attenuation means to the variable attenuation means as an external signal to the attenuation amount based on the difference. The features.

The dynamic range expansion device of the present invention is
An A / D converter for converting the input signal into digital data,
An expansion degree setting means for setting an expansion degree; a dynamic range expander for inputting an output of the A / D converter and expanding a dynamic range by digital signal processing based on the expansion degree set by the expansion degree setting means; D / that converts the output of the dynamic range expander into an analog signal
An A converter and an amplifier for amplifying the output of the D / A converter,
Variable attenuator that receives the output of the amplifier as an input and whose attenuation is controlled based on an external signal, attenuation amount setting means that sets the attenuation amount by the main volume, storage means that stores a correction amount based on the expansion degree, and expansion. The correction amount based on the expansion degree set by the degree setting means is read from the storage means, the difference between the read correction amount and the attenuation amount by the main volume is added to the gain of the amplifier, and the attenuation is calculated based on the calculated value. Control means for outputting a signal for controlling the amount of attenuation of the variable attenuator to the variable attenuator as an external signal.

[0011]

In the dynamic range extending apparatus according to the first aspect of the present invention, the dynamic range of the input signal is extended by the dynamic range extending unit, and the output of the dynamic range extending unit is a correction amount based on the extension degree of the dynamic range extending unit and the main value. The variable attenuator attenuates the amount of attenuation based on the difference from the amount of attenuation by the volume. As a result, the dynamic range expander can increase the average level of the output without overflow, and can obtain the enhancement effect by the dynamic range extension without lowering the average level of the output for the input level region to be enhanced.

According to another 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 expansion degree of the dynamic range expander and the attenuation amount due to the main volume. Is attenuated by the variable attenuator with an attenuation amount based on. As a result, the dynamic range expander can increase the average level of the output without overflow, and can obtain the enhancement effect by the dynamic range extension without lowering the average level of the output for the input level region to be enhanced. Further, since the output from the dynamic range expander is amplified, the limit of the attenuation amount due to the main volume is widened.

[0013]

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

A dynamic range expansion apparatus 10 according to an embodiment of the present invention expands a dynamic range by a converter 1 for A / D converting an input analog signal and digital signal processing of A / D converted input data. Dynamic range expander 2, D / A converter 3 for D / A converting the output of dynamic range expander 2, electronic volume 6 for attenuating the output of D / A converter, attenuation by expansion degree and 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 an expansion coefficient G which receives the expansion degree information sent from the keyboard 4. A microcomputer for converting and controlling the attenuation amount by the electronic volume 6 based on the attenuation amount by the main volume and the correction amount. 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 on the basis of the sensation of a listener who listens to the reproduced sound reproduced from the output of the dynamic range expanding device 10. In this embodiment, not the actual volume but the attenuation amount is designated, so that the signal is attenuated based on the designated attenuation amount.

The dynamic range expander 2 expands by digital signal processing, but if schematically shown, 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. Buffer amplification circuit 22, a level detection circuit 23 for detecting the 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, the operation circuit 24 calculates the gain a based on the expansion coefficient G, and a variable gain amplifier circuit. The gain of 21 is controlled to a, the output of the dynamic range expander 2 becomes (xin × a), and the dynamic range is expanded based on the expansion degree. The thing that made the same as in the conventional example. xin is an input of the dynamic range expander 2.

The information stored in the memory 7 is the expansion coefficient G and the correction amount based on the expansion degree, and is schematically shown in FIG. 3, for example.

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

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

Following step S1, the expansion coefficient G based on the expansion degree is read from the memory 7 (step S2).
In the case of execution subsequent to the initial setting, the expansion degree is 0 as described above, and 0 is read out 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 expander 2 is output as it is from the dynamic range expander 2. Following step S3, the correction amount based on the degree of expansion is read (step S4). In the case of execution subsequent to the initial setting, the expansion degree is 0 as described above, and the correction amount 0 is read from the memory 7.

Subsequent to step S4, the amount of attenuation set in the electronic volume 6 is calculated (step S5). In the case of execution subsequent to the initial setting, the attenuation amount 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 attenuation amount in the electronic volume 6 is controlled by the attenuation amount of this calculation result (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.
Controlled to dB.

Subsequent to step S6, it is checked whether or not the attenuation amount in the main volume has been set by operating the operation key 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 in the main volume is insufficient or too large.

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

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

The operation in step S7 will be described by taking the case where the expansion degree is set to 2 as an example. The correction amount +16 dB corresponding to the expansion degree 1 is read out, and the main volume attenuation value is initially set to -40 dB. Since it is set in (4), (40 dB-16 dB = 24 dB) is calculated and the electronic volume 6 is set to the attenuation amount of 24 dB.

If the electronic volume 6 is not provided, the attenuation by the main volume is 40 dB, and the extension degree is set to 2, as shown in FIG. The average level of the output has decreased over the region, and the attack sound has not been emphasized. Hereinafter, the area α indicates an area in which the average output level is lower than that in the case where the extension degree is 0. Therefore, 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, as shown in FIG. The average level of the level area (referred to as attack area β) that occupies the majority is increased.

Further, in the case of the dynamic range expanding device 10 of this embodiment, the dynamic range expanding device 2
Since the average level of the output is not corrected by, the overflow does not occur in the dynamic range expander 2, and in order to correct the level of the output signal by the electronic volume 6, when the input signal is in the β region,
The reduction of the average output level is prevented, and the effect of the dynamic range extension can be obtained without reducing the average output level.

In the above-mentioned embodiment, the memory 7 stores the expansion coefficient and the correction value when the expansion degree is 0, 1, 2, but it corresponds to more expansion degrees. The expansion coefficient and the correction amount can be stored. Further, although the electronic volume 6 has been illustrated, any volume whose attenuation amount 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 expansion coefficient and the correction amount can be set by the user by operating the operation keys of the keyboard 4 similarly to 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 expansion degree has been set, 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 is set, the stored contents of the memory 7 are 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 of the dynamic range extending apparatus of the present invention.

The dynamic range expansion device 11 in the other embodiment has the output of the D / A converter 3 between the D / A converter 3 and the electronic volume 6 in the dynamic range expansion device 10 in the above-described embodiment. It is configured by connecting an amplifier 9 for amplifying and outputting 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 γ dB by the amplifier 9 before being attenuated by the electronic volume 6.
Is amplified. As a result, the amount of attenuation of the electronic volume 6 is
(Memory 7 based on attenuation value of main volume-extension
(Correction value read from + gain γ of amplifier 9).

When the dynamic range expanding device 10 in one embodiment is used, the attenuation value of the main volume is 0.
When set to dB, the electronic volume 6 is set to the attenuation amount, that is, since the electronic volume 6 does not have the function of amplifying, the electronic volume 6 is set to 0 dB and the correction stored in the memory 7 is performed. The value is effectively invalid.

On the contrary, in the example shown in FIG. 3, since the maximum value of the correction amount is +16 dB, the attenuation amount by the main volume when the electronic volume 6 is set to 0 dB is 16 d.
The amount of attenuation due to the main volume is 16 dB or less. The input / output characteristic diagram in this case is shown in FIG.
As shown in. Thus, when the dynamic range expansion device 10 is used, the amount of attenuation by the main volume is limited.

However, in the dynamic range expansion device 11 according to the other embodiment, since the amplifier 9 (gain γ dB) is provided, the value at the same expansion degree as in the case of the one embodiment is used. When calculated, the set attenuation amount of the electronic volume 6 is 56 dB (= 40 dB−0 dB + 16) when the extension degree is 0.
dB) When the extension degree is 1; 48 dB (= 40 dB-8 dB + 16)
dB) When the extension degree is 2; 40 dB (= 40 dB-16 dB + 1)
6 dB).

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

[0038]

As described above, according to the dynamic range expanding apparatus of the present invention, the input digital data corresponding to the input signal is inputted and the dynamic range of the input signal is expanded by the digital signal processing based on the set expansion degree. The output from the dynamic range expander for expansion is output after being converted into an analog signal, the output is attenuated by the variable attenuator and output, and the attenuation amount of the variable attenuator is attenuated by the correction amount based on the extension degree and the main volume. Since the amount of attenuation is controlled based on the difference from the amount, the average level of the output for the input level region to be emphasized can be increased without overflowing the dynamic range expander, and the output for the input level region to be emphasized can be increased. Enhancement effect by extending the dynamic range without reducing the average level An effect that is obtained.

Furthermore, the output from the dynamic range expander is converted into an analog signal and output, the output is amplified, the amplified output is output after being attenuated by the variable attenuator, and the variable attenuator is output. Since the attenuation amount of is controlled to the attenuation amount based on the difference between the correction amount based on the extension degree and the attenuation amount due to the main volume plus the amplification gain, the input that you want to emphasize without overflowing the dynamic range expander. The average output level for the level region can be increased, the enhancement effect can be obtained by extending the dynamic range without lowering the average output level for the input level region to be enhanced, and the limit of the attenuation amount by the main volume is further expanded. The effect is obtained.

[Brief description of drawings]

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

FIG. 2 is a flow chart for explaining the operation of one embodiment of the dynamic range extending apparatus according to the present invention.

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

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

FIG. 5 is a flow chart for explaining the operation of a modified example of the embodiment of the dynamic range extending apparatus according to the present invention.

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

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

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

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

11A and 11B are a waveform diagram and an input / output characteristic diagram for explaining characteristics of the dynamic range expander.

[Explanation of symbols]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H03G 5/16 C

Claims (2)

[Claims] 1. An A / which converts an input signal into digital data.
A D converter, an extension degree setting means for setting the extension degree, and A /
The output of the D converter is input and the dynamic range is expanded by digital signal processing based on the expansion degree set by the expansion degree setting means, and the output of the dynamic range expander is converted into an analog signal D / A converter, variable attenuation means for controlling the attenuation amount based on an external signal with the output of the D / A converter as input, attenuation amount setting means for setting the attenuation amount by the main volume, and extension amount The storage means storing the correction amount and the correction amount based on the expansion degree set by the expansion degree setting means are read from the storage means, the difference between the read correction amount and the attenuation amount by the main volume is calculated, and the calculated difference is calculated. And a control means for outputting a signal for controlling the attenuation amount of the variable attenuation means to the variable attenuation means as an external signal. Dynamic range expansion device according to symptoms. 2. An A / which converts an input signal into digital data.
A D converter, an extension degree setting means for setting the extension degree, and A /
The output of the D converter is input and the dynamic range is expanded by digital signal processing based on the expansion degree set by the expansion degree setting means, and the output of the dynamic range expander is converted into an analog signal D / A converter, an amplifier for amplifying the output of the D / A converter, variable attenuator whose input is the output of the amplifier and whose attenuation is controlled based on an external signal, and attenuation for setting the amount of attenuation by the main volume. An amount setting means, a storage means for storing a correction amount based on the expansion degree, a correction amount based on the expansion degree set by the expansion degree setting means, read from the storage means, and the read correction amount and the attenuation amount by the main volume The signal for controlling the amount of attenuation of the variable attenuator is calculated by adding the gain of the amplifier to the difference and calculating the 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..