JP6901362B2 - Volume control device and control method - Google Patents

Description

The present invention relates to a volume control device for digitally processing an audio signal (analog signal), and more particularly to a volume control device and a volume control method for amplifying / attenuating an audio signal input from a line-in to control the volume.

In the volume control device of an electronic musical instrument, when processing the audio signal input from the line-in, it is amplified / attenuated by the operator provided in the analog circuit that becomes the electronic volume, and the volume is controlled on the software (DSP) by another setting. Is being done. As shown in FIG. 4, the volume control device includes an electronic volume (analog circuit) 1 that inputs an audio signal and adjusts the volume, an A / D converter 2 that converts an analog input signal into a digital signal, and digital signal processing. A DSP (digital signal processor) 3 for performing the above, a D / A converter 4 for converting a digital signal into an analog output signal, an amplifier 5 for amplifying the analog output signal, and a speaker 6 for sound generation are provided. Has been done. The electronic volume 1 is provided with an operator 7, and the DSP 3 is provided with an operator 9 having a CPU 8 interposed therebetween, and the volume emitted from the speaker 6 is controlled.

In the above volume control device, in order to obtain the optimum dynamic range for the analog output signal, the analog input signal that is the output of the electronic volume (analog circuit) 1 does not become full scale at the input value of the A / D converter 2. As described above, it was necessary to adjust the volume with the operator 7 and further reduce the volume with the signal processing of the DSP 3 controlled by the CPU 8 with the operator 9.

In a volume control device having such a configuration, when amplification / attenuation is performed only by the controller 7 of the electronic volume 1, the noise of the A / D converter 2 itself when the gain of the electronic volume 1 is large cannot be reduced. .. Further, when the attenuation is performed only by the controller 9 of the DSP3, when the analog input signal exceeding the full scale is input to the A / D converter 2, the waveform is distorted at the time of being input to the DPS3, and the adjustment is made. Can not.
That is, according to the volume control device described above, there are two controls for changing the volume, and unless the user understands the adjustment contents of each control, the operations of the controls 7 and 9 are optimal. It was difficult to obtain a dynamic range setting.

Further, Patent Document 1 proposes a mixer device in which one operator is provided for the electronic volume 1 and the DPS, and the analog input signal from the microphone is amplified and output to the outside only by the operator.
In this mixer device, an amplifier (electronic volume) that gain-amplifies and outputs in the first adjustment width unit and a digital signal obtained by analog-digital conversion of the amplifier output are subdivided into the first adjustment width unit. A second adjustment width unit, which is a width unit, has a configuration having a signal processing means (DSP) that digitally amplifies the gain and outputs it to the outside, and gain adjustment is performed by hardware (electronic volume) and software (DSP). As a result, the gain resolution is improved without being affected by noise.

Japanese Unexamined Patent Publication No. 2001-298335

However, according to the mixer device described above, the gain is adjusted by a combination in which the gain fluctuates greatly with the hardware (electronic volume) and the gain fluctuates with the software (DSP) in small steps (see FIG. 3 of Patent Document 1). Therefore, when the gain is fluctuated by the electronic volume, the drawback described in the volume control device of FIG. 4 described above that the noise of the A / D converter 2 itself cannot be reduced when the gain of the electronic volume 1 is large still remains. It has not been resolved.

The present invention has been proposed in view of the above circumstances, and in adjusting the volume of an audio signal (analog signal), a hard gain fluctuation (electronic volume) and a soft gain fluctuation (DSP) can be performed with one controller. ) At the same time, it is an object of the present invention to provide a volume control device and a control method capable of reducing the noise level over the entire output.

In order to achieve the above object, the volume control device according to claim 1 includes an analog circuit (electronic volume 1) that amplifies an analog signal, an A / D converter (2) that converts the amplified analog signal into a digital signal, and the like. In a volume control device provided with a digital signal processing circuit (DSP3) that amplifies the converted digital signal,
A processing unit (CPU10) that simultaneously controls the analog circuit (electronic volume 1) and the digital signal processing circuit (DSP3), and
The processing unit (10) is provided with one operator (11) that outputs operation information according to the operation amount.
A single threshold value is set for the operation amount of the operator (11), and the operation amount is set.
When the operation amount of the operator (11) is less than the threshold value, both the analog circuit (electronic volume 1) and the digital signal processing circuit (DSP3) operate to increase or decrease the gain.
When the amount of operation of the operator (11) is equal to or greater than the threshold value, the analog circuit (electronic volume 1) alone operates so as to increase or decrease the gain.

The second aspect of the present invention is the volume control device of the first aspect.
The threshold value is 50% of the manipulated variable of the operator (11).

A third aspect of the present invention is the volume control device according to the second aspect.
When the operation amount of the operator (11) is 50%, the gains of the analog circuit (electronic volume 1) and the digital signal processing circuit (DSP3) are both 0 dB.

The volume control method according to claim 4 is to amplify an analog signal by an analog circuit (electronic volume 1), convert the amplified analog signal into a digital signal by an A / D converter, and process the converted digital signal into a digital signal. In the volume control method that amplifies by a circuit (DSP),
When controlling the analog circuit and the digital signal processing circuit at the same time with the amount of operation by one operator,
When the amount of operation by the operator is less than 50% of the total amount of operation, both the analog circuit and the digital signal processing circuit are controlled to increase or decrease the gain.
When the amount of operation by the operator is 50% or more of the total amount of operation, the analog circuit alone is characterized in that the gain is controlled to be increased or decreased.

According to the volume control device and the volume control method of the present invention, the analog circuit (electronic volume 1) and the digital signal processing circuit (DSP3) can be controlled by one operator (11), so that the operator (11) can control the volume. Optimal settings can be obtained for the inputs of the analog circuit (electronic volume 1) and the digital signal processing circuit (DSP3) simply by combining only the two.

When controlling the volume, the input signal that is less than the full scale of the A / D converter (2) can be analog-amplified by the analog circuit (electronic volume 1), and the input signal that exceeds the full scale of the A / D converter (2). Can be analog-attenuated by an analog circuit (electronic volume 1), so when an analog signal with a volume that is actually used is input to the A / D converter 2, the noise level of the output signal of the A / D converter 2 Can be lowered and the optimum dynamic range can be obtained.

Further, when the input = output when the operation amount of the operator (11) is 50%, the gains of the analog circuit (electronic volume 1) and the digital signal processing circuit (DSP3) are both set to 0 dB. Noise that depends on the analog circuit (electronic volume 1) is not unintentionally amplified.

It is a block diagram for demonstrating the structure of the volume control device which concerns on this invention. It is explanatory drawing of the operator of a volume control device. (A) is a table diagram for performing gain fluctuation in the electronic volume of the volume control device, and (b) is a table diagram for performing gain fluctuation in the DSP of the volume control device. It is a block diagram for demonstrating the structure of the conventional volume control apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a volume control device according to an embodiment of the present invention.

The volume control device includes an electronic volume (analog circuit) 1 that inputs an audio signal and adjusts the volume, an A / D converter 2 that converts an analog input signal into a digital signal, and a DSP (digital signal) that performs digital signal processing. A processor) 3, a D / A converter 4 that converts a digital signal into an analog output signal, an amplifier 5 that amplifies the analog output signal, and a sounding speaker 6 are provided.

A processing unit (CPU) 10 is connected to the electronic volume 1 and the DSP 3, and one operator 11 is provided in the processing unit 10. The operator 11 is composed of a slider, a knob, a button, and the like, and is composed of, for example, a rotary operator as shown in FIG. The rotation operator is capable of reciprocating rotation within the range P of 270 degrees from 45 degrees to 315 degrees when the position directly below is 0 degrees, and this part corresponds to the total operation amount (volume value). There is. That is, when the position directly below is the 0 degree position, the volume value is 0 at the 45 degree position, the volume value is 50% at the 180 degree position (directly above), and the maximum volume value (100) is at the 315 degree position. %).
The operation information according to the rotation amount (operation amount) of the operator 11 is output to the processing unit (CPU) 10, and the processing unit 10 controls the electronic volume 1 and the DSP 3 according to the operation amount (volume value). ..

The control of the electronic volume 1 and the DSP 3 according to the rotation amount (operation amount) of the operator 11 will be described with reference to the table diagrams of FIGS. 3A and 3B.

FIG. 3A shows the gain of DSP3 according to the amount of rotation (operation amount) of the operator 11, and the rotation angle of the operator is 50% (the position of 180 degrees of the operator in FIG. 2, which is the threshold value). ) Is increased to 0 dB at 50%, and 0 dB is maintained when the rotation angle is 50 to 100% (the position of the operator at 180 to 315 degrees in FIG. 2) (DSP3). Gain does not change).
That is, until the rotation angle of the operator 11 is up to 50%, when the volume is turned down, the noise of the A / D converter 2 acts to decrease. Therefore, when the rotation angle of the operator 11 is smaller than 50%, the noise generated by the A / D converter 2 itself can be attenuated by the DSP 3 in the subsequent stage.

FIG. 3B shows the gain of the electronic volume 1 according to the rotation amount (operation amount) of the operator 11, and the volume continuously increases according to the rotation amount (rotation angle) of the operator 11. Is set to. When the rotation angle of the controller 11 is 50%, the output to the input is 0 dB, and when the rotation angle is 100%, the output to the input is +10 dB.

In the volume control method using the volume control device described above, when the electronic volume 1 and the DSP 3 are simultaneously controlled by the operation amount by one operator 11, when the operation amount by the operator 11 is less than 50% of the total operation amount, Both the electronic volume 1 and the DSP 3 are controlled to increase or decrease the gain, and when the operation amount by the operator 11 is 50% or more of the total operation amount, the gain is controlled to be increased or decreased by the electronic volume 1 alone.
That is, by setting the control of the electronic volume 1 and the DSP 3 with respect to the rotation amount (rotation angle) of the operator 11 as shown in FIG. 3, when controlling the volume, the input is less than the full scale of the A / D converter 2. The signal is analog-amplified by the electronic volume 1, and the input signal exceeding the full scale of the A / D converter 2 is analog-attenuated by the electronic volume 1.
Therefore, when an analog signal having a volume that is actually used is input to the A / D converter 2, the noise level of the output signal of the A / D converter 2 can be lowered, and an optimum dynamic range can be obtained. be able to.

Further, when the rotation angle of the operator 11 is 50%, the gains of the electronic volume 1 and the DSP 3 are both 0 dB, so that the inputs and outputs of the electronic volume 1 and the DSP 3 are equal to each other.
Further, when the rotation angle of the operator 11 is lowered from the 50% position, the outputs of the electronic volume 1 and the DSP 3 are both attenuated.
When the rotation angle of the operator 11 exceeds the 50% position, only the output of the electronic volume 1 is increased.

When the electronic volume 1 and the DSP 3 are controlled by the above-mentioned operator 11, when the rotation angle of the operator 11 is 50%, the input to the electronic volume 1 and the output from the DSP 3 become equal, and the audio signal becomes large. When it is the optimum input signal, the optimum dynamic range can be taken and the noise in the A / D converter 2 can be reduced.
When the volume is desired, the region where the rotation angle of the controller 11 is 50% or more is used, the DSP3 does not have a gain, and the electronic volume 1 has a gain only. Therefore, when the audio signal is a small signal, the electronic volume is used. By giving a gain at 1, the input to the A / D converter 2 can be set to an appropriate value.
When it is desired to lower the volume, the region where the rotation angle of the controller 11 is smaller than 50% is used, and the electronic volume 1 is attenuated while the DSP 3 is also digitally attenuated, so that the input to the A / D converter 2 is suitable. Can be set to a value.

According to the volume control device described above, the gain of the electronic volume (analog circuit) 1 and the gain of the DSP (digital signal processing circuit) 3 are set to 0 dB when the operation amount is 50% by using one same operator 11. Since the adjustment is made in a separate table, the noise in the A / D converter 2 to which the output of the electronic volume (analog circuit) 1 is input can be reduced, and the noise level can be reduced over the entire output of the DSP3. Can be planned.

1 ... Electronic volume (analog circuit), 2 ... A / D converter, 3 ... DSP (digital signal processor), 4 ... D / A converter, 5 ... Amplifier, 6 ... Speaker, 7 ... Operator, 8 ... CPU, 9 ... Operator, 10 ... Processing unit (CPU), 11 ... Operator.

Claims (4)

In a volume control device including an analog circuit that amplifies an analog signal, an A / D converter that converts the amplified analog signal into a digital signal, and a digital signal processing circuit that amplifies the converted digital signal.
A processing unit that simultaneously controls the analog circuit and digital signal processing circuit,
The processing unit is provided with one operator that outputs operation information according to the operation amount.
A single threshold value is set for the operation amount of the operator, and
When the operation amount of the operator is less than the threshold value, both the analog circuit and the digital signal processing circuit operate so as to increase or decrease the gain.
A volume control device characterized in that when the operation amount of the operator is equal to or greater than the threshold value, the analog circuit alone operates so as to increase or decrease the gain. The volume control device according to claim 1, wherein the threshold value is 50% of the operation amount of the operator. The volume control device according to claim 2, wherein when the operation amount of the operator is 50%, the gains of the analog circuit and the digital signal processing circuit are both 0 dB. In a volume control method in which an analog signal is amplified by an analog circuit, the amplified analog signal is converted into a digital signal by an A / D converter, and the converted digital signal is amplified by a digital signal processing circuit.
When controlling the analog circuit and the digital signal processing circuit at the same time with the amount of operation by one operator,
When the amount of operation by the operator is less than 50% of the total amount of operation, both the analog circuit and the digital signal processing circuit are controlled to increase or decrease the gain.
A volume control method characterized in that when the amount of operation by the operator is 50% or more of the total amount of operation, the analog circuit alone controls the gain to be increased or decreased.

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