JPH11284459A - Acoustic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high sound quality by preventing saturation at the time of high volume input, while suppressing the degradation of arithmetic accuracy to a minimum for a digital signal processor, such as DSP for performing digital signal processing. SOLUTION: An A/D converter 3 converts an analog audio signal from an LPF 2 into a digital signal, a digital signal processor 4 generates audio signal level data from that signal and outputs them to a control part 9, volume level control is performed by the internal processing of the digital signal processor 4 corresponding to a volume level control signal from the control part 9, and the audio signal, to which the volume level control is performed, is converted into an analog signal by a D/A converter 5, passed through an LPF 6 and a power amplifier 7 and outputted from a loudspeaker 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio apparatus for controlling a sound field by digital signal processing such as a DSP.

[0002]

2. Description of the Related Art Conventionally, there has been known an acoustic device having a function of adjusting and controlling a volume level using digital signal processing.

[0003]

However, in the conventional adjustment and control of each sound volume level using digital signal processing, a manual operation is performed by a user's operation, or a calculation process setting in which an input sound volume level is predicted in advance is performed. It was not possible to automatically adjust the level according to the input level of each music source.

The present invention solves such a problem in the prior art, and minimizes deterioration of calculation accuracy due to digital signal processing by automatically adjusting the level according to the input level of each music source. It is an object of the present invention to provide an excellent acoustic device which realizes high sound quality while keeping saturation at a low level and preventing saturation at the time of inputting a large volume.

[0005]

In order to solve the above-mentioned problems, an audio apparatus according to the present invention generates volume level data by a digital signal processing device such as a DSP and outputs the data to a control unit. The volume level control is performed in the internal processing of the digital signal processing device by the volume level control signal.

[0006] Thus, in an audio device such as a DSP which performs sound field control by digital signal processing, compared to the conventional system, it is necessary to manually operate the device by a user or to set a calculation process in which an input volume level is predicted in advance. There is no need to perform this operation, and an excellent audio device capable of controlling the volume level in the internal processing of the digital signal processing device according to the volume level of the music to be reproduced is obtained.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is an A / D converter for converting an analog audio signal from a music source into a digital signal, and a digital audio signal from the A / D converter. The volume level data is generated and output to the control unit, and the volume level control signal from the control unit performs volume level control based on the volume level control signal in the internal processing of the digital signal processing device, The controlled audio signal is D / A
A digital signal processing device for outputting to the converter; a control unit for generating a volume level control signal from the volume level control data from the digital signal processing device and outputting the volume level control signal to the digital signal processing device again; A D / A converter for converting an audio signal from a signal processing device into an analog signal, wherein the digital signal is obtained by performing control based on a volume level control signal of a music source. This has the effect of minimizing the deterioration of the calculation accuracy due to the processing and preventing the saturation at the time of inputting a large volume, thereby realizing high sound quality.

According to a second aspect of the present invention, when the data having a higher volume level than the reference value is input from the digital signal processing device, the control section lowers the volume level calculated inside the signal processing. 2. The audio device according to claim 1, wherein said audio device generates a volume level control signal. The audio device has high sound quality by minimizing deterioration of calculation accuracy due to digital signal processing and preventing saturation when a large volume is input. It has the effect that it can be realized.

According to a third aspect of the present invention, when data having a volume level lower than the reference value is input from the digital signal processing device, the control unit increases the volume level calculated inside the signal processing. 2. The audio device according to claim 1, wherein said audio device generates a volume level control signal. The audio device has high sound quality by minimizing deterioration of calculation accuracy due to digital signal processing and preventing saturation when a large volume is input. It has the effect that it can be realized.

According to a fourth aspect of the present invention, the control unit comprises:
The audio device according to claim 1, wherein a process of displaying a volume level adjustment value to be controlled is performed, and has an effect that the adjusted volume level can be visually confirmed.

Next, embodiments of the present invention will be described in detail with reference to the drawings. (Embodiment) FIG. 1 is a block diagram showing a configuration of an audio apparatus according to an embodiment of the present invention, which is used for an acoustic effect such as car audio.
In FIG. 1, reference numeral 1 denotes a music source playback device for playing back a music signal stored in an audio storage medium such as a CD as an audio signal, and 2 denotes a low-pass filter (LPF) for performing a filtering process on the audio signal from the music source playback device 1. 3 is LP
An A / D converter 4 converts an analog audio signal from F2 into a digital signal, and 4 generates audio signal level data from the digital audio signal from A / D converter 3 to control unit 9
And a volume level control signal from the control unit 9 performs volume level control based on the volume level control signal in internal processing of the digital signal processing device,
A digital signal processor for outputting a sound signal whose volume level has been controlled to a D / A converter 5, a D / A converter 5 for converting a digital sound signal from the digital signal processor 4 into an analog signal, and a D / A converter 6. Low-pass filter (LP) for performing a filtering process on the audio signal from / A converter 5
F) and 7 are power amplifiers that amplify the audio signal from the LPF 6, 8 is a speaker that outputs the audio signal from the power amplifier 7 as a music signal, and 9 is a digital signal based on audio signal level data from the digital signal processor 4. A volume level control signal for performing volume level control in the internal processing of the processing device 4 is generated and output to the digital signal processing device 4, control of an input signal from the operation unit 10, and display data to the display unit 11. A control unit constituted by a microcomputer or the like for performing processing such as output control of the LCD, an operation unit for outputting a control signal in response to an operation by a user, and an LCD for displaying display data from the control unit 9 And the like.

Next, the operation of this embodiment will be described. In FIG. 1, the music source is a music source playback device 1
And outputs the music signal to the LPF 2. LPF2
Performs a filtering process on the music signal from the music source reproducing apparatus 1 and outputs the filtered signal to the A / D converter 3. A / D converter 3
Converts the music signal from the LPF 2 into a digital signal and outputs the digital signal to the digital signal processing device 4. The digital signal processing device 4 generates audio signal level data from the digital audio signal from the A / D converter 3 and outputs the data to the control unit 9. The control unit 9 generates a volume level control signal for controlling the volume level in the internal processing of the digital signal processing device 4 from the audio signal level data from the digital signal processing device 4, and outputs the signal to the digital signal processing device 4. I do. The digital signal processing device 4 includes a control unit 9
Performs a volume level control in the internal processing of the digital signal processing device 4 according to a volume level control signal from the digital signal processor 4, and converts the audio signal subjected to the volume level control into a D / A converter 5.
Output to The D / A converter 5 converts the audio signal from the digital signal processing device 4 into an analog signal and outputs the analog signal to the LPF 6. The LPF 6 filters the music signal from the D / A converter 5 and outputs the music signal to the power amplifier 7. The power amplifier 7 amplifies the audio signal from the LPF 6 and
Output to The speaker 8 outputs a sound signal from the power amplifier 7 as sound. The control unit 9 controls an input signal from the operation unit 10 and controls output of a volume level adjustment value (control level) to the display unit 11. The operation unit 10 outputs a control signal for an operation from a user to the control unit 9. The display unit 11 displays the display data from the control unit 9.

FIG. 2 is a functional block diagram of a device for generating and outputting audio signal level data in the digital signal processing device 4. In FIG. 2, the digital audio signal from the A / D converter 3 is supplied to a frequency component dividing device 41. The frequency component dividing device 41 is constituted by a digital filter that allows only a designated frequency component to pass, and passes the digital audio signal to the absolute value calculating device 42 while passing only the designated frequency component. The absolute value calculating device 42 includes the frequency component dividing device 41
Of the digital audio signal passed therefrom, is converted into a signal having only a level component, and is output to the peak hold device 43. The peak hold device 43 detects and stores peak hold data of the audio signal subjected to the absolute value processing for a certain period of time, and outputs the data to the output control device 44. The output control unit 44 outputs the peak-held audio signal level data in response to a data request from the control unit 9. The control unit 9 can acquire the peak hold level based on the data from the output control device 44.

FIG. 3 is a functional block diagram of a device for performing audio level control in the digital signal processing device 4. In FIG. 3, a volume level control signal from the control unit 9 is supplied to an audio level control device 49. The audio level control device 49 adjusts the levels of the preceding level control device 45 and the subsequent level control device 48 based on the volume level control signal from the control section 9. The level control device 45 in the preceding stage converts the digital audio signal from the A / D converter 3 into
The control according to the audio level control device 49 is performed, and output to the internal signal processing device 46. Internal signal processing device 46
Performs the desired signal processing by the audio device, and outputs it to the volume control device 47. The volume control device 47
The volume is controlled according to the purpose of the user, and output to the level control device 48 at the subsequent stage. Subsequent level control device 48
Performs D / A control on the audio signal from the volume controller 47 according to the audio level controller 49.
Outputting to the converter 5 enables level adjustment.

FIG. 4 is a flowchart showing the processing in the control unit 9. In FIG. 4, the control unit 9 obtains audio signal level data from the digital signal processing device 4 (S1), obtains a reference value (S2), and compares them (S3). As a result of the comparison, if the level data is larger, a process of outputting a control signal to the digital signal processing device 4 so as to lower the volume level calculated inside the digital signal processing is performed (S4). Also, as a result of the comparison,
If the level data is smaller, a process of outputting a control signal to the digital signal processing device 4 to increase the volume level calculated inside the digital signal processing is performed (S
5).

FIG. 5 is a flowchart showing processing in the digital signal processing device 4. In FIG. 5, the digital signal processing device 4 acquires a level control signal from the control unit 9 (S11), and checks what the content is (S11).
12). If the level control signal is a control signal for lowering the operation level inside the digital signal processing device 4, control for lowering the audio level is performed by the preceding level control device (S13), and further control is performed by the subsequent level control device. Control for raising the audio level is performed (S14). For example,
The previous level control device performs control to lower by 2 dB,
Further, by performing the control of increasing the level by 2 dB by the subsequent level control device, the saturation of the sound level due to the decrease in the sound level of the internal arithmetic processing is prevented, and the input / output level is kept constant.

When the level control signal from the control section 9 is a control signal for increasing the operation level inside the digital signal processing device 4, the digital signal processing device 4 Is controlled (S15), and the control of lowering the audio level is performed by a subsequent level control device (S16). For example, by performing control to increase by 2 dB by the level control device in the preceding stage and by performing control to decrease by 2 dB by the level control device in the subsequent stage, it is possible to improve the calculation accuracy by increasing the audio level of the internal calculation process, and to improve the input accuracy. The output level is kept constant.

FIG. 6 shows a display example on the display unit 11. In FIG. 6, COMMO for performing vertical display control
The display in each mode is controlled by controlling the signal output to N and the SEGMENT for performing the horizontal display control. For example, FIG. 6 is a display example in the case where control is performed so as to raise the operation level inside the digital signal processing by two steps, and COMMON 6, 7, and SE
The level control state of the audio level is displayed by GMENT1.

[0019]

As is apparent from the above description, according to the present invention, the deterioration of the calculation accuracy in the digital signal processing such as the DSP and the internal processing of the digital signal processing apparatus is minimized by the control unit such as the microcomputer. In this case, high sound quality can be achieved by preventing saturation when a large volume is input.

[Brief description of the drawings]

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

FIG. 2 is a functional block diagram of a device for generating audio signal level data in the digital signal processing device.

FIG. 3 is a functional block diagram of a device for performing audio level control in the digital signal processing device.

FIG. 4 is a flowchart showing processing in a control unit.

FIG. 5 is a flowchart showing processing in the digital signal processing device.

FIG. 6 is a schematic diagram showing a display example on a display unit.

[Explanation of symbols]

 Reference Signs List 1 music source reproducing device 2, 6 low pass filter (LPF) 3 A / D converter 4 digital signal processing device 5 D / A converter 7 power amplifier 8 speaker 9 control unit (microcomputer) 10 operation unit 11 display unit

Claims (4)

[Claims] 1. An A / D converter for converting an analog audio signal from a music source into a digital signal, generating volume level data from the digital audio signal from the A / D converter and outputting the data to a control unit. And performing a volume level control based on the volume level control signal in an internal process of the digital signal processing device according to a volume level control signal from the control unit, and outputting the audio signal subjected to the volume level control to a D / A converter. A digital signal processor, a controller for generating a volume level control signal from volume level control data from the digital signal processor, and outputting the volume level control signal to the digital signal processor again; And a D / A converter for converting the audio signal into an analog signal. 2. The control unit according to claim 1, wherein, when data having a volume level higher than a reference value is input from the digital signal processing device, the control unit generates a volume level control signal so as to lower the volume level calculated inside the signal processing. The acoustic device according to claim 1, wherein: 3. The control unit generates a volume level control signal so as to increase a volume level calculated inside the signal processing when data having a volume level lower than a reference value is input from the digital signal processing device. The acoustic device according to claim 1, wherein: 4. The acoustic device according to claim 1, wherein a process of displaying an adjustment value of a volume level controlled by the control unit is performed.