JPH0563198U - Audio signal processor - Google Patents

Abstract

(57) [Abstract] [Purpose] Electronic devices. In an audio signal processing device, an analog signal is provided between a D / A converter for converting a digital audio signal into an analog left (L) signal and a right (R) signal, and a low-pass filter arranged on the output side. A switch circuit is arranged.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an audio signal processing device, and more particularly to an audio signal processing device adapted to convert a digital audio signal into an analog signal for reproduction.

[0002]

[Prior Art]

 FIG. 3 shows a typical conventional circuit for processing an audio signal from a device storing a digital audio signal such as a CD-ROM or a CD. In FIG. 3, 11 is a CD-ROM. , A signal processing circuit composed of an LSI for converting a digital audio signal extracted from a disk device such as a CD into a form in which a right signal (R) and a left signal (L) are combined, and 12 acts on the signal processing circuit 11. Then, the control device (CPU) 13 for performing the control necessary for taking out the above-mentioned signal is composed of an IC for converting the input digital audio signal into an analog audio signal under the control of the control device 12. The D / A converter 14 is a low-pass filter composed of an IC having an amplification function for filtering the signal divided into the L and R signals by the D / A converter 13.The output of the low-pass filter 14 is sent to the subsequent stage as a line output. Reference numeral 15 is an emphasis circuit, and 16 is an independent mute circuit, which under control of the controller 12 modify the L and R signals sent from the D / A converter 13. Reference numeral 17 denotes an independent mute circuit arranged in the subsequent stage of the low-pass filter 14, which modifies the L and R signals output from the low-pass filter 14 under the control of the control device 12. Reference numeral 18 denotes a headphone circuit connected to the output side of the low pass filter. Each of the above-mentioned components is usually composed of an IC.

[0003]

[Problems to be solved by the device]

 In the configuration as shown in FIG. 3, when it is desired to switch the audio part in order to support the following multimedia, a mechanical changeover switch is arranged on the output side of the low pass filter 14 to perform the changeover control. Was there. (1) LR independent mute (sound output of L channel or R channel only) (2) Swap (output of R channel to R channel sound, R channel to L channel sound) (3) Mixing (monaural sound (4) L channel monaural (outputs L channel audio from both L and R channels) (5) R channel monaural (outputs R channel audio from both L and R channels) (6) L and R independent Attenuator (Variable output level independently for left and right) However, as mentioned above, if the multimedia switching process of the audio part is performed by the mechanical switching switch on the output side of the low pass filter, the space factor becomes worse and the device is compact. It was an obstacle to the conversion.

[0004]

[Means for Solving the Problems]

 In order to solve such a problem, an analog switch is arranged between the D / A converter and the low pass filter.

[0005]

[Action]

 With this configuration, it is possible to digitize multimedia-compatible switches.

[0006]

【Example】

 FIG. 1 shows an embodiment of the present invention, and the same reference numerals are used for the same components or those having the same functions as those of FIG. In the figure, the difference from FIG. 1 is that an analog switch 21 is arranged between the D / A converter 13 and the low-pass filter 14.

FIG. 2 shows an example of the analog switch 21, which is configured to perform an operation except for the above-mentioned multimedia function switch function (6). Further, this switch can be configured by an IC (semiconductor integrated circuit), and for example, an analog multiplexer is used. The analog switch 21 shown in FIG. 2 includes double throw switches 21a, 21b and 21c having three neutral positions, and eight combinations can be selected by combining three control signals from the control device 12. It has become.

In this case, the analog switch 21, which is composed of an IC, has a large internal resistance. Therefore, if it is provided in the subsequent stage of the low-pass filter 14, the output impedance will be reduced. On the other hand, if an analog switch is provided between the D / A converter 13 and the low-pass filter 14 as in the present invention, it is possible to suppress variations in the internal resistance of the IC of the analog switch 21 and stabilize the characteristics. Can be

[0009]

[Effect of the device]

 As described above, according to the audio signal processing device of the present invention, the device can be made electronic when carrying out the multimedia compatible processing of the audio part, and the device can be made more compact than the conventional one and the characteristics can be improved. It has the effect of making it stable.

[0010]

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing an example of an analog switch used in FIG.

FIG. 3 is a block diagram showing a configuration of a conventional audio signal processing device.

[Explanation of symbols]

 11 signal processing circuit 12 CPU 13 D / A converter 14 low-pass filter 15 enhancement circuit 16 independent mute circuit 17 mute circuit 18 headphone circuit 21 analog switch

Claims (1)

[Scope of utility model registration request] 1. An analog switch circuit is arranged between a D / A converter for converting a digital audio signal into analog left (L) and right (R) signals, and a low-pass filter arranged on the output side. An audio signal processing device characterized by the above.