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DA converter device and sound system

A technology of a conversion device and a conversion circuit is applied in the field of DA conversion devices to achieve the effect of low distortion

Active Publication Date: 2014-05-28
PANASONIC SEMICON SOLUTIONS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] However, in the DA conversion device described in Patent Document 2, the DA conversion device using a D-class amplifier generates only odd-order higher harmonics (3rd, 5th... sub-harmonics), for this reason, there is a disadvantage that only odd-order high-order harmonic distortion can be corrected and it is limited to DA converters using class-D amplifiers.

Method used

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  • DA converter device and sound system
  • DA converter device and sound system
  • DA converter device and sound system

Examples

Experimental program
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Effect test

Embodiment approach 1

[0041] figure 1 Showing an example of the DA conversion device according to the first embodiment of the present invention, it is a block diagram showing an oversampling type DA conversion device.

[0042] exist figure 1 Among them, 10 is a digital filter, so that the sampling frequency of the input digital signal is n times (n≥2). 11 is a noise shaper, which receives the output from the digital filter 10 as an input, limits the word length, and changes the frequency characteristic of the noise to a given characteristic. Also, 12 is a decoder that takes the output of the noise shaper 11 as input and converts it into a 1-bit signal sequence corresponding to the value of the input digital signal. 13 is a 1-bit DA converter string including a plurality of 1-bit DA converters, and converts the 1-bit signal string from the decoder 12 into an analog signal. 14 is an analog adder which sums up the outputs of the respective 1-bit DA converters in the 1-bit DA converter string 13 . ...

Embodiment approach 2

[0096] Next, a second embodiment of the present invention will be described.

[0097] Figure 10 A block diagram showing a DA conversion device according to a second embodiment of the present invention. In this embodiment, instead of figure 1 The storage device 20 , nonlinear correction circuit 21 , and subtractor 22 are shown, and a DSP (calculation unit) 30 and subtractor 22 are arranged in the preceding stage of the digital filter 10 .

[0098] In this embodiment, the DSP (correction value output unit) 30 receives a digital input signal, and calculates based on the distortion correction function g1(x) derived from the distortion information of the result of frequency analysis of the analog output signal as described above. The corrected value corresponding to the digital input signal is calculated, and the calculated corrected value is output to the subtractor 22 . other components and figure 1 same.

[0099] Therefore, in this embodiment, instead of dividing the disto...

Embodiment approach 3

[0101] Figure 12 The overall schematic configuration of the audio system using the DA converter described above is shown.

[0102] Figure 12 The sound system of the company has an LSI50 that accepts signals from media such as CDs and DVDs. The LSI 50 includes: an AD conversion device 51 for performing AD conversion on a signal from the medium, an AUDIO DSP 52 for performing predetermined processing on a digital signal from the AD conversion device 51, and a digital signal processed by the DSP 52. The DA conversion device 53 for performing DA conversion is composed of the DA conversion device described in the first or second embodiment. The analog signal from the DA converter 53 of the LSI 50 is configured to be output to a speaker 57 via a low-pass filter (signal processing circuit) 55 and an amplifier (signal processing circuit) 56 .

[0103] Then, frequency analysis is performed on the analog output signal of the amplifier 56 at the final output stage of the acoustic sy...

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Abstract

In a DA converter device, a distortion correction function (g1(x)) of harmonics that is obtained as a result of a frequency analysis of an analog output signal of a DA converter circuit (15) is obtained, and correction values set on the basis of the correction function (g1(x)) in accordance with inputted digital signal values are stored in a storage device (20) in advance. A nonlinear correction circuit (21) reads, from the storage device (20), a correction value corresponding to the value of the digital signal output of a digital filter (10), and sends the correction value to a subtractor (20). The subtractor (20) subtracts the read out correction value from the digital signal output of the digital filter (10).

Description

technical field [0001] The present invention relates to a DA (Digital / Analog) converter for converting a digital signal into an analog signal. Background technique [0002] As one of the DA conversion devices, the present applicant proposes a DA conversion device in, for example, Patent Document 1 and Non-Patent Document 1, as an oversampling type DA that performs DA conversion at a high sampling frequency higher than the sampling frequency of a digital input signal. The conversion device uses a noise shaper and a 1-bit DA converter string composed of a plurality of 1-bit DA converters, and does not require a high clock frequency and does not require output deviation accuracy between the 1-bit DA converters. [0003] However, it is not limited to the above-mentioned oversampling type DA conversion device, and it is desirable to suppress distortion components included in the analog output signal of the DA conversion device in all DA conversion devices. [0004] For this reas...

Claims

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Application Information

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IPC IPC(8): H03M1/10
CPCH03M1/66H03M1/1038H03M1/10G10L19/00H03M3/50H03M3/388H03M1/12H03M1/00H03M1/785H03M1/747H03L7/0891
Inventor 鸟居纪宏堀井庆裕内田将史中塚淳二佐藤贵昭
Owner PANASONIC SEMICON SOLUTIONS CO LTD