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Signal processing device and D/A converter

A signal processing device and converter technology, which is applied to digital-to-analog converters, recording signal processing, analog-to-analog conversion, etc., to achieve the effect of reducing the processing bit width and circuit area

Inactive Publication Date: 2003-10-22
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Furthermore, when a D / A converter or an equivalent element is required, the same problem as above occurs when an element with high resolution is required

Method used

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  • Signal processing device and D/A converter
  • Signal processing device and D/A converter
  • Signal processing device and D/A converter

Examples

Experimental program
Comparison scheme
Effect test

no. 1 Embodiment approach

[0050] figure 2 The configuration of the PLL block 8A according to the first embodiment of the present invention is shown. The PLL block 8A of this embodiment is equipped with a D / A converter 86A instead of Figure 15 The D / A converter 86.

[0051] The PLL block 8A includes: a phase comparator 81; a frequency comparator 82; a digital filter 83 that outputs an 8-bit digital control signal after smoothing the phase error; a digital filter 83 that outputs an 8-bit digital control signal DT11 after smoothing the frequency error filter 84; D / A converters 85, 86A; an adder 87 that adds the outputs of the D / A converters 85, 86A; a VCO 88 that changes the oscillation frequency of the output clock CK1 according to the output of the adder 87 and outputs A frequency divider 89 for generating a frequency-divided clock after frequency division of the clock CK1 . In addition, the comparators 81, 82 and the digital filters 83, 84 correspond to the digital part of the present invention, a...

no. 2 Embodiment approach

[0070] Image 6 The configuration of the PLL block 8B according to the second embodiment of the present invention is shown. The PLL block 8B of the present embodiment includes a D / A converter 86B instead of the D / A converter 86A in the PLL block 8A of the first embodiment. Hereinafter, the D / A converter 86B will be described in detail.

[0071] D / A converter 86B is composed of bit modulation unit 15A, D / A conversion unit 16 , analog filter 17 , current source 20 , and adder 21 . In addition, the current source 20 corresponds to the power supply unit of the present invention.

[0072] Figure 7 The configuration of the bit modulation unit 15A is shown. The bit modulation unit 15A outputs a 7-bit signal DT21 and a 1-bit modulation bit DT23 based on the input digital control signal DT11 .

[0073] The output of the register 151 is a 7-bit signal DT21 output from the bit modulation unit 15A. Therefore, the signal DT21 outputs the upper 7 bits of the digital control signal DT...

no. 3 Embodiment approach

[0080] Figure 10 The configuration of the PLL block 8C according to the third embodiment of the present invention is shown. The PLL block 8C of the present embodiment includes a D / A converter 86C instead of the D / A converter 86A in the PLL block 8A of the first embodiment.

[0081] Generally, the variable range of the oscillation frequency of the VCO 88 controlled in the phase loop (81-83A-85-87-88-89) is the same as that of the frequency loop (82-84A-86C-87-88-89). Very narrow compared to the variable range. For example, the output range of the D / A converter 85 of the phase loop is set to about 10% of the output range of the D / A converter 86C of the frequency loop.

[0082] However, in recording media such as CDs, the recording frequency differs between the inner and outer discs. When reproducing a signal recorded on such a medium, the frequency of the reproduced data changes slowly after the phase loop becomes stable. Therefore, in the phase loop, it is necessary to slo...

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Abstract

A D / A converter in an analog-digital mixed loop is realized with a reduced circuit area without sacrificing the resolution. A bit modulation section modulates an m-bit digital control signal, which is output from a digital section, into an n-bit (n<m) intermediate digital signal whose temporal average precision is substantially m bits. A D / A conversion section converts the intermediate digital signal into an intermediate analog signal having a range corresponding to m bits. Then, by the smoothing operation through an analog filter, the intermediate analog signal is output as an analog control signal that has an m-bit precision as that of the original signal. In this way, it is possible to reduce the bit width for the internal operation and thus to reduce the circuit area without sacrificing the resolution of a D / A converter.

Description

technical field [0001] The present invention relates to a signal processing device and a digital / analog (D / A) converter, in particular to D / A in a signal processing device for converging the loop output to a target value through an analog-digital hybrid loop composed of a digital part and an analog part. A transformation technique. Background technique [0002] As an example of a signal processing device with an analog-digital hybrid loop, Figure 14 Shows the structure of the playback signal processing device. The pickup 1 reads information recorded on a recording medium 3 such as an optical disk or a magnetic disk, which is rotationally driven by a rotating motor 2, and outputs it to a variable gain amplifier 4 as a reproduced signal. The amplitude of the reproduced signal is adjusted by the variable gain amplifier 4 so as to match the input dynamic range of the A / D converter 6 . Then, high-frequency noise is removed by the analog filter 5, quantized by the A / D converter...

Claims

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Application Information

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IPC IPC(8): H03L7/08H03L7/087H03L7/113H03M1/68H03M1/74H03M1/82H03M3/00
CPCH03M1/74H03M1/68H03M3/50H03M7/3002H03L7/06H03M3/30G11B20/10H03L7/08H03M3/00H03M1/82H03M1/66H03L7/093G11B20/10037H03L7/087H03L7/113
Inventor 冈本好史
Owner PANASONIC CORP
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