Arrangment for adaptive bit recovery

An adaptive and self-adaptive equalization technology, applied in recording/reproducing/deleting methods, digital recording, information storage, etc., can solve problems such as unstable self-adaptive process

Inactive Publication Date: 2008-01-02
THOMSON LICENSING SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, in certain circumstances such as initialization or when dealing with errors in the data stream caused by scratches or fingerprints, the adaptive process tends to become unstable and counterproductive

Method used

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  • Arrangment for adaptive bit recovery
  • Arrangment for adaptive bit recovery
  • Arrangment for adaptive bit recovery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach

[0037] C new =C old +μ·∑(tfout-eqout*)·x (3)

[0038] Basically, the filtered feedback ref_data_n of the recovered data is compared with the equalizer output eq_out, weighted by an adaptive constant MU at the equalizer input x_del, and combined in a set of accumulators 72 . To reduce the number of filter coefficients, some quality degradation is accepted by employing symmetric filters. This in turn allows for simplified calculations. For this purpose, an averager 71 is provided. The feedback filter (target filter) 5 is a linear FIR filter comprising a delay unit 51 and a MAC unit 52 and follows the local response estimation of the considered data channel. Typically, this filter 5 is defined by declaring (symmetric) filter coefficients PR(abba). For example, it is common for DVD (Digital Versatile Disc) PR (1111) and BD (Blu-ray Disc) PR (1221).

[0039] In order to match the coefficients, the equalizer output eq_out and the X vector, ie the equalizer input, are delayed b...

example 1

[0070] PR(1221), data sequence 1110→1×(+1)+2×(+1)+2×(+1)+1×(-1)=+4 Therefore, the most likely next state of this conversion is state '4'.

example 2

[0072] PR(1221), data input 120, 120, 120, 100, assumes the first three bits have been detected, and specifies to scale the partial response sequence output to the range +128 to -128.

[0073] target value:

[0074] Unscaled: -6 -4 -2 0 +2 +4 +6

[0075] Scaled: -102 -68 -34 0 +34 +68 +102

[0076] Path 5: 120×(102)+120×(102)+120×(102)+100×(68)

[0077] Path 6: 120×(102)+120×(102)+120×(102)+100×(102)

[0078] The next state value is given by the minimum path value added to the current state value. Thus, for state '5', two paths are possible, etc. The state with the smallest value is the most likely next state. Therefore, the decoder only needs to know this state to discern the most probable bit.

[0079] Returning to FIG. 8, since the path storage and surviving control unit 153 needs to store paths, each path has an ID. Since only four different path decisions are required in the Trellis graph, binary number storage is sufficient for each desired choice. Therefore, the...

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PUM

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Abstract

The present invention relates to an arrangement for adaptive bit recovery, and to an apparatus for reading from and / or writing to recording media using such arrangement. According to the invention, an arrangement for adaptive bit recovery including an adaptive equalizer (13) and an adaptive partial response maximum likelihood detector (14) further includes an overflow control block (86) for the adaptive equalizer (13) for monitoring one or more of the adaptation coefficients and / or a state violation checker (162) for monitoring the allowed states and indicating state violations as well as and a noise detector (155) for detecting larger deviations of the target values.

Description

technical field [0001] The present invention generally relates to an adaptive bit recovery device, and more particularly relates to a device for adaptive bit recovery from an optical recording medium. It also relates to a device for reading from and / or writing to a recording medium using such a device. Background technique [0002] Recently, techniques for channel-adaptive recovery of data from optical recording media have been developed. However, due to the large number of possible media types such as Compact Disc, Digital Versatile Disc, Blu-ray Disc, and the fact that some recording media types are not protected by casings, strong monitoring of the adaptation process is required. To this end, several schemes are proposed to achieve a reliable data acquisition process. One scheme is depicted in Figure 1. The high-frequency data stream HF captured from the recording medium is sampled and quantized in the analog-to-digital converter 1, resampled to the data channel clock ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03M13/41G11B5/09G11B20/10
CPCG11B20/10111G11B2020/1288G11B20/10481G11B20/10046G11B20/10296G11B20/10009G11B20/10287G11B2220/2541
Inventor 阿克塞尔·科哈尔德克·施密特斯特凡·拉普
Owner THOMSON LICENSING SA
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