Signal Processing Apparatus for Suppressing Nonlinear Noise in Optical Media
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Solution Overview
Problem
High-density multilayered optical recording media generate mixed nonlinear noise components, making it difficult for existing filters like FIR, neural network, Volterra, and ARML filters to sufficiently suppress noise and perform adaptive control effectively.
Innovation Solution
A signal processing apparatus with a combination of bandpass filter, offset canceler, Volterra filter, ARML filter, and noise estimator, which sequentially suppresses offset, nonlinear distortion, and correlation noise components in the reproduction signal, using Volterra filtering and adaptive tap coefficient updates to stabilize noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-density multilayered optical recording medium is used to increase data capacity, then recording capacity increases, but nonlinear noise components increase making reproduction accuracy difficult to secure
Solution Approach 1:
The patent segments the noise suppression task into multiple specialized filters: offset suppressor for DC offset, Volterra filter for nonlinear distortion, and ARML filter for correlation noise. Each filter targets specific noise components separately rather than using a single general-purpose filter, enabling effective suppression of mixed nonlinear noise from high-density multilayered media.
Solution Approach 2:
The patent employs a composite filtering system combining multiple different filter types (offset suppressor, Volterra filter, ARML filter) working in sequence. This composite approach leverages the strengths of each filter type to handle different aspects of nonlinear noise, achieving superior noise suppression compared to any single filter type alone.
2Ease of manufacture
If FIR filter is used for noise suppression, then linear equalization is achieved, but nonlinear noise component suppression is insufficient
Solution Approach 1:
The patent replaces the single FIR filter with segmented specialized filters: offset suppressor for offset removal, Volterra filter for nonlinear distortion, and ARML filter for correlation noise. This segmentation allows each filter to be optimized for its specific function while maintaining overall system simplicity.
Solution Approach 2:
The patent changes the filtering parameters and approaches by introducing adaptive control mechanisms that dynamically adjust filter coefficients based on input signal characteristics. This enables the filter system to adapt to varying nonlinear noise conditions while maintaining ease of implementation through standardized filter structures.
3Reliability
If single nonlinear filter (neural network, Volterra, ARML) is used for nonlinear equalization, then specific nonlinear noise suppression is achieved, but stable adaptive control becomes difficult with mixed noise components
Solution Approach 1:
The patent segments the adaptive control task across multiple filters with different control bandwidths. The offset suppressor handles offset adaptation, the Volterra filter handles nonlinear distortion with medium control bandwidth, and the ARML filter handles correlation noise with narrow control bandwidth. This segmentation prevents any single filter from becoming unstable while adapting to mixed noise components.
Solution Approach 2:
The patent applies different control bandwidths to different filters based on their specific functions: wider bandwidth for offset suppression, medium bandwidth for nonlinear distortion, and narrower bandwidth for correlation noise. This local optimization of control parameters ensures stable adaptive control for each filter type while maintaining overall system performance.
Data Source
AI summary
According to an embodiment, a signal processing apparatus includes a first signal processor, a second signal processor and a third signal processor. The first signal processor suppresses an offset component remaining in a reproduction signal read from an optical recording medium to obtain a first signal. The second signal processor suppresses a nonlinear distortion component remaining in the first signal to obtain a second signal. The third signal processor suppresses a correlation noise component remaining in the second signal to obtain a third signal.