State-Split Encoder-Decoder Graphs for Constrained Data Channels

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Solution Overview

Problem

Designing read channel devices to encode and decode data for constrained systems, such as hard disk drives, is challenging due to the need to avoid complex circuitry while ensuring accurate data retrieval, particularly in reducing long runs of consecutive transitions or ones, which existing technologies struggle to achieve efficiently.

Innovation Solution

The implementation of state-split based encoders and decoders that generate a directed graph to reduce hardware complexity by simplifying the memory structure, resulting in a final digraph with fewer branches per state, thereby easing the design of encoders and decoders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional encoder and decoder circuits are designed to handle constrained systems, then data encoding and decoding can be achieved, but hardware complexity increases due to the need to track multiple branches in the directed graph

Engineering Contradiction:
Improvedata integrityVSAvoidhardware complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the complex directed graph into multiple simplified sub-graphs, where each sub-graph represents a specific constraint condition. The encoder and decoder are designed to operate on these segmented sub-graphs rather than the complete complex graph, reducing hardware complexity while maintaining data integrity through systematic decomposition of the encoding/decoding task across multiple simpler computational paths

Inventive Principle:
Principle #1Segmentation

2Device complexity

If the directed graph is simplified to reduce hardware complexity, then encoder and decoder design becomes easier, but the ability to accurately represent constraint sets may be compromised

Engineering Contradiction:
Improveencoder complexityVSAvoidconstraint representation accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent employs dynamics by making the encoder and decoder adaptive to different constraint conditions. The system dynamically selects and switches between different simplified sub-graph representations based on the specific constraint set being applied, allowing the hardware to maintain accuracy for various constraint types without requiring a single complex fixed structure. This dynamic adaptation enables precise constraint representation while keeping individual encoder/decoder implementations simple

Inventive Principle:
Principle #15Dynamics

3Device complexity

If memory structure is simplified to reduce hardware complexity, then state tracking becomes easier, but the precision of tracking state changes across branches may be reduced

Engineering Contradiction:
Improvememory structure complexityVSAvoidstate tracking precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces intermediary computational elements that act as mediators between the simplified memory structure and the constraint satisfaction requirements. These intermediaries process and transform state information in a way that allows accurate tracking of constraint compliance using simpler memory structures. The intermediaries effectively bridge the gap between reduced memory complexity and the need for precise state tracking across what would traditionally require complex multi-branch tracking

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS9003263B2Encoder and decoder generation by state-splitting of directed graph
Publication Date: 2015.04.07 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • US9003263B2 patent drawing
  • US9003263B2 patent drawing
  • US9003263B2 patent drawing

AI summary

A method of generating a hardware encoder includes generating a first directed graph characterizing a constraint set for a constrained system, identifying a scaling factor for an approximate eigenvector for the first directed graph, applying the scaling factor to the approximate eigenvector for the first directed graph to yield a scaled approximate eigenvector, partitioning arcs between each pair of states in the first directed graph, performing a state splitting operation on the first directed graph according to the partitioning of the arcs to yield a second directed graph, and generating the hardware encoder based on the second directed graph.