Multi-Input Adaptive Equalizer for Crosstalk Cancellation
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Solution Overview
Problem
Existing technologies for canceling crosstalk in reproducing devices are limited in performance, particularly for devices not equipped with three beams and are complex in configuration, failing to effectively address dynamic crosstalk components and requiring accurate phase synchronization.
Innovation Solution
A data detecting device with a multi-input adaptive equalizer that performs partial response equalization and maximum-likelihood decoding, using a binarizing unit and equalization error calculating unit to optimize tap coefficients for crosstalk cancellation, allowing for accurate cancellation of crosstalk components with a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a phase difference detecting circuit and a phase synchronizing circuit are disposed before a crosstalk canceller to achieve accurate phase synchronization, then crosstalk cancellation accuracy is improved, but device complexity increases
Solution Approach 1:
The system uses the reproduction signal itself to generate the reference signal needed for correlation calculation, eliminating the need for separate phase synchronization circuits. The reproduction signal from the adjacent track serves dual purposes: as the signal to be processed and as the reference for calculating the crosstalk component, achieving self-service functionality.
Solution Approach 2:
A delay element is introduced as an intermediary component to adjust the timing of the reproduction signal from the adjacent track, enabling it to serve as an effective reference signal for correlation calculation without requiring complex phase synchronization circuits. The delay element mediates between the timing requirements of the reproduction signal and the reference signal.
2Device complexity
If conventional crosstalk cancellation technologies are used, then device configuration is simplified, but cancellation accuracy deteriorates under dynamic conditions and narrow track pitch scenarios
Solution Approach 1:
The system employs correlation calculation between the reproduction signal and the delayed reproduction signal to generate a crosstalk component estimate, which is then subtracted from the original reproduction signal. This feedback mechanism continuously adapts to dynamic conditions and maintains high cancellation accuracy without requiring complex device configuration.
Solution Approach 2:
The system dynamically adjusts the delay amount based on the track pitch and rotation speed variations, allowing the crosstalk cancellation to maintain high accuracy under different operating conditions. By changing the delay parameter adaptively, the system achieves accurate cancellation without increasing device complexity.
3Measurement precision
If three beams are used in the reproduction pickup to synchronize phase differences among reproduction signals, then crosstalk cancellation accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The reproduction signal from the adjacent track serves multiple functions: it is both the signal to be processed and the reference signal for correlation calculation. This multi-functionality eliminates the need for separate phase synchronization circuits or three-beam pickups, achieving high accuracy with simpler device configuration.
Solution Approach 2:
The system creates a delayed copy of the reproduction signal from the adjacent track to use as a reference signal for correlation calculation. This copied signal maintains the phase relationship needed for accurate crosstalk cancellation without requiring additional beams or complex synchronization hardware.
Data Source
AI summary
A data detecting device includes a multi-input adaptive equalizer, a binarizing unit, and an equalization error calculating unit. The multi-input adaptive equalizer includes a plurality of adaptive equalizers and outputs a reproduction information signal from a target track and a reproduction information signal from a close track close to the target track as equalization signals by calculating outputs of the adaptive equalizers, the reproduction information signals being input to the adaptive equalizers, respectively as reproduction information signals. The binarizing unit obtains binarized data by performing a binarization process on the equalization signals. The equalization error calculating unit obtains an equalization error from an equalization target signal obtained from the binarization result of the binarizing unit and an equalization signal output from the multi-input adaptive equalizer, and supplies the equalization error as a tap coefficient control signal for equalization to the adaptive equalizers.