Magnetic Recording Medium Evaluation Using Digital Filtering
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Solution Overview
Problem
Existing magnetic recording medium evaluation apparatuses require sophisticated signal processing circuits to measure error rates, limiting their applicability when comparing media with different structures, as they fail to provide good correlation between signal-to-noise ratio and error rates.
Innovation Solution
A magnetic recording medium evaluation apparatus and method that utilize digital filters and signal generators to calculate a signal-to-noise ratio without requiring complex signal processing circuits, using arbitrary recording signals and square-wave signals to evaluate media with different structures, and estimating coefficients based on signal intensities at multiple linear recording densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated signal processing circuit is used to measure error rates directly, then measurement precision is improved, but device complexity increases and adaptability decreases
Solution Approach 1:
The patent replaces complex dedicated signal processing circuits with digital signal processing implemented through software algorithms. The evaluation apparatus uses a general-purpose evaluation circuit that processes signals through digital filtering and correlation analysis, substituting specialized hardware circuits with flexible software-based processing to reduce device complexity while maintaining measurement precision.
Solution Approach 2:
The patent creates a universal evaluation apparatus that can assess multiple types of magnetic recording media with different structures using the same basic circuitry. By employing adaptable digital signal processing algorithms that can be configured for different media types, the apparatus achieves multi-functionality without requiring dedicated specialized circuits for each media type, thus reducing overall device complexity.
2Ease of operation
If MF-SpiSNR is used for evaluation, then ease of operation is improved, but measurement precision deteriorates when comparing media with different structures
Solution Approach 1:
The patent implements a feedback mechanism where the evaluation circuit continuously processes reproduced signals through digital filtering and compares them against the original recording signals. This feedback loop enables real-time correction and optimization of the evaluation process, allowing the system to adapt to different media structures while maintaining precise error rate correlation through iterative signal processing and comparison.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting digital filter coefficients and processing parameters based on the specific characteristics of the magnetic recording medium being evaluated. The system can modify evaluation parameters such as sampling intervals, filter characteristics, and correlation thresholds to optimize performance for different media structures, thereby maintaining measurement precision across diverse media types while preserving ease of operation.
Data Source
AI summary
This invention provides a magnetic recording medium evaluation apparatus and evaluation method which yield results having good correlation with error rate measurements even when comparing media with different structures. Signals from a function generator are recorded in a magnetic recording medium. The recording signals are also passed through a first digital filter to obtain ideal restored signals. Reproduced signals from the magnetic recording medium are sampled in synchronization with the output from the function generator, and the discrete signals are passed through a second digital filter to obtain restored signals. The outputs from the first and second digital filters are input to an operational amplifier, and the difference between the restored signals and the ideal restored signals is taken for each sampling of the recording signals. The signal-to-noise ratio of the ideal restored signal to the average of the absolute value of this difference is used to evaluate signal quality.