RF Signal Quality Determination for High-Density Optical Discs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As data recording density on optical discs increases, the magnitude of RF signals decreases, leading to larger signal distortion from small noise amounts, causing jitter circuits to malfunction and making it difficult to accurately determine signal quality.
Innovation Solution
An RF signal quality determining device that includes a signal estimator, channel identifier, and quality calculator, which classify sample values into levels, calculate signal quality values such as SNR, ASNR, and PASNR, and use these values to improve signal processing and compensation techniques like focus and tilt compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data recording density on optical disc increases, then storage capacity is improved, but RF signal magnitude decreases causing larger signal distortion and jitter circuit malfunction
Solution Approach 1:
The patent changes the parameter used for signal quality evaluation from jitter value to signal-to-noise ratio (SNR). This parameter change allows accurate signal quality determination even when RF signal magnitude is small, as SNR can effectively measure signal quality without being affected by the absolute signal level, thus resolving the contradiction between increased recording density and maintained signal quality reliability
Solution Approach 2:
The patent replaces the jitter-based evaluation mechanism with an SNR-based evaluation mechanism. The jitter circuit that malfunctions at high densities is substituted with a signal quality determination device that calculates SNR using correlation between RF signals, which remains effective regardless of signal magnitude, thereby resolving the reliability issue at high recording densities
2Quantity of substance
If data recording density increases, then storage capacity is improved, but jitter value becomes large due to signal distortion from small noise amounts
Solution Approach 1:
The patent changes the measurement parameter from jitter value to signal-to-noise ratio (SNR). This substitution allows for precise measurement of signal quality even when jitter values become unreliable at high recording densities, as SNR can accurately reflect signal quality without being distorted by the effects of high-density recording
Solution Approach 2:
The patent introduces signal correlation calculation as an intermediary mechanism to determine SNR. By calculating the correlation between RF signals and using this to determine signal quality, the system bypasses the unreliable jitter measurement and achieves accurate signal quality assessment even at high recording densities where jitter circuits malfunction
Data Source
AI summary
A recording and/or reproducing apparatus and method with signal quality determining device and a method thereof, with the signal quality determining device including a signal estimator determining a level corresponding to a sample value of the RF signal using binary data obtained from the RF signal and generating a selection signal corresponding to the determined level, a channel identifier classifying the sample value into a plurality of levels according to the selection signal and obtaining an average value of the sample values classified into each level, and a quality calculator outputting a signal quality value representing quality of the RF signal using each sample value output from the channel identifier and the average value of the sample values classified into each level. Accordingly, quality of an RF signal can be determined more exactly, and focus compensation, tilt compensation, detrack compensation, and recording signal optimization can be performed using the determined signal quality.