STW Signal Demodulation Using Digital Timing Control
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Solution Overview
Problem
Conventional methods for demodulating saw tooth wobble (STW) signals in Blu-ray disks are costly due to the use of expensive band-pass filters and multipliers, which are necessary to separate wobble and data signals.
Innovation Solution
An apparatus and method utilizing a determining unit, a calculating unit, and a comparing unit to determine calculating timings and modes, generate calculating results, and output demodulated data based on threshold settings, reducing the need for expensive components by employing phase locked loops, integrators, adders, or sample-and-hold circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional band-pass filter and multiplier are used to demodulate STW signal, then demodulation accuracy is maintained, but device cost increases significantly
Solution Approach 1:
The patent replaces expensive band-pass filters and multipliers with inexpensive computational operations (integration, addition, sampling) that can be implemented in software or simple digital circuits. The calculating unit performs demodulation through mathematical operations rather than expensive analog components, dramatically reducing device cost while maintaining demodulation accuracy.
Solution Approach 2:
The patent substitutes the mechanical/electrical analog system (band-pass filter and multiplier circuits) with a digital computational system. The determining unit calculates optimal timing points, the calculating unit performs integration/addition/sampling operations, and the comparing unit makes decisions based on calculated results, replacing physical filtering and multiplication with mathematical computations.
2Reliability
If band-pass filter and multiplier are used for STW signal demodulation, then signal separation is achieved, but device complexity increases
Solution Approach 1:
The patent replaces the analog signal separation mechanism (band-pass filter and multiplier) with digital computational operations. The calculating unit separates wobble and data signals through integration and addition operations at specifically determined timing points, achieving reliable signal separation without complex analog circuitry.
Solution Approach 2:
The determining unit automatically determines the optimal timing points for calculation based on the input signal characteristics, eliminating the need for manual configuration or complex external control circuits. The system self-adjusts to achieve accurate signal separation.
Data Source
AI summary
An apparatus and method for demodulating an input signal modulated from a reference signal and a data signal are disclosed. The apparatus includes a determining unit, a first calculating unit, and a comparing unit. The determining unit is utilized for determining a plurality of first calculating timings of changing different calculating modes according to the input signal. The first calculating unit is coupled to the determining unit and utilized for generating a first calculating result of the input signal according to the first calculating timings and the calculating modes thereof. The comparing unit is coupled to the first calculating unit and utilized for generating a comparing result according to the first calculating result of the input signal and a threshold setting, and for outputting a demodulated data of the input signal according to the comparing result.