Oversampled Data Reading for Frequency-Drifting Digital Signals
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Solution Overview
Problem
Conventional DisplayPort systems face challenges in accurately sampling auxiliary channel signals due to fluctuations in sampling frequency caused by environmental pressures, temperature, and voltage variations, leading to imprecise data retrieval.
Innovation Solution
A method and device that utilize oversampling with a higher frequency to synchronize digital signals, defining sampling points and data reading ranges to correctly interpret data signals by tracking potential changes and resetting counters, thereby stabilizing data transfer despite frequency shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a ring oscillator clock is used to sample the auxiliary channel signal, then cost and power consumption are reduced, but sampling frequency fluctuates due to environmental pressure, temperature, and voltage variations, causing imprecise data retrieval
Solution Approach 1:
The patent changes the sampling frequency parameter by using an oscillator that generates a sampling frequency higher than the signal frequency (e.g., 16 MHz for a 1 MHz signal), enabling oversampling. This higher frequency sampling rate compensates for fluctuations caused by environmental factors, maintaining data accuracy without requiring complex frequency stabilization circuits.
Solution Approach 2:
The patent applies excessive sampling by taking more samples than the minimum required (Nyquist rate). By sampling at a frequency significantly higher than the signal frequency, the system obtains multiple samples per signal cycle, allowing selection of the most accurate sample and compensating for frequency variations without additional hardware.
2Device complexity
If a ring oscillator clock is used to sample the auxiliary channel signal, then device complexity is reduced by avoiding phase-locked loops, but sampling frequency fluctuates causing incorrect data reading
Solution Approach 1:
The patent changes the sampling frequency parameter to be significantly higher than the signal frequency (e.g., 16 times higher). This parameter change allows the simple ring oscillator to achieve reliable data reading through oversampling, eliminating the need for complex phase-locked loops while maintaining data accuracy despite environmental variations.
Solution Approach 2:
The patent creates multiple copies of samples through oversampling. By taking multiple samples at different time points within each signal cycle, the system can identify and select the correct data value even when the sampling frequency fluctuates, thereby maintaining reliability without increasing circuit complexity.
3Measurement precision
If oversampling with higher frequency is used to synchronize digital signals, then data reading accuracy is improved, but more sampling points and processing operations are required
Solution Approach 1:
The patent extracts only the necessary information from the oversampled data by identifying transition points (rising and falling edges) and reading data at specific sampling points. This extraction approach processes only the critical samples needed for accurate data retrieval, reducing processing complexity despite the high sampling rate.
Solution Approach 2:
The patent performs preliminary detection of signal transitions (rising and falling edges) before actual data reading. By identifying these transition points in advance, the system can focus processing only on relevant sampling points, reducing overall processing complexity while maintaining high data reading accuracy.
Data Source
AI summary
A method of reading data includes: receiving a digital signal, wherein the digital signal includes a sync signal and a data signal; performing an oversampling operation to the digital signal, and calculating a plurality of sampling points according to the oversampling operation; by a first counter counting the sampling points to obtain a first count value; based on the first count value defining a second count value; defining a unit interval; in the unit interval, defining a data reading range; and in the data reading range, reading the data signal corresponding to data of the unit interval as a first value when a potential of each of the sampling points counted is changed from a first potential to a second potential.