Crystal Oscillator Drift Compensation for Burst Synchronization
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Solution Overview
Problem
Low-cost digital television (DTV) receivers for hand-held devices experience performance degradation due to short-term and long-term frequency drift caused by temperature changes, leading to synchronization loss with the transmitter.
Innovation Solution
A method and device that compensate for long-term and short-term frequency drift by determining the intercept and slope of frequency drift based on a burst of data, using a frequency offset computation module, drift estimation module, and error correction module to adjust subsequent bursts, thereby eliminating drift and improving receiver performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If crystal oscillators are used without temperature compensation to reduce cost, then device cost decreases, but frequency stability deteriorates due to temperature-induced drift
Solution Approach 1:
The patent changes the operational parameters of the crystal oscillator by dynamically adjusting its frequency based on temperature compensation data. The system measures temperature-induced frequency drift and applies correction factors to maintain stable operation without requiring a temperature-compensated crystal oscillator, thus reducing cost while maintaining frequency stability.
Solution Approach 2:
The patent replaces the mechanical/physical temperature compensation mechanism (temperature-compensated crystal oscillator) with an electronic/software-based frequency drift compensation system. By using digital signal processing to calculate and apply frequency corrections, the system achieves temperature compensation without the hardware complexity and cost of temperature-compensated components.
2Stability of the object's composition
If temperature-compensated crystal oscillators are used to improve frequency stability, then frequency drift decreases, but device cost and complexity increase
Solution Approach 1:
The patent replaces the physical temperature compensation mechanism with an electronic frequency drift compensation system that uses digital signal processing. The system calculates frequency drift based on temperature changes and applies corrections through software algorithms, eliminating the need for complex hardware temperature compensation circuits.
Solution Approach 2:
The system performs self-compensation by continuously monitoring its own frequency drift and automatically applying corrections. The frequency drift compensation module uses the received signal to calculate drift parameters and adjusts the local oscillator frequency accordingly, making the system self-regulating without external intervention.
3Reliability
If frequency drift compensation is implemented to maintain synchronization, then receiver performance improves, but processing complexity increases
Solution Approach 1:
The patent divides the frequency drift compensation process into distinct functional modules: a frequency drift estimation module that calculates drift parameters from received signals, and a frequency drift compensation module that applies corrections. This segmentation allows each module to perform its specific function efficiently, managing processing complexity through modular design.
Solution Approach 2:
The system performs preliminary frequency drift estimation using the received signal before applying compensation to subsequent processing. By calculating drift parameters in advance from the burst signal and applying these corrections to future receptions, the system prepares compensation data beforehand, reducing real-time processing complexity.
Data Source
AI summary
In at least some disclosed embodiments, a method includes receiving a burst of data out of multiple bursts of data subject to long-term frequency drift and short-term frequency drift, determining an intercept of the long-term frequency drift based on, at most, the entire burst, and compensating for the long-term drift of a subsequent burst based on the intercept. The method further includes determining a slope of the short-term frequency drift, and compensating for the short-term frequency drift of a subsequent burst based on the slope.