Digital Data Phase Tracking via FIR Tap Adjustment
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Solution Overview
Problem
Conventional communication devices require complex configurations and external analog components like VCOs, filters, and D/A converters for clock synchronization, leading to increased costs and noise issues.
Innovation Solution
A data phase tracking device using an FIR filter and tap coefficient adjuster for digital signal processing, eliminating the need for external analog components by adjusting tap coefficients to synchronize sampling with a fixed-frequency oscillator, allowing phase tracking without external circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional clock synchronization using PLL and analog VCO is used, then clock synchronization is achieved, but device complexity increases and noise characteristics worsen
Solution Approach 1:
The patent replaces the mechanical/analog PLL system with a digital sampling system. Instead of using analog VCO and external filters, the invention uses digital sampling of the reception signal at multiple phases followed by digital signal processing to determine the optimal sampling phase, thereby substituting complex analog clock synchronization circuitry with simpler digital processing.
2Reliability
If analog VCO and external circuits are used for clock synchronization, then phase locking is achieved, but manufacturing cost increases
Solution Approach 1:
The invention substitutes expensive analog components (VCO, external filters, D/A converters) with digital processing circuits. The phase locking function is achieved through digital sampling and correlation processing, eliminating the need for costly analog components and simplifying manufacturing.
3Adaptability or versatility
If analog VCO is used for clock generation, then frequency adjustment is possible, but noise characteristics deteriorate
Solution Approach 1:
The patent replaces the noisy analog VCO with a digital sampling system that uses a fixed-frequency oscillator. The frequency adjustment and phase optimization are achieved through digital processing of multiple phase samples, eliminating the noise inherent in analog voltage-controlled oscillation while maintaining adaptability through digital control.
Data Source
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AI summary
An FIR filter (7) convolutes sampled data obtained by sampling a reception signal with tap coefficients. A phase difference detector (8) detects a phase difference between a synchronization timing of a signal waveform estimated from an output signal of the FIR filter (7) and a sampling timing of the output signal. A tap coefficient adjuster (9) adjusts the tap coefficients so as to reduce the phase difference detected by the phase difference detector (8) and causes the sampling timing of the output signal of the FIR filter (7) to track the synchronization timing.