Clock Recovery Circuit Filtering RFI-Affected Phase Deviations
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Solution Overview
Problem
In communication systems using clock recovery technology, radio frequency interference (RFI) causes frequency information oscillation at the signal receiving terminal, leading to inaccurate signal decoding due to the lack of an efficient anti-RFI mechanism.
Innovation Solution
A signal receiving apparatus and method incorporating an ADC circuit, equalization circuit, and clock recovery circuit that performs analog to digital conversion, equalization, and phase adjustment using statistics on phase deviation information within a time window, discarding phase deviation amounts when the signal interference parameter exceeds a threshold to generate an adjusting signal for the internal clock signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If clock recovery technology is used to extract frequency information from data stream, then data decoding capability is improved, but frequency information oscillates due to RFI causing inaccurate decoding
Solution Approach 1:
The time window is divided into multiple sub-time windows to segment the phase deviation amount information. This allows the system to process and evaluate phase deviations in smaller, manageable units, enabling identification and exclusion of RFI-affected segments without compromising the entire frequency extraction process.
Solution Approach 2:
The system changes the parameter evaluation approach by determining signal interference parameters for each sub-time window and comparing them against threshold values. This parameter-based filtering mechanism enables dynamic adjustment of frequency extraction based on RFI conditions, maintaining reliability while preserving decoding capability.
2Measurement precision
If phase deviation amount information is used for frequency extraction, then clock recovery accuracy is improved, but RFI causes misjudgment leading to system crashes
Solution Approach 1:
The system performs preliminary evaluation by determining signal interference parameters for each sub-time window before using the phase deviation amount information for frequency extraction. This preliminary action identifies and flags RFI-affected segments, preventing them from causing misjudgment and system crashes while preserving accurate frequency extraction from clean segments.
Solution Approach 2:
The signal interference parameter acts as an intermediary between the raw phase deviation amount information and the frequency extraction process. This intermediary layer filters out RFI-affected data by comparing interference parameters against threshold values, ensuring that only reliable phase deviation information influences frequency extraction, thus maintaining both precision and stability.
3Adaptability or versatility
If continuous calibration of frequency information is performed to compensate for transmission delay, then temperature-induced delay compensation is improved, but RFI interference causes oscillation during calibration
Solution Approach 1:
The system dynamically adjusts the calibration process by continuously evaluating signal interference parameters during frequency extraction. When RFI is detected in certain sub-time windows, the system adaptively excludes those segments from calibration, allowing continuous temperature compensation while maintaining calibration stability despite RFI interference.
Data Source
AI summary
The present disclosure provides a signal receiving apparatus having anti-RFI mechanism that includes an ADC circuit, an equalization circuit and a clock recovery circuit. The ADC circuit performs conversion of an input analog signal according to an internal clock signal, to generate an input digital signal. The equalization circuit equalizes the input digital signal such that the clock recovery circuit adjusts a phase of the internal clock signal and extracts a frequency by performing statistics on phase deviation amount information in a unit of a time window. The clock recovery circuit discards a corresponding phase deviation amount when a signal interference parameter of one of a sub time window is larger than a threshold value to update the phase deviation amount information, and generates an adjusting signal to adjust a frequency of the internal clock signal accordingly.