Wireless Receiver AFC Unit Frequency Synchronization
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Solution Overview
Problem
Conventional wireless reception devices face challenges in maintaining frequency and phase synchronization due to noise and interference, leading to failure in locking operations and difficulty in re-establishing synchronization once it is lost.
Innovation Solution
The device includes an automatic frequency control unit and a carrier recovery unit that detect frequency and phase deviations, generate synchronization detection reference signals, and utilize match detection to control the locking operations, ensuring the device can re-establish synchronization in asynchronous states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AFC circuit performs locking operation in a predetermined period, then frequency synchronization is established, but the locking operation may fail due to noise and interference signals
Solution Approach 1:
The patent introduces a feedback mechanism where the AFC circuit continuously monitors the synchronization state and receives feedback signals to adjust its locking operation. When noise or interference causes locking failure, the feedback loop detects this and re-initiates the locking operation, thereby maintaining reliable frequency synchronization despite harmful signals.
Solution Approach 2:
The patent implements preliminary action by performing the locking operation in a predetermined period before actual communication begins. This preliminary locking ensures that the AFC circuit is in a synchronized state before receiving actual signals, preventing noise and interference from causing synchronization failures during normal operation.
2Reliability
If the AFC circuit is controlled to locking state when reception signal is blocked, then frequency synchronization can be re-established, but the control timing must be precise to avoid unnecessary locking operations
Solution Approach 1:
The patent uses feedback signals from the reception device to control the AFC circuit's locking operation. When the reception signal is blocked and synchronization is lost, the feedback mechanism automatically triggers the AFC circuit to return to the locking state, enabling reliable synchronization recovery without requiring complex timing control.
3Ease of operation
If the bandwidth is widened during locking operation, then frequency locking becomes simpler, but the steady state synchronization becomes less stable
Solution Approach 1:
The patent applies dynamics by making the bandwidth of the AFC circuit adjustable rather than fixed. During the locking operation, the bandwidth is dynamically widened to simplify frequency locking. Once locking is complete and the system transitions to steady state, the bandwidth is dynamically narrowed to enhance synchronization stability. This dynamic adjustment resolves the contradiction between ease of locking and stability of steady state.
Data Source
AI summary
The wireless reception device has automatic frequency control unit for detecting, from a reception modulation signal frequency-converted to the baseband, a frequency deviation component of a carrier wave between transmission and reception sides that is contained in the reception modulation signal and removing the frequency deviation component from the reception modulation signal, the automatic frequency control unit having a frequency locking operation state and a steady state following the frequency locking operation. The wireless reception device further has modulation component removal unit for generating a synchronization detection reference signal by removing the modulation component of the received modulation signal; and match detection unit that detects a mismatch between the synchronization detection reference signal and the frequency deviation component detected by the automatic frequency control unit, wherein, when the match detection unit detects the mismatch, the automatic frequency control unit are controlled to the frequency locking operation state.