Reflected Signal Suppression in Transmission-Reception Apparatus
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Solution Overview
Problem
Existing transmission-reception apparatuses struggle to effectively suppress reflected signals from antennas, especially in environments with varying antenna impedance, as they rely on noise canceller circuits that require known amplitude and phase information, which is not always available.
Innovation Solution
A transmission-reception apparatus comprising a first RF circuit, a second RF circuit, an antenna duplexer, a demultiplexer, a signal adjusting unit, and a multiplexer, along with a sensing unit and a control unit that detects transmission and reflected signals to determine adjustment factors for amplitude and phase, using a table to store discrete adjustment factors for amplitude and phase differences, allowing for precise cancellation of reflected signals even when the combination is not pre-stored.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a noise canceller circuit is used to suppress reflected signals, then the reflected signal can be cancelled when amplitude and phase are known, but the system cannot appropriately suppress reflected signals when antenna impedance varies or when amplitude and phase information is unknown
Solution Approach 1:
The system performs preliminary detection of the reflected signal characteristics (amplitude and phase) using a sensing unit before the cancellation process. The control unit stores detection results and determination tables in advance, allowing the signal adjusting unit to quickly retrieve and apply appropriate adjustment factors without requiring real-time complex calculations when impedance varies.
Solution Approach 2:
The system establishes a feedback loop where the sensing unit continuously detects transmission and reflected signals, the control unit determines adjustment factors based on detection results, and the signal adjusting unit applies these factors to the demultiplexed signal. This closed-loop feedback mechanism enables the system to adapt to varying antenna impedance conditions dynamically.
2Measurement precision
If discrete adjustment factors are stored in a determination table for all possible amplitude and phase combinations, then accurate cancellation can be achieved, but data storage requirements increase significantly
Solution Approach 1:
The control unit segments the adjustment process by storing determination tables that contain adjustment factors for different amplitude and phase difference ranges separately. Instead of storing all possible combinations, the system divides the parameter space into discrete segments and stores representative adjustment factors for each segment, reducing overall storage requirements while maintaining sufficient accuracy.
Solution Approach 2:
The system changes the parameter representation by storing adjustment factors as discrete values in determination tables rather than continuous functions. The sensing unit detects continuous amplitude and phase differences, but the control unit maps these to discrete adjustment factors from the determination table, enabling efficient storage and quick retrieval without losing essential cancellation accuracy.
Data Source
AI summary
An amplitude phase parameter calculator in a control unit or circuit in a transmission-reception apparatus calculates an amplitude difference voltage and a phase difference voltage between a transmission detection signal and a reflected detection signal. Adjustment factors including a combination of an amplitude control voltage and a phase control voltage corresponding to a combination of the amplitude difference voltage and the phase difference voltage are discretely stored in an adjustment factor determination table in the control unit. An adjustment factor determiner in the control unit determines the adjustment factors using the combination of the amplitude difference voltage and the phase difference voltage and the adjustment factor determination table. If the adjustment factors do not exist in the adjustment factor determination table, the adjustment factor determiner calculates target adjustment factors using the relationship among the adjustment factors stored in the table, the amplitude difference voltage, and the phase difference voltage.