Adjustable Low Pass Filter Bandwidth for Phase Mismatch Correction
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Solution Overview
Problem
As data throughput demands increase, existing communication systems face challenges in reducing frequency-dependent image distortion, which limits signal quality and is not adequately addressed by current frequency-independent distortion correction methods.
Innovation Solution
A method and circuit for wireless terminals that adjust the bandwidth of in-phase and quadrature phase low pass filters based on determined phase mismatches, using bandwidth control signals to reduce the phase mismatch and thereby minimize frequency-dependent image distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If frequency-independent image distortion correction is used, then frequency-independent distortion is reduced, but frequency-dependent distortion remains unresolved
Solution Approach 1:
The patent applies dynamics by making the low pass filter bandwidth adjustable rather than fixed. The system dynamically adapts the filter bandwidth based on the operating frequency to correct frequency-dependent image distortion. This resolves the contradiction by enabling the system to handle different frequency conditions adaptively, transforming a static correction approach into a dynamic one that can address frequency-dependent issues.
Solution Approach 2:
The patent changes the parameter of low pass filter bandwidth from a fixed value to an adjustable parameter. By varying the filter bandwidth according to the signal frequency and detected image distortion characteristics, the system effectively addresses frequency-dependent distortion while maintaining frequency-independent correction capabilities.
2Productivity
If data throughput is increased, then transmission capacity improves, but image distortion becomes more severe
Solution Approach 1:
The patent implements feedback by detecting the actual image distortion in the transmitted signal and using this information to adjust the low pass filter bandwidth. The system creates a closed-loop control mechanism where distortion measurement directly influences filter parameter adjustment, enabling the system to maintain high throughput while dynamically compensating for distortion effects.
Solution Approach 2:
The system dynamically adjusts the low pass filter bandwidth in response to changing transmission conditions and distortion levels. This dynamic adaptation allows the system to optimize the balance between data throughput and distortion correction, resolving the contradiction by making the correction mechanism responsive to actual operating conditions rather than static.
3Device complexity
If low pass filter bandwidth is fixed, then system design is simple, but phase mismatch cannot be corrected
Solution Approach 1:
The patent transforms the fixed low pass filter configuration into a dynamic one where the bandwidth can be adjusted based on detected phase mismatch and image distortion. This adds controllability to the filter system, enabling phase mismatch correction while maintaining relatively simple hardware implementation through parameter adjustment rather than complex reconfiguration.
Solution Approach 2:
The system changes the filter bandwidth parameter from a fixed design choice to an adjustable parameter that can be optimized for different operating conditions. This parameter change enables the system to correct phase mismatch and reduce image distortion without requiring fundamental redesign of the filter architecture, thus balancing complexity and performance improvement.
Data Source
AI summary
A method and terminal device for reducing an image distortion are provided. The terminal device generates a radio frequency signal from a first path that includes first and second low pass filters of in-phase and quadrature phase paths, produces a decomposed signal having in-phase and quadrature phase components in digital form based on the radio frequency signal, and determines a phase mismatch between the in-phase and quadrature phase components. Then the terminal device generates a bandwidth adjustment value based on the determined phase mismatch, further generates, based on the bandwidth adjustment value, first and second bandwidth control signals; and adjusts a bandwidth of first and second low pass filters based on the first and second bandwidth control signals to reduce the phase mismatch.