Wireless Receiver Filter Switching for Nonlinear Signal Distortion
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Solution Overview
Problem
Existing wireless apparatuses experience degradation in band limiting characteristics when the power level or amplitude of received signals deviates from a linear region, leading to increased distortion due to the use of digital filters in conjunction with analog band pass filters.
Innovation Solution
A digital filter control unit is implemented to disable filtering by the digital filter when the reception power level or amplitude level is outside the linear region, preventing further distortion and maintaining the band limiting characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a digital filter is used to correct distortion caused by an analog band pass filter, then the band limiting characteristic is improved, but when the received signal power level deviates from the linear region, the distortion increases and the band limiting characteristic deteriorates
Solution Approach 1:
The patent implements dynamic control of the digital filter based on the received signal power level. The digital filter is enabled only when the signal power is within the linear region of the analog components, and disabled when the power level deviates from this region. This dynamic adjustment prevents the digital filter from worsening distortion in nonlinear regions while maintaining its corrective function in linear regions.
Solution Approach 2:
The patent changes the operational state parameter of the digital filter (enabled/disabled) based on the received signal power level parameter. By monitoring the power level and adjusting the digital filter's operational state accordingly, the system optimizes performance across different signal conditions without requiring complex circuit modifications.
2Manufacturing precision
If the digital filter is always enabled to correct analog filter distortion, then the band limiting characteristic is maintained, but the circuit complexity increases
Solution Approach 1:
Instead of keeping the digital filter continuously enabled, the system dynamically adjusts its operational state based on signal conditions. This reduces the effective circuit complexity by having the filter inactive during nonlinear regions, while still providing correction when needed in linear regions.
Solution Approach 2:
The system uses the received signal power level information to automatically control the digital filter's operation. The power level detection and control unit enables or disables the digital filter autonomously based on whether the signal is in the linear region, eliminating the need for external complex control circuits.
3Reliability
If the digital filter is disabled when signal power is outside linear region, then distortion is prevented, but the band limiting correction is lost
Solution Approach 1:
The system dynamically switches between two operational modes: digital filter enabled when signal power is within the linear region (for optimal band limiting), and digital filter disabled when power is outside the linear region (to prevent distortion). This dynamic adaptation resolves the contradiction by selecting the appropriate mode for each signal condition.
Solution Approach 2:
The system preliminarily detects the signal power level before applying digital filtering. By checking whether the signal is in the linear region beforehand, the system prepares to enable or disable the digital filter in advance, preventing distortion before it occurs while maintaining correction when conditions are favorable.
Data Source
AI summary
A wireless apparatus which performs a frequency conversion on a received signal with a mixer and an analog filter, and which corrects for distortion of the received signal, which occurs because the analog filter is not an ideal one, using a digital filter disables the filtering of the received signal by the digital filter when determining from the reception power level (or reception amplitude level) of the received signal that the filtering of the received signal by the digital filter will increase the distortion of the received signal.