Radio Receiver DSP Multipath Noise Mitigation via Signal Blending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio receivers face challenges in effectively mitigating multipath noise, which causes audio disruptions like clicking or popping due to signal interference from multiple paths, and hard mute techniques can result in volume changes or audible muting issues.
Innovation Solution
A digital signal processor (DSP) with parallel paths, including a high cut circuit and a low pass filter, blends signals based on a blend control signal generated from RMS values and noise floor estimation to mitigate multipath noise, avoiding the need for hard muting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hard mute is used to mitigate multipath noise, then noise reduction is improved, but audio quality deteriorates due to volume changes and audible mute
Solution Approach 1:
The audio signal is divided into multiple frequency bands using parallel filter paths (high cut circuit and low pass filter). Each path processes different frequency components, allowing selective noise mitigation without completely muting the audio output. This segmentation enables noise reduction while preserving audio quality.
Solution Approach 2:
The system dynamically switches between different filter paths based on detected multipath noise conditions. A controller monitors the signal and adjusts which path is active, transitioning smoothly between high cut and low pass filter outputs. This dynamic adaptation prevents audible muting while maintaining noise mitigation effectiveness.
2Object-affected harmful factors
If signal filtering is applied to reduce multipath noise, then noise reduction is improved, but signal quality may deteriorate due to filter distortion
Solution Approach 1:
Different filter characteristics are applied to different frequency bands through parallel paths. The high cut circuit handles high-frequency noise while the low pass filter preserves low-frequency signal integrity. This segmented filtering approach reduces overall noise without distorting the complete signal spectrum.
Solution Approach 2:
The system changes filter parameters (cutoff frequencies, filter orders) based on the detected noise conditions and signal characteristics. By adapting filter parameters dynamically, the system optimizes the balance between noise reduction and signal preservation, minimizing filter-induced distortion.
Data Source
AI summary
In one embodiment, a method for processing radio frequency signals includes estimating an average value of a demodulated signal and a noise signal, both obtained from a radio frequency signal, estimating a noise floor based on the noise signal, generating a blend control signal based on the average values and the noise floor, and blending at least two path signals based on the blend control signal to obtain a blended signal. This blended signal may be output for further processing when multipath noise is detected.