Receiver Attenuation Control for Broadband Intermodulation Mitigation
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Solution Overview
Problem
Conventional radios, such as Land Mobile Radios, experience significant interference from broadband signals, leading to increased noise floors and degraded performance due to high peak-to-average power ratios, which existing solutions like adaptive notch filters and Cartesian loop transmitters do not adequately address.
Innovation Solution
The system continuously monitors communication channels, estimates noise floor levels, and adjusts the variable attenuator to apply optimal attenuation, determining the optimal level by measuring incremental changes in noise power and comparing slopes to thresholds, thereby mitigating intermodulation interference and improving receiver sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If broadband signals are received by conventional radios, then communication coverage is extended, but intermodulation interference increases and receiver sensitivity degrades
Solution Approach 1:
The system dynamically adjusts the attenuation level of the variable attenuator based on real-time detection of intermodulation interference. The attenuation level is changed from static to adaptive, allowing the receiver to optimize performance under varying interference conditions while maintaining broad coverage area.
Solution Approach 2:
The system changes the attenuation parameter of the receiver based on detected interference levels. By monitoring the noise floor and determining when intermodulation interference is present, the system adjusts the attenuation parameter to mitigate harmful effects while preserving communication coverage.
2Area of stationary object
If broadband signals with high peak-to-average power ratio are received, then signal coverage is improved, but noise floor increases and receiver performance degrades
Solution Approach 1:
The system employs feedback by continuously monitoring the received signal and detecting intermodulation interference levels. Based on this feedback, the system automatically adjusts the variable attenuator to maintain optimal receiver performance while preserving signal coverage area.
Solution Approach 2:
The receiver performance is dynamically optimized by adjusting the attenuation level in response to detected interference conditions. This dynamic adjustment allows the system to maintain high reliability even when receiving broadband signals with high peak-to-average power ratios.
3Measurement precision
If no attenuation is applied to broadband signals, then receiver sensitivity is maintained, but intermodulation interference products increase
Solution Approach 1:
The system dynamically adjusts the attenuation level based on real-time detection of intermodulation interference. When interference is detected, attenuation is increased to reduce interference products; when interference is absent, attenuation is reduced to maintain receiver sensitivity.
Solution Approach 2:
The attenuation parameter is changed adaptively based on detected interference conditions. The system monitors for intermodulation interference and adjusts the attenuation parameter accordingly, changing from zero attenuation to optimal attenuation levels to balance sensitivity and interference reduction.
Data Source
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AI summary
Systems and methods for operating a communication device so as to mitigate intermodulation interference to a signal. The methods comprise: continuously monitoring several communication channels by the communication device; using a noise floor level estimate of the communication device to detect when the communication device is under an influence of hig interference; determining an optimal level of attenuation to be applied by a variable attenuator of the communication device's receiver so as to mitigate the influence of intermodulation interference to the signal; and selectively adjusting an amount of attenuation being applied by the variable attenuator to achieve the optimal level of attenuation for mitigating intermodulation interference.