Tunable Band-Stop Filter for Wideband RF Interference Suppression
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Solution Overview
Problem
Current wideband RF interference detection and suppression systems face challenges such as high power consumption, limited bandwidth, and slow response times, particularly in identifying and mitigating interferers of unknown frequency and power, as well as requiring prior knowledge of blocker frequencies.
Innovation Solution
A system comprising an open-circuit stub, voltage peak detectors, an analog-to-digital converter, and a controller that generates a filter control signal to adjust a tunable band-stop filter based on detected standing wave patterns, allowing for rapid suppression of interference signals across a two-octave bandwidth without prior knowledge of frequency or power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If broadband high-power active limiters are employed to protect receivers from saturation, then receiver protection is improved, but power consumption increases
Solution Approach 1:
The patent extracts only the necessary interference suppression function from the entire signal path by inserting a frequency-selective limiter only where interference occurs, rather than protecting the entire receiver bandwidth. This selective approach reduces power consumption while maintaining receiver protection against specific interferers.
Solution Approach 2:
The patent applies frequency-selective limiting only at specific frequencies where interferers are detected, rather than applying broadband limiting across the entire frequency range. This local化的 approach allows the system to protect against interferers while maintaining high power consumption efficiency by avoiding unnecessary limiting action in clean frequency bands.
2Reliability
If frequency-selective limiters are used to suppress high-power interferers, then interference suppression is improved, but bandwidth is limited
Solution Approach 1:
The patent employs dynamically tunable frequency-selective limiters that can adapt their center frequency and bandwidth in real-time based on detected interferer characteristics. This dynamic adjustment allows the system to maintain effective interference suppression across a wide range of frequencies, overcoming the fixed bandwidth limitation of static frequency-selective limiters.
Solution Approach 2:
The patent changes the operational parameters (center frequency, bandwidth, Q-factor) of the frequency-selective limiters based on detected interferer properties. By adjusting these parameters dynamically, the system can suppress interferers across a broad bandwidth while maintaining the selectivity and suppression capability of frequency-selective limiting.
3Reliability
If frequency-selective limiters are used to protect against interferers, then interference suppression is improved, but response time is slow
Solution Approach 1:
The patent implements preliminary detection and characterization of interferers using wideband detectors that continuously monitor the signal spectrum. Once interferers are detected and their parameters are pre-characterized, the frequency-selective limiters can be rapidly tuned to match the detected interferer frequencies, significantly reducing the overall response time compared to systems that must first detect and then react to interferers.
4Reliability
If broadband limiters are used to protect receivers, then receiver protection is improved, but the communication channel cannot be recovered
Solution Approach 1:
The patent applies local quality by using frequency-selective limiters that only affect specific frequency bands where interferers are present. This localized approach allows the communication channel to be recovered by simply adjusting the limiter parameters or switching to alternative frequency bands, whereas broadband limiters block all frequencies and prevent channel recovery.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables detection and suppression of arbitrary interferers within 1.1 microseconds across a 2-8 GHz frequency band and -5 dBm to +15 dBm power range, using low-cost components and minimizing impact on the frequency response of the transmission line.
Implementation Method 1
The first voltage signal and the second voltage signal can collectively quantify a standing wave pattern representative of the portion of the input signal
Data Source
AI summary
Systems and methods for wideband RF interference detection and suppression include an open-circuit stub, a first voltage peak detector, a second voltage peak detector, an analog-to-digital converter (ADC), and a controller. The open-circuit stub is configured to receive an input signal. The first voltage peak detector is coupled at the open end of the open-circuit stub and configured to output a first voltage signal based on a portion of the input signal. The second voltage peak detector is coupled a distance away from the open end of the open-circuit stub and configured to output a second voltage signal based on the portion of the input signal. The controller is configured to generate an output control signal operable to adjust a signal filter based on the first digital voltage signal and the second digital voltage signal to suppress the portion of the input signal.