Wideband Receiver Filtering for Interferer Rejection and SNR Hold
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Solution Overview
Problem
Conventional wideband receivers are susceptible to interference signals, which can cause automatic gain control circuitry to attenuate desired signals, degrading the signal-to-noise ratio and suppressing the desired signal.
Innovation Solution
A wideband receiver system with a dual receiver architecture, comprising a primary receiver and an auxiliary receiver, where the auxiliary receiver identifies interferer signals and tunes tunable filters to maintain the signal-to-noise ratio of desired signals above a threshold level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the receiver monitors the entire wide band signal spectrum, then the receiver can capture all desired signals across the wide band, but the receiver becomes more susceptible to interference signals such as jammer signals
Solution Approach 1:
The patent divides the wide band receiver into two functional segments: a first receiver that monitors the entire wide band spectrum for interference signals, and a second receiver that receives desired signals. This segmentation allows the system to maintain wide band capability while protecting the desired signal reception from interference through coordinated operation of the two segments.
Solution Approach 2:
The patent introduces tunable filters as an intermediary component between the antenna and the second receiver. These filters are controlled by interference signal characteristics (frequency, bandwidth) identified by the first receiver, allowing dynamic adjustment to block interference signals while passing desired signals, thus mediating between the wide band reception need and interference rejection requirement.
2Object-affected harmful factors
If the automatic gain control circuitry attenuates strong interference signals, then the interference signal power is reduced, but the desired signal power is also reduced, degrading the signal-to-noise ratio
Solution Approach 1:
The patent applies local quality by making the gain control selective rather than uniform. The tunable filters provide localized attenuation at specific interference frequencies while maintaining full gain for desired signal frequencies. This allows the system to reduce interference power locally without degrading the SNR of desired signals, resolving the contradiction between interference rejection and signal quality maintenance.
Solution Approach 2:
The patent dynamically changes the parameters of the tunable filters (center frequency, bandwidth, attenuation level) based on the characteristics of detected interference signals. By adapting these parameters in real-time, the system can precisely target and attenuate interference signals while preserving desired signals, thereby reducing interference power without compromising SNR.
3Device complexity
If a single receiver is used to identify interferer signals and recover desired signals, then the device complexity is reduced, but the processing load and difficulty of detecting and measuring increase
Solution Approach 1:
The patent segments the signal processing functions into two separate receivers: the first receiver handles interference signal detection and characterization, while the second receiver handles desired signal recovery. This functional segmentation reduces the processing load on any single receiver and simplifies the detection and measurement tasks by dedicating specific hardware to specific functions.
Solution Approach 2:
The patent merges the control functions by having the processing unit of the first receiver (or a shared controller) generate control signals that adjust the tunable filters in the second receiver. This merging of control functionality allows coordinated operation without requiring complete functional integration, balancing device simplicity with processing effectiveness.
Data Source
AI summary
A receiver system has at least one antenna that receives a plurality of signals, including a desired signal, across a wide band of frequencies. At least one tunable filter is in signal communication with the at least one antenna, and filters the plurality of signals to produce a plurality of filtered signals. Gain control circuitry is in signal communication with the at least one tunable filter, and produces a gain adjusted version of the filtered signals. A processing unit processes received signals in a portion of the wide band to extract signal characteristics of at least one undesired signal in the portion of the wide band. The at least one tunable filter is tuned based at least in part on the signal characteristics of the at least one undesired signal to maintain the SNR of the desired signal above a threshold level at the output of the gain control circuitry.