Two-Stage RF Interference Cancellation Architecture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radio receivers face challenges in tolerating high levels of in-band interference, where existing methods struggle to distinguish and filter out interfering signals that overlap with the signal of interest, leading to distortion or saturation of the receiver.
Innovation Solution
A self-calibrating, two-stage interference cancellation architecture is implemented, where the first stage reduces signal overload before amplification and the second stage removes residual interference after amplification, using a digital signal processor to generate cancellation signals that are converted to analog and summed with the incoming signal, ensuring the signal remains within the receiver's capacity and avoiding irreversible distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a filter is applied to block the interferor, then interference is reduced, but the signal of interest is distorted or degraded when the interferor and signal overlap
Solution Approach 1:
The patent introduces an intermediary cancellation signal that is generated based on a model of the interfering signal. This cancellation signal is then combined with the received signal to actively subtract the interferor, rather than using a passive filter that would affect both the interferor and the overlapping signal of interest.
Solution Approach 2:
The patent creates a model (copy) of the interfering signal that replicates its characteristics. This model is then used to generate the cancellation signal, allowing the system to subtract the interferor without directly manipulating the received signal in a way that would distort the signal of interest.
2Object-affected harmful factors
If active signal cancellation is used to remove interferors, then interference is reduced, but the system complexity increases due to the need for accurate modeling and real-time processing
Solution Approach 1:
The patent divides the interference cancellation process into two distinct stages: a first stage that operates before the receiver's active circuits to reduce signal overload, and a second stage that operates after amplification to remove residual interference. This segmentation allows each stage to be optimized independently, managing overall system complexity.
Solution Approach 2:
The first stage of interference cancellation is performed preliminarily, before the signal enters the receiver's active circuits. This preliminary action reduces the interferor amplitude to prevent saturation and damage, simplifying the requirements for subsequent processing stages.
3Measurement precision
If high gain is applied to amplify the signal of interest, then signal detection sensitivity is improved, but the receiver saturates or is damaged by strong interferors
Solution Approach 1:
The patent applies preliminary anti-action by using the first stage interference cancellation to counteract the harmful effect of strong interferors before they can cause saturation or damage to the receiver. This allows high gain to be applied in subsequent stages without the risk of overload.
Solution Approach 2:
The first stage interference cancellation acts as a cushioning mechanism that protects the receiver's active circuits from the full force of strong interferors. By reducing the interferor amplitude beforehand, the system can tolerate high gain operation without saturation or damage.
Data Source
AI summary
A radio frequency receiver subject to a large in-band interferor employs active cancellation with coarse and at least one fine cancellation signal, each with a respective radio frequency combiner, in order to increase the effective dynamic range of the receiver for weak signals of interest. One or both can be digitally synthesized. This is particularly applicable for co-site interference, whereby the interfering transmit signal is directly accessible. A similar system and method may also be applied to external interferors such as those produced by deliberate or unintentional jamming signals, or by strong multipath signals. An adaptive algorithm may be used for dynamic delay and gain matching. In a preferred embodiment, a hybrid technology hybrid temperature system incorporates both superconducting and semiconducting components to achieve enhanced broadband performance.