Parallel Adaptive Filter Circuit for Narrowband Interference Suppression

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Modern communication systems face challenges in effectively reducing narrowband interference due to intentional or unintentional jamming and multipath distortion, especially in wideband radio channels, where existing adaptive filters often require complex designs and may not efficiently handle multiple interferers while meeting hardware constraints.

Innovation Solution

A communications system employing a circuit with multiple parallel adaptive filters, each with varying numbers of taps and adaptive gain, utilizing a selection mechanism to choose the best filter based on output power and demodulator state, along with a variable delay circuit to improve multipath performance and reduce narrowband interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a single adaptive filter with many taps is used to handle multiple interferers, then interference suppression capability improves, but device complexity and hardware resource consumption increase

Engineering Contradiction:

Improvenarrowband interference suppressionVSAvoidfilter design complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent divides a single complex adaptive filter into multiple parallel simpler adaptive filters, each handling a specific interferer. This segmentation reduces the complexity of individual filters while collectively maintaining strong interference suppression capability across multiple frequency bands.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The parallel adaptive filter structure provides multi-functionality by simultaneously handling multiple types of narrowband interferers with different characteristics. Each filter in the parallel structure can be optimized for specific interference types while the overall system maintains universal applicability across various jamming scenarios.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If adaptive filter coefficients are continuously adjusted to track changing interferers, then adaptability improves, but processing time and computational load increase

Engineering Contradiction:

Improveadaptability to changing signal conditionsVSAvoidfilter adaptation time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent initializes multiple adaptive filters with different starting configurations before actual signal processing begins. This preliminary setup allows the system to quickly adapt to changing interferers by switching between pre-configured filters rather than reconfiguring a single filter from scratch, reducing adaptation time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically selects and switches between multiple adaptive filters based on real-time signal conditions and interferer characteristics. This dynamic approach allows rapid adaptation to changing environments without the computational overhead of continuously reconfiguring a single complex filter.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If the number of filter taps is increased to improve interference suppression, then suppression performance improves, but power consumption and hardware resource usage increase

Engineering Contradiction:

Improveinterference suppression performanceVSAvoidpower consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent segments the filtering function across multiple parallel filters with fewer taps each, rather than using a single filter with many taps. This segmentation reduces the computational complexity and power consumption of individual filter operations while achieving comparable or superior overall suppression performance through coordinated parallel processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each individual adaptive filter in the parallel structure uses fewer taps (partial action) than a single comprehensive filter would require, reducing per-filter power consumption. The collective action of multiple such filters provides excessive coverage across different frequency bands, ensuring complete interference suppression without requiring any single filter to consume excessive power.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8121236B1Communications system using adaptive filter circuit using parallel adaptive filters

Publication Date: 2012.02.21 L3HARRIS GLOBAL COMMUNICATIONS INC

AI summary

A communications system receives a modulated communication signal that carries encoded communications data. A signal input receives the communication signal. An adaptive filter circuit is connected to the signal input and comprises N number of parallel adaptive filters. Each adaptive filter has non-adaptive and adaptive taps with weighted coefficients that are different in number from the respective other parallel adaptive filters within the adaptive filter circuit. A selection output circuit is connected to each adaptive filter and selects for output the adaptive filter having the most suppression or least output power or other criterion which can indicate a best choice to use of the N parallel adaptive filters. A demodulator demodulates the signal and a decoder receives the filtered output signal from the demodulator and decodes the signal to obtain the communications data.