Multi-channel adaptive median signal filter

This study aims to develop a novel structure of an N-channel adaptive median signal filter with dynamic input exclusion. The proposed design is intended for highly reliable, fault-tolerant modular redundant power supply systems for spacecraft. To investigate the functionality of the proposed N-channel filter, we developed a simulation model for a 7-channel median signal filter using MATLAB Simulink. A model-based design approach was applied to validate the performance of the proposed element using the Altera Cyclone IV EP4CE115F29C7 field-programmable gate array (FPGA). The verification process involved the use of automatic code generation tools within MATLAB Simulink for the FPGA implementation. A novel structure of the N-channel median signal filter was proposed, featuring a dynamic exclusion of unused inputs from the median calculation. This guarantees that only valid input signals from operational modules within the power supply system be included in the median calculation. The simulation results demonstrated that, in contrast to existing counterparts, the proposed filter is capable of reliably outputting the median signal as the number of active input signals decreases from N to 1. The implementation of the filter as an intellectual property (IP) block based on the Altera Cyclone IV EP4CE115F29C7 FPGA demonstrated efficient resource utilisation, occupying 541 logic cells, while fully adhering to the specified operational logic. The proposed structure of the adaptive median signal filter can be employed in highly reliable, fault-tolerant spacecraft redundant power supply systems, maintaining functionality even in the event of multiple module failures, down to the last operational module. The developed solution meets the stringent fault-tolerance requirements of spacecraft power systems.

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