Software Time-Delay Modulation for Fixed-Sampling EMI Reduction
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Solution Overview
Problem
Systems with fixed sampling frequencies face challenges in reducing electromagnetic interference (EMI) due to periodic current consumption, making it difficult to apply conventional methods like spread spectrum clock generators, which require complex algorithms and additional hardware.
Innovation Solution
A method that modulates a time delay software each cycle of the fixed sampling frequency, allowing for software-based distribution of EMI generation by adjusting the time period between ADC signal reading and digital signal processing, using pre-stored modulation profiles or calculations, and applying modulation methods like sawtooth wave, triangular, Hershey-Kiss, and Sigma delta modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a spread spectrum clock generator (SSCG) is used to reduce EMI, then EMI levels are reduced, but additional hardware and complex algorithms are required
Solution Approach 1:
The patent replaces the hardware-based SSCG mechanism with a software-based time delay modulation approach. Instead of using a physical spread spectrum clock generator circuit, the invention implements EMI reduction through software-controlled timing variations in ADC sampling and DSP operations, thereby eliminating additional hardware while achieving EMI spectrum spreading
Solution Approach 2:
The patent creates a software model that replicates the functionality of a hardware SSCG. By implementing time delay modulation algorithms in software that mimic the spectral spreading effect of hardware SSCG, the system achieves equivalent EMI reduction without requiring physical hardware implementation of the spread spectrum clock generator
2Object-affected harmful factors
If a spread spectrum clock generator (SSCG) is used to reduce EMI, then EMI levels are reduced, but additional hardware components are required
Solution Approach 1:
The patent replaces the hardware-based SSCG mechanism with a software-based time delay modulation approach. Instead of using a physical spread spectrum clock generator circuit, the invention implements EMI reduction through software-controlled timing variations in ADC sampling and DSP operations, thereby eliminating additional hardware while achieving EMI spectrum spreading
Solution Approach 2:
The patent enables the existing processor and timing circuits to perform EMI reduction functions without requiring dedicated SSCG hardware. The system uses its own internal timing mechanisms and software control capabilities to generate the necessary time delay modulations, making the existing components serve dual purposes of normal operation and EMI reduction
3Object-affected harmful factors
If clock modulation is implemented in hardware, then EMI is reduced, but flexibility is low when varying modulation amount
Solution Approach 1:
The patent implements dynamic time delay modulation where the modulation amount can be varied in real-time through software parameters. The time delay applied to ADC sampling and DSP operations can be adjusted based on different sampling periods and EMI conditions, providing flexible adaptation that hardware implementations cannot achieve
Solution Approach 2:
The patent enables easy modification of modulation parameters such as time delay magnitude and modulation waveform characteristics through software variables. This allows the system to adapt to different EMI scenarios, sampling frequencies, and operational conditions without requiring hardware reconfiguration, thereby achieving high flexibility in modulation amount variation
4Object-affected harmful factors
If complex algorithms are used to modify sampled signals through spread spectrum sampling, then EMI is reduced, but processing complexity increases
Solution Approach 1:
The patent extracts and isolates the essential EMI reduction function from complex spread spectrum sampling algorithms. Instead of implementing full spread spectrum sampling with its complex signal modification requirements, the invention extracts only the necessary time delay modulation component, applying it selectively to ADC and DSP timing to achieve EMI reduction with minimal processing overhead
Data Source
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AI summary
A method for reducing electromagnetic interference (EMI) in a system that periodically operates with a fixed sampling frequency includes reading a digital signal to which an analog signal received from a sensor is converted, generating a time delay that is modulated each cycle of the fixed sampling frequency with software, starting to execute a digital signal processing algorithm by applying the time delay that is modulated, and transmitting to another device through write of the digital signal. Accordingly, the EMI spectrum is spread through the time delay that is modulated with software, resulting in reduced EMI level.