Microcontroller FFT Butterfly Operation Latency
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Solution Overview
Problem
The existing methods for performing Fast Fourier Transforms (FFTs) face challenges in achieving a balance between power efficiency, speed, and resolution, particularly as the number of samples increases, leading to high latency and increased power consumption due to the need for sequential processing and reliance on parallel processing which can burden resources.
Innovation Solution
The method involves initializing butterfly operations before all samples are received, allowing for the performance of a first butterfly operation as soon as the necessary data is available, and continuing with subsequent operations as more samples are collected, thereby reducing the number of unperformed operations and spreading computations over a longer period to improve power efficiency and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all N samples are collected before performing FFT operations, then computational accuracy is maintained, but latency increases and processing speed decreases
Solution Approach 1:
The patent applies preliminary action by performing butterfly operations as soon as sufficient samples are available, rather than waiting for all N samples. The system initializes butterfly operations when a predetermined number of samples are received, and continues performing operations as additional samples arrive, thereby reducing latency while maintaining computational accuracy through progressive computation.
Solution Approach 2:
The patent segments the FFT computation into multiple stages: initial butterfly operations performed when minimum samples are available, intermediate operations as more samples arrive, and final operations to complete the transform. This segmentation allows partial results to be computed and utilized earlier, reducing overall latency while maintaining full computational accuracy.
2Productivity
If parallel processing is used to reduce latency, then processing speed improves, but power consumption and resource burden increase
Solution Approach 1:
The patent applies dynamics by making the processing parallelism dynamic rather than static. The system adjusts the degree of parallelism based on sample availability and computational progress, performing butterfly operations progressively as samples arrive. This dynamic approach allows the system to utilize available resources efficiently without sustaining maximum parallelism throughout, thereby reducing power consumption while maintaining improved processing speed.
Solution Approach 2:
The patent ensures continuity of useful action by continuously performing butterfly operations as samples become available, rather than having idle periods followed by intensive processing. This continuous computation keeps the processor actively engaged at moderate levels, improving throughput while avoiding the power spikes associated with burst parallel processing.
3Use of energy by moving object
If sequential processing is used to reduce power consumption, then power efficiency improves, but latency and processing time increase
Solution Approach 1:
The patent applies preliminary action by initiating butterfly operations before all samples are collected, performing computations in advance when data becomes available. This preliminary computation reduces the overall processing time while maintaining power efficiency by spreading computations over the data collection period rather than concentrating them in a single intensive phase.
Solution Approach 2:
The patent implements periodic action by performing butterfly operations at regular intervals as samples become available, rather than continuously or all-at-once. This periodic computation pattern allows the system to balance power consumption with processing progress, achieving better power efficiency than sustained parallel processing while reducing latency compared to pure sequential processing.
Data Source
AI summary
A method of operating a microcontroller to perform a Fast Fourier Transform, the method including receiving, by the microcontroller, N samples from a signal; and performing, by the microcontroller, a first butterfly operation of the Fast Fourier Transform before all of the N samples have been received from the signal, based on the performing of the first butterfly operation, the microcontroller performs the Fast Fourier Transform at a higher performance to power efficiency than a Fast Fourier Transform operation that begins after all of the N samples are received.