In-Place FFT RAM Sub-Memory Segmentation
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Solution Overview
Problem
In-place fast Fourier transform (FFT) operations in systems with single-port memory face bandwidth limitations due to the need to read and write data one element at a time, which slows down processing, especially when multiple elements from the same sub-memory are required for algorithm steps.
Innovation Solution
A system with a RAM divided into multiple sub-memory spaces, where inputs and outputs are always from different sub-memories, utilizing a division circuit for address conversion and a butterfly processor to perform FFT operations efficiently, allowing simultaneous reading and writing of data elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-port memory is used for in-place FFT operations, then device complexity is reduced, but memory bandwidth becomes a limiting factor on processing speed
Solution Approach 1:
The patent divides the single memory into multiple sub-memories (first sub-memory, second sub-memory, etc.) to enable parallel data access. This segmentation allows simultaneous reading from different sub-memories without creating harmful interactions, thereby increasing memory bandwidth and processing speed while maintaining relatively simple device architecture.
2Speed
If memory is divided into sub-memories to increase bandwidth, then processing speed improves, but device complexity increases
Solution Approach 1:
The memory is segmented into multiple sub-memories that can be accessed in parallel, enabling simultaneous data reads and writes without bandwidth bottlenecks. This segmentation strategy achieves high processing speed while keeping the overall structure manageable through systematic division.
Solution Approach 2:
The patent introduces an intermediary mechanism (control logic/address generation circuitry) that manages the complex addressing and data flow between multiple sub-memories. This intermediary layer simplifies the system by automatically handling the coordination between sub-memory accesses, reducing the burden on the main processing unit.
3Device complexity
If data is read and written one element at a time in single-port memory, then device complexity is minimized, but loss of time increases due to sequential operations
Solution Approach 1:
By segmenting the memory into multiple sub-memories, the system can perform parallel data reads and writes simultaneously, eliminating the sequential bottleneck. This reduces operation time significantly while maintaining relatively simple access mechanisms through the segmented architecture.
Solution Approach 2:
The patent enables continuous data processing by allowing overlapping read and write operations across different sub-memories. The useful action (data processing) continues without interruption as data is continuously transferred between sub-memories, eliminating idle time associated with sequential single-port operations.
4Adaptability or versatility
If multiple elements from the same sub-memory are required for algorithm steps, then computational functionality is maintained, but memory bandwidth becomes a bottleneck
Solution Approach 1:
The memory is divided into multiple sub-memories that can be accessed simultaneously in parallel. This segmentation allows the algorithm to retrieve multiple elements from different sub-memories at the same time, maintaining full computational functionality while eliminating the bandwidth bottleneck that would exist in a single-port memory system.
Data Source
AI summary
Various embodiments of the present technology may comprise a method and apparatus for in-place fast Fourier transform (FFT). According to various embodiments, the apparatus comprises a RAM, having a single address space, divided into a plurality of sub-memory spaces, where the number of sub-memory spaces is a function of a length of the FFT such that the two inputs are always from different sub-memories, as are the two outputs. According to various embodiments, the apparatus may further comprise a division circuit configured to perform a “bitwise” division operation in order to convert addresses from the aforementioned single address space to the particular sub-memories and addresses within them. According to various embodiments, the apparatus may further comprise a butterfly processor capable of performing a butterfly operation.