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A New Approach to Pipeline FFT Processor. Speaker: Group B3 B93901023 徐誠羿 B93901135 高翊軒 Adviser: Prof. An-Yeu Wu Date: 2006-10-25. Outline. DFT FFT Previous pipeline FFT processor architectures New FFT processor radix- 2 2 Comparison
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A New Approach to Pipeline FFT Processor Speaker: Group B3 B93901023 徐誠羿 B93901135 高翊軒 Adviser: Prof. An-Yeu Wu Date: 2006-10-25
Outline DFT FFT Previous pipeline FFT processor architectures New FFT processor radix-22 Comparison New FFT processor Radix-23 Conclusion Simulation References
DFT • Definition of Discrete Fourier Transform and Inverse DFT.
FFT • An algorithm which computes DFT. A method of multiplying Discrete Fourier Transform. • Concept: Divide and conquer. • points only (using butterfly structure)
Previous Pipeline FFT Processor Architectures • R2MDC( Radix-2 Multi-path Delay Commutator )
R4MDC(Radix-4 Multi-path Delay Commutator) • R4SDC(Radix-4 Single-path Delay Commutator)
Radix-2 (Radix-2 Single-path Delay Feedback) • DIT (bit reverse->normal) • DIF (normal->bit reverse)
Radix-4(Radix-4 Single-path Delay Feedback) multipliers
Ideal Architecture Minimum multipliers Minimum adders Minimum memory size
New FFT processor radix-22 It has the same multiplicative complexity as radix-4 algorithm, but retain butterfly structure of radix-2 algorithm. For length-N DFT compution, it requires: complex multipliers complex data memory -> minimum in the above processor
Simulation • Input x(n) = n + n*j , n=[0,63]
Simulation(Comparison) • Compare with MATLAB FFT
Conclusion • Radix-22;multiplicitive complexity => Radix-4. butterfly structure => Radix-2. • Use single delay feedback. • Using fixed points arithmetic and a complex array multiplier. • An ideal architecture for VLSI implementation of pipeline FFT processors.
New FFT Processor Radix-23(1/4) It has the same multiplicative complexity as radix-8 algorithm, but retain butterfly structure of radix-2 algorithm. • Faster and smaller than radix-2 and radix-22 . • Combine radix-8 and radix-2. • multiplier only.
Reference • Alan V.Oppenheim, Ronald W.Schafer, “Discrete-time signal processing” 2nd edition. • Shousheng He and Trkelson, M.,”A new approach to pipeline FFT processor,” Procesdings of IPPS’96, 15-19 April 1996, pp 766-770. • Signals and system. Chen.. • Signals and system. Haykin.1st edition. • OFDM Radix 23 website .hsu.cc.orz • Discrete Signal processing.4th ed