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Masters Presentation at Griffith University

Masters Presentation at Griffith University. Master of Computer and Information Engineering Magnus Nilsson 2000 - 2001. Masters Presentation. FFT, Realization and Implementation in FPGA Speaker Verification in JAVA Demonstration of FFT and JAVA application.

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Masters Presentation at Griffith University

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  1. Masters Presentation at Griffith University Master of Computer and Information EngineeringMagnus Nilsson 2000 - 2001

  2. Masters Presentation • FFT, Realization and Implementation in FPGA • Speaker Verification in JAVA • Demonstration of FFT and JAVA application

  3. FFT, Realization and Implementation in FPGA • Technical Function • History of Fourier Transform • Discrete Fourier Transform • Fast Fourier Transform • The Radix-2 Algorithm • The Radix-4 Algorithm • FPGA • Complex FFT • Bit Length and Implementation • Results • Conclusion

  4. Technical Function • Background • Ericsson Microwave System • XILINX FPGA 1024-point FFT • Task • Study, Implement and evaluate FFT in FPGA • Technical Function • Collect data, execute a FFT and output the data. • The implementation shall be optimized on execution time, area and cost.

  5. History of Fourier Transform • Jean-Baptiste-Joseph Fourier • Problem of flow of heat in solid bodies • The analytical theory of heat, 1815 • Universal problem solving technique Radar Speaker Verification Medical Science

  6. Discrete Fourier Transform • N2 complex multiplications • (N)(N-1) complex additions • ~ 2N2 additions and multiplications

  7. Fast Fourier Transform • Early 1960’s • John W. Tukey and James W Cooley • An algorithm for the machine calculation of complex Fourier series • Runge and König • Radix - 2 algorithm

  8. The Radix-2 Algorithm ~ 2N2 additions and multiplications for DFT, Vs. N2/2 for FFT

  9. The Radix-4 Algorithm • Base 4 i.e. N = 4x • More complex but less computation power utilized • The Radix-4 algorithm consists of v steps (log(N)/log(4)) • Each step involves N/4 number of butterflies • 3*v*N/4 = (3N/8)log2N number of complex multiplications • (3N/2)log2N complex additions • Radix-2 Vs. Radix-4: • 25% reduction of complex multiplications • Complex additions will increase by 50%

  10. Radix-4 Dragonfly

  11. FPGA • Field Programmable Gate Array • For fast time to market hardware implementation • Xilinx Virtex-E • PCB with a Xilinx Virtex-E 1000

  12. Complex FFT • Specification • Minimum: 16 complex samples • Maximum: 1024 complex samples • Typical: 16 or 64 • Number of bits for the input signal • Minimum: 10 bits • Maximum: 16 bits • Typical: 12

  13. Construction configuration

  14. Bit Length • Implementing in hardware • Multiplications • Nbits x Nbits = 2 Nbits • Minimize the phase and amplitude error • Realizable • Different types of bit lengths

  15. Implementation • Ease, Eale, Modelsim and Symplify • Virtex-E 2000 @ Fc = 55 MHz, Computation phase = 640 ns my FFT • Xilinx Virtex LogiCore block @ 110 MHz, Computation phase = 1.92 ms • LogiCore = Serial • My FFT = Parallel

  16. Result • Tested using a Logical Analyser, Hewlett Pacard HP16555D (2.0 M Samples, 110/500 MHz) and a Pattern Generator

  17. Result

  18. Conclusion • As the Radix-4 FFT algorithm utilizes less complex multipliers than the Radix-2 FFT algorithm, the Radix-4 algorithm is preferable for hardware implementation. • A parallel programming approach seems to be the model when a real time system with high sampling rate is desired. • To reach an acceptable level of phase error, it is desirable to use 16 bits precision on the input signal and the phase factor

  19. Speaker Verification in JAVA • Technical Function • JAVA • Speaker Verification and Speaker Recognition • VQ Speaker Verification • Hardware Parallel Port Extension and access • Results • Conclusion

  20. Technical Function • Background • It would be interesting to develop a Speaker Verification system/software in JAVA, since the JAVA language is said to be platform independent and would be interesting as a research language. • Task • To study, implement and evaluate a VQ (Vector Quantization) Speaker Verification system in JAVA, using MFCC’s (Mel Frequency Cepstral Coefficients). • Technical Function • A graphical software implementation which shall record speech from a person through a microphone, verify the person as true speaker or false speaker.

  21. JAVA • 1991 @ Sun Microsystems by James Gosling & Co • Address the problem of building software for network consumer devices • Survive transport across networks • Operate on any client • Safe to run • Capability to work on a wide range of platforms and CPU's • Virtual Machine • Applet and Application • Platform portability

  22. Speaker Verification and Speaker Recognition

  23. Speaker Verification and Speaker Recognition • Accessing confidential information areas • Access to remote computers • Voice dialing • Banking by telephone • Telephone shopping • Database access services • Information services • Voice mail • PIN code for your ATM

  24. VQ Speaker Verification Speech Feature Extraction

  25. Mel Frequency Cepstral Coefficients

  26. Mel Frequency Wrapping

  27. Cepstral Coefficients • Power of the triangular filter = summarized • Log calculated • Convert them to time domain using the Discrete Cosine Transform (DCT) • Result is called the mel frequency cepstral coefficients (MFCC).

  28. Feature Matching • Dynamic Time Warping (DTW) • Hidden Markov Modeling (HMM) • Gaussian Mixture Model (GMM) • Vector Quantization (VQ) • High Accuracy • Interesting to implement

  29. LBG algorithm

  30. MFCC’s and Codebook

  31. Verification • Threshold • Cohort Speakers • Ratio

  32. Graphical Implementation of application in JAVA

  33. Results

  34. Conclusion • Since Java is said to be platform independent, some experiments has been conducted that has showed this is not always the case. As soon as you would like to access the hardware through Java you will face problems that will make your software to become platform dependent. • It is interesting to note that all the algorithm developed for the speaker verification system is platform independent, except for those parts accessing the sound card of the users computer, and can easily be executed under both Microsoft Windows and Linux. • Testing, simulation and verification of the speaker verification program show a total error rate of four percent.

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