1. Voice Activated Calculator Shuab Khan Siddharth Yereddi

2. Outline • Objectives • Design • Tests • Challenges • Conclusions

3. Why Voice Activated? • Convenient • Marketable Consumer Device • Way of the Future • Applications

4. Project Objectives • Speaker Independent • Performs Basic Calculations • Works in Natural Environment

5. Design • Pre-filter and Preamplifier • Speech analysis on Digital Signal Processor (DSP) • Calculations on PIC microcontroller • Output displayed on LCD

6. Microphone (Input) Analog Filter (90Hz – 5 kHz) Amplifier Gain Factor: 450 V/V Speech Detection and Recognition (DSP) Digital Filter (300Hz – 5kHz) (DSP) PIC Microcontroller LCD Display Realtime System

7. Testing

8. Preamplifier Test Measured Gain = 450 V/V

9. Prefilter Simulated Frequency Response 6 kHz [cutoff]

10. Pre-Filter Test – 2V input

11. Digital Highpass Filter

12. Digital Lowpass Filter

13. Endpoint Detection

14. Noisy Signal

15. Accuracy vs Noise

16. Anagrams • Spectrum ------> Cepstrum • Filtered ------> Liftered • Frequency ------> Quefrency

17. Speech Recognition – MFCC’s

18. Speech Recognition - Liftering

19. Speech Recognition – LPCC’s

20. TI Fixed Point DSP

21. Issues on DSP • Memory limit • Overflow handling • Quantization Errors • Processing Time • Environment Noise Level

22. Future Developments • Floating Point DSP • External Memory Chip • Larger Training Data

23. Questions??? ?