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# Microphone array

Microphone array. Raymond Sastraputera. Overview. Introduction Problem Solution Implementation Experimentation Conclusion. Introduction (Problem). Signal coming to a microphone Speech signal Noise signal Good signal consist of High speech signal Low noise signal.

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## Microphone array

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1. Microphone array Raymond Sastraputera

2. Overview • Introduction • Problem • Solution • Implementation • Experimentation • Conclusion

3. Introduction (Problem) • Signal coming to a microphone • Speech signal • Noise signal • Good signal consist of • High speech signal • Low noise signal

4. Introduction (Solution) • Microphone array • Beam forming theory • VAD • Cross correlation • Ref(1)

5. Implementation • Matlab • Examine(file) • Combine(file) • VAD(file) • Data source • Ref(2)

6. Samples in the Project Speaker 100 cm 1 2 3 4 5 6 7 8 Microphone Array 7 cm Microphone • Microphone array signal • Position

7. Beam forming Theory Source delay travel distance Microphone

8. Microphone array output • Known source position • Easily combine • Unknown • Approximate the position • VAD • Combine

9. VAD • Uses two size window • Small • Large • Based on energy change • Small window > large window

11. Cross correlation • Obtaining delay in aligning several signals

12. Extra Solution • Simulate the position of source • Std array of the signals • Lowest std = perfect alignment Speaker y 1 2 3 4 5 6 7 8 Microphone Array 7 cm Microphone

13. Result of Comparison • Microphone array output .wav sound • Speech voice enhanced • Noise signal is reduced • Delay calculation

14. Conclusion and Summary • 1. Microphone array enhance or amplify the speech signal (from a single source) and decrease the effect of the noise or other speech signal. • 2. Beam forming theory works well if the distance between microphone is much smaller than the distance to the signal source. In this experiment, because the ration of the distance is not that much, the error rate is pretty high.

15. Reference • 1. Weinstein, Eugene. “LOUD: A 1020-NODE MICROPHONE ARRAY AD ACOUSTIC BEAMFORMER”. Courant institute of Mathematical Science. Ed. Kenneth Steele. Tilera Corporation. Anant Agarwal, and James Glass. MIT Copmuter Science and Artificial Intelligence Laboratory. • 2. Campbell, Davik K. “Adaptive Beamforming Using a Microphone Array for Hands-Free Telephony.” LOUD: A 1020-NODE MICROPHONE ARRAY AD ACOUSTIC BEAMFORMER”. February 16, 1999. Blacksburg, Virginia. • 3. multi-microphone data recorded by Tom Sullivan (tms@cs.cmu.edu) at Carnegie Mellon University

16. Thank you • Any Questions?

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