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Poly seminar-mems microphone jamsheed

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mems microphone seminar ppt

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Poly seminar-mems microphone jamsheed

  1. 1. WELCOME…WELCOME… A SEMINAR ON MEMS MICROPHONE Jamsheed . p ES5 NO : 13
  2. 2. OUT LINE…OUT LINE…  Introduction  MEMS technology  Microphone structure  Microphone structure  Working  Performance parameters  Applications  Advantages  Conclusion
  3. 3. INTRODUCTIONINTRODUCTION  MEMS technology provides a promising implementation for microphones.  Here, we discuss the design , characteristics & applications of MEMS microphone.
  4. 4. MEMS TECHNOLOGYMEMS TECHNOLOGY MEMS is a process technology used to create tiny integrated devices or systems that combine mechanical and electrical components. They are fabricated by integrated circuit (IC) batch processing techniques.
  5. 5. MEMS TECHNOLOGY …..MEMS TECHNOLOGY ….. Can range from a few micrometers to millimeters. These devices have the ability to sense , control and actuate on the micro scale and generate effects on macro scales.
  6. 6. MICROPHONE STRUCTUREMICROPHONE STRUCTURE
  7. 7. MICROPHONE ARCHITECTUREMICROPHONE ARCHITECTURE
  8. 8. WORKING….WORKING….
  9. 9. WORKING…WORKING…  Transduction principle is the coupled capacity change between a fixed plate and a movable plate.  Change in air pressure created by sound waves cause the thin membrane to flex while the thicker back-plate remains stationery .  The movement of membrane creates a change in capacitance between the membrane and back plate, which is translated to an electrical signal by an interface IC.
  10. 10. Performance parameters…Performance parameters… Sensitivity It is the measure of microphones response to a given sound. Sensitivity of microphone can be adjusted by changing the gain. Normally specified in dB FS (for digital mic) or dBV (for analog mic). Sensitivity of microphone sensor is an important factor in determining the SNR. Sensors with higher sensitivity increases the SNR.
  11. 11. Performance parameters…Performance parameters… ((cntd)cntd) Noise floor It is the measure of amount of noise created by itself. The noise floor of the microphone is its output amplitude in the absence of sound. Normally specified in dB FS (for digital mic) or dBV (for analog mic).
  12. 12. Performance parameters…Performance parameters… ((cntd)cntd) Signal to noise ratio It is defined as the difference between its sensitivity and its noise floor. Sound pressure level Sound pressure level is the logarithmic measure of change in air pressure caused by sound and specified in dB SPL . Acoustic overload point it is the maximum sound level that a microphone can faithfully capture.
  13. 13. Performance parameters…Performance parameters… ((cntd)cntd) Dynamic range The dynamic range of microphone is the difference between its acoustic overload point and its noise floor . It is Measured in dB.
  14. 14. TYPES OF MEMS MICROPHONE …TYPES OF MEMS MICROPHONE … Analog type: which converts sound input to corresponding voltage output Digital type: Gives a digit output typically a pulse density modulation
  15. 15. APLLICATIONS…APLLICATIONS…
  16. 16. ADVANTAGES…ADVANTAGES…  Can be manufactured using surface mount technology  Can withstand high temperature , vibrations  Easily integrated with CMOS process  Provides Improved noise cancellation  Low power consumption  High signal to noise ratio (70 dB)  Very small size (1.05 mm)
  17. 17. CONCLUSIONCONCLUSION  MEMS technology provides a promising implementation for microphones.  MEMS microphone is an excellent choice for applications with size constraints.
  18. 18. ReferencesReferences  S. D. Senturia, Microsystems Design. New York: Kluwer Academic, 2001.  V. P. Klimashin, “Mems technology,” Pribory i Tekhnika Eksperimenta,  Internet  www.st.com/microelectronics
  19. 19. THANKS….THANKS….

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