The problems of Microphone and Amplifier.

Discussion in 'General Electronics Chat' started by sanjam kaur, Apr 27, 2015.

  1. sanjam kaur

    Thread Starter New Member

    Apr 27, 2015
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    i have to acquire a wrist pulse signal using micriphone, and for that i have used microphone and instrumentation amplifier INA110, i have grounded the negative terminal of microphone and the second terminal is given to 2 pin of INA110 to provide differential signals to amplifier. in order to provide potential to 1 pin i have connected a 1 Mohm potentiometer. But when i am observing results on ossciloscope the signal gets saturated and it is showing constant dc voltage. what should i do eliminate this problem.
     
  2. ScottWang

    Moderator

    Aug 23, 2012
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  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    What kind of microphone do you have?

    What is the lowest sound level that the microphone can respond to?

    Do you have any type of cone around your microphone to isolate from other sounds and maybe acquire more audio energy.
     
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  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Please post a schematic of your circuit. Without it we cannot know what you are doing.

    ak
     
  5. sanjam kaur

    Thread Starter New Member

    Apr 27, 2015
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    the microphone i have used is condenser microphone of 6 mm dia and is omni directional.

    i will post schematic of the circuit soon.
     
  6. Alec_t

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    Is it actually an electret microphone (i.e. the common, inexpensive type)?
     
  7. sanjam kaur

    Thread Starter New Member

    Apr 27, 2015
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    yes it is an electret microphone
     
  8. #12

    Expert

    Nov 30, 2010
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    Can you post the schematic today, or are you limited to one post per 24 hours?
     
  9. sanjam kaur

    Thread Starter New Member

    Apr 27, 2015
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    no its nt lyk dis...i am drawing the schematic and its taking time.
     
  10. #12

    Expert

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    The first stage depends very much on your microphone. Here are some sample drawings.
     
  11. sanjam kaur

    Thread Starter New Member

    Apr 27, 2015
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    thanks...
     
  12. Alec_t

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    :confused:Translate please?
     
  13. sanjam kaur

    Thread Starter New Member

    Apr 27, 2015
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    thanks...one of the circuit diagrams you suggested above worked...and i got good results.
     
  14. sanjam kaur

    Thread Starter New Member

    Apr 27, 2015
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    i have now acquired the same signal in labview using daq card. and further i want to filter the signal ..what kind of filter should i use.
    the sampling rate of the signal is 100 hz. and no of samples read are 300.
     
  15. Veracohr

    Well-Known Member

    Jan 3, 2011
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    What frequency range is the signal you're interested in, and what noise is present?
     
  16. GopherT

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    "No, it's not like this"
     
  17. sanjam kaur

    Thread Starter New Member

    Apr 27, 2015
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    i m interested in a frequency range below 25 hz.
     
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