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Measurement of sound amplitude... — Parallax Forums

Measurement of sound amplitude...

ArchiverArchiver Posts: 46,084
edited 2001-12-14 22:37 in General Discussion
Hi!

Here is my problem:

I would like to make a device that re-act to sound, like music. My
main problem is making a circuit that take the signal from a
microphone and amplify it. I tough about using a ADC 0831 after the
amplifier or using a /LM3904 (Not sure about # it's a chip that
convert analog sig to 10 different output step..)
Can someone help me with the microphone issue....which amplifier
should I use with it...

Any suggestion for a microphone, what type?

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2001-12-14 22:37
    You need to determine what microphone you will be using and it's
    characteristics. What impedance is it? What is the frequency response of the
    microphone? What frequency range do you want to record? The signal output
    from a microphone at very low signal levels is around -50dbm. Average
    conversation around -30 dbm and loud music around -10 dbm. The noise floor
    is -125 dbm. Select a low noise amp chip like the National LM381and set the
    gain for around 40 db. Their application note AN-64 shows the circuit
    details.
    The out of this ckt would then feed you A to D.

    Original Message
    From: "robinalmasi" <robinalmasi@y...>
    To: <basicstamps@yahoogroups.com>
    Sent: Friday, December 14, 2001 8:39 AM
    Subject: [noparse][[/noparse]basicstamps] Measurement of sound amplitude...


    > Hi!
    >
    > Here is my problem:
    >
    > I would like to make a device that re-act to sound, like music. My
    > main problem is making a circuit that take the signal from a
    > microphone and amplify it. I tough about using a ADC 0831 after the
    > amplifier or using a /LM3904 (Not sure about # it's a chip that
    > convert analog sig to 10 different output step..)
    > Can someone help me with the microphone issue....which amplifier
    > should I use with it...
    >
    > Any suggestion for a microphone, what type?
    >
    >
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