flatulent
Joined: 19 Jul 2002
Posts: 4848
Helped: 289
Location: Middle Earth
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 24 Sep 2004 3:00 Re: Background noise question |
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| One thing to keep in mind is to stop measuring the background when your piezo emits sound. One simple way to measure the background is with a cheap microphone, op amp amplifier stages, half wave rectifier stage feeding a RC network with a large time constant. This will produce a DC level proportional to the background noise. You can shunt one of the AC amplifier stage inputs with a FET or BJT to cut off the background measurement when the piezo sounds.
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