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Author Topic: Measuring a -10dB 1Khz tone  (Read 1033 times)
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Nova Scotia
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I was wondering what the best way would be to measure and display a on an LCD a -10dB audio tone. Possibly and A2D converter of some type or maybe use the analog pins on the Arduino? I have little analogue experience.
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Manchester (England England)
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Quote
display a on an LCD a -10dB audio tone
dB is a relative measure, what is the absolute peak to peak amplitude of the signal you have.
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Left Coast, CA (USA)
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 An audio tone, being a AC voltage is not directly measurable by an arduino analog input pin without external components/circuity. Most economical method is to rectify and filter the signal and measure the resulting equivalent DC voltage value.
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I just measured with the scope now the max audio output and the max peak to peak voltage is 2 volts. Rectifying and filtering is fine if that is the best recommended method.

Mike
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Yes that will give you a 1V signal to measure. Do you expect it to go up or down from this level?
If up then no problem, if down you might want to amplify it to give yourself a bit more head room.
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What is it you want to display? The actual waveform? Or do you want to measure its frequency and/or amplitude and display those?

Pete
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It is a long term tester that needs to monitor a -10dB signal over time and display the value on an LCD. I could expand on this and have an indicator let me know if the signal increases or drops over time.
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