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fvnktion
Joined: 27 Jun 2006 Posts: 39
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measure audio level with ADC |
Posted: Wed Aug 12, 2009 1:13 pm |
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I have a requirement to be able to be able to measure the audio level of an audio line. I am wondering if anyone has done anything like this using an adc of of PIC?
I am thinking about setting up an integrator circuit with some time constant to capture how much audio signal was present over a period. The ADC value would roughly correspond to the volume?
Any thoughts on how well an ADC would interpret this as the level of volume? |
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languer
Joined: 09 Jan 2004 Posts: 144 Location: USA
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Posted: Wed Aug 12, 2009 2:29 pm |
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Do you have a definition for the audio signal? Frequency Range? Periodic or not?
Ideal would be an RMS-type detection (integrator comes close), or LOG-detection. Less ideal, but widely used would be peak-detection.
Few links which showed up in Google: |
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fvnktion
Joined: 27 Jun 2006 Posts: 39
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Posted: Wed Aug 12, 2009 4:38 pm |
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I'll have a look at the links.
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Do you have a definition for the audio signal? Frequency Range? Periodic or not?
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The signal will be the output stage of an audio amp from an MP3 player. The signal, so mixed frequencies from 50 - 16khz or so. Non-Periodic, could be any song or audio signal coming from the media source.
Quote: | Ideal would be an RMS-type detection (integrator comes close), or LOG-detection. Less ideal, but widely used would be peak-detection. |
I'll take a look at these methods.
Thanks |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Wed Aug 12, 2009 4:51 pm |
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a full wave RMS or simple 2 diode AVErage value detector will make the ripply DC input you are after - feeding audio direct will just return random trash |
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