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doc:appunti:linux:audio:audio_recording

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doc:appunti:linux:audio:audio_recording [2019/04/23 12:52]
niccolo [Web References]
doc:appunti:linux:audio:audio_recording [2019/05/22 15:51] (current)
niccolo [Electrical compatibility and hardware autodetection]
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 As stated above, the first problem is **powering the microphone** itself, because generally we will use an **electret** one. It is a **common practice** to provide the power on the same line of the microphone signal, so **requiring just two wires** for both power (from the device to the mic) and for signal (from the mic to the device). The power, also called //bias current//, is generally in the range of **2.5** to **5.0 volt**. As stated above, the first problem is **powering the microphone** itself, because generally we will use an **electret** one. It is a **common practice** to provide the power on the same line of the microphone signal, so **requiring just two wires** for both power (from the device to the mic) and for signal (from the mic to the device). The power, also called //bias current//, is generally in the range of **2.5** to **5.0 volt**.
  
-FIXME: How much current ​is provided in our test? Is the current always present or switched-on only at jack insertion?+On a Xiaomi Mi A1 smartphone, which has a **TRRS 3.5 mm jack, CTIA standard**, we measured a bias current ​of **2.19 volt** between ​the microphone (sleeve) and the ground (ring).
  
 Another parameter which should be considered is the **impedence** FIXME Another parameter which should be considered is the **impedence** FIXME
doc/appunti/linux/audio/audio_recording.txt ยท Last modified: 2019/05/22 15:51 by niccolo