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Entry  Fri Oct 26 18:25:02 2012, Ayaka, Update, Adaptive Filtering, Microphone noise again mic_noise.png
    Reply  Fri Oct 26 19:06:14 2012, Den, Update, Adaptive Filtering, Microphone noise again 
       Reply  Mon Oct 29 08:41:22 2012, Ayaka, Update, Adaptive Filtering, Microphone noise again 
Message ID: 7633     Entry time: Fri Oct 26 18:25:02 2012     Reply to this: 7634
Author: Ayaka 
Type: Update 
Category: Adaptive Filtering 
Subject: Microphone noise again 

[Raji, Ayaka]

Thanks to Den, power supplies for microphone circuit are changed.
So I measured the microphone noise again by the same way as I did last time.

mic_noise.png
  solid lines: acoustic noise
 dashed lines: un-coherent noise
black line: circuit noise (microphone unconnected)

The circuit noise improves so much, but many line noises appeared.
Where do these lines (40, 80, 200 Hz...) come from?
These does not change if we changed the microphones...

Anyway, I have to change the circuit (because of the low-pass filter). I can check if the circuit I will remake will give some effects on these lines.

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