We are experiencing some problem with the sound (CODEC 1341) on Neponset.
The problem is when recording the sound (using the onboard microphone on
Neponset) we get a lot of background noise.  We do not have this problem
with the use of Assabet only (CODEC 1341).  (I use the following command for
testing: cat /dev/dsp > filename and cat filename > /dev/dsp)

On Neponset we can play MP3 files and WAV files without background noise.
So, something is wrong with either the input to the CODEC 1341 (hardware) or
the CODEC 1341 setting (software).  The problem can be found on our three
Neponsets.

The following is the setup of the CODEC 1341 (all the other setting is set
to the default value as specified in the UDA1341 specification):

DATA0_0.volume = 15;                    Volume Control of -14dB
DATA0_2.mode = 3;                       Mode filter to maximum
DATA0_ext2.mixer_mode = 2;              Mixer mode to select input channel 2
DATA0_ext2.mic_level = 4;               Microphone sensibility setting of
+15dB
DATA0_ext4.AGAC_ctrl = 1;               AGC enable
DATA0_ext6.AGC_level = 3;               AGC output level setting to -17.5dB

I tried many setting and the best solution that I have is with the
Microphone sensibility setting of 0dB.  With this setting, I reduced the
background noise level by a factor of 2 but still some background noise.
  
NOTE: In order to be able to configure the CODEC from software, we have
unsoldered the jumper wire at J7, and move it to immediately adjacent J4.

Does anyone have experiencing this problem.  If no, what was your CODEC
setting.  If yes, what is your suggestion to eliminate those background
noise.

The kernel that I use for testing the sound is 2.4.1-rmk1-np2. 

 <<...>> 
Sylvain Pérusse
Software Engineer

225 boul. Du Séminaire Sud              Email:   [EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]> 
Saint-Jean-sur-Richelieu                Phone: (450) 542-5798
Québec Canada J3B 8E9           Fax:     (450) 358-7704

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