in our custom board we are getting some background noise when we record audio. I checked the recorded wav file using Audicity and the noise is easy to identify during the silence periods. Using the noise removal effect from Audicity I was able to clean that noise with a couple of mouse clicks. As far as I know, Audicity use a noise gating function to achieve that.
So, I connected the AIC3105EVM to my PC and use the headset of it as input to the Line1's EVM. I played the noisy wav file, just to "simulate" the effect of our custom board. Using the AIC3105EVM Evaluation Tool I tried to setup the codec in order to use the built-in noise gate, but after changing the setting in the AGC tab (Threshold, Hystesis, AGC settings, etc), I couldn't make any substancial improvenment, it even get worse in the most of the cases.
I am not really sure what I am doing wrong, so I hope that someone may enlighten me to find the correct way to configure the noise gate of the codec to get the same/similar result as in Audicity.
Thanks in advance.
Here is an app note that goes over the AGC function on this family of products:
thanks for your reply. Yes, I know already that app note and I already tried with the values suggested in the examples there, without success. Should the noise gate of the AIC3105 work in a similar way as the one in the Audicity plug-in? I moved the threshold through all the possible levels, varying also the max. AGC gain and I did not get any noise reduction.Or Am I missing anything? I am not sure if the noise gate needs a special setup (i.e other components like the PGA gain) that I am not aware of...
thanks in advance.
If you can send your register settings, I can take a look at what you are doing. If you are using the GUI, you can go to the Command Line Interface Tab and copy and paste to a text file. The noise gate should work pretty much as it would in audicity. The ADC's need to be powered up since the feedback is digital from the ADC. Aside from that I would have to review your settings.
I tried to post a picture of our HW setup in the last post together with other files but somehow the post is empty (I think I missed the "insert". So I will try again.
Thanks in advance for your help.
just to extend a little bit my last post, i do the following EVM SW setup:
1) in Audio Input/ADC tab:
- After connecting the PC-EVM via USB, I start the EVM software tool and execute e software reset.
- Unmute (active) Line1R/Line1R "L ADC" and "R ADC" options.
- Left and Right ADC power up.
2) In High Power Outputs tab
- set the HPL Output to i.e 4.
- set PGA_L and PGA_R to i.e. -15.5
-activate Power up.
3) Play audio in PC
4) In In AGC tab
- start to modify all the settings in different ways. No positive results whatever I change.
Hope that it helps to find what I could be doing wrong.
the case is taken offline.
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