Volume control with potentiometer - ADAU1467
Thread Summary
The user asked about reducing the noise floor when using a 10-bit ADC output that is left-shifted to a 1.24 number format. The final answer suggested using a Look-Up Table (LUT) method to control the input more effectively, providing a project file for implementation. The LUT method helps in managing the gain and ensuring the signal goes to zero when the potentiometer is at its minimum setting.AI Generated Content
Hi Dave,
You wrote:
"This will left shift the 10 bit output of the ADC that is right justified to be a 1.24 number. This will give you a larger range going from almost "1" to a very low gain. Usually this is down into the noise floor. I have run into issues where the debounce block might not let it go down to zero, or there is noise on the ADC input, then you might still hear the signal way down into the noise floor when the pot is at minimum. There are ways to get around that if needed but most applications this simple method works well. This will left shift the 10 bit output of the ADC that is right justified to be a 1.24 number. This will give you a larger range going from almost "1" to a very low gain. Usually this is down into the noise floor. I have run into issues where the debounce block might not let it go down to zero, or there is noise on the ADC input, then you might still hear the signal way down into the noise floor when the pot is at minimum. There are ways to get around that if needed but most applications this simple method works well."
Could you please tell us what would be a way to get around this issue?
Thanks in advance
Audio Signal Processors
adau1467
SigmaDSP Audio Processors
Hello,
I hope you have already seen this method. It would work for you. In this method you will have more control over the input.
1467-LUT-vol.dspproj
Regards,
Harish
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