How to remove noise?
Hello,friends!
My platform is MCU+ 1940 SigmaDSP, sound system.
Nowadays there is noise: when I adjust the Single volume control (slew), when 0dB or below, there is no noise.
While above 0dB, the noise appear.
Not consider the hardware, is there any soft method to remove the noise?
I once used the De-Emphasis , I can remove the noise, I can't hear the noise even the volume is max (not link input).
But, at the same time some useful signal of hight frequence was also removed, or something,
Anyway, some useful effect sound disappear if I add De-Emphasis .
The De-Emphasis 's parameter can't be adjusted, is there any other module of SigmaStudio I could use for removing the noise?
Thank you!
ad1940
Audio Signal Processors
microcontroller
noise
sigmastudio
SigmaDSP Audio Processors
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Michaelc21,
The de-emphasis block is not intended to be used as a general noise-reduction block. This is a specific filter that is designed for reducing the level of high-frequency signals that have had pre-emphasis added (the opposite filter of the de-emphasis block). By adding this to your signal flow, you are implementing a shelving filter to lower level at high frequencies.
The effect that you are likely seeing when you raise the gain over 0 dB is distortion caused by clipping the data outputs. The AD1940's output signals must be limited to a maximum of 0 dB, or else they will clip. Internally, the AD1940 has 24 dB of headroom, but the output level must be kept to 0 dB or below. This is illustrated on page 14 of the AD1940 datasheet.
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Thank you,
EZ Admin
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