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Design >> Mixed-Signal Design >> Folding Effect: Choosing ADC Input Frequency to Observe Unwanted Tones
https://designers-guide.org/forum/YaBB.pl?num=1686208979

Message started by niloun on Jun 8^th, 2023, 12:22am

Title: Folding Effect: Choosing ADC Input Frequency to Observe Unwanted Tones
Post by niloun on Jun 8^th, 2023, 12:22am

Hi,

I know that we choose the ADC input frequency slightly lower than half of the sampling frequency so that all unwanted tones (mainly input harmonics) fold down to the main band (0 to Fs/2). But I cannot make sense of it. How does a frequency slightly less than Fs/2 help fold the unwanted tone back to the band of interest in comparison to input frequencies much lower than Fs/2?

Thanks

Title: Re: Folding Effect: Choosing ADC Input Frequency to Observe Unwanted Tones
Post by niloun on Jun 9^th, 2023, 5:15pm

Is it because distortion increases with the input signal frequency?