houly
Advanced Member level 4
Anti aliasing filter
Hello
I have design an antialiasing filter (14 bits ADC), my bandpass is about 300kHz and the sampling frequency is 1MHz. So Ideally, I would want to have a 84dB of attenuation (14 bits ADC quantum) @ Fsampling/2. This give me a very big filter that can't be realized with analog design. I never see a big filter before an ADC so what kind of filter can I need ? I often see a simple RC before the ADC, is it enough ? and how can I decide the cuttof frequency for my application ?
PS : Order of the filter :
84db/(6*(1E6/(2*314E3))) = 8 see figure 3.8 in the application note :
https://www.google.fr/url?sa=t&sour...zt37CA&usg=AFQjCNEq4LXRjGd5AlUXJXcBA51bV3Dp-w
Hello
I have design an antialiasing filter (14 bits ADC), my bandpass is about 300kHz and the sampling frequency is 1MHz. So Ideally, I would want to have a 84dB of attenuation (14 bits ADC quantum) @ Fsampling/2. This give me a very big filter that can't be realized with analog design. I never see a big filter before an ADC so what kind of filter can I need ? I often see a simple RC before the ADC, is it enough ? and how can I decide the cuttof frequency for my application ?
PS : Order of the filter :
84db/(6*(1E6/(2*314E3))) = 8 see figure 3.8 in the application note :
https://www.google.fr/url?sa=t&sour...zt37CA&usg=AFQjCNEq4LXRjGd5AlUXJXcBA51bV3Dp-w