Dear friends,
Thank you very much for your response to my post
I have double read and check the documents from Texas Instrument I have posted in #4, and it is misleading
If I follow that procedure to have fc > 10 fsignal with passband ripple less than 1 lsb error, it will not be practical at all
The standard bandwidth of a filter should accept signal drop-3 dB at fc (as Suta noticed that), it means that I should design fc equal to the maximum input signal information frequency, maybe a little bigger if we want less drop but not 10 times as they are suggesting in the first document.
The filter stop band frequency at (f= fs/2 )should have attenuation gain equal to the half LSB of the intended ADC. By this way, the aliasing is avoided.
If I take an example of commercial audio signal anti-aliasing filter used in CDs and audio equipment, they use standard sampling frequency of 44.1KHz, and fc = 20 kHz leaving 2 kHz space between fs/2 and fc.
However, I have here a question, with 3 kHz space that will be used as stop band range of the filter, how many orders required to have 8 bit of resolution (filter stop band gain at fs/2 = 51 dB) ??
Thank you once again
Regards