Post History
Signal characteristics are: 0 to 3.3V span 0 to 100Hz range( there will be noise superposed on top with unknown characteristics) Output resistance Rout=4700 ohm I want to sample that with a...
#2: Post edited
by
Lorenzo Donati
·
2023-07-31T22:24:39Z (over 1 year ago)
Removed ambiguous tag: SAR alone means Synthetic Apertur Radar. Added more specific tag.
#1: Initial revision
by
2kind
·
2022-04-01T13:56:04Z (over 2 years ago)
When do I need to put anti-aliasing filter in front of SAR ADC?
Signal characteristics are: - 0 to 3.3V span - 0 to 100Hz range( there will be noise superposed on top with unknown characteristics) - Output resistance Rout=4700 ohm I want to sample that with a SAR ADC built in the MCU. ADC has following characteristics: - internal sample and hold capacitance --> Csh = 7pF - sampling switch resistance --> Rsh = 6kOhm - sampling time range --> programmable from t_s = 0.1us to t_s = 16us My idea was to sample the input signal at a much higher rate than needed and implement an RC filter in the firmware so I can modify it easily. Is there a benefit and what would the benefit of putting an RC filter in front of the ADC be? Or I can implement it purely in FW without drawbacks?