In my system I measure signals with interesting bandwith from DC to 2 kHz. I have an analog low-pass filter with 200 kHz cutoff frequency in order to filter noise. The ADC samples the signal with 500 kHz. The signals are then used for a feedback controller that runs in a task with 20 kHz. So my questions are the following:
Can I expect alias on the signals used in the control task of 20 kHz?
Should in this case a digital filter at the sampling rate of 500 kHz applied that has a maximal cutoff frequency of 10 kHz (Half of control task rate)?
Would it be possible to apply a further low pass filter with 10 kHz cutoff frequency in the 20 kHz program task?