Does the ADC has a builtin antialiasing filter?

Official Hardware Mega Due
1

Hi,

I've already looked in the SAM3X datasheet and arduino.cc documentation, but without success.

I want to sample a signal whose highest frequency is greater than 1MHz but I'm only interested in the frequency range the ADC can sample. According to Nyquist–Shannon sampling theorem we must sample the signal with a sampling rate >= 2 * signal highest frequency or we will get alias.

This can be fixed with a LPF with a cut frequency equal to ADC sampling rate / 2. But what I want to know is if the SAM3Xs ADC (and others ucontrollers ADCs) already has this LPF inside it.

2

But what I want to know is if the SAM3Xs ADC (and others ucontrollers ADCs) already has this LPF inside it.

No, most ucontrollers do not have LPF built in.
Long time back I used to use

There are 3V and 5V models available.
And a lot of others:

3

Practically in industry you will find : 10x rather than 2x sample rate to reconstruct a signal and AAF cuttoffs set to 1/3 to 1/4 the sample rate. See the thread in this forum on data acquisition to empirically figure out max sample rate in a polling mode using the arduino libraries. I've been meaning to do a test and post results. Data aquisition with arduino Due - Arduino Due - Arduino Forum