Hi,
Explain how exactly you "tried" it.
What exactly is the sampling frequency? How is it generated? Is it aligned somehow to the carrier frequency?
What does this mean: " the low intensity signal is skipped"?
And: Is this good or bad?
Aliasing: Generally you need to get rid of the "other channel" before sampling.
All frequencies in the source signal get mirrored down to fs/2 bandwidth. So your filter in the source side needs to suppress all frequencies outside this band.
On the digital side you may use additional filters to suppress signal within this band.
Klaus