Hi Alfonso,

Thank you so much for your reply.

That make sense. In fact, after doing RegBP I did not have any problem. But, considering that bandpassing at these very low frequency ranges ("0.002 - 0.01" and "0.012 - 0.028") removes the majority of the independent components of the signal, will the resulting output has any statistical validity? 

Thanks in advance.

Best regards,
Karel