Sorry if the question was re-posted.
Can anyone reply this entry level question?
In complex data representation such as the attached image by grc,
the LPF cut the frequency in both direction(+/- freq)
which the center frequency is 0Hz
When I set the base frequency to a large positive value such as 10MHz,
the cutoff shows on both side apart from the center frequency too.
What’s the frequency lower then the center frequency represent?