[Discuss-gnuradio] About the -ve represenation on FFT graph.

[rono]

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

http://www.fungkai.com/~howie/sdr/complex_1_basefreq0.gif

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.


http://www.fungkai.com/~howie/sdr/complex_1_basefreq10.gif

What's the frequency lower then the center frequency represent?