Any real-valued signal consists of both positive and negative frequency components (with complex-conjugate amplitudes) in a Fourier decomposition into complex exponentials. Harminv usually is set up to find just one sign of the frequency, but occasionally converges to a negative-frequency component as well; these are just as meaningful as the positive frequencies.
If you google "negative frequency" you'll find several pages that attempt to explain this. On Sep 2, 2012, at 4:11 AM, [email protected] wrote: > Dear professor Johnson, > > what is the meaning of negative frequencies in harming results? > > Thanks. > > > _______________________________________________ > meep-discuss mailing list > [email protected] > http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss _______________________________________________ meep-discuss mailing list [email protected] http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/meep-discuss
