Hi chucck,
Chuckk Hubbard wrote:
On 6/20/06, Piotr Majdak piotr@majdak.com wrote:
If I understand you correctly, this is similar to what Miller's book talks about. Pairing every complex filter with another with the conjugate of its coefficient, so that the real signal can be treated as the sum of two complex signals which are conjugates of each other. Hallelujah, I just made it work. Not so hard. Far easier than trying to make a real signal complex.
Glad to hear it!
Writing the original signal and the real and imaginary parts of the output to graphs shows lots of alterations. It is fine with a block containing an integer number of cycles, but otherwise gets weird results. See attached.
Every time you write the signals to the tables, the phase of the original signal changes. Because of the windowing effects the processed signal (FT->Re{}->IFT) changes dramatically: the real part of the FT result contains the information about the symmetric part of the original signal (=cosines), which changes with its phase.
Thanks for the nice example - it took me a while to analyze what happens here.
br, Piotr