Hi I think Brian is just referring to the fact that you can see that the HBFs are implemented as symmetric FIR filters (the coefficients). A HBF is just a special filter that is designed so that the cutoff frequency will always be at fs/2, so if you filter with it and decimate by 2 afterwards (which is why you would use an HBF), you don't get aliasing. Also, the decimation in the CIC filters can be set to a wide range of values, so the HBF will always have to cut at fs/2 regardless of the decimation in the CIC. From what I've read, Goodman and Carey came up with them so you can probably look for some papers if you're interested.
Sebastiaan -- Sebastiaan Heunis Radar Remote Sensing Group, University of Cape Town, South Africa Tel: +27 72 950 9370 _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
