Re: [Discuss-gnuradio] time triggered filter

[Kevin Reid]

On Apr 6, 2016, at 20:14, Philip Hahn <address@hidden> wrote:

> Related question: I'm having trouble notch negative frequencies. I understand 
> it needs to be a complex->complex with complex taps but most of the filter 
> blocks don't seem to support this. In my case a band reject filter is what 
> I'm looking for to remove spurious noise. I guess the answer is to frequency 
> xlate, filter and then frequency xlate back?

This is just a limitation in some of the canned blocks, not in GNU Radio 
itself. Instead of picking a 'band reject filter' block, pick the 'FIR Filter' 
block (either the decimating or interpolating type, doesn't matter), and in the 
Taps field insert a call to firdes --

Huh. firdes doesn't have a complex band reject function. Well, you can use 
gnuradio.filter.firdes.complex_band_pass and apply standard techniques to turn 
the result into a band-reject filter: see http://www.dspguide.com/ch14/5.htm if 
you need info.

> thank you Kevin,

Please make sure to “reply all” (include the mailing list in your replies) so 
other people can follow the discussion and offer advice.

-- 
Kevin Reid                                  <http://switchb.org/kpreid/>