Re: [Discuss-gnuradio] time triggered filter

[Philip Hahn]

Ah, sorry for not hitting reply-all. Yeah, I tried firdes and figured I was missing something as is usually the case. Thanks again,

philip

On Wed, Apr 6, 2016 at 8:24 PM, Kevin Reid <address@hidden> wrote:

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/>