Re: [Discuss-gnuradio] FIR filters and set_history()

[George Nychis]

George Nychis wrote:
> I had thought I could use gr_fir_filter_ccc, setting my taps to be the 
> time reversed version of the input signal, but found that it wasn't 
> correlating.  I think what I was missing is the fact you are suggesting 
> that the taps be the complex conjugate of the input signal?

You are apparently correct :)

Using the FIR with time reversed complex conjugate of the desired input 
signal:
http://cyprus.cmcl.cs.cmu.edu/matched_filter/graphs/mf_fir_conjugate.jpg

Using the "matched filter block" that uses the complex/real-wise inner 
product:
http://cyprus.cmcl.cs.cmu.edu/matched_filter/graphs/mf_block.jpg

The FIR filter method seems to have much better properties, creating a 
much larger magnitude in the output.

- George