Re: [Discuss-gnuradio] Angle manipulation & other concerns

[Eric Blossom]

On Mon, Feb 20, 2006 at 09:56:52AM +0100, Martin Dvh wrote:
> joe j wrote:
> 
> 
> src1=your first source of complex data
> src2=your second source of complex data
> mult=gr.multiply_cc()
> c2conj=gr.conjugate_cc()
> dummy=gr.add_const_cc(0.0) #This is just a block which should have the same 
> delay as c2conj and do nothing further
> c2arg=gr.complex_to_arg()
> fg.connect(src1,dummy,(mult,0))
> fg.connect(src2,c2conj,(mult,1)
> fg.connect(mult,c2arg)
> 
> Now the output of c2arg should have the angle of the phase difference 
> between your two signals.
> You could put an average block after that to filter the phase difference
> avg_alpha=0.01
> avg=gr.single_pole_iir_filter_ff  (  avg_alpha )
> fg.connect(c2arg,avg)
> 
> explanation:
> If you multiply a signal with the conjugate of another complex signal, the 
> output is a complex signal with amplitude=amp1*amp2 and phase=phase1-phase2
> This is why you get a real signal if you multiply a signal with the 
> conjugate of itsself.

> The dummy in the above script is just a hack so every path has the same 
> (processing) delay.  To do this the "right" way you should put all
> this in one processing block.  (That is the only way to be sure
> everything has the same processing delay) 

FYI, you don't need the dummy block.

Just use

  src1=your first source of complex data
  src2=your second source of complex data
  c2conj=gr.conjugate_cc()
  mult=gr.multiply_cc()
  c2arg=gr.complex_to_arg()

  fg.connect(src1, (mult,0))
  fg.connect(src2, c2conj, (mult,1)
  fg.connect(mult, c2arg)

Eric