Normally, this kind of delay detection is done using cross-correlation (or some more applicable variant thereof such as MRC). Note also that a delay will give a frequency-dependent phase shift, so you may wish to use a delay block rather than phase shift if your signal is broadband (although I must admit I don't know what the phase shift block does internally).
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio