On Sat, Jul 13, 2013 at 8:54 PM, Andrew Davis <glneolistm...@gmail.com> wrote: > Hello all, > > When using pll_carriertracking_cc, the returned spectrum seems to be > inverted about 0MHz, when looking though the code line 113 of > gr-analog/lib/pll_carriertracking_cc_impl.cc looked odd: > >> optr[i] = iptr[i] * gr_complex(t_real, -t_imag); > > could someone explain why the the imaginary component of the NCO is > inverted? > > Thank you all, > Andrew
Andrew, That block was written so that it would lock to a carrier at a tone that is then used to downshift the signal. So you have a signal at fc; the PLL would lock onto that and produce a tone at -fc. This is then multiplied against the original signal to shift it down to baseband directly. Tom _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
