Forum: GNU Radio usrp_spectrum_sense.py , gr_plot_psd and periodogram.

Hello All,
         I have few doubts regarding usrp_sepctrum_sense.py and
gr_plot_psd :
* Does usrp_sepctrum_sense.py use normal periodogram or any other
non-parametric PSD estimation method(like Barlett and/or Welch) ?
* Does gr_plot_psd use overlap and add method or just the overlap
method(I get this doubt because gr_plot_psd already considers file as
blocks) ?

Thanks in advance.

Regards,
Ravi Sharan