Hello folks,

i am doing my first steps on gnuradio, and as my first program i added 2

gr.sig_source_c using gr.add_ff.

gr.sig_source_c is a signal generator with gr_complex output, so i used

gr.add_ff because as you can see in [1] has been written that “Add

streams

of complex values”

but with this setup i take an error “ValueError: itemsize mismatch:

sig_source_c(1):0 using 8, add_ff(3):0 using 4”

on the other hand if i change gr.add_ff with gr.add_cc or

gr.sig_source_c

with gr.sig_source_f there isn’t any error.

In my opinion i think that python manual at this point is not correct

(from

the view of a new user). If i miss something or i am wrong please let me

know. If i am right , i think that

“gnuradio.gr.add_ffhttp://gnuradio.org/doc/sphinx/gr/math_blk.html#gnuradio.gr.add_ffAdd

streams of complex values.” should be changed to

“gnuradio.gr.add_ffhttp://gnuradio.org/doc/sphinx/gr/math_blk.html#gnuradio.gr.add_ffAdd

streams of float values” and "

gnuradio.gr.add_cchttp://gnuradio.org/doc/sphinx/gr/math_blk.html#gnuradio.gr.add_ccoutput

= sum (input_0, input_1, …)" should be changed to "

gnuradio.gr.add_cchttp://gnuradio.org/doc/sphinx/gr/math_blk.html#gnuradio.gr.add_ccAdd

streams of complex values"

–vg

[1] http://gnuradio.org/doc/sphinx/gr/math_blk.html#gnuradio.gr.add_ff