[Discuss-gnuradio] Using gr.vector_source_f()

[Suhrid Bhatt]

Hello All!

I am a new gnu radio user and am stuck with an elementary problem...

I am trying to generate a data-driven source using gr.vector_source_f()
with the following code:

#!/usr/bin/env python


from gnuradio import gr
from gnuradio import usrp

def build_graph ():
        fg = gr.flow_graph ()
        data = (-5000,5000)
        src0 = gr.vector_source_f ( data, 1 )
        dst = usrp.sink_c (0,64)
        f2c = gr.float_to_complex()
        fg.connect ( src0, f2c, dst )
        return fg

if __name__ == '__main__':
        fg = build_graph ()
        fg.start ()
        raw_input ('Press Enter to quit: ')
        fg.stop ()

I have a few questions and would really appreciate if someone could help:

1) Is it possible to generate square waves using this function? Or any
function? I just get different sinusoids for different vector inputs. For
example the above code gives me a perfect sine wave (which I did not
expect). And for vectors with length > 2, it is some other form of
sinusoid.

2) What is the quantitative relationship between the vector and the
waveform for this function? I see some trend but I am unable to quantify
it perfectly.

3) As of now, I am controlling the frequency of the waveform by varying
the interpolation rate as follows:

output frequency = 64M/interpolation rate

Is there another way?

Pardon me if my queries are inane...

Thanks in advance for the help!

Regards,
Suhrid