Re: [Discuss-gnuradio] Signal Multiplication

[Jonathan Shan]

On Sun, 5 Nov 2006, Eric Blossom wrote:

> I expect that your code is about 10 lines long.
> Can you please post it?

Between the time of originally posting and now, I changed the length of 
the vector and now am able to see a decent received signal.

The relevant code:

                src_data = (0,)*800 + (1,)*800
                vectordata = gr.vector_source_c(src_data, True)
                multiplier = gr.multiply_cc ()
                self.connect (adder, (multiplier, 0))
                self.connect (vectordata, (multiplier, 1))
                self.connect (multiplier, self.u)

adder is gr.sig_source_c(2000000, gr.GR_SIN_WAVE, 20000, 1000, 0).
self.u is the usrp sink.

Now the amplitude of the sine wave appears modulated but it looks like the 
frequency changes slightly which might make demodulating hard(?).

Example: 
http://www.winlab.rutgers.edu/~jonshan/images/amlooptest2.dat.jpeg

Jonathan