When we multiply two complex signals in GNU Radio companion and see the
result using WX FFT block then there is no frequency difference
component(f1-f2) but only the addition component(f1+f2)…why is that??
On 08.05.2014 08:59, ali hanif wrote:
When we multiply two complex signals in GNU Radio companion and see the
result using WX FFT block then there is no frequency difference
component(f1-f2) but only the addition component(f1+f2)…why is that??
That is actually the mathematically correct thing.
M
Can you plz explain Martin or give me a link atleast…thnx in advance
I think you are confused because you’re doing the math on paper with
real sin/cos functions. The complex signal sources produce complex
oscillations ($s_f(t)=e^{j2\pi f t}$), which do not have symmetrical
spectrum.
Do the math with the exponential function; it get’s easier than what you
have to do to prove the real intermodulation signals, and you clearly
see that $s_a s_b = s_{a+b}$.
Greetings,
Marcus