Re: [Discuss-gnuradio] Measuring phase between channels

[Marcus Müller]

Hi David,

for starters, you could just divide one channel by the other and
calculate the result's argument. There are blocks for both operations :)

Short explanation:
Just consider the complex signals $s_1, s_2$ in polar coordinates
(instead of the usual real/imag representation)
$s_1(t) = a_1(t) * e^{j \phi_1(t)}$.
Dividing that by $s_2(t) = a_2(t) * e^{j \phi_2(t)}$ gives you
$p(t) = a_1(t)/a_2(t) * e^{j \phi_1 - \phi_2(t)}$, of which you can take
the argument to get the phase difference.

Greetings,
Marcus

On 17.06.2014 19:06, David Miller wrote:
> Hello,
> I want to measure the phase difference between three synchronised USRP
> channels (Common Ref & PPS), does software exist to do this, and to
> what accuracy, please?
> Sorry, this is a bit of a newbie question, and probably already covered!
> Dave
>
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