Re: phase difference between Tx/Rx1 Tx/Rx2

[Xiang Ma]

Think about this.

The signal transmitted at USRP TX is 

Then after transmission, received at USRP RX is 

Here, ignore the Doppler shift, and just consider the phase change due to the transmission distance,

I know due to the wavelength, the phase received might be mod 2*pi, however, how can we get the received below in USRP?

Should we use analog signals to get the phase offset? or After ADC?

Thx

On Wed, Oct 7, 2020 at 5:21 PM Marcus D. Leech <patchvonbraun@gmail.com> wrote:

On 10/07/2020 07:13 PM, Xiang Ma wrote:
> Should the TX be the signal before it been received and after it been
> transmitted?
>
> Thx
>
>
The phase of the TX signal, as seen at the RX will be some function of
the propagation delay between the two, and the initial phase at the TX.
   That's basic conceptual stuff.

Since the TX and RX phase is determined by hardware that isn't
necessarily mutually synchronized, (that is the RX LO and TX LO don't
   originate from the same hardware), determining the initial phase will
require estimating what the phase difference due to
   geometry between the TX and RX is.    In radar applications, I
understand that coding is used to help with this.  But I'm not a radar guy.

  But again this is basic conceptual stuff that is, to a first
approximation, unrelated to the hardware that is being used.

--

Xiang Ma, Ph.D. Student

College of Engineering

Utah State University

E-mail:marxwolfs@gmail.com