[USRP-users] DOA with N310 or X310+TwinRX

Sammy Welschen sammywelschen at gmail.com
Mon Jan 27 09:39:54 EST 2020


Thank you for the information Robert! Isn't it 6 GHz? However, 4 GHz would
also be sufficient for me.

How many channels does your system have?  I suppose you use some algorithm
for phase calibration after power cycling? I plan to do the same, so the
180 deg ambiguity should be manageable.

I looked at the N32x, however, they cost twice as much and I dont't plan on
using 200 MHz of bandwidth. If I have an external LO signal I can feed it
to the N310, so the only difference between N310 and N32x in this regard
would be that I need to generate the LO externally when using the N310,
right?

<Robert.Poehlmann at dlr.de> schrieb am Mo., 27. Jan. 2020, 14:42:

> We use the N310 for DoA estimation, however:
>
> -          you are limited to 4 GHz
>
> -          after power-cycling you get a 180° ambiguity between the two
> radios (I do not know if this could also happen when you just change the LO
> frequency)
>
>
>
> If you want to have >4 channels, have a look at the new N320/N321. No
> experience with those, but apparently they can do LO distribution.
>
>
>
> Also take into account if maybe later in the project you want to be able
> to transmit, which you cannot do with TwinRX.
>
>
>
> Regards,
>
> Robert
>
>
>
> *From:* USRP-users [mailto:usrp-users-bounces at lists.ettus.com] *On Behalf
> Of *Sammy Welschen via USRP-users
> *Sent:* Monday, January 27, 2020 2:19 PM
> *To:* usrp-users at lists.ettus.com
> *Subject:* Re: [USRP-users] DOA with N310 or X310+TwinRX
>
>
>
> Thank you Marcus! So the N310 would be the way to go? I was unsure since
> the TwinRX is recommended for phase coherent applications.
>
>
>
> Marcus D. Leech via USRP-users <usrp-users at lists.ettus.com> schrieb am
> So., 26. Jan. 2020, 18:57:
>
> On 01/25/2020 11:43 AM, Sammy Welschen via USRP-users wrote:
> > Dear all,
> >
> > I am planning a system with 5-10 channels that is capable of DOA
> > estimation.
> >
> > Concerning the calibration of the resulting array, would there be a
> > difference between a system made up of N310 and one made up of X310
> > with TwinRX boards? Would there be other important differences that
> > influence estimation performance?
> >
> > As I understand it, the TwinRX allows LO sharing between the boards in
> > a single X310, but this would not help me if I have two or three X310.
> > On the other hand, the N310s could be connected to a shared LO.
> >
> > Are the following thoughts correct?
> >
> > Suppose I turn on my system. Then I have to calibrate phase offsets
> > between channels in any case. Now I change the center frequency. If I
> > have N310s without shared LO, I have to recalibrate. Same for the
> > X310s, since LOs are shared only internally. If I have N310s with a
> > shared LO, I do not have to recalibrate.
> >
> > If I restart the system, I have to recalibrate in any case.
> >
> > The devices would by synchronized with PPS in any case and with the 10
> > MHz reference if no external LO is used.
> >
> > What is the better choice for DOA estimation (N310 or X310 with TwinRX
> > or something different)?
> >
> > Thank you very much
> >
> > Sammy
> >
> >
> Sammy:
>
> Your characterization of the two scenarios is correct.
>
> There may be some folks on this list who have implemented DOA schemes,
> but likely few-to-none who have done it on both X310 and N310
>    and can comment on the differences they encountered.
>
>
>
>
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>
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