Empathy List Archives

usrp-users@lists.ettus.com

Discussion and technical support related to USRP, UHD, RFNoC

View all threads

Re: [USRP-users] Two RX channels in the B210

Marcus D. Leech

Mon, Mar 16, 2015 9:28 PM

On 03/16/2015 05:16 PM, Patrick Sathyanathan wrote:

Thanks for the reply, Marcus. Here is the link on the analog devices
website:

http://wiki.analog.com/resources/eval/user-guides/ad-fmcomms2-ebz/ad9361

--Patrick

Not sure how to interpret that diagram. Suffice it to say that if such
functionality exists (sharing the TX LO on one of the RX channels),
there isn't
current support for it.

Perhaps one of the Ettus hardware folks can comment.

Date: Mon, 16 Mar 2015 17:10:56 -0400
To: usrp-users@lists.ettus.com
Subject: Re: [USRP-users] Two RX channels in the B210
From: usrp-users@lists.ettus.com

On 03/16/2015 05:04 PM, Patrick Sathyanathan via USRP-users wrote:

 Hi All,
 I am a hobbyist newcomer to SDR so any help would be appreciated.
 In deciding between the B200 and B210 I purchased the latter
 because a cursory read of the specs said it had 2 receive
 channels. I assumed this meant that I could monitor two different
 portions of the spectrum simultaneously.

 Now on digging further post-purchase I have discovered that the
 two RX channels share a common LO which means they cannot be tuned
 independently. The block diagram of the AD9361 at analog devices
 website shows a connection from the TX LO to the receive
 block. What is the purpose of this connection ? Is it feasible
 that one RX channel can use the receive LO and the other use the
 transmit LO ?

 Is it at all feasible to receive different frequencies at the same
 time ? Given that I am not doing MIMO is there any advantage to
 having 2 receivers ?

 Thanks,

 --Patrick

I haven't seen that link you're referring to, and I haven't heard of
anything other than a single, shared LO between the two RX channels on
the B210.

However, if your channels are within about 40Mhz of each other, then
the FPGA can downconvert them independently.

_______________________________________________ USRP-users mailing
list USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

On 03/16/2015 05:16 PM, Patrick Sathyanathan wrote: > Thanks for the reply, Marcus. Here is the link on the analog devices > website: > > http://wiki.analog.com/resources/eval/user-guides/ad-fmcomms2-ebz/ad9361 > > --Patrick > Not sure how to interpret that diagram. Suffice it to say that if such functionality exists (sharing the TX LO on one of the RX channels), there isn't current support for it. Perhaps one of the Ettus hardware folks can comment. > ------------------------------------------------------------------------ > Date: Mon, 16 Mar 2015 17:10:56 -0400 > To: usrp-users@lists.ettus.com > Subject: Re: [USRP-users] Two RX channels in the B210 > From: usrp-users@lists.ettus.com > > On 03/16/2015 05:04 PM, Patrick Sathyanathan via USRP-users wrote: > > Hi All, > I am a hobbyist newcomer to SDR so any help would be appreciated. > In deciding between the B200 and B210 I purchased the latter > because a cursory read of the specs said it had 2 receive > channels. I assumed this meant that I could monitor two different > portions of the spectrum simultaneously. > > Now on digging further post-purchase I have discovered that the > two RX channels share a common LO which means they cannot be tuned > independently. The block diagram of the AD9361 at analog devices > website shows a connection from the TX LO to the receive > block. What is the purpose of this connection ? Is it feasible > that one RX channel can use the receive LO and the other use the > transmit LO ? > > Is it at all feasible to receive different frequencies at the same > time ? Given that I am not doing MIMO is there any advantage to > having 2 receivers ? > > Thanks, > > --Patrick > > I haven't seen that link you're referring to, and I haven't heard of > anything other than a single, shared LO between the two RX channels on > the B210. > > However, if your channels are within about 40Mhz of each other, then > the FPGA can downconvert them independently. > > > > > _______________________________________________ USRP-users mailing > list USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Ben Hilburn

Tue, Mar 17, 2015 5:56 PM

Hello -

It is not possible to use the TX LO for an RX chain on the AD9361. I
agree that the block diagram is somewhat confusing, but unfortunately that
is not possible.

That connection is used for internal self-tests and calibrations.

Cheers,
Ben

On Mon, Mar 16, 2015 at 2:28 PM, Marcus D. Leech via USRP-users <
usrp-users@lists.ettus.com> wrote:

On 03/16/2015 05:16 PM, Patrick Sathyanathan wrote:

Thanks for the reply, Marcus. Here is the link on the analog devices
website:

http://wiki.analog.com/resources/eval/user-guides/ad-fmcomms2-ebz/ad9361

--Patrick

Not sure how to interpret that diagram. Suffice it to say that if such
functionality exists (sharing the TX LO on one of the RX channels), there
isn't
current support for it.

Perhaps one of the Ettus hardware folks can comment.

Date: Mon, 16 Mar 2015 17:10:56 -0400
To: usrp-users@lists.ettus.com
Subject: Re: [USRP-users] Two RX channels in the B210
From: usrp-users@lists.ettus.com

On 03/16/2015 05:04 PM, Patrick Sathyanathan via USRP-users wrote:

Hi All,
I am a hobbyist newcomer to SDR so any help would be appreciated. In
deciding between the B200 and B210 I purchased the latter because a cursory
read of the specs said it had 2 receive channels. I assumed this meant that
I could monitor two different portions of the spectrum simultaneously.

Now on digging further post-purchase I have discovered that the two RX
channels share a common LO which means they cannot be tuned independently.
The block diagram of the AD9361 at analog devices website shows a
connection from the TX LO to the receive block. What is the purpose of this
connection ? Is it feasible that one RX channel can use the receive LO and
the other use the transmit LO ?

Is it at all feasible to receive different frequencies at the same time ?
Given that I am not doing MIMO is there any advantage to having 2 receivers
?

Thanks,

--Patrick

I haven't seen that link you're referring to, and I haven't heard of
anything other than a single, shared LO between the two RX channels on the
B210.

However, if your channels are within about 40Mhz of each other, then the
FPGA can downconvert them independently.

_______________________________________________ USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Hello - It is *not* possible to use the TX LO for an RX chain on the AD9361. I agree that the block diagram is somewhat confusing, but unfortunately that is not possible. That connection is used for internal self-tests and calibrations. Cheers, Ben On Mon, Mar 16, 2015 at 2:28 PM, Marcus D. Leech via USRP-users < usrp-users@lists.ettus.com> wrote: > On 03/16/2015 05:16 PM, Patrick Sathyanathan wrote: > > Thanks for the reply, Marcus. Here is the link on the analog devices > website: > > http://wiki.analog.com/resources/eval/user-guides/ad-fmcomms2-ebz/ad9361 > > --Patrick > > > Not sure how to interpret that diagram. Suffice it to say that if such > functionality exists (sharing the TX LO on one of the RX channels), there > isn't > current support for it. > > Perhaps one of the Ettus hardware folks can comment. > > > ------------------------------ > Date: Mon, 16 Mar 2015 17:10:56 -0400 > To: usrp-users@lists.ettus.com > Subject: Re: [USRP-users] Two RX channels in the B210 > From: usrp-users@lists.ettus.com > > > On 03/16/2015 05:04 PM, Patrick Sathyanathan via USRP-users wrote: > > Hi All, > I am a hobbyist newcomer to SDR so any help would be appreciated. In > deciding between the B200 and B210 I purchased the latter because a cursory > read of the specs said it had 2 receive channels. I assumed this meant that > I could monitor two different portions of the spectrum simultaneously. > > Now on digging further post-purchase I have discovered that the two RX > channels share a common LO which means they cannot be tuned independently. > The block diagram of the AD9361 at analog devices website shows a > connection from the TX LO to the receive block. What is the purpose of this > connection ? Is it feasible that one RX channel can use the receive LO and > the other use the transmit LO ? > > Is it at all feasible to receive different frequencies at the same time ? > Given that I am not doing MIMO is there any advantage to having 2 receivers > ? > > Thanks, > > --Patrick > > I haven't seen that link you're referring to, and I haven't heard of > anything other than a single, shared LO between the two RX channels on the > B210. > > However, if your channels are within about 40Mhz of each other, then the > FPGA can downconvert them independently. > > > > > _______________________________________________ USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > >