Parallel data reception

GNU Radio
1

Hello everyone,

I am using USRP1 + RFX2400.

You know there are two antenna ports on RFX2400 daughter card those are
RX2,
TX/RX. Is it possible to use both these ports in parallel for data
reception. If yes then pelase provide me little clue how I should do it,
or
may be refer me to some existing example.

I have two RFX2400 daughter cards and my problem is to use two different
ports for data reception, it doesnt matter if I use two ports on a
single
card (i.e RX2, and RX/TX), or two ports on two different cards (e.g. RX2
on
each card). Please let me know which one is possible and easier to
implement
and please also refer me to some application where I can find relevant
code.

Thanks and Best Regards

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2

each card). Please let me know which one is possible and easier to implement
and please also refer me to some application where I can find relevant code.

I do not believe it is possible to receive data from the TX/RX and TX
port simultaneously, I believe the are tied to the same set of ADCs.
You should use two RFX cards if you are planning on doing MIMO
reception. Check in the examples section, I don’t think there is a
specific 2 antenna receive example with the 2400’s; but there is a 4rx
fm receiver that you should be able to extrapolate from.

Jason

3

Hallo,

We use following when there is only one RFX2400 daughter card (I think
there
is onle one subdev in RFX2400 card…Is it correct???).

u = usrp_source(…)

u.set_mux(usrp.determine_rx_mux_value(u, rx_subdev_spec))

Can some one guide me how do I change it when two RFX2400 daughtercards
are
used.

And what additional processing needs to be done to separate data streams
from RX2 antennas of both
cards.

Best Regards

Jason U. wrote:

I have two RFX2400 daughter cards and my problem is to use two different
port simultaneously, I believe the are tied to the same set of ADCs.
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4

There is a handy dual_usrp wrapper in grc:
http://gnuradio.org/trac/browser/gnuradio/trunk/grc/src/grc_gnuradio/usrp/dual_usrp.py

You can use it like:
from grc_gnuradio import usrp as grc_usrp
grc_usrp.dual_source_c(…)

Or use the code as an example

-Josh

5

usrp_dual_source want antennas which should be used as input parameters,
as
follows (I copied this line from a question posted on a thread which was
using LFRX daughter cards)

self.usrp_dual_source_x_0 = grc_usrp.dual_source_c(which=0, side_a=‘A’,
rx_ant_a=‘RXA’, side_b=‘A’, rx_ant_b=‘RXB’)

But I am using RFX2400 daughter cards, which have antennas, RX2, RX/TX,
and
I want to use only RX2 for both daughter cards (I have 2 RFX2400
daughter
cards installed with USRP1), please tell me which of the following
should I
use:

1- self.usrp_dual_source_x_0 = grc_usrp.dual_source_c(which=0,
side_a=‘RX2’,
rx_ant_a=‘RX/TX’, side_b=‘RX2’, rx_ant_b=‘RX/TX’)

2- self.usrp_dual_source_x_0 = grc_usrp.dual_source_c(which=0,
side_a=‘RX2’,
side_b=‘RX2’)

If 1 is correct then how can I set RX2 antennas after that.

Best Regards

Josh B.-2 wrote:

-Josh

u.set_mux(usrp.determine_rx_mux_value(u, rx_subdev_spec))
Best Regards

reception. If yes then pelase provide me little clue how I should do
on
fm receiver that you should be able to extrapolate from.

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6

Thanks Jason, I am trying this, hopefully it will solve my problem.

Best Regards

Jason U. wrote:

This is correct (assuming you are using GRC) The side A and side B

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7

http://gnuradio.org/trac/browser/gnuradio/trunk/grc/src/grc_gnuradio/usrp/dual_usrp.py#L24
The source, the source!

8

usrp_dual_source want antennas which should be used as input parameters, as
follows (I copied this line from a question posted on a thread which was
using LFRX daughter cards)

self.usrp_dual_source_x_0 = grc_usrp.dual_source_c(which=0, side_a=‘A’,
rx_ant_a=‘RXA’, side_b=‘A’, rx_ant_b=‘RXB’)

This is correct (assuming you are using GRC) The side A and side B
refer to the side of your usrp, not the ports on the RFX board itself.
Since you can have two daughter boards, the are side A ad B
respectively, you will have to use the rfx antenna select function to
choose between TX/RX and RX2.

If you are not using grc I have attached a file that I use to capture
data from two RFX2400 boards in the same usrp, it will probably
require some modifications for your application, but its a start.

Jason