[USRP-users] What is the largest data transfer rate between the PC & USRP2/USRP N Series through a GB ethernet cable?

Nazmul Islam mnislam at winlab.rutgers.edu
Sun Jun 3 01:36:26 EDT 2012

I am using gnuradio companion to transmit a BPSK modulated data. I have the
following questions:

1. Does the complex int16 data type of the UHD: USRP sink correspond to the
16 bit per complex sample scenario?

2. I don't need to transmit any Q data since I am using BPSK modulation. If
I connect a float data to the complex int16 input port of the USRP sink,
does the USRP consider the input as a 16 bit real data? The grc file
captured in the attached png picture shows the type of connection that I am
asking about.



On Wed, May 30, 2012 at 12:58 PM, Josh Blum <josh at ettus.com> wrote:

> On 05/30/2012 07:11 AM, Nazmul Islam wrote:
> > Hello,
> >
> > I found a tutorial on GNUradio (
> > http://www.snowymtn.ca/gnuradio/gnuradiodoc-4.pdf) that mentions that
> > downconverts the signal to 8 Mega Sample per second before passing it to
> > the USB cable. They do it due to the 32 Mega byte data transfer rate of
> > cable and 16 bit I & Q samples. I assume that this information applies to
> > USRP1 with USB cable.
> >
> > I am planning to use USRP2 & USRP N series along with GB ethernet cables
> in
> > my experiments. Do these USRP's downconvert the signal before passing on
> to
> > the computer? If my computer is fast enough, can I transmit and receive
> (in
> > seperate USRP's) a signal with 20 MHz bandwidth?
> >
> There is a downconversion and upconversion chain in the USRP. The
> practical rate limitations are 25 Msps at 32 bits per complex sample or
> 50 Msps at 16 bits per complex sample.
> Is your computer fast enough? Thats an open ended question, but if you
> can test your processing IP without a USRP pretty easily: send samples
> from another computer over GigE and benchmark performance to see if your
> application can process the samples fast enough.
> -josh
> _______________________________________________
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Muhammad Nazmul Islam

Graduate Student
Electrical & Computer Engineering
Wireless Information & Networking Laboratory
Rutgers, USA.
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