Setting the XCVR2450 Bandwidth

GNU Radio
1

Hi,

This is a two part question

  1. What are the XCVR2450 bandwidth options?
    I’ve looked at the website and discussion list threads on the matter and
    seen different answers on what the the bandwidth options are for the
    XCVR2450 daughterboard.
    The spec sheets seem to indicate different answers too… which muddle me
    further as I’m unsure if i’m reading them wrong.
    Can someone clarify for me what they are? Have there been two revisions
    of
    this hardware of something?

  2. How do I se the bandwidth?
    I’m trying to use the Bandwidth block on the UHD_Sink.
    However I don’t get any confirmation messages or indicators if i’ve set
    it
    wrong… how can I check?

Help would me much appreciated!

-Michael

2

On 07/08/2012 04:28 AM, Michael H. wrote:

Can someone clarify for me what they are? Have there been two revisions of
this hardware of something?

Maybe there is some confusion about specifying the bandwidth of a
baseband filter. See this for available rates.
20 MHz means +/- 10 MHz about the center of the baseband signal.
http://files.ettus.com/uhd_docs/manual/html/dboards.html#xcvr-2450

  1. How do I se the bandwidth?
    I’m trying to use the Bandwidth block on the UHD_Sink.
    However I don’t get any confirmation messages or indicators if i’ve set it
    wrong… how can I check?

RX defaults to 19MHz and TX 24MHz. You really cant see the filter
profile unless sample rate > filter BW

-josh

3

Thanks Josh,

I’ve still been toying with this though… and aren’t really having any
success.
E.g. if I pick a Tx bandwidth of 24MHz… and transmit

and use 8bit I&Q samples transmitted at 50MHz… then shouldn’t I see
some
signs of the filter?
What should I be looking for on my spec amp?

I assume by baseband filter, that you mean this is a digital filter that
applies what I send from the CPU to the USRP…

Cheers

-Michael

4

Awesome, thanks Josh - I’ll give this a try tomorrow!

5

On 08/22/2012 06:11 AM, Michael H. wrote:

Thanks Josh,

I’ve still been toying with this though… and aren’t really having any
success.
E.g. if I pick a Tx bandwidth of 24MHz… and transmit

and use 8bit I&Q samples transmitted at 50MHz… then shouldn’t I see some
signs of the filter?
What should I be looking for on my spec amp?

Just transmit some wideband noise and zoom out on the spectrum analyzer.
You should easily see the filter profile.

(Flow graph attached).

I assume by baseband filter, that you mean this is a digital filter that
applies what I send from the CPU to the USRP…

This is an analog baseband filter on the XCVR 2450.

-Josh