Cannot Change USRP Interpolation Rate Dynamically

Hi,

It seems that there is a bug in gnuradio 3.1.1 (and up to today latest
truck
revision) in the USRP rbf standard file. When trying to change the
interpolation rate dynamically, the output get distorted badly even if
the
program restore the started interpolation value. I have an old gnuradio
3.0.3 (Revision 6082) which does not have this problem at all. Checked
with
two RFX2400 boards, the same problem (it is an FPGA Problem).

To check this , start the test (for example) with interpolation rate 128
and
change it dynamically to 16 (it will be badly distorted). Now, try to
restore it back to 128, and you will see that it stacked at the 16 with
distorted waveform.

Best Regards,

Firas

View this message in context:
http://www.nabble.com/Cannot-Change-USRP-Interpolation-Rate-Dynamically-tp15495473p15495473.html
Sent from the GnuRadio mailing list archive at Nabble.com.

Firas - This is a known bug, but I don’t think it ever made it into
the bug tracker. See the threads from <
http://lists.gnu.org/archive/html/discuss-gnuradio/2007-10/msg00159.html

. If you have time (I don’t for a few weeks), could you please
enter it in as a new bug ticket? Try out the script from the link,
and see if it doesn’t work for you. If this script shows what you’ve
found, please also enter it in the ticket. - MLD

Hi Michael,

Michael D.-2 Wrote :
If you have time (I don’t for a few weeks), could you please
enter it in as a new bug ticket? Try out the script from the link,
and see if it doesn’t work for you.

I used your code http://www.nabble.com/file/p15502528/test.py test.py
and
recorded the spectrum picture as shown in :

  1. When the TX started (before changing the interpolation rate
    Dynamicly) :
    http://rapidshare.com/files/92067855/before.JPG

  2. After changing it (after the 15 seconds) :

http://rapidshare.com/files/92068144/after.JPG

If this script shows what you’ve found, please also enter it in the
ticket.

I will do it.

Regards,

Firas A.

View this message in context:
http://www.nabble.com/Cannot-Change-USRP-Interpolation-Rate-Dynamically-tp15495473p15502528.html
Sent from the GnuRadio mailing list archive at Nabble.com.