USRP continues to transmit after usrp_siggen.py stopped


#1

Using a PowerMac G5 to control the USRP, if I stop usrp_siggen.py, the
USRP continues to transmit. Is this expected?

This behavior is different than on a PowerBook G4, where the USRP stops
transmitting when usrp_siggen.py is stopped.

Leo Kimminau


#2

On Sun, Jan 25, 2009 at 9:21 PM, Kimminau Jr., Leo F. removed_email_address@domain.invalid
wrote:

Using a PowerMac G5 to control the USRP, if I stop usrp_siggen.py, the USRP
continues to transmit. Is this expected?

No.

This behavior is different than on a PowerBook G4, where the USRP stops
transmitting when usrp_siggen.py is stopped.

Can you elaborate on any other differences between the configurations?
OS version, GNU Radio version, developer tools (GCC, swig, Python),
etc.?

Thanks

-Johnathan


#3

On Mon, Jan 26, 2009 at 09:03:32PM -0800, Johnathan C. wrote:

Can you elaborate on any other differences between the configurations?
OS version, GNU Radio version, developer tools (GCC, swig, Python),
etc.?

Thanks

-Johnathan

I think this is a known problem (not sure there’s a ticket on it). I
believe that what is happening is that on the faster machine, the Tx
pipeline in the FPGA is getting disabled before it has a chance to
drain. The result of this is that the pipeline is halted with a
non-zero constant value getting clocked into the DACs resulting in a
carrier for all daughterboards that contain an LO.

Eric