Thanks for the guidance here. I'd actually like to save timestamps to a file, along with data - it sounds like this would require not only a custom copy handler but also a custom source block to pass the timestamp up to the flow graph. Am I on the right track here?
I'm not sure I totally understand the interactions of the low-level code, is there any further documentation for that? Thanks, Dan -----Original Message----- From: Douglas Geiger [mailto:doug.gei...@bioradiation.net] Sent: Thu 3/12/2009 10:51 AM To: Cocuzzo, Daniel C. Cc: Pham, Thanh; Discuss-gnuradio@gnu.org Subject: Re: [Discuss-gnuradio] extract timestamp data -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Cocuzzo, Daniel C. wrote: > I'm also wondering about how to extract ethernet packet information, > such as timestamp. If anyone has any pointers to reference materials it > would be greatly appreciated. > > Thanks, > Dan > > The easiest way (depending on what you are doing with the timestamps) is probably by dealing with the low-level libusrp2, and writing a custom copy handler (look at rx_streaming_samples.cc in usrp2/host/apps). The metadata structure (in usrp2/metadata.h) provides the timestamp from the fpga. I'm playing around right now with creating a custom source block that has access to the timestamps (i.e. the copy handler passes it from the low-level library into the source block - but not to the rest of the flowgraph). I'm only interested in it as far as providing aligned samples from two USRP2 (like usrp_multi does for the USRP1). Depending on what you need the timestamps for, that may be the way to go. Doug - -- Doug Geiger Research Assistant Communications and Signal Processing Lab Oklahoma State University http://cspl.okstate.edu douglas.gei...@okstate.edu doug.gei...@ieee.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Cygwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFJuSFmgfOzzR5bXIgRAl9uAKCbn2HziekL8O+kUIyg9uG4qwjB/QCfXxQL sGldNGn6AVsCnzkM8gVFPqM= =GDET -----END PGP SIGNATURE-----
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