On Thu, Aug 27, 2009 at 12:46:13PM +0200, Mattias Kjellsson wrote: > adib_sairi wrote: >> Dear All, >> As i being experimenting with USRP and GNU Radio, i notice that some of the >> last packet of my data that i receive is keep inside the USB buffer. this >> data will be flush out to my PC only if i transmit (receive) new data. i >> believe that this is due to the minimum byte data needed by the USB buffer >> (fusb_block_size - 512). so even though there is some receive packet inside >> the USRP, it won't be send to the PC until it is a group of 512 byte of >> data. am i correct?
Yes. >> so at the transmitter, i should send an extra 512byte of data for each of my >> last packet that is transmitted for one session.. > I think there is more to it than just the usrp and usb. Today I have > been working on a test- case > where I have the following flow- graph (in c++ if that might matter) > > file_source-> "some blocks" -> file_sink > > If the file- sink was not exactly 8k = 8192 bytes large the whole flow- > graph gave unpredictable output in terms of size of the output. Note > that I used "repeat = false" in the file- source. > > I'm not sure if it's the number of items in the source or the size of > it, since it in my case is the same (using a bit- file- source). The length of the output should be reproducible from run to run. (Assuming you let it run to completion and aren't ^C-ing it.) If it's not, there's a bug somewhere (unless you're deliberately introducing some random input to the system somewhere). > Hope this helps (and that someone else has more input) > //Mattias Eric _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
