On 06/03/2014 03:59 PM, David Halls wrote: > Hey Martin, > > Good to hear from you as always. Gnuradio scheduling baffles me more > than anything else on this planet. The day I get my head around it will > be a happy day indeed. :0
Some things aren't meant for us mere mortals :) > The problem with using 'sob', 'eob' is because I have two inputs to the > USRP UHD sink. One is constantly transmitting and has items coming in > from time=0, but the other has no input items from time=0, they only > arrive later on. As a result the sink seems to block waiting for items > on *both* inputs before it will transmit anything. I don't want the USRP > to have to wait for the second stream to be populated before it > transmits anything... Hm, this is an interesting use case I think we might want to address at some point. But this doesn't help you right now. > I thought 'forecast' may help me out, but wasn't sure what to put in the > function to make it schedule even when there are no input items? Haven't tried this, but maybe you can just tell it that ninput_items_required = 0 for some values of noutput_items. Again, this might produce too many zeros. Maybe you need something more sophisticated. Cheers, Martin > > David > > -----Original Message----- > From: Martin Braun [mailto:martin.br...@ettus.com] > Sent: 03 June 2014 14:53 > To: David Halls; discuss-gnuradio@gnu.org <mailto:discuss-gnuradio@gnu.org> > Subject: Re: [Discuss-gnuradio] Scheduling a block even with no input > items RE: Flow graph blocking when doing 2x1 transmission > > On 06/03/2014 03:30 PM, David Halls wrote: >> Dear All, >> >> Had anyone tried to implementing a gnuradio block that will output >> zeros if there are no items at the input, and will simply copy the >> input to output otherwise? >> >> I find that if there are no items at the input, the block never gets >> scheduled. >> >> I want this block to feed zeros to my USRP until actual data is ready >> to be passed to it. > > Hey David, > > any reason you can't use eob/sob? > > Also, did you set forecast accordingly? > > Note that this can go wrong easily: If this blocks produces a bajillion > zeros very quickly, nothing will happen until the USRP has consumed them > all. > > M > > > ________________________________ > > NOTE: The information in this email and any attachments may be > confidential and/or legally privileged. This message may be read, copied > and used only by the intended recipient. If you are not the intended > recipient, please destroy this message, delete any copies held on your > system and notify the sender immediately. > > Toshiba Research Europe Limited, registered in England and Wales > (2519556). Registered Office 208 Cambridge Science Park, Milton Road, > Cambridge CB4 0GZ, England. Web: www.toshiba.eu/research/trl > <http://www.toshiba.eu/research/trl> > > > ------------------------------------------------------------------------ > This email has been scanned for email related threats and delivered > safely by Mimecast. > For more information please visit http://www.mimecast.com > ------------------------------------------------------------------------ _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
