I actually tried using filters to implement the delay and they do NOT work as expected:
I used "Interpolating FIR filter" with taps equal to (0,)*delay+(1,) and i didn't see any difference as i was changing the delay parameter dynamically.... Achilleas On Tue, Nov 15, 2011 at 3:05 PM, Marcus D. Leech <mle...@ripnet.com> wrote: > On 15/11/2011 3:00 PM, Achilleas Anastasopoulos wrote: >> >> I made a simple example with a cosine and a delayed version of that >> going through >> a multiplier, and observing the output together with a slider that >> changes the delay dynamically. >> However i do not see any change (eg, elimination of the dc component >> when delay ~ pi/2). >> >> >> Looking at the code of the block gr_delay it shows that the delay can >> dynamically change >> and this results essentially in a call to set_history() in gr_block. >> Looking further into the set_history() method, it sets the private >> variable d_history. >> >> The question is: does the dynamic change of history have any effect in >> gr_block? >> What happens in the guts of the block when d_history changes? >> and why don't i see any effect in the example above? >> >> thanks >> Achilleas > > I ran into the exact same thing a couple of weeks ago. It has to do with > the deep-structure of the schedule, and Jonathan Corgan had > indicated he was going to look into it. > > The weird thing is that FIR filters do the same thing when you change the > number of tapes (muck with d_history), but they actually > *work* dynamically after you change them. > > > > -- _______________________________________________________ Achilleas Anastasopoulos Associate Professor EECS Department Voice : (734)615-4024 UNIVERSITY OF MICHIGAN Fax : (734)763-8041 Ann Arbor, MI 48109-2122 E-mail: anas...@umich.edu URL: http://www.eecs.umich.edu/~anastas/ _______________________________________________________ _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
