I can confirm that if my FIR taps are defined as: (0,)*delay+(1,)+(0,)*(19-delay)
then i can change the delay dynamically for any values between 0 and 19 in the grc file that i sent earlier (attached here as well) EVEN without the second (trivial) FIR filter present! So it is clearer now that the problem with delay/filters is in the setting of history... thanks for the hints! Achilleas PS: Johnathan, could you give us a simple explanation of what happens in the internals when there is a history change so that at least we understand the computational model. On Tue, Nov 15, 2011 at 11:19 PM, Johnathan Corgan <[email protected]> wrote: > On Tue, Nov 15, 2011 at 16:44, Marcus D. Leech <[email protected]> wrote: >> >> But clearly, there's some brokenness there, and it's not clear to *me* how >> to fix it, although I desperately want dynamically-settable >> gr_delay() blocks to work as well, for some interferometry work. > > Sorry, I've been buried in some commercial projects that haven't left me > with much time to look at the issue more in depth. > > I can confirm that dynamically changing the delay in gr_delay does not (and > never has) worked. The fix for this is not that complex but it would be a > change in the runtime that would need a lot of regression testing. > > In the FIR-based delay scenario, it would be useful to know if there is a > difference between changing the taps from, say [0, 0, 0, 0, 1] to [0, 0, 1], > so the taps end up changing length, or changing the position of the 1 but > leaving trailing 0's so the tap length would remain the same. > > Johnathan > -- _______________________________________________________ Achilleas Anastasopoulos Associate Professor EECS Department Voice : (734)615-4024 UNIVERSITY OF MICHIGAN Fax : (734)763-8041 Ann Arbor, MI 48109-2122 E-mail: [email protected] URL: http://www.eecs.umich.edu/~anastas/ _______________________________________________________
test_delay.grc
Description: Binary data
_______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
