Re: [Discuss-gnuradio] Filter delays and direction of time.

[Achilleas Anastasopoulos]

Point well taken!

Essentially I am trying to synchronize
two sinusoids, one of which is passing through a
filter and is thus gaining some phase/time over the other.

I think I found a way to solve my problem
by using the "advance" (as opposed to delay)
"block" of GnuRadio, ie, the filter with taps [0,1].

Thanks,
Achilleas

Eric Blossom wrote:


> I think there's a bit of an impedance mismatch between how you are
> thinking and how GNU Radio works.  GNU Radio is not an isochronous
> data flow engine.  We've got lots of implicit buffering between
> blocks.  You have virtually no control over the amount of buffering
> that's taking place between blocks.  Thus, implementing a delay with the
> filter block isn't going to get you what I think you want.  You're
> probably noticed that there's no "delay" primitive.  If you've got
> something with a feedback loop in it, it needs to be implemented in a
> single block.  E.g., PLL's.
>
> What are you really trying to do?  What's the problem you're trying to
> solve, or the computation you're trying to make?
>
> FYIW, in the gr_hilbert_fc.{h,cc} block we implement the hilbert filter and
> the parallel delay line in the same block, thus ensuring goodness.
>
> Eric