Re: [Discuss-gnuradio] zero ninput_items_required[0]

[Nemanja Savic]

Well, I still didn't try with interpolator, cause it seems that it will work. I'd rather try to make it with general block and also learn more about how the stuff work.
That's why I said that I used principles used for interpolator.

Ok, I am now tracking number of produces items and it works ok, from the buffers point of view.

Thanks guys very much

On Tue, Oct 22, 2013 at 2:26 PM, Martin Braun (CEL) <address@hidden> wrote:

On Tue, Oct 22, 2013 at 02:20:04PM +0200, Nemanja Savic wrote:
> Hello guys again!
>
>
> Based on Martins suggestion and Marucs' explanation I copied some principles
> from sync_interpolator and situation looks much better. I used function
> set_output_multiple and set_relative rate and now the outcome of calling

FYI: When using sync_interpolator, it will call set_relative_rate for
you (that's why you specify an interpolation rate).

> forecast function is much better. For example, for symbol rate of 10k and
> sampling rate of 500k i get following:
>
> ninput_items_required 8, noutput_items 4000
> ninput_items_required 4, noutput_items 2000
> ninput_items_required 2, noutput_items 1000
> ninput_items_required 1, noutput_items 500
> ninput_items_required 8, noutput_items 4000
>
>
> And as u can see it always offers integer multiple of samp_rate/sym_rate. The
> problem comes now when i run the flowgraph with vector source that repeats the
> pattern. After calling forecast program executes work function but it provides
> me 32768 input samples which is of course silly:
>
> work function, ninput: 32768, noutput: 4000

Don't worry about that. In all sync blocks, the output buffer is what's
relevant. If you fill up the output buffer in this case, you will
consume 8 input items.
How are you even getting the number of input items?
sync_interpolator::work() doesn't tell you that.

It still seems like you're abusing the API somehow.

MB


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Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin Braun
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KIT -- University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association

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Nemanja Savić