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Re: [Discuss-gnuradio] dynamically changing delay in gr_delay (or histor


From: Achilleas Anastasopoulos
Subject: Re: [Discuss-gnuradio] dynamically changing delay in gr_delay (or history in any gr_block)
Date: Tue, 15 Nov 2011 19:24:54 -0500

Marcus,

The grc file that i sent does not support your theory:
I have 2 filters:

one with taps:   (0,)*delay+(1,)
and the other with taps  (1,)+(0,)*delay

then I can change the delay dynamically, which also means that the
history is also changed dynamically (NOT ONLY AT INIT) and there is no problem
whatsoever.
Clearly the second filter is not needed but if i get rid of it then the whole
thing does not work...

I am really confused...
Achilleas

On Tue, Nov 15, 2011 at 6:21 PM, Marcus D. Leech <address@hidden> wrote:
> On 11/15/2011 06:16 PM, Achilleas Anastasopoulos wrote:
>>
>> Take a look at the attached grc file:
>>
>> As implemented, it does not work (changing the delay does not have an
>> effect).
>>
>> If I introduce the "fictitious" filter (1,0,0,0,0,..)
>> it works as expected.
>>
>> AM I doing something wrong in the first case?
>>
>> Achilleas
>>
> It seems that the runtime machinery pays attention to d_history *only* on
> block init, and at no other time, which leads to unexpected
>  results.  But, surely, this must have worked at some point?
>
> I mean, I regularly use filters whose parameters I change dynamically, and
> they apparently do what I want, although, perhaps at the moment
>  of changing parameters, the phasing isn't "right", but they seem to work.
>
> Someone with more exposure to the gr-runtime stuff should comment here.
>
>
>>
>>
>
>
> --
> Marcus Leech
> Principal Investigator
> Shirleys Bay Radio Astronomy Consortium
> http://www.sbrac.org
>
>



-- 
_______________________________________________________
Achilleas Anastasopoulos
Associate Professor
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