Re: [Discuss-gnuradio] dummy block has huge impact on usability fir filter

[Eric Blossom]

On Mon, Dec 27, 2004 at 02:43:22AM +0100, Martin Dvh wrote:
> 
> I found a very strange effect in the code in the AM receiver I am using.

Hi Martin,

I'll take a look at this.  I suspect that there may be a bug somewhere
in the interaction between the buffer allocator and the scheduler when
dealing with very high decimation ratios.

Thanks for providing detailed info about the problem.

Eric

> If I connect a gr.freq_xlating_fir_filter_scf directly to my high speed
> ADC source I can only use very wideband fir filters.Everything narrower
> as 123 kHz gives no output or only about one second of audio and then 
> dead silence.
> If I add a dummy block after the source (adj_in = gr.add_const_ss(0))
> before the gr.freq_xlating_fir_filter_scf I get an output even with
> filters as narrow as 2.5 kHz.
> (narrower filters mean more filter taps, more processing power)