beautiful, thanks: adding #define CHUNK_SIZE 1024 set_output_multiple(CHUNK_SIZE); to the constructor yields resonable results N=1024: _N is zero N=1024: _N is zero N=1024: _N is zero N=1024: _N is zero
Still not sure why my original option was not working, but this is definitely a fine solution. I had forgotten you previous post on the topic, Thanks, JM -- JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe, 25000 Besancon, France April 5, 2020 10:58 AM, "Ron Economos" <w...@comcast.net> wrote: > I would use set_output_multiple() instead. See my previous e-mail for an > example. > > https://lists.gnu.org/archive/html/discuss-gnuradio/2019-08/msg00188.html > > Ron > > On 4/5/20 01:36, jean-michel.fri...@femto-st.fr wrote: > >> I am using the opportunity of porting gr-acars to GNU Radio 3.8 to >> re-write the processing algorithm. As part of this reorganization, >> I want to analyze the baseline standard deviation and detect the AM >> modulated message as a rise in standard deviation (ie custom squelch). >> Since there is hardly any plane flying over France at the moment, I run >> the analysis from a recorded file, in which case the scheduler provides >> few samples at each batch. So I want to accumulate a statistically relevant >> length of samples before assessing the variance. Rather than implementing >> a custom circular buffer, I want to benefit from the GNU Radio scheduler >> as explained slide 7 of http://jmfriedt.org/slides_gnuradiodays2019/18h00 MM >> GR scheduler.pdf >> >> "not forced to consume all input -- can consume less at single-item >> granularity >> “leftovers” beginning of next call’s input_items" >> >> So the work function of my sink block (no output item) is >> >> {_N+=noutput_items; >> printf("N=%d ",_N); >> if (_N>1000) >> {consume_each (_N); >> _N=0; >> printf("_N is zero\n");// make sure counter is reset >> } >> else consume_each (0); // accumulate more samples >> return 0; // noutput_items; >> } >> >> and I am confused by the output of this block which states >> >> N=170 N=340 N=510 N=680 N=850 N=1020 _N is zero >> N=15534 _N is zero >> N=170 N=340 N=510 N=680 N=850 N=1020 _N is zero >> N=15534 _N is zero >> >> so indeed once out of two sequences we accumulate up to 1000 samples, >> detect the targeted number of samples is reached, consume the buffer and >> reset the counter. But after resetting the counter, I get 15534 samples. >> Is this indeed a behavior of the scheduler or a mistake on my side of >> handling >> the counter ? (can hardly do anything wrong with such a simple example it >> seems). >> >> Is this the correct way of accumulating a minimum number of samples before >> processing each batch ? >> >> Thanks, Jean-Michel
