Hi, thank you Adeel for your answer. I implemented almost the same approach yesterday. I bring signal from USRP through rms and log calculator directly to the block for sampling symbol value. On every symbol I read RSSI and send that value forward. As soon as I detect premble i start calculating RSSi for the packet based on number of symbols. The problem that I have now is how to ensure that samples from demodulator chain and samples from RSSi calculator come in the same time to the symbol decision block. How can I tune this delay and is it deterministic?
Many thanks, Nemanja On Thu, Jul 18, 2013 at 2:33 AM, Adeel Anwar <adeela...@gmail.com> wrote: > Nemanja, > > I built this block sometime back. The ideas is to construct a custom RSSI > Measurement block having input > > 1: complex IQ-samples after USRP-SRC or before "AGC" > 2: byte-stream after "digital_correlate_access_code_bb". Output byte > stream has data in LSB (1st bit) while Flag in 2nd bit shows header > detection) > 3: Calculate system/filters group-delay between the complex-IQ samples > stream and output-of-correlate-access-code. This delay will depend on the > a) No. of filters in system e.g. FLL-Filter, PFB-Timing-Synch etc > b) No. of filter Taps > 3: Delay the complex IQ-samples stream by amount calculated in 3 > 4: In Custom RSSI-Measurement Block use following logic > if (2-bit of correlate-access-code-stream) is High: > Take average of N-items from IQ-samples stream > > where "N" depends on > a) No of symbol in packet > b) Samples-per-Symbol > > Hope this helps > > -Adeel > > > > On Wed, Jul 17, 2013 at 12:36 AM, Nemanja Savic <vlasi...@gmail.com>wrote: > >> This looks a bit silly cause I am speaking with myself. Anyway, maybe I >> can do something with probe_avg_mag_sqr, but maybe somebody can tell me how >> can I access that block's values from another block? >> >> Best, >> Nemanja >> >> >> On Tue, Jul 16, 2013 at 3:16 PM, Nemanja Savic <vlasi...@gmail.com>wrote: >> >>> The only way that is on my mind is to detect burst and store it in a >>> file, and then to send a message to the block that will read that file, and >>> in case of successfull demodulation and decoding to calcualte signal power, >>> but it looks pretty robust and non elegant. >>> >>> Cheers, >>> Nemanja >>> >>> >>> On Tue, Jul 16, 2013 at 2:26 PM, Nemanja Savic <vlasi...@gmail.com>wrote: >>> >>>> Any suggestions on this topic, opinions? >>>> >>>> Best >>>> Nemanja >>>> >>>> >>>> On Tue, Jul 9, 2013 at 4:23 PM, Nemanja Savic <vlasi...@gmail.com>wrote: >>>> >>>>> Hi again gnuradioers, >>>>> >>>>> as always, I would like to ask for your opinion before starting to >>>>> write my own block. >>>>> Basically, I would like to add a feature to my receiver to be able to >>>>> calculate average signal strength during signal reception. When I receive >>>>> a >>>>> valid packet I would like to have a RSS value. My question is what is >>>>> the best way to accomplish this in GNURADIO? Using tags or messages, >>>>> ...? IS there anything similar already provided so that I can take a look? >>>>> >>>>> Thank you and best >>>>> >>>>> -- >>>>> Nemanja Savić >>>>> >>>> >>>> >>>> >>>> -- >>>> Nemanja Savić >>>> >>> >>> >>> >>> -- >>> Nemanja Savić >>> >> >> >> >> -- >> Nemanja Savić >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > -- Nemanja Savić
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