Hi, Helmut, for me RTL-SDR support is required. I will not be testing with another SDR hardware for reception as my application is meant to work with the USB stick (small dynamic range or not).
Glen, have a look at http://www.etsi.org/deliver/etsi_etr/300_399/30001/01_60/etr_30001e01p.pdf specifically section 6.2.2 and below. Faces exactly the same issues. FM is also affected by fast Rayleigh fading.. Anyway, Doppler shift will be a bigger issue than multipath. Cheers, Adrian On 9/18/17, glen english <g...@cortexrf.com.au> wrote: > HI Adrian > > good stuff! > > OK, now try the analog versus the digital, with a copy of the TX signal > at 30uS delay and -10dB with respect to the wanted signal.... (a common > multipath ) , and also 30uS delay and 0dB. > > Let me know... > > > On 15/09/2017 9:10 PM, Adrian Musceac wrote: >> Hi, >> >> I present a three way comparison between narrow band FM (5 kHz), QPSK >> Codec2 1300 (2.4 kHz) and QPSK Opus 19 kbit/s (16 kHz): >> >> https://www.youtube.com/watch?v=vApRe6R1gnk >> >> The comparison is taking place in the ISM band of 433 MHz with >> interference present from some temperature sensors in an adjacent >> channel. >> >> Conditions: same antenna locations, same RX chain gain, varying >> transmit gain (LCD like number on the top left of the screen) >> >> Results: both digital modes cope better with interference and are more >> intelligible than FM. The numbers on top left of RX application are >> expressed in dB of amplification in the SDR transmitter chain. >> >> Hardware: for transmit one USRP B200 with 433 MHz filter installed, >> for RX one RTL-SDR filter with 433 filter installed. >> Software: QRadioLink running on top of Gnuradio (GNU/Linux): >> https://github.com/kantooon/qradiolink >> >> 73, >> Adrian YO8RZZ >> >> >> ------------------------------------------------------------------------------ >> Check out the vibrant tech community on one of the world's most >> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> >> >> _______________________________________________ >> Freetel-codec2 mailing list >> Freetel-codec2@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Freetel-codec2 mailing list > Freetel-codec2@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
