On Thu, 2011-04-28 at 23:19 +0300, Stefan Gofferje wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi, > > On 04/28/2011 10:03 PM, Nick Foster wrote: > >> Without any details at all on what systems you're trying to communicate > >> with, the answer is "very probably, but you'll have to do it all > >> yourself". In other words, the hardware when used with Gnuradio will > >> generate and receive pretty much any signal less than [25MHz for N210, > >> 8MHz for USRP1, ~4MHz for E100] wide. But you're going to have to > >> implement the whole transceiver system yourself, and that's not a > >> plug-and-play proposition by any stretch of the imagination. > > Basically, we are just talking about good old analog FM narrowband radio > com. MAYBE - as I said as a creamtip - ETSI DMR 2 Analog. But if nobody > has written a trx yet, I guess, I have to forget about that. My > developer skills are way out of that league. There might be a chance > that I could get our boss to put out a bounty for that but I have to > prove that the USRPs are what we need before that.
If you're just doing NBFM that's pretty braindead simple. > > >> This is readily accomplished with existing Gnuradio blocks when combined > >> with Python code for the main application. You may or may not be able to > >> get such a system working entirely within GRC. There are multiple > >> existing squelch blocks based on tone decoding and/or receive power > >> level. I've been meaning to put in an "FM quieting" squelch like COTS > >> handheld FM radios use, but haven't gotten around to it. Power squelch > >> works fine for most uses. > > Marcus has already given me some pointers about the squelch / PTT thing. > One thing however is not totally clear to me. > A conventional radio has some "startup time" for the PLL to "swing in" > when you start transmitting. How is that with SDRs or the USRP in > specific? Does feeding data to the TX immediately result into a clear > and stable signal or is there also some "swing in" time to consider? > > Specifically, does one have to consider some prerun time of transmitting > some "filler" before transmitting the actual payload? Every time you tune the TX you'll have to wait a few ms for it to become stable. For voice transmission purposes, a few ms is effectively instantaneous anyway. And if you aren't retuning, then it will come up instantly, because the LO will still be running in between sample bursts. --n > > - -S > > - -- > (o_ Stefan Gofferje | SCLT, MCP, CCSA > //\ Reg'd Linux User #247167 | VCP #2263 > V_/_ Heckler & Koch - the original point and click interface > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v2.0.16 (GNU/Linux) > > iEYEARECAAYFAk25y+EACgkQbQKZlCdPOMPVJQCfZqKNEhkMosJlL2KdYWEbUwIA > bJsAnj86sCxAu/gLNTB4T5+Z2Q4mOdnv > =0LrP > -----END PGP SIGNATURE----- > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
