On Wed, May 10, 2006 at 07:24:07PM -0700, Eric Blossom wrote: > On Thu, May 04, 2006 at 02:01:31PM -0400, Michael Milner wrote: > > Hello, > > > > I was just wondering if anyone has used GNURadio for any non-radio > > applications, specifically phone line modulation/demodulation. > > > > It shouldn't be too difficult to design a daughter board for the USRP to > > sample phone line voltage (with an appropriate line interface circuit of > > course). After that it should be rather easy in GNURadio to generate DTMF > > tones for dialing, and modem tones for data communication. > > > > Any thoughts? > > Mike > > A simple DAA (Data Access Arrangement) plus the LF daughterboard would > probably work. There are two chip DAA's available. Been a while > since I looked, but I think that Crystal Semiconductor used to make > them. Google "solid state daa" There's also the classic Midcom > transformer plus a couple of other discretes. These things are tricky > to get right. You definitely want to find somebody's reference design > and use that. Or use the pre-approved chipset. > > The USRP is pretty much thermonuclear overkill for this application. > You could just use a sound card with a DAA. That's how all the > "soft-modems" work. IIRC some of the the AC97 codecs support a second > channel for telecom (modem) apps.
Here is an example that uses a sound card, <http://www.araneus.fi/audsl/>. <idle-musing> It would be neat if there were the PC audio-out equivalents of the iGo iTips power adapter plugs, with plugs that adapt audio-out to media such as AC powerline, phone wire, Cat5, and television cable. A suitable software modem would adapt to whatever medium was on hand, adding a new dimension to "ad hoc networking." </idle-musing> Dave -- David Young OJC Technologies [EMAIL PROTECTED] Urbana, IL * (217) 278-3933 _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
