On Sun, Jun 08, 2003 at 09:08:12AM -0400, Russell Nelson wrote: > Douglass Turner writes: > > I'm starting to get up to speed on SDR and had a question about the extent > > to which a given SDR device can morph chameleon like into another. For > > example, could a WiFi AP be implemented via SDR so that it could play the > > dual role of a RFID reader? > > We (the Public Software Fund, http://pubsoft.org/) are funding Eric > Blossom to work on SDR full-time. He's working on a volksSDR, to be > interfaced via USB. Bad news: it's slow. Too slow. Nowhere near the > 900 Mhz band, even, much less 2.4 Ghz. And even at that slow rate, > it's expensive: estimated to be $300-400 with availability 4Q this > year. The DACs will only go up to 50 Mhz, the ADCs up to 200 Mhz.
It's not quite as bad as that. 50 MHz is an adequate sampling rate for a 25 MHz-wide 802.11b channel, and virtually every 802.11b radio shifts from the carrier frequency to some lower frequency (374 MHz is typical) where the modulator/demodulator runs. An 802.11b SDR will be no different, but the shift will be longer. Regarding an RFID-reading AP, it might be more cost-effective to use two radios. I think that it was someone at Intel who estimated SDR is only really cost-effective when you want to do 4 or more different modulations, e.g. a device that "speaks" 802.11b, HDTV, "3G", and Bluetooth. They were not knocking SDR, either: they foresee laptop computers that will receive such a large variety of signals. Dave > > Lots of good info at http://gnuradio.org/ . > > -- > --My blog is at angry-economist.russnelson.com | Rebecca's incredibly neat > Crynwr sells support for free software | PGPok | County Fair quilt is now > 521 Pleasant Valley Rd. | +1 315 268 1925 voice | at http://rebeccanelson.com/ > Potsdam, NY 13676-3213 | +1 315 268 9201 FAX | quilt/index.html > -- > general wireless list, a bawug thing <http://www.bawug.org/> > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless -- David Young OJC Technologies [EMAIL PROTECTED] Urbana, IL * (217) 278-3933 -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
