On Wed, 2011-01-12 at 01:57 +0900, Songsong Gee wrote: > Same as Title, What Modulation Scheme does RFX400 can perfom? > > > If I draw a flow graph like below: > http://dl.dropbox.com/u/11382666/02_RXTX/TX.grc.png > > > What Modulation Scheme is used by default? > > > Can I change it?
Songsong, The modulation can be anything you want it to be. It's a little confusing if you aren't used to thinking about DSP and SDR. The USRP+RFX will happily output the raw samples you put into it, and it's up to you to encode them with a reasonable modulation. The same works for receive. If you FM modulate your data, it will be FM modulated when it goes out on the air. If you AM modulate it, it will be AM modulated. For another example, the process to AM demodulate a signal is just a complex-to-magnitude transform (i.e., y=|x|). So you can use gr.complex_to_mag as an AM demodulator. There are existing blocks to do FM demodulation as well. They can be found in gnuradio-companion under "Modulators". Any other modulation scheme you can come up with can be used as well, if you can mathematically describe it and code it up. Take a look at the examples in gnuradio/gnuradio-examples/python/usrp for an idea as to what I'm talking about. The AM and FM receivers are a good place to begin. --n > > > -- > Seokseong Jeon (aka Songsong Gee) > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
