On Thu, 17 Nov 2005 15:41:15 -0800, Eric Blossom [EMAIL PROTECTED]
>>On Thu, Nov 17, 2005 at 04:16:55PM -0500, [EMAIL PROTECTED] wrote: >> I am also in the process of studying this part of the software to see if I >> can use it to recreate my data from the demodulated signal. > Let me start by saying that you'd be *much* better off studying the > packet framing / deframing and clock recovery code that is used in the > new gmsk2.py and gmsk2_pkt.py files in gnuradio-core/src/python/gnuradio/blksimpl > and the corresponding examples in gnuradio-examples/python/gmsk2 > The new code is much cleaner and faster, and since it tracks symbol > timing, works for long packets. > As Bob pointed out, the so called GMSK receiver will receive pretty > much any kind of FSK data. It is brand spanking new code, I had to get a new cvs. I did a very quick look and it is very different than the frame/correlate code. Will this work for very low data rate? I saw in on of the files, digital_voice.py.real, that the frame adds 10 bytes of overhead. In my application I am need to keep it to 1 byte. Is this possible with this code? > With the new code you specify the nominal samples/baud (spb), which > needn't be an integer, and it recovers the clock, resamples the > incoming data so that we're sampling in the middle of a bit, and then > passes the properly timed data off to the packet sink. The packet > sink correlates for the sync pattern in a similar fashion to > gr_simple_correlator, but is simpler, since it's not dealing with > oversampled data. The clock recovery code take a parameter that > specifies the maximum relative frequency error that it will track out. > The default value is 200 parts per million (ppm), which should be > plenty loose for anything with a xtal oscillator in it. > Trust me, you really want to be studying the new code... I do trust you and this code sound real good. Any reference material that this was based on? >Eric Thanks a bunch, Mike PS: Back to some heavy studying of this new code. -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ . _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
