On Fri, Mar 20, 2009 at 1:27 PM, Johnathan Corgan <[email protected]> wrote: > A common, non-coherent method for FSK demodulation and baud rate > detection is to multiply each succeeding sample by the complex > conjugate of the preceding sample, then take the phase of the product. > This turns the sample series into baseband "level" shifts. If you > are at zero IF, then the sample stream will be roughly symmetrical > about zero (frequency offsets are turned into DC offsets, though). > From here you can use zero crossings to estimate baud rate and > integration between transitions to improve noise performance. The > success of this technique relies on sufficient zero crossing density, > and has a higher bit error rate than coherent detection and > demodulation.
Assuming an FSK system with unknown frequency separation and baudrate, is the above algorithm robust enough to determine said parameters to then pass along to a coherent demodulator to achieve a better BER? I would assume yes - since you're just taking a quick guess/estimate and letting the coherent demodulator actually timetrack, figure out the bits, etc. Brian _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
