On Wed, Mar 3, 2010 at 03:26, srinivas naga vutukuri <srinivas.vutuk...@gmail.com> wrote:
> I am transmitting the sinusoidal wave form (IQ samples), in the following > methods, and found that when i stem plot in the MATLAB both the input wave > form data on one USRP2 and the received data on another USRP2, initially the > waveform is exactly fitting (i mean overlapping), and after certain samples, > it starts ie., in the input wave form and the output data waveform drifting > slightly and at the end samples both the waveforms overlaps perfectly. Why > this slight drifting is happening when transmitting the I Q samples from one > USRP2 to another USRP2. This is almost certainly due to receiver frequency and timing drift between transmitter and receiver USRPs. It's a fact of life in real-world radio systems, requiring significant design effort to compensate for; you're seeing exactly what you should expect to see. The digital demodulators in GNU Radio typically use DSP blocks like Costas loops for frequency/phase synchronization and Mueller&Mueller timing recovery blocks to track timing drift. Johnathan _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
